A&P EXAM 3 REVIEW GUIDE. 2023
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PN 103 Anatomy and Physiology FALL 2023/ SCHMITT
EXAM # 3 Study Guide
CHAPTER 13 ENDOCRINE
Describe the function of the endocrine system
The endocrine system consists of a variety of glands and specialized cells throughout the body. These glands and cells secrete chemicals (called hormones) that influence almost every cell and organ in the body.
Discuss the relationship of the endocrine and nervous systems
Endocrine system: in charge of body processes that happen more slowly, such as cell growth.
•
Employs hormones to relay messages
•
Distributes hormones throughout the body via the bloodstream
•
Responds slowly to stimuli (seconds to days)
•
Exerts long-lasting effects
•
Adapts slowly to continual stimulation
Nervous system: ideal for time-sensitive processes as breathing and movement.
•
Employs neurotransmitters to relay messages
•
Secretes neurotransmitters into tiny space of a synapse
•
Responds to stimuli quickly (milliseconds)
•
Exerts short-lived effects
•
Adapts quickly to continual stimulation
The endocrine and nervous systems often work hand-in-hand to promote communication between cells, allowing them to coordinate and integrate their activities. Although they share a common goal—homeostasis—their methods for accomplishing this vary.
Discuss the relationship of the pituitary gland and the hypothalamus
Neurons within the hypothalamus synthesize various hormones that stimulate or suppress the anterior pituitary to secrete its hormones.
The neurons of the hypothalamus release their hormones into the hypophyseal portal system (blood vessels). The blood travels straight to the anterior pituitary, where the hormones from the
hypothalamus act on target cells in the anterior pituitary.
This stimulates the anterior pituitary to release, or to suppress the release of, certain hormones into the general circulation.
Locate the major glands of the endocrine system, explain their functions, and name the hormones produced
Anterior Pituitary: the larger of the 2 pituitary glands, synthesizes and secretes a number of very
important hormones, all under the direction of the hypothalamus.
Thyroid-stimulating hormone (TSH), or thyrotropin
: stimulates the thyroid gland to secrete thyroid hormone.
Growth hormone (GH), or somatotropin
: acts on the entire body to promote protein synthesis,
lipid and carbohydrate metabolism, and bone and skeletal muscle growth.
Luteinizing hormone (LH)
: *a gonadotropin* stimulates ovulation and estrogen and progesterone synthesis in females and the secretion of testosterone by the testes in males.
Prolactin
: stimulates milk production in the mammary glands in females. In males, it may make the testes more sensitive to LH.
Follicle-stimulating hormone (FSH)
: *one of the gonadotropins* stimulates the production of eggs in the ovaries of females and sperm in the testes of males.
Adrenocorticotropic hormone (ACTH)
: stimulates the adrenal cortex to secrete corticosteroids.
Posterior Pituitary: Stores hormones synthesized by the hypothalamus
ADH: Antidiuretic hormone
: acts on the kidneys to reduce urine volume and prevent dehydration. ADH is also called vasopressin.
OT: Oxytocin
: stimulates contraction of the uterus during childbirth. It also triggers the release of milk from the breasts during lactation.
Adrenal Medulla: The inner portion, consists of modified neurons, functions as part of the SNS.
Catecholamines
(
epinephrine and norepinephrine
): Prepare the body for physical activity by increasing P & BP, stimulate circulation to the muscles, dilate the bronchioles; to maximize blood flow to the areas needed for physical activity, they also inhibit digestion and urinary production. Boost glucose levels by breaking down glycogen into glucose (glycogenolysis) and converting fatty acids and amino acids into glucose (gluconeogenesis).
Adrenal Cortex: The outer portion, secretes steroid hormones called corticosteroids.
Zona glomerulosa (the outermost layer): Secretes mineralocorticoids; Aldosterone
acts on the kidneys to promote Na+ retention and K+ excretion. Causes water retention.
Zona fasciculata (the middle layer): Secretes glucocorticoids; cortisol.
Glucocorticoids help the body adapt to stress and repair damaged tissue by stimulating the breakdown of fat and protein, converting fat and protein to glucose, and releasing fatty acids and glucose into the blood. They have an anti-inflammatory effect. They also suppress the immune system if secreted over a long term. Essential for maintaining a normal BP
Zona reticularis (the innermost layer): Secretes sex steroids; Androgen
(weak form of testosterone), converted to the more potent androgen testosterone. Androgens stimulate development of pubic and axillary hair and sustain sex drive (libido) in both sexes. Also, small amounts of estrogen
. The only source of estrogen after menopause.
Pineal Gland: Produces melatonin. Melatonin
: rises at night, when sunlight is absent, and falls during the day. High melatonin levels trigger sleepiness, making it a key factor in the sleep-wake cycle
Thymus: Although it secretes hormones, making it a member of the endocrine system, the actions of the hormones make the thymus part of the immune system.
Thymosin
and thymopoietin
: two hormones having a role in the development of the immune system.
Thyroid Gland: The largest endocrine gland, the thyroid, consists of two large lobes connected by a narrow band of tissue called the isthmus. T3
(
triiodothyronine
) and T4
(
thyroxine
): Increases rate of metabolism
Calcitonin
: Secreted by the cells between the thyroid follicles (parafollicular cells), in response to rising blood calcium levels, calcitonin triggers the deposition of calcium in bone, thus promoting bone formation. The effects of calcitonin are particularly important in children. Has antagonistic effects on PTH.
Thyroid hormone (TH)
: Increases the body’s metabolic rate, which, in turn, increases heat production. Increased rate and strength of heart contractions, increased respiratory rate, and increased appetite. Crucial for growth and development: promotes the development of bone; the
nervous system; and skin, hair, nails, and teeth.
Parathyroid Glands: Located on the posterior surface of the thyroid are four parathyroid glands. These glands secrete PTH in response to low blood levels of calcium.
Parathyroid hormone (PTH)
: The main hormone the body uses to maintain normal levels of calcium in the blood. Inhibits new bone formation while stimulating the breakdown of old bone, causing calcium (and phosphate) to move out of bone and into the blood. Encourages the kidneys to reabsorb calcium—blocking its excretion into the urine—while promoting the secretion of phosphate. Prompts the kidneys to activate vitamin D, necessary for intestinal absorption of calcium. Pancreas: Contains both endocrine and exocrine tissues. The vast majority of the pancreas acts
as an exocrine gland, but a small percentage serves an important endocrine function.
Glucagon
: Secreted by Alpha cells in the Islets of Langerhans. Between meals, when blood glucose levels fall, glucagon stimulates liver cells to convert glycogen into glucose and also to convert fatty acids and amino acids into glucose. The resulting glucose is released into the bloodstream, causing blood glucose levels to rise.
Insulin
: Secreted by Beta cells in the Islets of Langerhans. After eating, the levels of glucose and amino acids in the blood rise. Insulin stimulates cells to absorb both of these nutrients, causing blood glucose levels to fall.
Somatostatin
: Secreted by Delta cells in the Islets of Langerhans. Works within the pancreas to
regulate the other endocrine cells. Specifically, it inhibits the release of both glucagon and insulin. It also inhibits the release of growth hormone.
Gonads: The testes in males and ovaries in females; are the primary sex organs. They produce sex hormones, which stimulate the production of sperm and eggs. They also influence the development of secondary sex characteristics during puberty.
