Understand How Homeostatic Mechanisms Operate in the Maintenance of an Internal Environment

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Understand how homeostatic mechanisms operate in the maintenance of an internal environment Homeostasis is keeping the body balanced to allow cells to function, despite external environment. Homeostasis is important because the cells, blood and tissue fluids can change by slowing down or even stop a vital chemical reaction. Its aim is to keep the body to stay the same, at a normal condition.

Negative feedback is when change is detected; there are steps when change is detected to get it back to its normal range. Change is detected by the receptors it can be any internal organ, then a message is sent to the brain which is the control centre then the effectors would react to get it back to normal.

Heart rate
Breathing rate
Body temperature
Blood glucose level

Homeostatic control of heart rate
Role internal receptors
Internal receptors detect change in blood pressure. For example when doing exercise, our heart rate speeds up, the change is detected by the receptors that can be the internal organs which then send a message to the control centre, the brain and then it activates the effectors which bring the heart rate back to normal. The sinoatrial node (SA) is part of the heart, it is known as the pacemaker. The SA controls the rate of contraction.

Autonomic nervous system
The heart is controlled by the autonomic nervous system which is two branches called the sympathetic nerves system and the parasympathetic nervous system. The sympathetic nervous system is active when the body is undergoing muscular work such when we are doing exercise, like when running or jumping. It causes the increase in the heart rate and strengths the heartbeat. The parasympathetic nervous system calms the heart down and is active when the body is at rest.

Heart rate is also increased by adrenaline. Adrenaline is a hormone from the adrenal gland and it is released duringwhen we are doing exercise, which increases the heart rate, this is the sympathetic...
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