Distinction assignment from BTEC Applied Science Unit 9- human regulation and reproduction. unit 9B includes how homeostatic mechanisms maintain normal function, as well as an explanation of the roles. It also includes an analysis of the impact homeostatic dysfunction has on the body.
Homeostasis
Homeostasis is the process where the body maintains a stable internal environment. This
causes dynamic equilibrium in the body. PH, temperature, blood glucose concentrations, and
salt concentrations all need to be regulated to ensure cells can function efficiently without
being harmed. Our body would not be able to survive without homeostasis. The nervous
system and hormones are involved in ensuring there is dynamic equilibrium in the body.
They do this with the help of receptors that detect the stimuli and cause a response which
brings it back to normal. It is important to control the internal temperature in the body as
the metabolic processes in the body are faster at higher temperatures. If the temperature is
too cold, the enzymes will not have sufficient kinetic energy to be able to move around and
collide with the substrate. Due to their not being a high number of successful collisions, the
enzymes are unable to sped up processes in the body. This will result in bodily processes
occurring much slower and less efficiently. However, if the temperature increases too high,
enzymes in the body can become denatured. When an enzyme becomes denatured, it loses
its tertiary structure which means the substrate will no longer fit the enzyme as the active
site has changed shape. It is important to control blood glucose concentration as glucose is
required to carry out respiration in the body. If the levels are too low, then cells will not be
able to respire, and if the levels are too high, water molecules will diffuse out of cells into
the blood due to the water potential being too low. It is important that water/salt
concentration is regulated because if it is too high, cells will swell and burst as they will get
flooded with water. If the concentration is too low, the cells will shrivel and die as water will
be leaving the cell causing them to be dehydrated.
Negative feedback
Negative feedback is a mechanism by
which homeostasis is achieved. A
change in one condition of the body
causes the effector to bring the change
back to normal. If there is a change in
the body, the specific receptor would
detect the change and generate an
action potential that would travel to
nervous system or hormonal system
where a response is coordinated. From
here, the impulse would travel to the effectors where a response will occur to bring the
change back to normal. This could be a change in temperature, PH, or salt concentration in
an organ in the body. The average bodyphj temperature is 37 degrees. When exercising, the
body temperature increases above 37 degrees as the muscles in the body are working
harder. Thermoreceptors in the body detect this change and generate an action potential
that travels along the sensory neuron to the hypothalamus. The hypothalamus coordinates a
response and releases hormones. This causes the sweat glands to release sweat. This causes
the bodies temperature to return back to normal (37 degrees).
, Positive feedback
Positive feedback is another mechanism; however, this does not cause homeostasis. During
positive feedback, when there is a change in the body, the effectors create a response to
amplify the change in the body rather than returning it back to normal. This is useful during
childbirth as when the cervix stretches and dilates, the stretch receptors send a nerve
impulse to the pituitary gland where the hormone oxytocin is released. This hormone causes
the uterus to contract harder to try and force the baby out. The cervix stretches and dilates
due to the baby's head pushing against it.
Exocrine glands
Exocrine glands are glands that secrete enzymes and different substances. These glands have
ducts and secrete substances to the site of action rather than into the blood. This causes
exocrine glands to have a faster response, however, they have short term effects on the
body. salivary glands, Brunner’s glands and sweat glands are all exocrine. Sweat glands are
located on the skin, and they secrete sweat to lower the body temperature. This occurs
when exercising as the body's temperature increases. The Brunner’s glands are located in
the duodenum of the small intestine. The function of this gland is to neutralise the stomach
acid. It does this by secreting alkaline mucus which is high in PH. This neutralises the acid
which protects the mucosa from being damaged.
Endocrine glands
Endocrine glands are glands that secrete hormones into the bloodstream. They are like
exocrine glands; however, they do not have ducts and have a much slower response. The
response is slow, but the effect is more long term. The hypothalamus, pituitary gland,
thyroid, and parathyroid gland are all different types of endocrine glands. The thyroid gland
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