Discuss the Functional Systems of the Body and their Contribution to Homeostasis.

-Extracellular fluid is transported through all body parts in two stages: firstly is movement of blood through blood vessels and secondly is movement of fluid between blood capillaries and the intercellular spaces between the tissue cells. As blood passes through blood capillaries there is continual exchange of extracellular fluid between plasma portion of blood and the interstitial fluid that fills the intercellular spaces. The capillary walls are permeable to most molecules in plasma, except the large plasma molecules. Thus, the extracellular fluid everywhere in the body – both that of plasma and that of interstitial fluid – is continually being mixed, thereby maintaining almost complete homogeneity of the ECF fluid throughout the body.

-For the respiratory system, each time blood flows throughout the body, it also passes through the lungs, whereby oxygen is picked up from the alveoli, thus acquiring the oxygen needed by the cells. The oxygen diffuses through the pores of alveolar membrane into the blood in a similar manner that water and ions diffuse through walls of tissue capillaries. At this time also, carbon dioxide is released from the blood into the lung alveoli

-For the gastrointestinal tract, a large portion of blood pumped by the heart also passes through the walls of the gastrointestinal tract. Here, different dissolved nutrients, including carbohydrates, fatty acids and amino acids, are absorbed from the ingested food into the extracellular fluid of the blood. The liver plays an important role in changing the chemical compositions of many of these substances to more usable forms. It is because not all substances absorbed from GIT can be used in their absorbed form by cells. Other tissues of the body – fat cells, gastrointestinal mucosa, kidneys and endocrine glands – help modify the absorbed substances or store them until they are needed.

-The musculoskeletal system also plays important role in homeostatic mechanisms of the body. If it were not for the muscles, the body could not move to the appropriate place at the appropriate time to obtain the foods required for nutrition. The system also provides motility for protection against adverse surroundings, without which the entire body, along with its homeostatic mechanisms, could be destroyed instantaneously.

-The kidneys play the role of removing from blood plasma, most of the other substances beside carbon dioxide that are not needed by cells. This takes place when blood passes through the kidneys. These substances include different end products of cellular metabolism, such as urea and uric acid; they also include excesses of ions and water from the food that might have accumulated in the extracellular fluid. Thus the kidneys perform their function by first filtering large quantities of plasma through the glomeruli into the tubules and then reabsorbing into the blood those substances needed by the body, such as glucose, amino acids, appropriate amounts of water and many of the ions.

-The nervous system is composed of three main parts: sensory input portion, central nervous system (integrative portion) and the motor output portion. Sensory receptors detect state of the body or state of surroundings. For instance, receptors in the skin alert the animal whenever an object touches the skin at any point. The brain stores information, generates thoughts, and determines reactions that the body performs in response to the sensations. Appropriate signals are then transmitted through the motor output portion of the nervous system to carry out the animal’s desires.

-Hormones are also involved in homeostatic mechanisms as they are transported in the ECF to all parts of the body to help regulate cellular function. For instance, thyroid hormones increase the rates of most chemical reactions in all cells. Insulin controls glucose metabolism and adrenocortical hormones control sodium ion, potassium ion and protein metabolism.
Reproduction sometimes is not considered a homeostatic function. But it helps maintain homeostasis by generating new beings to take the place of those that are dying.

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marto answered the question on April 16, 2019 at 07:00