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iambio iambio
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10 years ago
This is in regard of Homeostasis and negative feedback
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10 years ago
Endocrine and Nervous system both are the 2 major:
1.Homeostatic control systems and
2.Communicating system in the body.

They are 2 separate systems but often work together to help the body function properly (to maintain the homeostatic control system within the body).

A good example of Nervous system and Endocrine system working together in order to maintain the Homeostatic Control System within the body Would be:
a.The regulation of Blood Pressure and Blood Volume
b.Maintaining the needs of the body during the periods of Stress (fight-or-flight response)

The regulation of Blood Pressure:
Basically when the blood pressure decreases, the baroreceptors in the carotid sinuses and aortic arch are inhibited. The impulses from the baroreceptors stimulate the Sympathetic Nervous System activity and it consequently result in inhibition of the Parasympathetic Nervous System activity. The Sympathetic stimulation promotes the release of Renin Hormone by the granular cells in the Kidney. Renin inturn act as an enzyme and catalyse the conversion of Angiotensinogen to Angiotensin I. The Angiotensin I consequently is converted to Angiotensin II by Angiotensin Converting Enzyme (ACE).
The Angiotensin II will work in 5 different ways to stabilise the systemic blood pressure and blood volume:

1.Vasoconstriction of Arterioles throughout the body raising the mean arterial blood pressure.
2.Angiotensin II result in reabsorption of Na+ by acting on renal tubule (directly) AND (indirectly) by stimulationg the release of Aldostrone Hormone from the Adrenal Cortex of the Kidney, which also result in reabsorption of extra Na+ by acting on renal tubule. NOTE that as Na+ is reabsorbed the water follows osmotically and therefore increase the blood Volume and consequently the Blood pressure.
3. Angiotensin II stimulate hypothalamus to release ADH to increase water reabsorption by inserting aquaporins/water channels into the Collecting Duct.
4.Angiotensin II increases fluid reabsorption by decreasing peritubular hydrostatic pressure.
5.Angiotensin II stimulates mesangial cells to contract in order for the Glomerular Filteration Rate (GFR) to decrease.

OVERAL there is going to be a net increase in Blood Volume and Blood pressure and this was brought about by the incorporation of both Nervous System and Endocrine Systems.

Regulation of blood glucose during the periods of Stress (fight-or-flight response):
This is also a very good example as during the Period of STRESS the Sympathetic Nervous System is activated. Basically the Hypothalamus is stimulated to send impulses along the Preganglionic Sympathetic Nerve fibres to the Adrenal Medulla in order for the Adrenal Medulla to release Epinephrine and Norepinephrine Hormones. The Epinephrine and Norepinephrine reinforce and prolong the fight-or flight response. The body react in several ways during the fight-or flight response to maintain the need of the body during stress (for example when you're in an emergency! running away)

1. These hormones are stimulator of Metabolic Activities = In the liver the Glycogen is converted to Glucose (glycogenolysis) and Glucose is released into the blood to maintain the need for energy from glucose when you are Running away!
2.The hormones increase the blood flow to the Skeletal muscles and the heart (as more oxygen and glucose is needed by the skeletal muscles. Remember you need the muscles to run away!)
3.The hormones cause bronchial dilation to increase the blood oxygen levels and excretion of Carbon dioxide.
4.Increase the metabolic rate. (more glucose)
5.Peripheral vasoconstriction and increase the Blood Pressure. (to increase the oxygen and glucose delivery to the skeletal muscles)

Again the Nervous System and Endocrine System work together to maintain the Homeostasis control system during the period of Stress.  

I hope this helps Wink Face
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