Estrogen
: promotes the development of female characteristics and also contributes to the development of the reproductive system. Secreted by the cells of the ovarian follicle.
Progesterone
: in combination with estrogen, helps maintain the uterine lining during pregnancy. Secreted by the corpus luteum after ovulation.
Testosterone
: triggers the development of male sexual characteristics; it also sustains sperm production. Secreted by specialized cells within the testes.
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Explain how the negative feedback system controls the level of hormone production
When the pituitary stimulates another endocrine gland to secrete its hormone, that hormone is then fed back to the pituitary, telling it to stop further release of the tropic hormone. This process
is called negative feedback. Negative feedback loops are used extensively to regulate hormones in the hypothalamic-pituitary axis. Discuss various conditions that result from excess or deficient production of hormones
The secretion of too much growth hormone (hypersecretion) during a child’s growth years will trigger rapid, excessive skeletal growth, resulting in a condition called gigantism
. If the epiphyseal plates have already fused when the hypersecretion occurs, cartilage will form new bone, causing the hands, feet, face, and jaw to enlarge—a disorder called acromegaly
.
In contrast, a deficiency of growth hormone (hyposecretion) while a child is still growing will result in stunted growth. This is sometimes called
pituitary dwarfism
. The condition is usually treated with growth hormone injections.
Hypersecretion of cortisol from the adrenal gland results in a collection of symptoms called Cushing syndrome
. Classic symptoms include a “moon face” (a rounded face) and a “buffalo hump” (a hump between the shoulders resulting from a redistribution of body fat). Because excess cortisol also disrupts carbohydrate and protein metabolism, other symptoms include hyperglycemia, muscle weakness, and edema. The breakdown of protein causes muscle wasting and loss of bone mass, and the retention of sodium and water leads to hypertension. The hypersecretion of adrenal androgens often accompanies Cushing syndrome. This results in
premature puberty in children and the development of masculine characteristics in women.
Hyposecretion of mineralocorticoids and glucocorticoids occurs in a disorder called Addison’s disease
, also called adrenal cortical insufficiency. Symptoms include a loss of fluid and electrolytes, weakness, muscle wasting, dehydration, and weight loss. Without treatment, adrenal insufficiency is life threatening.
Low levels of melatonin have been linked to mood disorders, particularly seasonal affective disorder (SAD)
. Occurring during winter months, when exposure to sunlight is limited, people with SAD complain of sleepiness, depression, irritability, and carbohydrate cravings. Exposure to special high-intensity lights for several hours each day often relieves symptoms.
If a child is born without a thyroid gland, the lack of thyroid hormone (TH) leads to cretinism
: a condition characterized by retarded growth and sexual development, a low metabolic rate, and mental retardation. If the hyposecretion develops later in life, a lowered metabolic rate causes weight gain, hair loss, and fatigue. If hypothyroidism
is severe or prolonged, a condition called myxedema
may result, which involves swelling and firmness of the skin.
Hypersecretion of TH stimulates the body’s metabolism, resulting in a condition called Graves’ disease
. Thought to be due to an autoimmune disorder, Graves’ disease causes unexplained weight loss, increased heart rate, nervousness, and exophthalmos—a protrusion of the eyeballs
as a result of swelling of tissue behind the eye.
An enlarged thyroid gland caused by a dietary deficiency of iodine is called simple goiter
. Iodine is the basis for TH. Without enough iodine, the production of TH falls. Consequently, the anterior pituitary never receives a negative feedback message to stop producing TSH. Not only that, because TH levels are low, the anterior pituitary tries to stimulate the thyroid even more by
secreting greater levels of TSH. Instead of triggering the production of TH, the TSH stimulates growth of thyroid tissue, leading to thyroid enlargement and goiter.
In a calcium deficiency (
hypocalcemia
), nerve and muscle cells become more excitable. The excessive excitation leads to muscle tremors, spasms, or tetany—the sustained contraction of a
muscle. In fact, a cardinal sign of hypocalcemia is a tetany of the hands and feet called carpopedal spasm
. If calcium levels drop further, the muscles of the larynx can spasm enough to stop airflow.
When the blood contains too many calcium ions (
hypercalcemia
), the excess calcium ions bind
to the cell’s surface. Fewer sodium ions flow in and the cell becomes less responsive, resulting in such symptoms as muscle weakness, sluggish reflexes, and, in severe cases, cardiac arrest.
One of the most common endocrine disorders, the incidence of diabetes
in the United States
continues to rise. According to the American Diabetes Association, more than 30 million
Americans, or 9.4% of the population, have diabetes and another 84 million have
prediabetes (a condition in which blood glucose levels are elevated but are not high enough
to be classified as type 2 diabetes). It’s estimated that about 7 million of the people with
diabetes don’t even know they have the disease. Uncontrolled diabetes can have serious
health consequences. In 2015, almost 80,000 people died from the disorder, making it the
seventh leading cause of death.
Diabetes results from an inadequate amount of insulin or from a diminished number of
normal insulin receptors. Either way, without enough insulin, or without enough insulin
receptors, glucose can’t enter cells. As a result, cells are deprived of their main energy
source, and glucose builds up in the blood. This produces high levels of blood glucose
(
hyperglycemia
)—one of the cardinal signs of diabetes.
High levels of blood glucose trigger a number of physiological changes that produce the
classic signs of this disease. For example, the kidneys normally filter blood plasma and
convert it to urine; as it does, it removes glucose and returns it to the bloodstream. In
hyperglycemia, the high levels of glucose overwhelm the kidneys, and excess glucose “spills
over” into the urine (glycosuria).
To flush out this extra load of glucose, the kidneys produce more urine (polyuria). In turn,
this dehydrates the body, triggering excessive thirst (polydipsia). In addition to drinking
excessive quantities of fluids, people with untreated diabetes also experience continuous
hunger (polyphagia). That’s because, even though the blood is carrying an overabundant
supply of glucose, the cells are starving because the glucose can’t enter.
If left untreated, the body begins to burn protein and fat for energy. Besides causing
fatigue and weight loss, this abnormal metabolism produces an acidic byproduct called
ketone bodies. As ketones accumulate, blood pH drops, causing acidosis. Unchecked, this
will progress to diabetic ketoacidosis, causing symptoms such as nausea, vomiting, fruity
odor of the breath, and possibly coma and death.
Diabetes also damages blood vessels (resulting in heart attacks, strokes, decreased
circulation in the extremities, and even blindness from damaged blood vessels in the retina)
as well as nerves (resulting in numbness and tingling). Kidney disease is another common
complication.
Diabetes damages both the cardiovascular and nervous systems. Although experts
remain unclear as to why this occurs, it appears that chronic hyperglycemia triggers a metabolic
reaction that damages cells in small to medium-sized blood vessels. Vascular walls become thicker, restricting blood flow. Nerves, which require an adequate supply of blood to function, suffer ischemia and damage results.
Describe the regulation of blood glucose
After eating, blood glucose levels rise as glucose flows from the digestive tract into the bloodstream.
High glucose levels stimulate the beta cells of the pancreas to secrete insulin. Insulin triggers two reactions: Stimulates the cells to take up more glucose. Causes the liver to take up glucose and store it as glycogen. The combined result is that glucose levels return to normal levels.
