Week Eleven - The Digestive System (2 files merged_231121_193737

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Week Eleven – The Digestive System 1 ANAT 1500 / 2023 EXPLAIN THE GENERAL FUNCTIONS OF THE DIGESTIVE SYSTEM.  Provides the body with nutrients required for cellular processes  Changes food to a form our cells can use  Rids the body of the indigestible remains DESCRIBE AND LOCATE THE DIGESTIVE SYSTEM .  Long tube starting at the mouth and ending at the anus  Open at both ends  Runs the length of the trunk / through the thoracic cavity and abdominal pelvic cavity NAME AND LOCATE THE COMPONENTS OF THE DIGESTIVE SYSTEM AND THE ACCESSORY ORGANS.  Alimentary canal / extends from the mouth to the anus  Includes - mouth - pharynx - esophagus - stomach - small intestine - large intestine  accessory organs include - salivary glands - gallbladder - liver - pancreas DISCUSS THE STEPS IN PROCESSING FOOD: DIGESTION / ABSORPTION / ELIMINATION. INGESTION  food must be placed in the mouth  a voluntary process DIGESTION  Food breakdown  Food is broken down into their building blocks  A mechanical process / chewing and churning  A chemical process / enzymatic activity breaking the bonds that hold food molecules together  Glucose (monosaccharide)/ amino acids / fatty acids ABSORPTION  Movement of the digested end products in the blood / lymph from the GI tract

Week Eleven – The Digestive System 2 ANAT 1500 / 2023 ELIMINATION  Defecation of indigestible substances / wastes from the body via the anus / in the form of stool IDENTIFY THE END PRODUCTIONS OF DIGESTION AND THEIR SITES OF ABSORPTION. CHO  Begins in mouth / completed in the small intestine  Assisted by the enzyme amylase found in saliva / pancrease  End result – monosaccharides / absorbed by the villi into the blood capillaries PROTEIN  Begins in the stomach with the enzyme pepsin  Completed in the small intestine with enzymes of the intestinal mucosa and pancreas  Final product / amino acids  Absorbed by the villi into the blood capillaries FATS  Digested by enzymes from the intestinal mucosa and pancreas  Absorbed into the lymph lacteal and travel to the sublcavian veins to the venous return  Fats require pretreatment with bile to emulsify WATER  Absorbed via osmosis in the intestine ELECTROLYTES  Absorbed via active and passive transport into the blood DIFFERENTIATE BETWEEN MECHANICAL AND CHEMICAL DIGESTION. MECHANICAL  Physical preparation for chemical digestion  Processes include chewing and mixing food with saliva by the tongue  Food churns in the stomach  Segmentation / rhythmic constrictions locally in the intestine  Allows food to mix with digestive juices CHEMICAL  Catabolic process  Large molecules are broken down to their building blocks  Enzymes play a key role in digestion  Enzymes are secreted by various glands along the digestive tract

Week Eleven – The Digestive System 3 ANAT 1500 / 2023 EXPLAIN THE ROLE OF MASTICATION / CHURNING / PERISTALSIS AND EXZYMES IN DIGESTION. MASTICATION  Chewing  Food becomes mixed with saliva and torn into pieces small enough to swallow  Tongue rolls around to mix with saliva  Begins the breakdown of food CHURNING  The stomach acts as a storage tank / as well as a site for food breakdown  Multiple layers of smooth muscle that moves / churns food  Food is broken down to smaller pieces PERISTALSIS  Involuntary propelling the food along in wavelike motions  Rhythmic waves of muscular contraction that occurs in the walls of various tubular organs ENZYMES  Assist in the speeding up of the digestive process  Breaks down the molecular bonds of the food molecules  Catalyst NAME THE GROUP OF ENZYMES WHICH ACT ON PROTEINS, LIPIDS AND CARBOHYDRATES . FOOD MOLECULE ENZYME ORGAN Protein Pepsin Stomach Proteases Pancreas Intestinal enzymes Small intestine Lipids Emulsified by bile Small intestine Pancreatic lipase Pancreas CHO Salivary amylase Mouth Pancreatic amylase Pancreas Sucrase / maltase / lactase Small intestine

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Week Eleven – The Digestive System 4 ANAT 1500 / 2023 DESCRIBE THE GENERIC STRUCTURE OF THE WALLS OF THE DIGESTIVE ORGANS.  Walls of the GI tract consist of four distinct layers  Inner most to outer most - mucosa - submucosa - muscle layer - serosa MUCOUS MEMBRANE  surface epithelium  villi / projections extend into the lumen / increasing the surface area and absorption  various glands secrete mucous and digestive enzymes  functions to protect the underlying tissues / absorption / secretion SUBMUCOSA  loose connective tissue  contains blood vessels / lymphatics / nerves  provides nourishment  carries away absorbed materials MUSCULAR LAYER  2 coats of smooth muscle  inner / circular fibers / contract  outer / longitudinal / shortens SEROUS LAYER (SEROSA)  outer covering  visceral peritoneum (mesentery)  secretes serous fluid / keeps surface moist / lubricates DESCRIBE THE LOCATION AND STRUCTURE OF THE PERITONEUM AND DISTINGUISH BETWEEN THE VISCERAL AND PARIETAL PERITONEUM.  recall the structure and function of serous membranes  the peritoneum is a large continuous sheet of serous membrane  The portion that lines the wall of the abdominal cavity is the parietal peritoneum  the peritoneum folds and bends creating extensions that hold the abdominal organs in place (mesentery) LOCATE THE PERITONEAL CAVITY AND IDENTIFY IT CONTENTS.  A potential space between the parietal and visceral peritoneum  Secretes serous fluid that function in lubrication

