Chapter 2, Problem 1.1BGL

Summary Introduction

To review: The organ system functions and major organs in the given table 2.1.

Introduction: The organ system is the group of organs that functions together to maintain the biological system of the body. The organs are composed of tissue and each organ performs distict functions. The human body is consists of eleven organs system, namely integumentary, muscular, skeletal, nervous, circulatory, lymphatic, respiratory, endocrine, urinary/excretory, reproductive, and digestive system.

Explanation of Solution

The major organs of the organ system and its function is given as follows:

Cardiovascular system: The network of circulatory system consists of blood, blood vessels, and the heart. This entire network is involved in the transport of oxygen, carbon-di-oxide, and nutrients through out the body. The RBC cells present in the blood contains haemoglobin protein that carries the oxygen from the lungs to the tissue and carbon-di-oxide from the tissues to the lungs. The blood is pumped from the heart through the blood vessels. The arteries carries the oxygenated blood from the heart to tissues and the veins carries the deoxygenated blood from the tissues to the heart.

Respiratory system: The major organs of the respiratory system are nose, pharynx, larynx, trachea, bronchi, and lungs. This system involves in the process of inhaling of oygen and expelling of carbon-di-oxide. This organ system plays an important role in maintain the blood oxygen and carbon-di-oxide levels in the body. The haemoglobin protein present in the RBC cells involves in the transport of oxygen from lungs to tissues and carbon-di-oxide from tissues back to lungs. Each haemoglobin molecule carries four oxygen molecules from the alveoli of lungs. The affinity for both oxygen and carbon-di-oxide to haemoglobin depends upon the partial pressure.

Digestive system: The digestive system comprises of mouth, salivary glands, pharynx, esophagus, stomach, small intestine, pancreas, liver, gall bladder, colon, rectum, and anus. In the mouth, intaken food starts to get digest saliva through chewing. The chewed food is then passed to stomach through esophagus. The stomach secretes enzymes that tends to digest the complex food particles into the smaller particles that is absorbed by the small intestine. The waste particles are transported into the large intestine and expelled through anus.

Urinary system: The urinary system comprises of kidney, ureters, bladder, and the urethra. The functional unit of the kidney is nephron that consists of five structures, namely Bowman’s capsule, proximal convoluted tubule, distal convoluted tubule, loop of Henle, and collecting duct. The blood is filtered in the Bowman’s capsule and the filtrate is passed to the downstream parts of the nephron. These structures functions together in the formation of the urine, which is then passed to the bladder and expelled through the urethra. This sytem is also involved in maintaining the blood fluid volume, blood pH, and electrolytes level in the body.

Integumentary system: The skin, hair, nails, and exocrine glands are collectively called integumentary organ system. The skin is the largest organ of the body that weighs about 10 pounds of the total body weight. It consists of two layers namely epidermis, (outer layer) and dermis (inner layer). The sebaceous gland, an exocrine gland present in the dermis layer of skin secretes the oil substance in the skin. Thus, the skin acts barrier that prevents the entry of pathogenic particles into the body.

Lymphatic and immune system: The major organs of the lymphatic and immune system are lymphatic vessels, lymph nodes, spleen, thymus, bone marrow, and tonsils. The extensive network of vessels that carries the lymph fluid through out the body is called lymphatic system. About 600 lymph nodes are present within the human body. The lymphatic system involves in the maintaining of balance of fluid between the blood and tissues, helps in defending body against the pathogen such as bacteria, it enhances the absorption of fat and fat soluble vitamins from the intestine. It plays an important role in immune system by delivering the foreign particles into lymph node for its removal by immune cells.

Skeletal system: The major organs of the skeletal system are bone and cartilage. The human skeleton comprises of bones and cartilages that serves as the major framework of the body. At birth, the human body comprises of about 270 bones. As the individual ages, the bones are tend to fuse. Thus, the adult human body consist of about 206 bones. The skeletal system involved in body support, facilitates body movements, protects the internal organs, and deposits the essential minerals.

Muscular system: The muscular system comprises of skeletal muscles, smooth muscles, and tendons. The muscular sytem plays an important role in regulating the movements of bones. The muscular system consists of skeletal muscles and smooth muscles. The skeletal muscles are usually attached to the bones by the tough cords called tendons. These muscles causes the movement of bones by contraction that finally sends signal or nerve impulse  from the motor axon to the nerve fibre through neuromuscular junction.

Nervous system: The network of nervous system consists of brain, spinal cord, and nerves. The nervous system plays an important role in regulating the muscle contraction by inducing the nerve impulses. The nervous system is divided into three divisions namely central nervous sytsem, peripheral nervous system, and autonomous nervous system. Every movement of muscles is controlled by neuromuscular junction that carries the neurotransmitter between the motor neuron and muscle fibre. Defect in transmission of nerve impulses will lead to paralysis condition. Thus, the nervous system helps in homeostatis of mucluar function.

Endocrine system: The major organs of the endocrine system are hypothalamus, pituitary gland, pineal gland, thymus, thyroid gland, pancreas, adneral gland, ovaries, and testis. The endocrine glands produces chemical messengers called hormone to maintain the homeostasis. The hormones are produced at one site carried by the blood and executes its function in another site by binding to its receptor molecules. For example, the thyroid stimulating hormone produced by the pituitary gland binds to the receptor present in the thyroid gland and stimulates the production of thyroxine hormone. Both positive and negative feedback mechanism are involved in the regulation of hormone secretion.

Reproductive system: The reproductive system consists of two systems, namely male reproductive system and female reproductive system. The major organs of the male reproductive system are testis, vas deferens, prostate, epididymis, and penis. The female reproductive system consists of uterus, ovaries, uterine tubes, and vagina. The male gamete, sperm are produced and matured in the testis whereas the female gamete, egg is produced by the ovary. These structures functions together for the process of reproduction to produce the zygote, which contains two copies of chromosomes. These gamete cells are responsible for inheriting the genes from one generation to next generation.