When blood glucose levels drop below a certain point (such as after skipping a meal), the alpha cells of the pancreas release glucagon into the blood.
Glucagon stimulates the liver to break down stored glycogen into glucose, which it then releases
into the bloodstream. This causes blood glucose levels to rise.
Distinguish between Type I and Type II Diabetes.
Type 1 Diabetes Characteristics
; Type 2 Diabetes Characteristics
Average age at onset
: Before age 30
; Usually after age 40
Rate of onset
: Rapid
; Gradual
Percent of all diabetics
: 10%
; 90%
Cause
: Autoimmune condition in which the body’s antibodies attack the beta cells of the pancreatic islets, resulting in a deficiency of insulin
; Cells become resistant to insulin; in time, the body stops producing enough insulin and the body can no longer use glucose effectively
Contributing factors
: May be hereditary
; Heredity combined with excess body weight and sedentary lifestyle; also more prevalent in Native Americans, Hispanics, and African Americans
Treatment
: Daily supplemental insulin, which may be administered by injection or via a pump inserted under the skin in the abdomen
; Lifestyle changes may control disease; if not,
oral diabetic medications or insulin injections may be used
CHAPTER 14 BLOOD
Describe the basic composition of blood
Plasma
is the clear, extracellular matrix of this liquid connective tissue. It accounts for 55% of blood. The main component of plasma is water; however, plasma also contains proteins (the main one being albumin), nutrients, electrolytes, hormones, and gases. Plasma proteins play roles in blood clotting, the immune system, and the regulation of fluid volume. Plasma without the clotting proteins (which results when blood is allowed to clot and the solid portion is removed) is called serum
.
WBCs and platelets
form a narrow buff-colored band just underneath the plasma. Called the buffy coat, these cells constitute 1% or less of the blood volume.
Formed elements
—which include cells and cell fragments—make up 45% of blood. Specific blood cells include erythrocytes
(red blood cells, or RBCs), leukocytes
(white blood cells, or WBCs), and platelets
. RBCs are the heaviest of the formed elements and sink to the bottom of
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the sample. They account for most of the formed elements. This value—the percentage of cells in a sample of blood—is called the hematocrit.
Explain how blood is formed
The production of blood is called hemopoiesis
; tissues that produce blood cells are called hemopoietic tissues
. The body has two types of hemopoietic tissue: red bone marrow and lymphatic tissue.
Red bone marrow: found in the ends of long bones and in flat irregular bones such as the sternum, cranial bones, vertebrae, and pelvis; produces all types of blood cells.
Lymphatic tissue: found in the spleen, lymph nodes, and thymus gland; supplement blood cell production by producing lymphocytes, a specific type of WBC.
All blood cells can trace their beginnings to a specific type of bone marrow cell
called a stem cell
(also called a pluripotent stem cell). Stem cells are unspecialized cells that give rise to immature red blood cells, white blood cells, and platelet-producing cells.
Describe the structure and function and life cycle of red blood cells
A normal RBC is shaped like a disc with a sunken center. This shape gives the cell a large surface area through which O2 and CO2 can readily diffuse.
RBCs lose almost all of their organelles during development. Because they lack a nucleus and DNA, they cannot replicate themselves.
The cytoskeleton of the RBC contains stretchable fibers that make it flexible, allowing it to fold and stretch as it squeezes through tiny capillaries. When the cell emerges from the tight confines of a narrow vessel, it springs back to its original shape.
More than a third of the interior of an RBC is filled with hemoglobin—a red pigment that gives blood its color. Hemoglobin consists of four ribbon-like protein chains called globins. Bound to each globin is an iron-containing molecule called heme.
Each heme molecule can combine with one molecule of o2; therefore, one hemoglobin molecule can unite with four molecules of oxygen to form oxyhemoglobin. (Hemoglobin also carries CO2, but, instead of binding with heme, CO2 binds with globin.)
Red blood cells circulate for about 120 days before they die, break up, and are consumed by
phagocytic cells in the spleen and the liver.
The process of producing new erythrocytes (erythropoiesis) is maintained through a negative feedback loop.
As damaged RBCs are removed from circulation, oxygen levels fall.
The kidneys detect the declining levels of oxygen and respond by secreting a hormone called erythropoietin (EPO).
EPO stimulates the red bone marrow to begin the process of creating new erythrocytes.
An immature form of an erythrocyte, called a reticulocyte, is released into circulation.
After one to two days, the reticulocyte becomes a mature erythrocyte.
As the number of RBCs increases, oxygen levels rise.
Less EPO is produced and RBC production declines.
The process of erythropoiesis takes three to five days.
As an RBC ages, its membrane weakens, becoming fragile. As it passes through the narrow
capillaries in the spleen, it begins to break down.
Macrophages in the liver and spleen ingest and destroy old RBCs.
In the process, hemoglobin is broken down into its two components of globin and heme
Globin is further broken down into amino acids.
The amino acids are used for energy or to create new proteins.
Heme is broken down into iron and bilirubin
Iron is transported to the bone marrow, where it’s used to create new hemoglobin
Bilirubin is excreted into the intestines as part of bile
Describe the structure and function of the five types of white blood cells
Besides containing granules in the cytoplasm, granulocytes also contain a single multilobular nucleus. The three types of granulocytes are neutrophils, eosinophils, and basophils. Unlike granulocytes, agranulocytes lack cytoplasmic granules; the nuclei of these WBCs also lack lobes. There are two types of agranulocytes: lymphocytes and monocytes.
Neutrophils
Most abundant of the WBCs, neutrophils make up 60% to 70% of all the WBCs in circulation.
The nucleus of young neutrophils looks like a band or a stab wound; therefore, they are sometimes called band cells or stab cells.
They are also called polymorphonuclear leukocytes (PMNs) because the shape of the nucleus varies between neutrophils.
Highly mobile, neutrophils quickly migrate out of blood vessels and into tissue spaces, where they engulf and digest foreign materials.
Worn-out neutrophils left at the site of infection form the main component of pus.
Eosinophils
Eosinophils account for 2% to 5% of circulating WBCs.
Although few exist in the bloodstream, eosinophils are numerous in the lining of the respiratory and digestive tracts.
Eosinophils are involved in allergic reactions; they also kill parasites.
Basophils
The fewest of the WBCs, basophils comprise only 0.5% to 1% of the WBC count.
Basophils possess little or no phagocytic ability.
Basophils secrete heparin, which prevents clotting in the infected area so WBCs can enter; they
also secrete histamine, a substance that causes blood vessels to leak, which attracts WBCs. All granulocytes circulate for 5 to 8 hours and then migrate into the tissues, where they live another 4 or 5 days
Lymphocytes
The second most numerous of the WBCs, lymphocytes constitute 25% to 33% of the WBC count.
Lymphocytes are the smallest of the WBCs.
Lymphocytes are responsible for long-term immunity. There
are two types:
*T lymphocytes, which directly attack an infected or cancerous cell
*B lymphocytes, which produce antibodies against specific antigens
All lymphocytes begin in the bone marrow; whereas some mature there, others migrate to the thymus to finish developing.
After maturing, all lymphocytes colonize the organs and tissues of the lymph system. Afterward, they continually cycle between the bloodstream and lymph system.
Lymphocytes may survive from a few weeks to decades.
Monocytes
Monocytes comprise 3% to 8% of the WBC count.