Week Eleven – The Digestive System 5 ANAT 1500 / 2023 EXPLAIN THE TERM RETROPERITONEAL SPACE AND IDENTIFY ORGANS LOCATED HERE.  Retro = behind  Peritoneum = membrane  Pancreas / part of the duodenum / kidneys are termed retroperitoneal IDENTIFY THE LOCATION, STRUCTURE AND FUNCTION OF THE MESENTERY AND GREATER OMENTUM. MESENTERY  An extension of the parietal peritoneum  Located posteriorly / a double layer of parietal peritoneum that hangs like a drape  Suspends the small bowel / provides a route for blood vessels / lymphatics / nerves to the abdominal viscera  Holds organs in place  Stores fat GREATER OMENTUM  Also an extension of the peritoneum  Drapes anteriorly and downward covering the abdominal organs like a lacy apron  Riddled with fat / helps to cushion and protect  Contains a large connection of lymph nodes containing macrophages that function in body defense LOCATE AND DESCROBE THE STRUCTURES OF THE MOUTH (PALATE / SALIVARY GLANDS) AND EXPALIN THEIR FUNCTIONS. MOUTH  Receives food and begins preparation for digestion  Also known as the oral cavity  Surrounded by lips / cheeks / tongue / palate TONGUE  Fills the oral cavity when the mouth is closed  Mucous membrane covered  Attached to the floor of the mouth by the frenulum  Tongue is a skeletal muscle that functions to mix food particles  Papillae provide friction and contain taste buds PALATE  The hard and soft palate form the roof of the oral cavity  Review page ________  Anterior portion of the palate / hard / maxilla  Posterior portion of the palate / soft / muscular arch part of which is the uvula SALIVARY GLANDS

Week Eleven – The Digestive System 6 ANAT 1500 / 2023  Secrete saliva  Saliva moistens food particles and begins the digestions of CHO because it contains amylase  Functions as a solvent by dissolving various food chemicals which assist in tasting of food  Saliva also helps to cleanse the mouth and teeth  Salivary glands have two types of secretatory cells - serous cells - mucous cells  serous / secretes amylase which functions to split starch / glycogen into disaccharides / the first step in CHO digestion  mucous / secretes mucous which acts to bind together food particles / acts as a lubricant during swallowing  visual smells / thoughts of food can make our mouth water b/c of parasympathetic impulses eliciting the secretion of saliva  if food is unappealing no saliva is secreted making swallowing difficult MAJOR SALIVARY GLANDS  parotid / locate  largest  anterior / below each ear  secretes amylase SUBMANDIBULAR  locate / floor of the mouth  both serous and mucous cells / mixed gland  fluid more viscous than that of the parotid SUBLINGUAL  locate  smallest  under tongue / primarily mucous LOCATE DESCRIBE THE GROSS STRUCTURE, NAME THE PARTS AND IDENTIFY THE FUNCTIONS OF THE PHARYNX.  Pharynx / behind the mouth  Connects to the superior portion of the esophagus  Connects to the nasal / oral cavities / larynx / esophagus  Three divisions - nasopharynx - oropharynx - laryngopharynx  collectively the pharynx does not contribute to the digestive process but provides a passageway  muscular walls function in swallowing

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Week Eleven – The Digestive System 7 ANAT 1500 / 2023 EXPLAIN THE RELATIONSHIP BETWEEN THE PHARYNX, TONSILS AND EUSTACHIAN TUBES.  Locate - palatine tonsils - lingual tonsils - pharyngeal tonsils  tonsils form a ring of lymphatic tissue around the entrance to the pharynx  tonsils function to stop many pathogens from entering the pharynx in food or through respiration  recall the eustachian tubes  they connect directly to the throat / the tonsils protect the area from infection LOCATE, DESCRIBE THE GROSS STRUCTURE, DESCRIBE THE SPINCTERS AND IDENTIFY THE FUNCTION OF THE ESOPHAGUS.  Esophagus / a straight collapsible tube  25 cm / 10 inches  passageway between the pharynx and the stomach  extends from the base of the pharynx / descends posterior to the trachea / through the medisatinum  penetrates the diaphragm joins the stomach at the cardiac sphincter  structure of the esophageal walls are of the layers previously discussed  normally flattened LOCATE, DESCRIBE THE GROSS STRUCTURE, PARTS (FUNDUS / BODY / PYLORUS) SPHINCTERS, CURVES, RUGAE AND IDENTFY THE GENERAL FUNCTIONS OF THE STOMACH.  J shaped pouch like organ / hangs under the diaphragm / LUQ  Normal capacity / one liter  Inner lining / thick folds / rugae  Rugae increases expansion ability /allows stomach to distend  Receives food from the esophagus  Food becomes mixed with gastric juice in the stomach  Protein digestion begins in the stomach  Very little absorption (alcohol / water)  Food is propelled into the small intestine  Storage tank  Divided into four sections - cardiac - fundic - body - pyloric  sphincters - cardiac

