The human body internal environment is regulated by the kidney, liver and the skin.
The kidneys are a pair of bean-shaped organs lying close to the dorsal wall of the abdomen. They are highly vascularized and dark red in colour.
FUNCTIONS OF THE KIDNEY
i) Excretion of nitrogenous waste products, excess water and mineral salt in the form of urine.
ii) Regulation of salt and water balance of the body (osmoregulation).
iii) Regulation of blood PH 4 conservation / maintenance of blood plasma through selective re-absorption.
The liver is a reddish brown organ lying against the posterior surface of the diaphragm and partly covering the stomach. It is directly connected to the alimentary canal by the hepatic portal vein which delivers to it blood containing very high concentration of absorbed food molecules.
FUNCTIONS OF LIVER
i) Regulation of blood sugar: Regulation of blood sugar is the process of keeping the body in homeostasis. The liver maintains the level of glucose in the body.
ii) Deamination of protein: Deamination is the process by which amino acids are broken down when there is excess intake of protein. The broken down amino acid are converted to ammonia.
iii) Detoxification of harmful drugs and chemicals: The liver filters toxic matter such as dead cells, microorganisms, chemicals, drugs and particulate debris from the bloodstream
iv) Manufacture of blood plasma proteins: The liver produce proteins, plasma proteins, factors in hemostasis that are secreted into the blood stream.
v) Storage of iron: Liver is a storage of iron. The liver stores iron as ferritin or hemosiderin.
3. THE SKIN
The skin is composed of two main layers; the outer epidermis and the inner dermis. The epidermis is subdivided into three parts. Cornified layer, Grannular layer, Malphigianlayer.
FUNCTIONS OF THE SKIN
i) It protects the underlying tissues from damage and mechanical injury.
ii) It protects the body against bacteria and other ineffective microbes.
iii) It protects the body against ultra-violet rays.
iv) It excretes sweat which contains metabolic wastes.
v) It responds to stimuli or changes in the environment.
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