Monocytes are the largest of the WBCs.
Monocytes are highly phagocytic and can engulf large bacteria and viral-infected cells.
After circulating in the bloodstream for 10 to 20 hours, monocytes migrate into tissues, where they transform into macrophages: aggressive phagocytic cells that ingest bacteria, cellular debris, and cancerous cells.
Macrophages can live as long as a few years.
Describe the structure and function of platelets
Platelets play a key role in stopping bleeding (hemostasis).
Instead of being individual cells, platelets are actually fragments of larger bone marrow cells called megakaryocytes.
The edges of the megakaryocyte break off to form cell fragments called platelets. The platelets live only about 7 days.
When a blood vessel is cut, the body must react quickly to stop the flow of blood. It does so through the following sequence of events: vascular spasm, the formation of a platelet plug, and the formation of a blood clot.
Vascular Spasm
As soon as a blood vessel is injured, smooth muscle fibers in the wall of the vessel spasm. This constricts the blood vessel and slows the flow of blood. (This response is only temporary but
gives the other hemostatic mechanisms time to activate.)
Formation of a Platelet Plug
The break in the blood vessel exposes collagen fibers, creating a rough spot on the vessel’s normally slick interior. This rough spot triggers changes in the passing platelets, transforming them into sticky platelets.
The sticky platelets do as their name implies: stick to the vessel wall and to each other, forming a mass of platelets called a platelet plug. The platelets facilitate their clumping by secreting several chemicals, some cause the vessel to constrict further, whereas others attract even more
platelets.
The platelet plug forms a temporary seal in the vessel wall. A more stable solution requires the formation of a clot.
List the clot cascade and important factors involved in clot production
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When the damaged blood vessel and surrounding tissues—areas outside or extrinsic to the blood—release clotting factors, this kicks off a cascade of events called the extrinsic pathway. When the clotting factors are activated within the blood—such as by the platelets as they adhere to the collagen in the damaged vessel wall—this sets off a different cascade of events called the intrinsic pathway.
Both the extrinsic and intrinsic pathways result in the formation of factor X.
The end result of both the extrinsic and intrinsic pathways is the production of an enzyme called prothrombin activator
Prothrombin activator acts on a globulin called prothrombin (factor II), converting it to the enzyme thrombin. Thrombin transforms the soluble plasma protein fibrinogen into fine threads of insoluble fibrin.
The sticky fibrin threads form a web at the site of the injury. Red blood cells and platelets flowing through the web become ensnared, creating a clot of fibrin, blood cells, and platelets. A blood clot can effectively seal breaks in a smaller vessel; however, blood clotting alone may
not stop a hemorrhage from a large blood vessel.
The blood contains numerous proteins called clotting factors. Under normal conditions, these factors are inactive. However, the activation of one factor sets off a chain of reactions, with the product of the first reaction triggering another reaction in the next factor on a set pathway. A series of reactions in which each depends on the product of the preceding reaction is called a
reaction cascade. The process of coagulation involves more than 30 chemical reactions, with one following the other in a precise order. Many of the clotting factors involved in this process are identified by Roman numerals, such as factor VIII, factor X, etc. The numerals indicate the order in which they were discovered, not their order in the reaction cascade.
Explain the ABO and Rh blood type
The surface of each red blood cell carries a protein called an antigen (also called agglutinogen).
There are two antigens: A and B.
People with type A blood have the A antigen on their RBCs.
People with type B blood have the B antigen.
People with type AB blood have both A and B antigens.
People with type O blood have neither antigen.
While the blood cell carries antigens, the blood plasma carries antibodies (called agglutinins) against the antigens of the other blood types.
Type A blood has anti-B antibodies.
Type B blood has anti-A antibodies.
Type AB blood has no antibodies.
Type O blood has both anti-A and anti-B antibodies.
Besides being classified according to ABO type, blood is also classified as being Rh positive or Rh negative. Rh-positive blood contains the Rh antigen; Rh-negative blood lacks this specific antigen.
State the normal values in complete blood counts
Hemoglobin: Normal levels vary by age and gender but are typically around 13.8 to 17.2
g/dL for adult males and 12.1 to 15.1 g/dL for adult females.
Hematocrit: Normal levels are about 38.3% to 48.6% for adult males and 35.5% to 44.9% for
adult females.
White blood cell count: Normal levels range from 4,000 to 11,000 cells/mm³.
Platelet count: Normal platelet counts range from 150,000 to 450,000 cells/mm³.
CHAPTER 15 HEART
Describe the location and key structures of the heart
The heart lies in the thoracic cavity in the mediastinum, a space between the lungs and beneath
the sternum. The heart tilts toward the left, so 2/3 of it extends to the left of the body’s midline. The broadest part of the heart, called the base, is at the upper right, while the pointed end, called the apex, is at the lower left.
Base: Where the great vessels enter and leave the heart
Apex: The point of maximum impulse, where the strongest beat can be felt or heard
Key structures of the heart include the pericardium
, the heart wall
, the chambers
, and the valves
.
Surrounding the heart is a double-walled sac called the pericardium
. Anchored by ligaments and tissue to surrounding structures, the pericardium has two layers: the fibrous pericardium and serous pericardium.
The fibrous pericardium: a loose-fitting sac of strong connective tissue; is the outermost layer.
The serous pericardium, which consists of two layers, covers the heart’s surface.
At the heart’s base, the serous pericardium folds back on itself to form the:
*Parietal layer, which lines the inside of the fibrous pericardium, and the
*Visceral layer, which covers the heart’s surface.
Between these two layers is the pericardial cavity.
This cavity contains a small amount of serous fluid, which helps prevent friction as the heart beats.
The heart wall consists of three layers:
The endocardium
lines the heart’s chambers, covers the valves, and continues into the vessels. It consists of a thin layer of squamous epithelial cells.
The myocardium
, composed of cardiac muscle, forms the middle layer. It’s the thickest of the three layers and performs the work of the heart.
The epicardium
, which consists of a thin layer of squamous epithelial cells, covers the heart’s surface. Also known as the visceral layer of the serous pericardium, the epicardium is closely integrated with the myocardium.
The heart contains four hollow chambers. The two upper chambers are called atria
; the two lower chambers are called ventricles
.
The atria serve primarily as reservoirs, receiving blood from the body or lungs. The right and left
atria are separated by a common wall of myocardium called the interatrial septum
. Because the
atria move blood only a short distance, they don’t have to generate much force. The walls of the
atria are not very thick.
The ventricles serve as pumps, receiving blood from the atria and then pumping it either to the lungs (right ventricle) or the body (left ventricle). The right and left ventricles are separated by the interventricular septum
. Bc the ventricles pump rather than receive blood, they must generate more force than the atria. The walls of the ventricles are thicker. Bc the left ventricle must generate enough force to push blood throughout the body, rather than just to the lungs, its walls are thicker than those of the right ventricle.
Attached to the heart are several large vessels that transport blood to and from the heart. Called
great vessels, they include the superior and inferior vena
, pulmonary
artery
(which branches
into a right and left pulmonary artery), four pulmonary veins
(two for each lung), and the aorta
.
To ensure that blood moves in a forward direction through the heart, the heart contains four valves: One between each atrium and its ventricle and another at the exit of each ventricle. Each valve is formed by two or three flaps of tissue called cusps or leaflets.