Week Eleven – The Digestive System 8 ANAT 1500 / 2023 - pyloric  curves - lateral = greater curvature / convex - medial = lesser curvature / concave IDENTIFY THE SITE OF PRODUCTION AND COMPONENETS OF GASTRIC JUICE AND IDENTIFY THEIR FUNCTIONS.  Gastric juice is secreted from a collection of cells with the stomach wall  Pepsinogen is an inactive / is most active is an acid environment like that of the stomach (HCl)  Mucous is secreted in a large quantities to create a viscous alkaline layer /functions to protect the stomach wall  This prevents irritation form pepsin on normal stomach wall proteins and prevents the stomach wall from digesting itself  Intrinsic factor is another component of gastric juice and is necessary to absorb Vit B 12  Gastric juice components include - pepsin - HCl - Mucous - Intrinsic factor - Water EXPLAIN THE CONCEPT OF AUTODIGESTION.  Self digestion LOCATE, DESCRIBE THE GROSS STRUCTURE AND IDENTIFY THE ROLE OF THE PANCREASE IN DIGESTION.  Triangular gland / extends across the abdomen from the spleen to the duodenum  Lies posterior to the parietal peritoneum / therefore retroperitoneal  Dual function gland  Endocrine / insulin and glucagons  Exocrine / pancreatic juice that functions in digestion  Note the close association with the duodenum  Cells of the pancreas - beta / insulin - acinar / digestive juice - alpha / glucagons  acinar cells produce pancreatic juice and are clustered around tiny tubes into which they secrete their secretions  these tubes continue to merge with larger and larger ones until they reach the pancreatic duct which runs the full length of the gland where it connects with the duodenum

Week Eleven – The Digestive System 9 ANAT 1500 / 2023  pancreatic juice contains powerful enzymes capable of digesting CHO / fats / proteins  amylase splits starches  the protein splitting enzymes are collectively called proteases - trypsin - chymotrypsin - carboxypeptidase  they must all work together to split proteins and cannot split them individually  lipases split fats LOCATE, DESCRIBE THE GROSS STRUCUTE AND IDENTIFY THE ROLE OF THE LIVER.  Located RUQ / below diaphragm  Partially protected by the ribs /does not usually extend below the margins of the ribs  Functions to carry on many important metabolic processes for the body  CHO metabolism - Glucose to glycogen - Glycogen to glucose  Lipid metabolism - oxidation of fatty acids - synthesis of lipoproteins / phospholipids / cholesterol  protein metabolism / the most vital of the liver ’ s function - deamination of amino acids - synthesizing blood proteins / some of which are important for clotting  several non metabolic functions include - storage of glycogen / Vit A, D, B 12 / Fe - blood filtering / macrophages within the liver destroys damages RBC ’ s along with other foreign substances - detoxifies / i.e. alcohol - secretion / bile  structure - divided into lobes - right > than left  lobes are further divided into tiny hepatic lobes / the functional unit of the gland  between the cells are vascular channels /hepatic sinusoid  blood form the organs of the digestive viscera is carried to the liver via the portal vein and is rich with nutrients  the newly absorbed nutrients nourish the hepatic cells  phagocytic cells remove bacteria as the blood passes through  blood eventually moves into the central vein and moves out of the liver and returns to the heart via the vena cava  bile canals are found within the liver lobules and receive secretions from the hepatic cells  these canals merge to form larger ducts to become hepatic ducts to finally reach the common bile duct

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Week Eleven – The Digestive System 10 ANAT 1500 / 2023 IDENTIFY THE MAIN COMPONENTS AND EXPLAIN THE FUNCTION OF BILE.  Bile is continually being secreted by the hepatic cells  Content - water - bile salts - pigment - cholesterol - lytes  functions in the digestive process / assist the action of digestive enzymes  assist in the absorption of fatty acids and fat soluble vitamins  bile causes fat to emulsify / increasing the surface area / allowing fat to mix with water and digestive enzymes LOCATE, DESCRIBE THE GROSS STRUCTURE AND IDENTIFY THE ROLE OF THE GALLBLADDER.  Pear shaped / located on the posterior surface of the liver  Strong muscular walls  Concentrates and stores bile  Connects to the liver by the cystic duct which merges with the hepatic duct to form the common bile duct  Common bile duct leads to the duodenum at the Sphincter of Oddi  Usually this sphincter is contracted and allows bile to flow into the gallbladder for storage NAME, LOCATE AND DESCRIBE THE COMPONENTS OF THE BILIARY SYSTEM.  Liver - large gland RUQ - functions in various metabolic activities - produces bile  gallbladder - stores bile - located behind the liver  spleen - LUQ - Largest of the lymphatic organs - Behind the stomach - Filters blood  Pancreas - “ arms of the duodenum ” - endocrine / exocrine function

