The Mechanism of Negative Feedback

The Mechanism of Negative Feedback

Homeostasis means beatified sex. It is an ability of an organism to

control its internal environment, that is the composition of their

body fluids, for them to survive fluctuating external conditions.

Homeostasis is used to describe all the mechanisms by homeostatic

control. Maintenance of stability requires control systems capable of

detecting any deviation from the usual and making the necessary

adjustments to return it to its normal condition. The internal

environment can by controlled by hormones. Hormones are chemical

substances secreted into bloodstream by glands of the endocrine

system. In humans, more than a dozen tissues and organs produce

hormones. Some, including the pituitary, the thyroid, the parathyroid

glands and adrenal glands are endocrine specialists; their function is

to secrete one or more hormones. The endocrine system maintains

homeostasis, the balance of the body, by making sure the concentration

of many different substances in body fluids are kept at correct level.

Controls of blood sugar level, blood pH and water balance are all

examples of homeostasis.

Homeostasis is a characteristic of living things. Term is used for any

system, biological or non-biological, which is in a steady state.

Whenever a physiological factor changes, the body will detect the

change and by either using hormonal or nervous signals, or both, it

reverses the change. The extent of the correction is monitored by a

system called negative feedback. This makes sure that, as levels

return to normal, the corrective mechanisms are scaled down. This type

of system in which a change in level of a factor tr...

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erector pili muscles. The contraction of erector pili also leads goose

pimples. (diagram)

· The arteriole leading to the superficial capillaries constrict. As a

result blood flow to the surface of the skin is reduced, thereby

cutting down the loss of heat energy from the blood to the

surroundings. This vasoconstriction is brought about by the

sympathetic nervous system and is particularly powerful in exposed

structures such as ears, which are particularly susceptible to cold.

Blood largely passes beneath the insulating layer of subcutaneous fat

and so loses little heat to the outside. (diagram)

· Shivering-At low temperatures, the skeleton muscle of the body may

undergo rhythmic, involuntary contractions, which produce metabolic

heat. Asynchronous twitching of groups of muscle may precede this

shivering.