The atrioventricular (AV) valves regulate flow between the atria and the ventricles.
The right AV valve AKA tricuspid valve
(bc it has 3 leaflets): prevents backflow from the right ventricle to the right atrium.
The left AV valve AKA bicuspid valve (bc it has 2 leaflets) AKA mitral valve
: prevents backflow from the left ventricle to the left atrium.
The semilunar valves regulate flow between the ventricles and the great arteries. There are two semilunar valves:
The pulmonary valve
prevents backflow from the pulmonary artery to the right ventricle.
The aortic valve
prevents backflow from the aorta to the left ventricle.
A semi-rigid, fibrous, connective tissue called the skeleton of the heart
encircles each valve. Besides offering support for the heart, the skeleton keeps the valves from stretching; it also acts
as an insulating barrier between the atria and the ventricles, preventing electrical impulses from reaching the ventricles other than through a normal conduction pathway.
Name the valves of the heart
The right AV valve AKA tricuspid valve (bc it has 3 leaflets): prevents backflow from the right ventricle to the right atrium.
The left AV valve AKA bicuspid valve (bc it has 2 leaflets) AKA mitral valve: prevents backflow from the left ventricle to the left atrium.
The pulmonary valve prevents backflow from the pulmonary artery to the right ventricle.
The aortic valve prevents backflow from the aorta to the left ventricle.
Identify basic heart sounds
Aortic area: Second intercostal space, right sternal border
Pulmonic area: Second intercostal space, left sternal border
Tricuspid area: Fourth (or fifth) intercostal space, left sternal border
Mitral area: Fifth intercostal space, left midclavicular line
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The vibrations produced by the contraction of the heart and the closure of the valves produce
the “lub-dub” heart sounds that can be heard with a stethoscope. The first heart sound (S1) is
louder and longer; the second sound (S2) is a little softer and sharper.
Describe the flow of blood through the chambers, vessels and valves of the heart
The
right atrium
receives deoxygenated blood returning from the body through the superior and inferior vena cavae
.
Once the right atrium is full, it contracts. This forces the tricuspid valve
open and blood flows into the right ventricle
. When the right ventricle is full, the tricuspid valve snaps closed to prevent blood from flowing backward into the atria.
After filling, the right ventricle contracts, forcing the pulmonary valve
open. Blood is pumped into the right and left pulmonary arteries
and into the lungs
. After the right ventricle empties, the pulmonary valve closes to prevent the blood from flowing backward into the ventricle.
After replenishing its supply of oxygen in the lungs, the blood enters the pulmonary veins
and returns to the heart through the left atrium
.
When the left atrium is full, it contracts. This forces the mitral valve
open and blood is pumped into the left ventricle
.
When the left ventricle is full, the mitral valve closes to prevent backflow. The ventricle then contracts, forcing the aortic valve
to open, allowing blood to flow into the aorta
. From there, oxygenated blood is distributed to every organ in the body
.
Although the right and left sides of the heart act as separate pumps, they perform their work simultaneously. Both the right and left atria contract at the same time, as do both ventricles
.
Discuss the coronary circulation
Coronary arteries deliver oxygenated blood to the myocardium, while cardiac veins collect the deoxygenated blood.
Two main coronary arteries— the right and the left— arise from the ascending aorta and serve as the principle routes for supplying blood to the myocardium.
The right coronary artery supplies blood to:
• the right atrium
• part of the left atrium
• most of the right ventricle
• the inferior part of the left ventricle
The left coronary artery, which branches into the anterior descending and circumflex arteries, supplies blood to:
• the left atrium
• most of the left ventricle
• most of the interventricular septum
The most abundant blood supply goes to the myocardium of the left ventricle. Bc the left ventricle does the most work and needs more o2 and nutrients than the rest of the myocardium.
After flowing through the capillaries in the myocardium, the cardiac veins collect the now deoxygenated blood.
Most cardiac veins empty into the coronary sinus, a large transverse vein on the heart’s posterior, which returns the blood to the right atrium. (The exception is the anterior cardiac veins, which empty directly into the right atrium.)
Explain the cardiac conduction system
Specialized cells, called pacemaker cells, that generate action potentials to stimulate contraction (automaticity). Also, because the heart beats regularly, it is said to have rhythmicity. The electrical impulses generated by the heart follow a very specific route through the myocardium:
Normal cardiac impulses arise in the sinoatrial (SA) node
from its spot in the wall of the right atrium just below the opening of the superior vena cava.
An interatrial bundle of conducting fibers rapidly conducts the impulses to the left atrium, and both atria begin to contract.
The impulse travels along three internodal bundles to the atrioventricular (AV) node
. There, the impulse slows considerably to allow the atria time to contract completely and the ventricles to fill with blood. The heart’s skeleton insulates the ventricles, ensuring that only impulses passing through the AV node can enter.
After passing through the AV node, the impulse picks up speed. It then travels down the bundle
of His
, also called the atrioventricular (AV) bundle
The AV bundle soon branches into right and left bundle branches
Purkinje fibers
distribute the impulses to the muscle cells of both ventricles, causing them to contract almost simultaneously.
Relate cardiac function to cardiac output
Cardiac output increases with activity, but the average resting cardiac output is between 5 and 6
liters per minute.
If an individual’s heart has a greater stroke volume, the heart would have to beat fewer times to maintain a cardiac output of 5 liters per minute. This explains why athletes tend to have slower pulse rates.
Because cardiac output equals heart rate times stroke volume, the only two ways to affect cardiac output are:
1. Change the heart rate
2. Change the stroke volume
Keep in mind, though, that these two factors are interdependent. When heart rate increases, stroke volume decreases. That’s because the faster the heart rate, the less time the ventricles have to fill.
The body’s total volume of blood is 4 to 6 liters. Because a normal cardiac output is 5 liters per minute, that means the body’s total volume of blood passes through the heart every minute.
Discuss the relationship of the heart and the nervous system
The medulla in the brain contains a cardiac center. In turn, the cardiac center contains an:
Acceleratory Center and an Inhibitory Center
Factors such as exercise and stress stimulate the acceleratory center.
The acceleratory center sends out impulses via the Sympathetic Nervous System.
The sympathetic nervous system sends impulses through cardiac nerves (which secrete
norepinephrine) to the SA node, the AV node, and the myocardium. This accelerates the heart rate and increases the force of contractions. Factors such as a rise in blood pressure stimulate the inhibitory center.
The inhibitory center sends signals via the Parasympathetic Nervous System.
The parasympathetic nervous system sends signals via the vagus nerve (which secretes acetylcholine) to the SA and AV nodes, which slows the heart rate.
KEY POINTS
ACTH- what is it/ what does it do- stimulates cortisol
Adrenocorticotropic hormone (ACTH): stimulates the adrenal cortex to secrete corticosteroids.
ADH- function - decreases the loss of water- secretes hormones that act from sympathetic nervous system
ADH: Antidiuretic hormone: acts on the kidneys to reduce urine volume and prevent dehydration. ADH is also called vasopressin.
Aldosterone is secreted by the adrenal cortex.
Zona glomerulosa (the outermost layer): Secretes mineralocorticoids; Aldosterone acts on the kidneys to promote Na+ retention and K+ excretion. Causes water retention.
Which gland is part of both immune and endocrine system
Thymus: Although it secretes hormones, making it a member of the endocrine system, the actions of the hormones make the thymus part of the immune system.