Week Eleven – The Digestive System 11 ANAT 1500 / 2023  right and left hepatic duct - allows bile to drain from sinusoids  cystic duct - duct exits the gallbladder merges with the common bile duct to become the common bile duct  the common bile duct leads to the duodenum / guarded by the Sphincter of Oddi  the sphincter is normally closed / allowing bile to back up the collecting ducts and be stored in the gallbladder  the pancreatic duct runs the length of the pancreas collecting its secretions LOCATE, DESCRIBE THE GROSS STRUCTURE (SPHINCTER, VALVES) AND EXPLAIN THE FUNCTIONS OF THE SMALL INTESTINE.  Tubular organ  Extends from the pyloric sphincter to the ileocecal valve  20 feet / longest part of the alimentary canal  suspended from the mesentery fills much of the abdominal wall  three portions - duodenum - jejunum - ileum DUODENUM  25 cm / 10 inches long  lies behind the parietal peritoneum  follows a C shaped path/ passes in front of the right kidney and three upper lumbar vertebrae  remainder of the small intestine lies within the peritoneal cavity JEJUNUM  8 feet long ILEUM  12 feet long  terminal portion of the intestine  larger diameter than the jejunum with a thicker more vascular wall for greater absorption  the small intestine receives digestive juices and completes the digestion of various nutrients  absorbs the final products of digestion  pushes the remains on to the large bowel  the mixing movements / peristalsis continue in the small intestine  peristalsis is weaker /allowing for slow movement through the small intestine  transit time 3-10 hours

Week Eleven – The Digestive System 12 ANAT 1500 / 2023  distally the small intestine joins the large at the junction of the ileum and cecum / ileocecal valve  after a meal a reflex opens the valve to allow peristalsis to move the contents of the large bowel IDENTIFY THE SITE OF PRODUCTION AND COMPONENTS OF INTESTINAL JUICES AND EXPLAIN THEIR FUNCTIONS.  Many mucous secreting glands found within the small intestine producing a thick alkaline mucous that has a protective function  Between the intestinal villi are intestinal glands which secrete a large amount of watery fluid that is reabsorbed by the villi taking digestive products with it  Intestinal juice is largely water  Enzymes include - peptidases - amino acids - sucrase / maltase / lipase – CHO - lipase – fats LOCATE, DESCRIBE THE GROSS STRUCTURE (PARTS / FLEXURES / VALVES / SPHINCTERS) AND IDENTIFY THE FUNCTIONS OF THE LARGE INTESTINE.  Large intestine / 5 feet / 1.5 meters  Begins RLQ at the ileocecal valve  Ascends / transverse to the left / descends into the pelvis / distally opens to the outside at the anus  Functions to reabsorb water / lytes from the residue / forms and stores feces until defecation  Locate the cecum / a hanging pouch form which the appendix is suspended  Appendix = lymphatic tissue / no apparent digestive function  Colon divided into - ascending - transverse - descending - sigmoid - rectum - anal canal  anal sphincters = 2  internal / smooth muscle / involuntary  external / skeletal muscle / voluntary  structure of the colon / same four layers as previously discussed with some unique features  lacks villi /carries on little digestive function  contain many goblet cells / mucous is secreted  mucous protects the mucous membrane from abrasion as its contents pass through

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Week Eleven – The Digestive System 13 ANAT 1500 / 2023  mucous helps stick feces together and its alkalinity helps to control the pH of the large intestine  contents of the large bowel = - water - lytes - bacteria  water and lytes are reabsorbed in the first half of the large intestine  the remaining residue becomes feces EXPLAIN HOW THE SENSES AND THOUGH AFFECT DIGESTION. MOUTH  Parasympathetic – salivary glands  Sight  Taste  Smell  Thought STOMACH  Parasympathetic – gastric glands  Secrete gastric juice  Sight  Taste  Smell  Thought  HORMONE – GASTRIN SMALL INTESTINE  Parasympathetic  stimulus food entry  inhibits gastric juice secretion  pancreas releases pancreatic juice  HORMONE – SECRETIN stimulates pancreatic juice release  HORMONE – CHOLECYSTOKININ stimulated by protein fat content of the chime  CHOLECYSTOKININ stimulates the gallbladder  Peristalsis increased by parasympathetic nervous system  Peristalsis decreased by sympathetic nervous system  After a meal GASTROILEAL reflex is elicited allowing chime to enter large intestine LARGE INTESTINE  DEFACATION REFLEX is triggered as the rectum fills with stool CONTROL OF DIGESTION 1. nervous system (ANS – parasympathetic) 2. hormones 3. senses

Week Eleven – The Digestive System 14 ANAT 1500 / 2023 4. thought IDENTIFY THE SITE OF PRODUCTION, STIMULUS AND PRIMARY FUNCTIONS OF GASTRIN, CHOLECYTOKININ AND SECRETIN. HORMONE SITE OF PRODUCTION STIMULUS PRIMARY FUNCTION CHOLECYSTOKININ Duodenal mucosa High fat content of chyme Stimulates the pancreas to produces enzymes Stimulates the gallbladder to release bile GASTRIN Gastric mucosa The presence of food in the stomach High amounts of protein in food Increases the production of gastric juices SECRETIN Duodenal mucosa Acidic chime Stimulates the pancreas to produce sodium bicarbonate

