The is activated which then initiates a series of

The blood glucose level rises after we consume
food  which is digested and the nutrients
are absorbed. The beta cells of pancreas respond to the rise in glucose level
and secrete a  Insulin promoted the cells
to increase their glucose intake and increase the cellular rate to breakdown
glucose to produce ATP. However, In liver and muscle cells, the formation of
glycogen from glucose is increased. Furthermore, insulin stimulates the
synthesis of fats in adipose tissue. All these activities would cause the
glucose level to fall back into the normal level.


Another negative
feedback mechanism is blood glucose level regulation. The cells in our body
break down glucose as their main source of energy. The break glucose molecules
are broken down by the cells to produce Adenosine Tri-phosphate (ATP) which are
energy-rich molecules used to perform multiple cellular processes. The glucose
molecules are transported to the cells via circulation of blood. The glucose
level should thus be maintained at constant levels. The normal range is 70-110
milligrams of glucose per deciliter of blood. Disturbance in the blood glucose
level can lead to life-threatening situations. Maintaining constant glucose
level is necessary for the survival of the cells and health of the body.

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On the contrary, when the temperature of the
body falls below the set point because of low environmental temperature, the
heat-promoting centre of hypothalamus is activated which then initiates a
series of events. The skin surface blood vessels are vaso-constricted to reduce
heat loss, sweating is inhibited, and hairs of the skin are raised to increase
insulation. To produce more heat, the skeletal muscles are activated, and the
body tends to shiver and produce heat. Again, once the temperature increases to
optimal temperature, the heat-promoting center of the hypothalamus is shut off.
But if the homeostatic mechanism fails, the positive feedback mechanism would
decrease the temperature to the point of hypothermia, which is a condition
where the body temperature falls below 32ºC.

Temperature regulation is an examples of
negative feedback mechanism. The optimal body core temperature is about 36.8 ºC which is the homeostatic set point.
 This optimal temperature is closely
regulated due to factors like enzymes works best at certain temperatures. If
the temperature raises to 43ºC, it
may be fatal and cause death.  Whereas, if
the temperature falls below 32ºC, the
individual may go into coma and die. The changes in the temperature are
detected by nerve-endings in the skin and the hypothalamus of the brain. When
blood temperature raises above the optimal temperature, the heat-loss centre in
the hypothalamus is activated which then initiates an autonomic response. This
response triggers changes to the effectors like the blood vessels which
vasodilate and increase blood flow to the skin so that there is increase in
radiation, conduction and convection to lose heat. Subsequently, metabolic rate
and muscular activity are decreased to slow down further heat production. The
sweat glands, additional effectors, are activat

In negative feedback loop, has a
counteraction effect on its own influence. Therefore, the negative feedback
mechanism can increase or decrease the stimulus. If the level is high, the body
decreases it and if it is too low, it elevates it and thus it is known as
negative feedback. Homeostasis always tends to provide optimal internal
environment in which the body can function best.

Another positive feedback mechanism is blood
clotting. When a blood vessel is damaged, platelets arrive to the site and
stick to the site of the injury. They release chemical signals that attract
more platelets to the site and accelerate the process of clotting. This
continues until the clot repairs the damaged vessel.

During labor, the oxytocin hormone is
released by the hypothalamus and released by posterior pituitary. The oxytocin
stimulates and intensifies the contraction of the uterus, forcing the head of
the baby into the cervix. Subsequently, more oxytocin is release when stretch
receptors that are in the cervix are activated. In turn, more oxytocin is
released causing more contractions and maintaining labor. This cycle continues
until the baby is born. Once the baby is born, the stretch receptors are
deactivated and since the stimulus is not present anymore, the release of
oxytocin is stopped ending the positive feedback mechanism.

In positive feedback mechanism, the output is
amplified to maintain homeostasis. They are designed to push levels out of
normal ranges. This is achieved by initiating a series of events, which
originates to amplify the effect of the stimulus. This mechanism can be useful
but are rarely used due to its ability to become uncontrollable. For instance,
child birth and blood clotting are paramount examples of the use of positive
feedback mechanism.


ed to release perspiration and evaporate body
heat. Hairs on the skin are flattened to reduce insulation. When the body
temperature falls back to the set point, the heat-loss centre is shut off. If
by any reason this thermoregulation mechanism fails, the body temperature can
exceed 41ºC causing Hyperthermia.

The endocrine system plays a vital role in
homeostasis as it is responsible for releasing hormones that regulate the
cellular activities. The release of hormones is affected by the stimulus. The
stimulus may cause an increase or decrease in the amount of hormones released.
The response to the stimulus then changes the internal environment when is then
considered a new stimulus. This mechanism where the hormones self-adjust is
known as feedback mechanisms. Any feedback regulation takes place when the
response to a stimulus influence the original stimulus. According to the type
of effect the response has on the original stimulus, there are two types of
feedback mechanisms: positive and negative feedback. Positive feedback is when
the response increases the initial stimulus; and negative feedback is when the
response increases and decreases the original stimulus.

Regulation of homeostasis itself is
accomplished by control system which have three basic components: detector,
control center and effectors. The detector sends input to the control centre
which assesses it and if any change is required, it changes its output to the
effectors accordingly. The control systems set limits for which the variable
has to be maintained. When the control centre detects changes, it responds to
any changes in the internal environment. This dynamic process maintains the

Opdells depend on diffusion and osmosis.
These processes rely on the body’s salt and water concentration, which are
maintained by homeostasis. In addition to that, the cells also rely on various
enzymes that carry out the chemical reactions that cells need to survive and
function. These enzymes require temperatures to work which are also maintained
by homeostasis.

The internal environment needs to be constant
for the proper function of cells and the maintenance of a stable environment is
known as Homeostasis. The concept of “homeostasis” was first coined by Claude
Bernard, a French physiologist in 1865. In literal sense it means unchanging,
but practically, it is a dynamic and

human body is a complex yet single entity that is made up of various
independently operating systems. various tissues and organs work together to
form systems that work interdependently undertaking specific functions. The
survival and maintenance of a healthy of a body is greatly affected by the external environment that surrounds us
and the internal environment which is
the water based medium or interstitial fluid where the cells exist. The
external environment supplies the body with nutrients and oxygen that the cells
need and the waste products from cellular activities are excreted back into the
external environment. The transportation of oxygen, carbon dioxide, nutrients
and waste products occurs in the internal environment such as interstitial