PTH-what does it do? Effect on calcium.
Parathyroid hormone (PTH): The main hormone the body uses to maintain normal levels of calcium in the blood. Inhibits new bone formation while stimulating the breakdown of old bone, causing calcium (and phosphate) to move out of bone and into the blood. Encourages the kidneys to reabsorb calcium—blocking its excretion into the urine—while promoting the secretion of phosphate. Prompts the kidneys to activate vitamin D, necessary for intestinal absorption of calcium.
Hypothalamus regulates secretion of hormones in anterior pituitary
Neurons within the hypothalamus synthesize various hormones that stimulate or suppress the anterior pituitary to secrete its hormones.
The neurons of the hypothalamus release their hormones into the hypophyseal portal system (blood vessels). The blood travels straight to the anterior pituitary, where the hormones from the
hypothalamus act on target cells in the anterior pituitary.
This stimulates the anterior pituitary to release, or to suppress the release of, certain hormones into the general circulation.
Cortisol- what is it, what does it do- anti-inflammatory
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Zona fasciculata (the middle layer): Secretes glucocorticoids; cortisol. Glucocorticoids help the body adapt to stress and repair damaged tissue by stimulating the breakdown of fat and protein,
converting fat and protein to glucose, and releasing fatty acids and glucose into the blood. They have an anti-inflammatory effect. They also suppress the immune system if secreted over a long
term. Essential for maintaining a normal BP
Insulin-what is it-what does it do. (Moves glucose from blood into the cell)
Insulin: Secreted by Beta cells in the Islets of Langerhans. After eating, the levels of glucose and amino acids in the blood rise. Insulin stimulates cells to absorb both of these nutrients, causing blood glucose levels to fall.
High glucose levels stimulate the beta cells of the pancreas to secrete insulin. Insulin triggers two reactions: Stimulates the cells to take up more glucose. Causes the liver to take up glucose and store it as glycogen. The combined result is that glucose levels return to normal levels.
What is WBC differential?
The count of each WBC
Hormone receptor. What is it/what does it do. Once a hormone reaches the target cell, it binds with a receptor to trigger changes within the cell. Steroid hormones, which are derived from cholesterol (a lipid), pass easily through a cell’s membrane.
Once inside the cell, they bind to receptors in the nucleus associated with the DNA. This triggers the synthesis of new proteins, which then alters metabolism in the cell.
Protein-based hormones can’t penetrate the cell wall. Consequently, they bind to receptors on the cell surface. The binding of the hormone activates a second messenger system: a cascade of processes that results in the production of a second messenger.
The second messenger activates specific enzymes. The enzymes influence cellular reactions, producing the cell’s response to the hormone.
Pituitary gland- what is its super power, what is unique about it. Influences more body processes than any other gland. The pituitary gland - "master gland,"
has the superpower of influencing more body processes than any other gland.
It secretes various hormones that regulate growth, reproduction, metabolism, and other
functions.
Eosinophil-
kills parasites and plays a role in allergic reactions
Neutrophils-
main component of pus
Hemostasis- platelet plug, how does it form.
Platelet plug formation is one of the steps in hemostasis, where platelets adhere to the site of injury and aggregate to form a plug, preventing further blood loss.
Melatonin comes from what gland
Pineal gland
Neutrophils-what is it, what does it do. Most abundant of the WBCs, neutrophils make up 60% to 70% of all the WBCs in circulation.
The nucleus of young neutrophils looks like a band or a stab wound; therefore, they are sometimes called band cells or stab cells.
They are also called polymorphonuclear leukocytes (PMNs) because the shape of the nucleus varies between neutrophils.
Highly mobile, neutrophils quickly migrate out of blood vessels and into tissue spaces, where they engulf and digest foreign materials.
Worn-out neutrophils left at the site of infection form the main component of pus.
RBC lives how long
Red blood cells circulate for about 120 days before they die, break up, and are consumed by
phagocytic cells in the spleen and the liver.
Negative feedback of endocrine glands
When the pituitary stimulates another endocrine gland to secrete its hormone, that hormone is then fed back to the pituitary, telling it to stop further release of the tropic hormone. This process
is called negative feedback. Negative feedback loops are used extensively to regulate hormones in the hypothalamic-pituitary axis.
Calcitonin-what is it/what does it do- from thyroid/ lowers blood calcium
. What organ system does it effect- Skeletal
.
Calcitonin: Secreted by the cells between the thyroid follicles (parafollicular cells), in response to
rising blood calcium levels, calcitonin triggers the deposition of calcium in bone, thus promoting bone formation. The effects of calcitonin are particularly important in children. Has antagonistic effects on PTH.
Unwanted part of hemostasis is Thrombus formation
. What is the normal process for hemostasis
The normal process of hemostasis involves vasoconstriction, platelet plug formation, and blood
clotting (coagulation) to stop bleeding.
Normal labs- WBC Platelets Hemoglobin Hct. Elevated WBC indicates infection
.
Hemoglobin: Normal levels vary by age and gender but are typically around 13.8 to 17.2
g/dL for adult males and 12.1 to 15.1 g/dL for adult females.
Hematocrit: Normal levels are about 38.3% to 48.6% for adult males and 35.5% to 44.9% for
adult females.
White blood cell count: Normal levels range from 4,000 to 11,000 cells/mm³.
Platelet count: Normal platelet counts range from 150,000 to 450,000 cells/mm³.
Effect of decreasing O2 levels -
stimulates production of new blood cells
Angina-what is it, what causes it.
A partially blocked vessel spasms— or the heart demands more oxygen than the narrowed vessel can supply (such as during a period of exertion). When the demand for oxygen exceeds the supply, ischemia and chest pain result.
Angina is chest pain or discomfort caused by reduced blood flow to the heart muscle.
It is usually a symptom of coronary artery disease.
Cardiac output. What is it. Blood pumped by LV in 1 min
Coronary arteries. What is their function. Blood vessels that supply oxygen to heart muscle
What is Automaticity
Automaticity: The unique ability of the cardiac muscle to contract without nervous stimulation
Iodine is needed for proper functioning of what gland
Thyroid
How are heart sounds created.
Heart sounds are created by the closing of heart valves.
The first heart sound (S1) is produced by the closure of the mitral and tricuspid valves,
second heart sound (S2) is produced by the closure of the aortic and pulmonary valves.
Hematopoietic tissue- what is it/where is it. Lymphatic tissue, red bone marrow
Hemostasis- what happens first when a blood vessel is injured/cut
In hemostasis, the first response when a blood vessel is injured or cut is Vascular Spasm
Glucagon-where is it stored, what does it do.
Glucagon: Secreted by Alpha cells in the Islets of Langerhans. Between meals, when blood glucose levels fall, glucagon stimulates liver cells to convert glycogen into glucose and also to convert fatty acids and amino acids into glucose. The resulting glucose is released into the bloodstream, causing blood glucose levels to rise.
Cause of MI myocardial infarction- blood clot or fatty deposit in coronary artery
Erythropoietin is secreted from where, what is its job.
Erythropoietin: Hormone secreted by the kidneys that stimulates the production of erythrocytes
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Oxygen binds to Iron found in heme. Location, function of pancreas
Located in the abdominal cavity, behind the stomach.