Week – Eleven – The Respiratory System 1 ANAT – 1500 / 2023 NAME AND LOCATE THE COMPONENTS OF THE RESPIRATORY SYSTEM.  Locate - nose - nasal cavities - sinuses - pharynx - larynx - trachea - bronchial tree - lungs DIFFERENTIATE BETWEEN THE UPPER AND LOWER RESPIRATORY SYSTEM.  Upper respiratory / those organs outside the thorax  Lower respiratory / those organs inside the thorax EXPLAIN THE FUNCTIONS OF THE RESPIRATORY SYSTEM.  Works in close conjunction with the CV system  Together they are responsible for supplying our cells with oxygen and removing carbon dioxide from our cells  The respiratory system oversees gas exchange between the blood and the external environment  The circulatory system transports gases in and out of the cells - from the lungs to the tissues - the blood being the transporting mechanism  Should either system fail the cells would die from hypoxia as oxygen levels are low and carbon dioxide levels rise  The exchange of gases between the atmosphere and our cells is called respiration  It includes the movement of air in and out of the lungs / breathing or pulmonary ventilation  The utilization of oxygen and production of carbon dioxide by the cells is cellular respiration DESCRIBE THE STRUCTURE AND EXPLAIN THE FUNCTIONS OF THE NOSE.  Located on the face  Supported internally by bone / cartilage  Bilateral nostrils / allows air to enter and leave  Within each are many hairs which function in protection  Nasal cavity / space behind the nose which is divided into right and left by the nasal septum  The cavity is filled with mucous membrane / secretes mucous from its many goblet cells  Many blood vessels are found within the nasal cavity / warms the air as it passes through the nasal cavity

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Week – Eleven – The Respiratory System 2 ANAT – 1500 / 2023 LOCATE AND IDENTIFY THE FUNCTIONS OF THE SINUSES AND EXPLAIN THEIR RELATIONSHIP TO THE NOSE.  Sinuses are air filled spaces located in the skull  Locate - maxillary - frontal - ethmoid - sphenoid  Open spaces lined with mucous membrane and are continuous with the nasal cavity  Main function / reduce the weight in our skull  Secondary / resonant chambers that affect the quality or out voice DESCRIBE THE LOCATION, THE STRUCTURE AND FUNCTION OF THE LARYNX.  Larynx / “ voice box ”  An enlargement at the top of the trachea / below the pharynx  Passageway for air  Houses vocal cords  Composed of muscles / cartilages bound together by elastic tissue  The largest of the cartilage include - thyroid - cricoid - epiglottic  within the larynx are two pair of horizontal folds of mucous - false - true  upper fold - false vocal cords - non-functioning in sound production - assist in closing the larynx during swallowing  lower fold - true - the elastic fibers within are responsible for vocal sounds - as air is forced over them / sounds are created - we change these sounds by forming words with our lips and tongue which changes the shape of our larynx and pharynx  usually, the glottis is relaxed and appears as a triangular slit  during swallowing the glottis is closed b/c of muscles within the false vocal cords / prevents aspiration  during swallowing the larynx raised pressing the epiglottis down / covering the larynx preventing aspiration

Week – Eleven – The Respiratory System 3 ANAT – 1500 / 2023  the larynx also serves in voice production  air is expired over and through the glottis /causing vibration of the true vocal cords / producing one ’ s voice  the size and shape of the nose / mouth / pharynx and bony sinuses also contribute to the quality of the voice DESCRIBE THE LOCATION, THE STRUCTURE AND THE FUNCTIONS OF THE TRACHEA.  Trachea / windpipe  Flexible cylindrical tube  Descends from the larynx / anterior to the esophagus / bifurcates to become the right and left bronchi  Interior lined with cilia / mucous membrane / goblet cells  Filters incoming air / trapping foreign particles  Trachea lined with C shaped cartilaginous rings of hyaline cartilage  The unprotected portion is posterior  Rings maintain the airway  Posterior is smooth muscle and connective tissue  Allows underlying esophagus to expand DESCRIBE THE LOCATION, THE STRUCTURE AND THE FUNCTION OF THE BRONCHIAL TREE.  The bronchial tree is a network of branched airways from the trachea to the microscopic air sacs in the lungs  Right and left primary bronchi arise from the trachea  They further bifurcate to secondary bronchi /smaller and smaller airways / to bronchioles  At the final division they become alveolar ducts / their terminal ends being surrounded by air sacs / alveoli  Capillary nets surround the alveoli / providing the structure for gas exchange  The smaller the bronchi become the less cartilage evident / until none is evident in the bronchioles  Smooth muscle is more prominent as the cartilage decreases / only a few muscle fibers are noted in the alveolar ducts  The bronchial tress functions as an air passageway / filter air / and distributes it evenly among the lungs  The alveoli provide gas exchange between the blood and the air IDENTIFY THE LOCATION, DESCRIBE THE STRUCTURE AND FUNCTION OF THE LUNGS.  Soft spongy / cone shaped organs / located in the thoracic cavity  Right and left / separated by the mediastinum  Enclosed by diaphragm and the thoracic cage  Suspended by their attachments (bronchi / large blood vessels)

