|
Learn the Concept of Homeostasis Here
1. What is metabolism?
Metabolism is the set of physical and chemical processes upon which the life of the cells of a living being depends.
2. What is the difference between anabolism and catabolism?
Metabolism comprises two opposing processes: anabolism and catabolism. Anabolism is a set of synthesis reactions that transform simpler compounds into organic molecules in general with energy spending. Catabolism is a set of reactions that break organic molecules into simpler and less complex substances in general with liberation of energy. The energy liberated in catabolism may be used in vital processes of the organism, including anabolism.
3. What is homeostasis? What are the sensors, controllers and effectors of homeostasis?
Homeostasis comprises the processes by which the organism maintains adequate intra and extracellular conditions to keep possible the normal reactions of the metabolism.
Homeostatic sensors are structures that detect information from the inner and outer environment of the body. These sensors may be nervous receptor cells, cytoplasmic or membrane proteins and other specialized molecules. Controllers are structures responsible for processing and interpreting information received from the sensors. Controllers in general are specialized regions of the central nervous system but on the molecular level there are also some of them, like DNA, a molecule that can get information from proteins to inhibit or stimulate the expression of some genes. Effectors are elements commanded by the controllers that have the function of bringing about actions that in fact regulate and maintain the equilibrium of the organism, like muscles, glands, cellular organelles, etc., and in the molecular level structures that participate in the genetic translation, the produced proteins, etc.
4. How do antagonistic mechanisms manage homeostatic regulation?
The homeostatic maintenance of the body mostly occurs by means of alternating antagonistic compensatory mechanisms. There are regulators that lower the pH and others that increase it, there are effectors whose function is to increase the body temperature and others that lower it, hormones exist that, e.g., reduce the level of glucose in the blood and others that increase the glycemic level. The use of antagonistic mechanisms is a strategy found by evolution to solve the problem of the maintenance of the body equilibrium.
5. What is an example of negative feeback of the homeostatic regulation?
Negative feedback happens when the response to a given action generates an effect that inhibits that action. For example, when the carbon dioxide concentration in blood is high the pulmonary respiration is stimulated for the CO2 excess to be expelled through expiration. Hyperventilation, however, lowers the carbon dioxide concentration in blood too much generating a negative feedback that commands the reduction of the respiratory frequency.
Negative feedback is the main mechanism of homeostasis and it occurs in a variety of processes, such as in blood pressure control, glycemic control, muscle contraction, etc.
6. What is an example of positive feedback of the homeostatic regulation?
In positive feedback the effect caused by an action stimulates the action even more. This is a rarer mechanism of the homeostatic regulation.
An example of positive feedback is the blood clotting process in which each chemical reaction produces enzymes that catalyze the following reaction until the formation of fibrin. Therefore the products of the antecedent chemical reactions are consumed and the equilibrium of each reaction is dislocated towards the production of more enzymes (a positive feedback).
|