It has both endocrine and exocrine functions. The endocrine portion of the pancreas secretes hormones such as insulin and glucagon, the exocrine portion produces digestive enzymes.
RBC how are they formed. Most numerous formed element in the blood
.
The process of producing new erythrocytes (erythropoiesis) is maintained through a negative feedback loop.
As damaged RBCs are removed from circulation, oxygen levels fall.
The kidneys detect the declining levels of oxygen and respond by secreting a hormone called erythropoietin (EPO).
EPO stimulates the red bone marrow to begin the process of creating new erythrocytes.
An immature form of an erythrocyte, called a reticulocyte, is released into circulation.
After one to two days, the reticulocyte becomes a mature erythrocyte.
Takes 3-5 days
Myocardium-muscular walls of the heart chambers-location, function
The myocardium, composed of cardiac muscle, forms the middle layer. It’s the thickest of the three layers and performs the work of the heart.
The heart contains four hollow chambers. The two upper chambers are called atria; the two lower chambers are called ventricles.
The atria serve primarily as reservoirs, receiving blood from the body or lungs. The right and left
atria are separated by a common wall of myocardium called the interatrial septum. Because the
atria move blood only a short distance, they don’t have to generate much force. The walls of the
atria are not very thick.
The ventricles serve as pumps, receiving blood from the atria and then pumping it either to the lungs (right ventricle) or the body (left ventricle). The right and left ventricles are separated by the interventricular septum. Bc the ventricles pump rather than receive blood, they must generate more force than the atria. The walls of the ventricles are thicker. Bc the left ventricle must generate enough force to push blood throughout the body, rather than just to the lungs, its walls are thicker than those of the right ventricle.
Smooth endocardium. Location, function. Why is it smooth.
The endocardium is very smooth, an important characteristic that helps keep blood from clotting
as it fills the heart's chambers.
The endocardium lines the heart’s chambers, covers the valves, and continues into the vessels. It consists of a thin layer of squamous epithelial cells.
Vit K why is it important, what does it do.
Because the liver synthesizes most of the clotting factors, abnormal liver function interferes with normal blood clotting. Even more interesting is that seemingly mild disorders, such as gallstones, can also interfere with blood clotting. That’s because the synthesis of clotting factors requires vitamin K. Vitamin K is absorbed into the blood from the intestine but, because vitamin K is fat soluble, it can be absorbed only if bile is present. Bile is secreted by the liver. If the bile ducts become blocked, such as by liver disease or gallstones, vitamin K can’t be absorbed and bleeding tendencies develop.
TSH- what is it, what does it do. Stimulates the secretion of T3 T4
Beta Cells- where are they located. What do they do.
Insulin: Secreted by Beta cells in the Islets of Langerhans. After eating, the levels of glucose and amino acids in the blood rise. Insulin stimulates cells to absorb both of these nutrients, causing blood glucose levels to fall.
Know the circulation of blood through the heart
The
right atrium
receives deoxygenated blood returning from the body through the superior and inferior vena cavae
.
Once the right atrium is full, it contracts. This forces the tricuspid valve
open and blood flows into the right ventricle
. When the right ventricle is full, the tricuspid valve snaps closed to prevent blood from flowing backward into the atria.
After filling, the right ventricle contracts, forcing the pulmonary valve
open. Blood is pumped into the right and left pulmonary arteries
and into the lungs
. After the right ventricle empties, the pulmonary valve closes to prevent the blood from flowing backward into the ventricle.
After replenishing its supply of oxygen in the lungs, the blood enters the pulmonary veins
and returns to the heart through the left atrium
.
When the left atrium is full, it contracts. This forces the mitral valve
open and blood is pumped into the left ventricle
.
When the left ventricle is full, the mitral valve closes to prevent backflow. The ventricle then contracts, forcing the aortic valve
to open, allowing blood to flow into the aorta
. From there, oxygenated blood is distributed to every organ in the body
.
Although the right and left sides of the heart act as separate pumps, they perform their work simultaneously. Both the right and left atria contract at the same time, as do both ventricles
.
Stroke volume-defined- the amount of blood ejected by the heart with each beat
. Why is it important
It is an important determinant of cardiac output and reflects the efficiency of the heart's pumping
function.
What is SA node Sinoatrial node: The heart’s primary pacemaker, where normal cardiac impulses arise
Universal donor/Universal recipient
Universal donor: Type O
Universal recipient: Type AB
KNOW characteristics/function of: Monocytes/Neutrophils/Erythrocytes/Eosinophils
Neutrophils
Most abundant of the WBCs, neutrophils make up 60% to 70% of all the WBCs in circulation.
The nucleus of young neutrophils looks like a band or a stab wound; therefore, they are sometimes called band cells or stab cells.
They are also called polymorphonuclear leukocytes (PMNs) because the shape of the nucleus varies between neutrophils.
Highly mobile, neutrophils quickly migrate out of blood vessels and into tissue spaces, where they engulf and digest foreign materials.
Worn-out neutrophils left at the site of infection form the main component of pus.
Monocytes
Monocytes comprise 3% to 8% of the WBC count.
Monocytes are the largest of the WBCs.
Monocytes are highly phagocytic and can engulf large bacteria and viral-infected cells.
After circulating in the bloodstream for 10 to 20 hours, monocytes migrate into tissues, where they transform into macrophages: aggressive phagocytic cells that ingest bacteria, cellular debris, and cancerous cells.
Macrophages can live as long as a few years.
Eosinophils
Eosinophils account for 2% to 5% of circulating WBCs.
Although few exist in the bloodstream, eosinophils are numerous in the lining of the respiratory and digestive tracts.
Eosinophils are involved in allergic reactions; they also kill parasites.