Week – Eleven – The Respiratory System 4 ANAT – 1500 / 2023  Narrow superior border of the lung is the apex  Broad base rests on the diaphragm  Lobes / right = 3 / left = 2 RECALL THE LOCATION AND STRUCTUE OF THE PLEURA AND PLEURAL SPACE.  Lungs - parietal pleura - visceral pleura  the visceral pleura covers each lung and then folds back onto itself to become the parietal pleura which lines the inner thoracic  produces a slippery fluid / serous fluid / function in lubrication  allows the lungs to slide easily over each other and functions in the mechanism of breathing  potential space between the membranes / the pleural cavity LOCATE, DESCRIBE THE STRUCTURE AND FUNCTION OF THE ALVEOLI.  They provide the surface area for gas exchange  Paper thin / epithelial cells EXPLAIN THE ROLE OF SURFACTANT.  Alveolar cells usually manufacture a lipoprotein / surfactant  The surface tension between the alveoli is very high / sufficient enough to cause collapse among the alveoli  Surfactant lowers surface tension / preventing collapsing  Usually not sufficiently present until after 28 weeks gestation EXPLAIN THE TWO PHASES OF VENTILATION.  Ventilation (pulmonary) = breathing  The movement of air from the outside into the lungs via the bronchial tree to the alveoli and the reversal of the same  Air moves in and out of the lungs continually changing and refreshing the air in the alveoli  Two phases / inspiration / expiration  The main function of the respiratory system is to supply the body with oxygen and rid it of carbon dioxide EXPLAIN BOYLE ’ S LAW.  Boyle's law states: - the product of the volume and pressure of a gas compressed at a constant temperature remains constant  Gases like liquids conform to the shape of their containers  Unlike liquids gases always fill their containers

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Week – Eleven – The Respiratory System 5 ANAT – 1500 / 2023  Therefore, in a large volume the gas molecules will be further apart and the pressure will be low  If the volume is reduced / the gas molecules will be compressed and the pressure will rise  Pulmonary ventilation or breathing is a mechanical process that depends on volume changes occurring in the thoracic cavity  Volume changes lead to pressure changes which lead to the flow of gases to equalize the pressure DESCRIBE ATOSPHERIC, INTRAPLEURAL AND INTRAPULMONARY PRESSURE.  Atmospheric pressure = 760 mm Hg / the weight of air  Intrapulmonary pressure = the pressure within the alveoli and always equalizes itself with atmospheric pressure  Intrapleural pressure = the pressure of the air within the pleural cavity / it is always 4 mm Hg less than atmospheric pressure (760 mm Hg)  Intrapleural pressure is negative to intrapulmonary and atmospheric pressure DESCRIBE THE PROCESS OF INSPIRATION AND EXPIRATION. INSPIRATION  Atmospheric pressure = the weight of the air = 760 mm Hg  Air pressure is exerted on all surfaces including the inside and outside of the lungs / pressures always attempt to equalize  If the pressure inside the lungs (alveoli) decreases air rushes in from the outside b/c of atmospheric pressure and we inspire  Muscle fibers in the diaphragm are stimulated to contract b/c of the phrenic nerve  When the diaphragm contracts it moves downward in the thoracic cavity / increasing the size of the thoracic cavity  This action decreases the pressure inside the thoracic cavity a few mm of Hg below atmospheric pressure / causing air to rush in to equalize / the lungs expand  As the diaphragm contracts the external intercostals muscles contract, raising the ribs and elevating the sternum / increasing the size of the thoracic cavity even more  The serous fluid found between the parietal and visceral pleura contain water molecules which are strongly attracted to each other / creating surface tension  Surface tension hold the membranes together / they move together when the thoracic wall expands / pulls the lung and expands it  Surfactant maintains the surface tension of the alveoli EXPIRATION  The elastic recoil of the tissue / surface tension assist in expiration  During inspiration the many elastic fibers are stretched  As the diaphragm lowers / compressed the abdominal organs beneath

Week – Eleven – The Respiratory System 6 ANAT – 1500 / 2023  When the diaphragm and intercostals muscles relax after inspiration / the elastic tissues recoil / the thoracic cavity returns to its original shape  The abdominal organs push the diaphragm upward also returning the thoracic cavity to its original shape  Meanwhile the surface tension of the alveoli decreasing the diameter / therefore increasing the pressure inside above atmospheric pressure  This forces air out through the respiratory passages causing expiration to occur IDNENTIFY THE ACCESSORY MUSCLES USED IN FORCED INSPIRATION AND FORECED EXPIRATION. FORCED INSPIRATION  If we need to take a deeper breath than usual the diaphragm and intercostals muscles can be contracted to an even greater extent  Additionally, the pectoralis minor and sternocleidomastoids can also be used to pull the thoracic cage even further upward and outward enlarging the thoracic cavity / decreasing internal pressure even more FORCED EXPIRATION  If a person needs to exhale more air than normal the posterior intercostals muscles can be contracted  These muscles pull the ribs and sternum downward and inward / increasing the pressure in the lungs  In addition, the abdominal wall muscles when tightened will squeeze the organs inward / this increase in pressure will force the diaphragm still higher pushing additional air out of the lungs DEFINE AND EXPLAIN HOW COMPLIANCE AND RESISTANCE AFFECT VENTILATION.  Friction in air passages cause resistance  Resistance decreases air passages / causes breathing movements to become more strenuous  Lung compliance depends on elasticity of the lung tissue and the flexibility of the bony thorax  When either is impaired / expiration becomes an active process / requiring energy expenditure IDENTIFY THE GOALS OF REGULATING BREATHING.  To continually provide cells with oxygen and rid them of carbon dioxide / consistently and evenly EXPLAIN HOW BREATHING IS PRIMARILY REGULATED CHEMICALLY.  Several factors play a role in regulation of breathing however the most important factors are the levels of carbon dioxide and oxygen

