MEANING OF HOMEOSTASIS
Simply put, Homeostasis is the process whereby the body keeps a stable environment inside itself.
Homeostasis is the regulation of the internal environment of the body so as to maintain a steady state by self-regulation adjustments in order to provide optimum conditions for normal and efficient functioning of the body cells.
An organism regulates its internal environment and keeps it in a steady state by constantly adjusting to any change in the physical and chemical conditions of its body fluids. These conditions include temperature, pH, osmotic pressure and concentrations of dissolved substances in the body fluids like carbon dioxide, oxygen, urea, food substances (glucose, amino-acids, etc.) and ions (sodium, potassium, chlorides).
Organs Involved in Homeostasis
In mammals, the main organs involved in homeostasis are:
- The hypothalamus and pituitary gland
- The lungs
- The skin
- The muscles
- The kidneys
- The liver and pancreas
The brain is also central to homeostasis. It controls behaviour, and the basic function of behaviour is to support life by taking action.
The pituitary gland consists of two parts: the anterior pituitary and the posterior pituitary. It is functionally linked to the hypothalamus by the pituitary stalk (also called the infundibulum). The pituitary controls a whole range of vital functions by secreting hormones. The Pituitary Gland is referred to as the master gland of the body because it regulates the activity of the endocrine glands.
The hypothalamus is a brain part at the base of the brain that controls body temperature, hunger, thirst and circadian cycles. It is the control system which regulates the pituitary gland. The hypothalamus is known as the master switchboard because it's the part of the brain that controls the endocrine system.
The lungs are a pair of spongy, air-filled organs located on either side of the chest. Lung enables blood to get oxygen from the air, and release carbon di-oxide.
The lungs are the area where gas exchange takes place. Without gas exchange, oxygen would not pass into the blood from the lungs so the body cells would not be able to receive the oxygen needed for respiration.
The alveoli are moist to allow oxygen to move from the lung through the alveoli into blood vessels and red blood cells. Carbon dioxide passes from the blood into the alveoli. The oxygen-filled blood goes back to the heart and the carbon dioxide in the alveoli is pushed out of the lungs and into the air we breathe out.
The skin is the outer covering of animals. It is the largest organ of the body; comprising about 15% of the body weight. The total skin surface of an adult is around 20 square feet. Many kinds of animals have hair or fur on their skin. Birds have feathers on their skin. Most fish, and reptiles, like snakes and lizards, have scales on their skin.
Muscles are tissues that help us to move our body parts. The muscular system is one of the major systems in our body
Types of muscles
There are three kinds of muscles:
- Skeletal muscle, the muscle attached to bones. They pull on bones to make movements.
- Smooth muscle, for example, the muscle in blood vessels and the bladder
- Cardiac muscle, the muscle of the heart
Muscle actions can be classified as being either voluntary or involuntary. Voluntary muscle actions are movements you control at will. Involuntary muscle actions are those muscle contractions you can’t consciously control.
Kidneys are two organs in the abdomen of vertebrates that are shaped like beans. They are part of the urinary system that produces urine.
The kidney's most important work is keeping homeostasis. The body needs to have the consistent and proper amount of water, salt, and acid in the blood. The kidney keeps these things constant. If there is too much water, the kidney puts more water in the urine. If there is not enough water, the kidney uses less water in the urine. This is why people make less urine when they are dehydrated.
THE LIVER and PANCREAS
The liver is a large organ that sits on the right side of the belly. Its main function is to filter the blood coming from the digestive tract, before passing it to the rest of the body
FUNCTIONS OF THE LIVER
- The liver makes bile. This is a bright yellow-green liquid that goes into the small intestines to help digest the big chunks of food we eat.
- The liver stores glucose when we eat and then puts the glucose into the blood when our blood glucose level goes down.
- The liver takes protein and fat and turns it into glucose. This is important if we have no food to eat. We can use the fat we have saved, and make it into glucose to use.
- The liver stores vitamins and minerals.
- The liver makes many proteins
The pancreas is an organ that makes hormones and enzymes to help digestion. The pancreas helps break down carbohydrates, fats, and proteins. It also works to keep the level of chemicals in the body balance.
The part of the pancreas that makes hormones is called the Islets of Langerhans. The Islets of Langerhans change which chemical they make depending on how much of other chemicals are already in the blood. If the Islets of Langerhans stop working, a person will suffer from a disease called diabetes.
The pancreas belongs to two systems of the body: the digestive system for its role in breaking down nutrients, and the endocrine system for producing hormones.