Erythrocytes: Red blood cells
Study endocrine diagram p. 251
P. 297 The heart chambers and great vessels diagram Key Terms:
Adenohypophysis
: Anterior pituitary gland
Adrenal cortex
: Outer portion of the adrenal gland that secretes corticosteroids
Adrenal gland
: Gland perched on top of the kidney; consists of two distinct glands (the adrenal medulla and the adrenal cortex)
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Adrenal medulla
: Inner portion of adrenal gland that functions as part of the sympathetic nervous system
Alpha cell
: Type of cell within the pancreatic islets that secretes the hormone glucagon
Beta cell
: Type of cell within the pancreatic islets that secretes the hormone insulin
Catecholamines
: Epinephrine and norepinephrine; secreted by the adrenal medulla
Corticosteroids
: Steroid hormones secreted by the adrenal cortex
Delta cell
: Type of cell within the pancreatic islets that secretes the hormone somatostatin
Endocrine gland
: Ductless glands that secrete hormones directly into the bloodstream
Glucocorticoids
: Hormones secreted by the middle layer of the adrenal cortex; primary glucocorticoid is cortisol
Gonads
: Primary sex organs, which are the testes in males and ovaries in females
Graves’ disease
: Disorder resulting from hypersecretion of thyroid hormone
Hormones
: Chemicals secreted by glands and specialized cells of the endocrine system
Hypophyseal portal system
: System of blood vessels connecting the hypothalamus with the anterior pituitary; receives hormones released by the hypothalamus
Inhibiting hormones
: Hormones that suppress hormone secretion by the anterior pituitary
Islets of Langerhans
: Endocrine cells inside the pancreas; also called pancreatic islets
Mineralocorticoids
: Hormones secreted by the outermost layer of the adrenal cortex; primary mineralocorticoid is aldosterone
Negative feedback
: Process whereby the output of a gland is fed back in a manner that reduces further output
Neurohypophysis
: Posterior pituitary gland
Pancreas
: Secretes digestive enzymes (exocrine function) as well as hormones used to regulate blood glucose levels (endocrine function)
Parathyroid glands
: Glands embedded on the posterior surface of the thyroid gland that secrete a hormone used to regulate blood calcium levels
Pineal gland
: Produces the hormone melatonin, which increases at night and decreases during
the day
Pituitary gland
: Small gland attached to the lower surface of the hypothalamus that secretes a number of hormones that regulate many bodily processes; consists of an anterior and posterior lobe
Releasing hormones
: Hormones that stimulate the anterior pituitary to secrete its hormones
Sex steroids
: Hormones secreted by the innermost layer of the adrenal cortex; sex steroids include androgen and estrogen
Target cells
: Cells having receptors for a particular hormone
Tetany
: Sustained muscle contraction; may result from hypocalcemia
Thymus
: Secretes hormones having a role in the development of the immune system
Thyroid gland
: Gland in the neck that secretes hormones that affect the body’s metabolic rate
Agglutination
: The process of clumping together to form a mass, such as occurs with red blood
cells during a transfusion reaction
Agranulocytes
: Classification of white blood cell; contains few or no cytoplasmic granules and the nucleus lacks lobes
Albumin
: A protein found in blood plasma
Anemia
: A deficiency of red blood cells or hemoglobin
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Antigen
: A protein carried on the surface of each red blood cell
Basophil
: The fewest of the WBCs; secretes heparin
Coagulation
: Blood clotting
Eosinophils
: White blood cells that protect against parasites; also involved in allergic reactions
Erythrocytes
: Red blood cells
Erythropoiesis
: Process of producing new erythrocytes
Erythropoietin
: Hormone secreted by the kidneys that stimulates the production of erythrocytes
Fibrin
: Insoluble protein fibers involved in forming a blood clot
Fibrinolysis
: Process of dissolution of a blood clot
Granulocytes
: Classification of white blood cell; contains granules in the cytoplasm and has a single multilobular nucleus
Hematocrit
: The percentage of red blood cells in a sample of blood
Hematology
: The study of blood
Hemoglobin
: Iron-containing pigment of red blood cells that carries oxygen
Hemolysis
: The destruction of red blood cells
Hemopoiesis
: The production of blood
Hemostasis
: An arrest of bleeding
Jaundice
: A yellowish hue in the skin and sclera resulting from the buildup of excess bilirubin in
tissues
Leukemia
: Cancer of the blood or bone marrow
Leukocytes
: White blood cells
Leukocytosis
: Elevated white blood cell count
Leukopenia
: Abnormally low white blood cell count
Lymphocytes
: Second most numerous of the WBCs; responsible for long-term immunity
Monocytes
: Largest and most long-lived of the WBCs; highly phagocytic
Neutrophils
: Most abundant of the white blood cells; highly mobile
Oxyhemoglobin
: Combination of four molecules of oxygen with one hemoglobin molecule
Plasma
: The clear extracellular matrix of blood
Platelets
: Blood cell fragments that play a key role in stopping bleeding
Polycythemia
: The state of an excess number of red blood cells
Reticulocyte
: An immature form of an erythrocyte
Serum
: Plasma without the clotting proteins
Stem cell
: Unspecialized bone marrow cell that give rise to immature red blood cells, white blood cells, and platelet-producing cells
Viscosity
: The thickness or stickiness of blood
Afterload
: The forces that impede the flow of blood out of the heart
Aortic valve
: Heart valve that prevents backflow from the aorta to the left ventricle
Apex
: Pointed end of the heart, the location of the point of maximum impulse
Ascites: Pooling of fluid in the abdomen
Atrial kick
: Atrial contraction that occurs late in the ventricular filling process; supplies the ventricles with the remaining 30% of blood
Atrioventricular (AV) node
: Group of pacemaker cells in the interatrial septum that relays impulses from the atria to the ventricles
Atrium
: The upper chamber of each half of the heart
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Automaticity
: The unique ability of the cardiac muscle to contract without nervous stimulation
Baroreceptors
: Pressure sensors in the aorta and carotid arteries that detect changes in blood pressure; also called pressoreceptors
Base
: Broadest part of the heart; where great vessels enter and leave
Bradycardia
: Persistent heart rate slower than 60 beats per minute
Cardiac cycle
: The series of events that occur from the beginning of one heartbeat to the beginning of the next
Cardiac output
: The amount of blood pumped by the heart in 1 minute
Chemoreceptors
: Sensors in the aortic arch, carotid arteries, and medulla that detect increased levels of carbon dioxide, decreased levels of oxygen, and decreases in pH
Chordae tendineae
: Tendinous cords that connect the edges of the AV valves to the papillary muscles to prevent inversion of the valve during ventricular systole
Contractility
: The force with which ventricular ejection occurs
Coronary arteries
: Vessels that deliver oxygenated blood to the myocardium
Coronary sinus
: Large transverse vein on the heart’s posterior that returns blood to the right atrium
Diastole
: The period of cardiac muscle relaxation
Electrocardiogram (ECG)
: Record of the electrical currents in the heart
Endocardium
: The endothelial membrane that lines the chambers of the heart
Epicardium
: The serous membrane on the surface of the myocardium
Interatrial septum
: Common wall of myocardium separating the right and left atria
Interventricular septum
: Common wall of myocardium separating the right and left ventricle
Mediastinum
: Space between the lungs and beneath the sternum
Mitral valve
: The valve that regulates blood flow between the left atrium and left ventricle
Myocardium
: The middle layer of the heart wall; composed of cardiac muscle
Papillary muscles
: Muscles located in the ventricles that attach to the cusps of the atrioventricular valves
Pericardial cavity
: Space between the visceral and parietal layers of the serous pericardium that contains a small amount of serous fluid
Pericardium
: The membranous fibroserous sac enclosing the heart and the bases of the great vessels
Preload
: The amount of tension, or stretch, in the ventricular muscle just before it contracts
Proprioceptors
: Sensors in muscles and joints that signal the cardiac center of changes in physical activity
Pulmonary edema
: Accumulation of fluid in the lungs
Pulmonary valve
: Heart valve that prevents backflow from the pulmonary artery to the right ventricle
Purkinje fiber
: Nerve-like processes that extend from the bundle branches to the ventricular myocardium; form the last part of the cardiac conduction system
Rhythmicity
: Term applied to the heart’s ability to beat regularly
Semilunar valves
: The two valves that regulate flow between the ventricles and the great arteries
Sinoatrial node
: The heart’s primary pacemaker, where normal cardiac impulses arise
Skeleton of the heart
: Semi-rigid, fibrous connective tissue encircling each heart valve
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Starling’s law of the heart
: States that the more the ventricle is stretched (within limits), the more forcefully it will contract
Stroke volume
: The amount of blood ejected by the heart with each beat
Systole
: Contraction of the chambers of the heart
Tachycardia
: Persistent heart rate greater than 100 beats per minute
Tricuspid valve
: The right atrioventricular valve, which regulates flow between the right atrium and right ventricle
Ventricles
: The two lower chambers of the heart
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