Week – Eleven – The Respiratory System 7 ANAT – 1500 / 2023  The levels of carbon dioxide and oxygen in the blood can and do affect the rate and depth of respirations  An increase in carbon dioxide and a decrease in pH ( an increase in H + ions) act directly on the medulla ’ s centers  Changes in the levels of oxygen are detected by the chemoreceptors in the aortic arch and the carotid arteries  When decreased oxygen levels are decreased and sensed / impulses are sent to the medulla to increase the RR  However, the oxygen levels must be dangerously low before this mechanism kicks in / this makes oxygen levels a minor factor in the control of normal respirations  It is our cells need to rid themselves of carbon dioxide that is the most important stimulus for breathing more rapidly  The increase in the RR rids more carbon dioxide from the body / decreasing the amount of carbonic acid on board / returning pH to normal EXPLAIN THE PURPOSE OF PULMONARY FUNCTION STUDIES.  The amount of air that is flushed in and out of the lung is dependent on the conditions of inspiration and expiration  Different respiratory volumes can be measured giving us information about one ’ s respiratory status  These volumes are measured with pulmonary function tests / studies  The capacity of the lungs / the exchange of carbon dioxide and oxygen is determined through pulmonary function test  Alterations in lung volumes / capillaries are abnormal in people with pulmonary disorders DISCUSS TIDAL VOLUME AND VITAL CAPACITY. TIDAL VOLUME  The amount of air (usually 500cc) moved in and out of the lung during quiet breathing VITAL CAPACITY  When we forced extra air into the lungs over our tidal volume is called - the inspiratory reserve volume / IRV = 3000 cc  Forced expiration result in about 1100 cc over tidal volume and is called the expiratory reserve / ERV = 1100 cc  Therefore, our amount of totally exchangeable air is about 4600 cc  VC = IRV + ERV + TV 4500 = 3000 + 1100 + 500  The maximum amount of air a person can exhale after taking the deepest breath possible

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Week – Eleven – The Respiratory System 8 ANAT – 1500 / 2023 DEFINE INSPIRATORY RESERVE VOLUME, EXPIRATORY RESERVE VOLUME, RESIDUAL VOLULME AND DEAD SPACE AIR.  INSPIRATORY RESERVE VOLUME = IRV - the maximum volume that can be moved into the respiratory tract after a normal inspiration  EXPIRATORY RESERVE VOLULME = ERV - maximum volume that can be moved out of the respiratory tract after normal expiration  RESIDUAL VOLUME - despite our most forceful expiration / 1200 cc will still remain in the lung  DEAD SPACE - during inspiration some air does not reach the alveoli (150ml) but instead remains in the passageways / no gas exchange occurs DEFINE RESPIRATION.  Recall cellular respiration / the process where energy is released form nutrients  Oxygen needs to be available to complete its full cycle  Takes place in the mitochondria / result = ATP  After decomposition of a glucose molecule / carbon dioxide and hydrogen molecules remain  Hydrogen combines with oxygen to become water (O 2 + H + = H 2 O)  The final products of glucose metabolism are - carbon dioxide - water - heat - energy - ATP RESPIRATION  The entire process of exchanging gases between the environment and our body cells is called respiration  Involves - moving air in and out of the lungs - gas exchange / oxygen loading / carbon dioxide unloading - transportation of respiratory gases to the and from the lungs - cellular exchange of gases between the blood and the cells IDENTIFY THE GASES INVOLVED AND THE SITES OF GAS EXCHANGE.  Oxygen – exchange between the environment and the alveoli / the alveoli and the blood / blood and the cell

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Week – Eleven – The Respiratory System 9 ANAT – 1500 / 2023  Carbon dioxide – exchange between the cell and the blood / the blood and the alveoli / the alveoli and the environment IDENTIFY AND APPLY THE PRINCIPLE OF DIFFUSION TO GAS EXCHANGE.  The alveolar walls are thin epithelial cells  Exterior cobwebbed with pulmonary capillaries  Between these structures is a basement membrane / adhering them together / the respiratory membrane  Air (gas) flow through the alveolar side while blood flows through the capillary side  Gas exchange occurs by simple diffusion through the respiratory membrane  Oxygen passes from the alveolar air into the capillary blood / carbon dioxide leaves the blood and enters the alveolar air EXPLAIN HOW THE CONCENTRATION OF GASES ARE MEASURED AND APPLY THIS TO GAS EXCHANGE USING A PARTIAL PRESSURE APPROACH.  Gases tend to move between areas of increased pressure to areas of decreased pressure  The pressure of a gas determines the rate of diffusion  Room air = 21% oxygen = 78 % nitrogen = .04% carbon dioxide  Therefore, all gases are responsible for a % of the total pressure of the mixture or their partial pressure  Partial pressure is then r/t atmospheric pressure  Since oxygen is 21% then its partial pressure = 21% of 760 mm Hg or PO 2 = 160 mm Hg  Carbon dioxide is 0.04% then its partial pressure = 0.04% of 760 mm Hg or PCO 2 = .3 mm Hg  Recall that diffusion moves substances from high to low until equilibrium is achieved or it will attempt to equalize its partial pressure  The capillary blood / PCO 2 is 46 mm Hg / PO 2 in the alveolus is 40 mm Hg  This causes diffusion of carbon dioxide out of the capillary to the alveolus until the pressure equalizes  As the blood leaves the capillary PCO 2 = 40 mm Hg  Review the same for oxygen  Capillary blood is 40 mm Hg / blood in the alveolus is 100 mm Hg oxygen diffuses from the alveolar air into the capillary until their pressures equalize OUTLINE THE PROCESS OF OXYGEN AND CARBON DIOXIDE EXCHANGE USING A PARTIAL PRESSURE APPROACH.  Answered in previous objective

