Unit 12 - Assignment 5 - Homeostasis - Distinction
For task 3 (where answers are in bullet points) I suggest you make a power point or slides and include pictures.
Homeostasis is a mechanism which maintains and controls the levels of chemical composition,
tissue fluid and other features of blood and other features of the internal environment. The balance
is controlled by regulating the limits continuously within a range that is safe for the body and
suitable to allow the body to function accurately, regardless of any changes to the external
environment. Some of the fluctuating changes that occur outside and inside the body include;
temperature, water potential and pH changes. Homeostasis is able to bring the changes back to
the optimal point to maintain equilibrium. Homeostasis also plays a key role in other functions
within the body such as;
- Allowing enzymes to work effectively by making sure that the temperature and pH are
within their optimum levels to prevent denaturing which could reduce the rate of reaction.
Enzymes are responsible for reactions that take place within cells and those are extremely
sensitive to any change that occurs, therefore, a suitable rate has to be maintained.
- Allowing cells to operate properly by altering the water potential of tissue fluid and blood to
prevent any bursting or shrinkage to occur. Homeostasis maintains a constant water
potential by maintaining a constant blood glucose concentration which is also crucial for
providing glucose to cells during respiration.
FEEDBACK MECHANISMS
The control of any self-regulating system contains several series of phases. Firstly, a receptor will
monitor the optimum point which is the range of the limit that the body functions properly at. The
receptor will indicate any fluctuation that might happen to those limits. This will then trigger the
stimulus causing it to respond quickly by informing the coordinator. The coordinator will then
synchronise the information received and will then send orders to the effector. The effector is
usually a gland or a muscle, it will immediately return the change to its optimum point, creating a
feedback mechanism where the stimulus that has been produced
by the change, causes the receptor to respond.
A feedback mechanism is a self-regulating system where by a
change in the control system a response from a receptor to a
stimulus is created. In the body, the feedback mechanism is
mainly negative. Negative feedback reverses the initial stimulus;
any change that has occurred and restores conditions to their
normal levels. For example, a negative feedback system controls
the blood sugar levels by insulin and glucagon. Firstly, alpha cell
receptors in the pancreas will detect a stimulus which in this case
is the fall in the concentration of glucose in the blood. The alpha cells will then secrete glucagon
right after the change is detected, the glucagon will then cause effectors which in this case are liver
cells that produce glucose by converting glycogen. The glucose is then released into the blood
which raises its glucose concentration. This blood containing raised glucose concentration will
circulate back into the pancreas.
Another example is temperature control, if the temperature rises above the optimum range,
vasodilation will occur. However, before it occurs, a receptor will detect this change and the central
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