Overview on Human Body Systems Functions

Subject: Sciences
Pages: 4
Words: 1074
Reading time:
5 min
Study level: College

Cardiovascular system

The function of the organ system is to ensure that the body has an effective transport of nutrients, oxygen, hormones, carbon dioxide, blood cells, drug materials, electrolytes, and waste materials from one place to another (Russ, Fagan & Sunthareswaran 2006). The major function is to provide the body cells with nourishment, the ability to fight disease, the right pH and temperature levels, and the appropriate homeostasis.

The cardiovascular system consists of several organs- the heart, veins, arteries, venules, arterioles, and blood tissue. Blood tissue consists of plasma, erythrocytes, leukocytes, and platelets. Veins, arteries, venules, and arterioles are hollow to allow the blood to circulate in them. Arteries carry blood under higher pressure than the blood in veins. Veins carry blood towards the heart from other parts of the body. Veins and arteries have cell layers known as the endothelium, epithelium, and the tunica system.

Respiratory system

The respiratory system helps in a gaseous exchange between the animal and its environment. The system consists of the lungs, bronchi, bronchioles, trachea, nasal cavity, and mouth. The lungs are located in the chest region and protected by the ribs and the pleural cavities. The bronchioles branches into bronchiolus in the alveoli (McGowan 2003). The alveoli are involved in the intake of oxygen and release of carbon dioxide because they have a large number of capillaries.

Digestive system

The digestive system consists of the mouth, salivary glands, esophagus, stomach, pancreases, small intestine, large intestine, rectum, and the anus.

The mouth is the first organ involved in breaking down the food particles mechanically using the teeth and the tongue. It mixes the food with salivary to allow gradual entry into the mouth through the esophagus. The stomach has a gastric lining of epithelial cells and gastric glands that release gastric enzymes and hydrochloric acid.

In the duodenum part of the small intestine, the chyme (food from the stomach) is combined with bile from the gall bladder (Stevens & Hume 2007). The duodenum has various secretive cells that secrete digestive enzymes as well as pancreases. The other parts of the small intestines have a large number of villi, the fingerlike structures that absorb the food materials into the blood system. The large intestine is wider than the small intestine. It is involved in the absorption of water from the remaining materials after nutrients have been absorbed.

Renal System

The urinary system is composed of two kidneys, the bladder, ureters, and the urethra. The purpose of the system is to eliminate liquid waste from the blood into the environment, regulate the pressure, pH, and volume of the blood and the levels of metabolites in the system (Field, Pollock & Harris 2011). The system is positioned below the lower abdomen and within the pelvic cavity in humans.

Each kidney has millions of functional units called the nephron and an extensive blood supply system from the renal arteries towards the renal veins.

Nervous system

The nervous system coordinates the voluntary and involuntary actions of an animal. It also transmits electrical signals from one part of the body to another. It consists of the nervous tissue that is divided into the central nervous system and the peripheral nervous system (Mai & Paxinos 2011). The CNS consists of the brain and the spinal cord. The cells of the nervous system are known as neurons.

Reproductive system

This system has sexual organs of the organism that ensure the continuity of the generation. The female reproductive organs include the vagina, the uterus, and the ovaries. The function of the vulva is to receive the male reproductive organ during intercourse. It has a large number of mucosal cells that lubricate the vulva. The vagina leads from the vulva to the cervix. The cervix forms the connection between the vagina and the uterus. Two fallopian tubes connect each ovary with the uterus. An ovum is released from the overall every 56 days and 28 days after the release of an ovum from the other ovary. They move along the fallopian tube to the uterus (Rogers 2010). The male reproductive system consists of the penis, the ureter, the testicles, epididymis, and prostate glands. The spermatogenesis process occurs in the testicles. Sperms are released during intercourse and flow through the epididymis towards the penis. The prostate glands release the semen that nourishes the sperms and gives them mobility to flow through the vulva, vagina, cervix, and uterus.

Endocrine system

This system is involved in the control of stimulation through special chemicals known as hormones released by various organs and glands in the body. The hormones flow through the blood to react on cells or organs located distant from the releasing gland because ducts are not involved (Neal 2008). The system consists of several glands and organs such as thyroid, parathyroid, pancreas, pituitary, pineal, hypothalamus, adrenal testes, ovaries, and gastrointestinal. The glands do not have ducts. In addition, they are vascular and a large number of vacuoles are used to store the hormones. Most of the glands in the system are placed in different regions from the others.

Lymphatic system

This system is connected to the circulatory system. Like the cardiovascular system, this system is spread all over the body. However, it is not a closed system and allows free movement of lymph fluid in and out of the vessels. It is composed of the lymphatic vessels, the lymph fluid, and several nodes and glands (Marshall Cavendish 2010). The bone marrow and thymus are the principal organs in this system.

Musculoskeletal system

The system is composed of bone and muscle organs that function by providing locomotion, structure, posture, stability, and form. They also protect the vital organs and organ systems in the body. It is composed of the skeleton, cartilage, muscles, joints, connective tissues, and tendons (Schuenke & Schulte 2012).

The skeletal system consists of bones, rigid organs rich in calcium phosphate (hydroxylapatite), and collagen. Bone cells are embedded in the organic matrix with a high content of minerals.

Immune system

This highly complex system protects the body and its components from diseases and infections. It is composed of various cells and organs that function to protect the whole body by detecting, attacking, and eliminating such foreign agents as pathogens, viruses, and worms (Schindler 2011).

The components include the white blood cells such as the T, B, gamma T, Killer, Helper, and antibodies. They are highly specific and recognize one or few regions of the foreign particle known as antigens.


Field, ‎MJ, Pollock, ‎C & Harris, D 2011, The renal system: Systems of the Body series, Elsevier, London.

Mai, JK & Paxinos, G 2011, The human nervous system, Academic Press, New York

Marshall Cavendish 2010, Exploring Life Science: Lymphatic systems – organisms, Marshall Cavendish, New York.

McGowan, P 2003, The respiratory system, Mosby, London.

Neal, JM 2008, How the endocrine system works, Wiley, London.

Rogers, K 2010, The Reproductive System, Rosen Publishing, London

Russ, RD, Fagan, T & Sunthareswaran, R 2006, Cardiovascular system, Elsevier, London.

Schindler, LW 2011, Understanding the Immune System, Daine Publications, New York

Schuenke, M & Schulte, E 2012, General Anatomy and Musculoskeletal System, OUP, London

Stevens, ICE & Hume, D 2007, Comparative Physiology of the Vertebrate Digestive System, Cambridge University Press, Cambridge, UK.