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Week – Eleven – The Respiratory System 10 ANAT – 1500 / 2023 EXPLAIN HOW VENTILATION, PARTIAL PRESSURES, SURFACE AREA AND PERFUSION AFFECT GAS EXCHANGE.  Partial pressures cause gases to equalize on either side of the respiratory membrane according to their pressure gradient  Surface area / the greater the surface area of the respiratory membrane / the greater the gas exchange  Ventilation / perfusion coupling / in order for gas exchange to be efficient there must be a precise match or coupling between ventilation (the amount of gas reaching the alveoli) and perfusion (blood flow) into the capillaries  Ventilation = perfusion IDENTIFY THE PRIMARY AND SECONDARY MECHANISMS RESPONSIBLE FOR TRANSPORTING OXYGEN AND CARBON DIOXIDE IN THE BLOOD, EXPLAIN HOW THEY ARE ASSESSES AND IDENTIFY THEIR NORMAL VALUES.  Oxygen / carbon dioxide are transported via the blood  These gases enter the blood and dissolve in the plasma where they are combined with atoms / molecules to be transported OXYGEN TRANSPORT  Oxygen combines readily with hgb  In the lungs oxygen combine with the Fe portion of the hgb / producing oxyhemoglobin  These chemical bonds are unstable and quickly release oxygen in areas of low oxygen concentration  Oxygen enters the cells from the blood by diffusion  Oxygen release is also dependent on - serum levels of carbon dioxide - serum pH - blood temperature  as carbon dioxide is released during intense skeletal exercise b/c more oxygen is used to produce more ATP / this causes a decrease in pH and an increase in T CARBON DIOXIDE TRANSPORT  carbon dioxide diffuses out of the cell b/c of the principles of diffusion and enters the blood  carbon dioxide needs to be removed from the body and needs to be transported to the lungs  transportation is one of three ways - dissolved in the plasma - carbaminohemoglobin - bicarbonate ions

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Week – Eleven – The Respiratory System 11 ANAT – 1500 / 2023  the least amount of carbon dioxide is dissolved in the plasma / about 7- 10% / the remainder of carbon dioxide enters the RBC where chemical reactions occur to carry carbon dioxide  20-30 % of carbon dioxide is transported as carbaminohemoglobin  carbon dioxide binds onto the protein portion of the hgb and not the Fe portion / so there is not any competition for binding sites with oxygen CO 2 + hgb  hgCO 2  This process is dependent upon the carbon dioxide levels / where they are low / carbon dioxide is released (lungs)  The largest % of carbon dioxide (60-70%) is converted to bicarbonate ions and then transported in the plasma  When carbon dioxide diffuses into the RBC / it combines with water forming an unstable carbonic acid / recall carbonic acid (H 2 CO 3 ) which is a buffer CO 2 + H 2 O  H 2 CO 3  H + HCO 3  Then it dissociates quickly to become hydrogen and bicarbonate ions  Within the RBC is an enzyme that assists in the conversion of carbon dioxide and water to become carbonic acid CO 2 + H 2 O  H 2 CO 3  The resulting H ion combines with the hgb molecule and the bicarbonate ion leaves the RBC by diffusion into the plasma and is carried to the lungs  In the lungs the process is reversed / the RBC lose their dissolved portion of carbon dioxide releasing it into the alveoli  Carbonic acid is reversed with the assistance of enzyme activity / carbon dioxide and water is reformed / both released from the body via expiration  Recall that our hgb molecule carries our oxygen molecules  When blood leaves the pulmonary circuit, it usually is 97-100% saturated  After completing the systemic circuit blood returns to the heart and is still 75% saturated  Oxygen saturation can be measured through arterial blood gases or pulse oximetry  ABG - pH measures the acidity (hydrogen ions) or alkalinity (hydroxyl ions) of a solution - pH of blood = 7.35 – 7.45 - within the range is normal - below 7.35 is acid - above 7.45 is alkaline  pH must remain within its homeostatic range to function normally and metabolism to take place  Hgb does not release oxygen when blood is alkaline while it releases it readily when blood is acidic  When blood falls below 6.8 or goes above 7.8 cells die

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Week – Eleven – The Respiratory System 12 ANAT – 1500 / 2023  PCO 2 - carbon dioxide is a normal product of metabolism - carried by the blood to the lungs for exhalation - normal = 35 to 45 mm Hg  PO 2 = 80 – 100 mm Hg  PCO 2 = 35 – 45 mm Hg EXPLAIN HOW THE RESPIRATORY SYSTEM ASSISTS IN THE MAINTENANCE OF SERUM Ph.  The respiratory center in the medulla oblongata (VCR) assists in the regulation of hydrogen ion concentration by increasing or decreasing the rate and depth of breathing.  When acids accumulate in the body the rate and depth of breathing increases which in turns “ blows off ” carbon dioxide  Without carbon dioxide / carbonic acid cannot be produced so the acid level in the body becomes balanced

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Week Eleven - The Digestive System (2 files merged_231121_193737

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