Every organism is faced with conditions that are constantly changing. Such conditions may be internally or externally. For an organism to survive, it must have to adjust to all these changing conditions. It must maintain a state of balance between its life activities and the conditions that affect such activities. For example, a human being adjusts to changing weather conditions by wearing either heavier or lighter clothing or by staying in warm or cool places.
These are changing conditions in internal environment to which humans adjust in order to maintain a steady state internally. Some hormones namely insulin and adrenaline in the body work to maintain the level of sugar in the plasma. This is a changing condition in the internal environment to which human body adjusts itself to maintain a state of balance internally.
The ability of an organism to maintain a state of balance in its internal environment is called Homeostasis.
Homeostasis is the ability of an organism to maintain a constant internal environment. Factors that must be kept constant include glucose, osmotic pressure, temperature, ions, etc.
Factors that must be kept constant include glucose, osmotic pressure, temperature, pH, and ions.
Parts involved in homeostasis includes the main organs and substances involved in homeostasis are kidneys, liver, skin, and hormones from the endocrine glands.
But the brain has the overall control over the homeostatic processes in the body.
The functions of the kidney are as outlined below;
1. Excretion of nitrogenous waste substances such as urea.
2. Maintenance of the acid-base balance.
3. Keeping the osmotic pressure of each cell constant hence osmoregulatory in function.
4. Maintenance of salts or ions in balance in the body.
5. Removal of harmful substances from the body.
6. Production of heat on a cold day by increasing its body activity.
1. Number 2, 3, and 4 are homeostatic processes.
2. Urea is produced in the liver while urine is formed in the nephrons of kidneys.
DISEASES OF THE KIDNEY
The following are the diseases of the kidney explained briefly;
NEPHRITIS: It is passing out much of the useful materials of the body fluid with urine. This is caused by incomplete ultrafiltration due to inflammation of the glomeruli. The symptoms are headache, fever, vomiting, oedema, and pain at the back.
KIDNEY STONES: The obstruction of the normal passage of urine due to the blockage of kidney tubules by some sort of growth. The symptoms include difficulty and pain in passing of urine. The urine may contain lood and albumen.
DIURESIS: Production of copious flow of dilute urine. This is caused by the failure of the kidney tubules to reabsorb water from the glomerular filtrate into the blood as a result of the deficiency of the Antidiuretic hormone, ADH. The symptoms includes permanent production of vast quantities of urine and loss of weight. This is sometimes referred to as Diabetes insipidus.
DROPSY: Retention of lots of water within the blood due to inability of the cells of the kidney tubules to absorb water from the blood. This causes oedema which leads to the swelling of some parts of the body.
EFFECTS OF KIDNEY DISEASES
1. They poison the cells of the kidneys.
2. They change the normal concentration of materials in the urine.
3. They lead to inefficiency of the kidneys to remove waste products.
4. They may cause death.
WAYS TO REMEDY KIDNEY DISEASES
1. Kidney dialysis.
2. Kidney transplants and surgery in case of kidney stones.
3. Avoiding the organisms that causes the diseases.
THE MAMMALIAN LIVER
The Liver is the largest organ in the body. It’s a dark-red organ which is made up of two large lobes and three small ones. It lies on the right side of the body just below the diaphragm.
FUNCTIONS OF THE LIVER
1. It regulates the glucose level in the blood by converting excess glucose into glycogen or reconverting it into glucose when the blood glucose falls below normal. This is a homeostatic process controlled by the hormones Insulin and adrenaline. Glucose is released in the blood during emergency or exercise.
2. It deaminates proteins by splitting amino acids into amino group and the carboxyl group. Amino group for ammonia which is converted into urea while the carboxyl group is converted into carbohydrates. Thus excess amino acids are broken down into ammonia and keto-acids.
3. It produces bile which is stored in the gall bladder.
4. It detoxifies toxins in the blood.
5. It stores iron and vitamins A, B12, D and K.
6. It produces essential blood plasma proteins such as fibrinogen, albumen, prothrombin and heparin.
7. It maintains the body temperature by producing and distributing heat around the body.
8. It eliminates and disintegrates old red blood cells.
9. It reserves blood since it contains many capillaries and blood spaces.
10. It produces red blood cells in the embryo or in the early life.
The diseases of the liver include;
1. HEPATITIS: This is the inflammation of the liver. This might be due to viral infection or drugs. This disease results in liver cells being unable to store excess sugar or reconvert already stored glycogen into glucose. Symptoms of the disease include loss of appetite, headache, dark urine and nausea.
2. CANCER OF THE LIVER: This is a disorderly over production of the liver cells. This leads to abnormal functions of the liver, the body will be exhausted owing to the use of energy for cell division and this causes death.
3. Gallstones: These are growths in the gall bladder which block the duct, thus making it impossible for the gall bladder to function well.
Acute infective hepatitis
1. Taking of drugs.
2. Bed rest.
3. Taking plenty of glucose.
4. Excluding fats in the diet and avoiding alcohol.
Gall stones is surgically operated to remove the stones.
The cancer of the liver is remedied by
1. Surgically removing the growth.
2. Treating with radioactive materials to kill the cancer cells..