Importance of Vitamin D and Calcium

The assignment delves into the significance of vitamin D and calcium for bone health, highlighting their impact on various bodily functions. It discusses the risks associated with deficiencies, including weakened muscles, cognitive impairment, and cardiovascular problems. Furthermore, it provides insights into dietary sources of these essential nutrients, emphasizing the importance of consuming foods rich in vitamin D and calcium to ensure optimal well-being.

Bioscience

TABLE OF CONTENTS
PART A...........................................................................................................................................3
1) Homeostatic feedback system in response to decreased temperatures....................................3
PART B............................................................................................................................................4
2) Homeostatic feedback system for elevated blood glucose level.............................................4
3) Consequence on bone health...................................................................................................5
REFERENCES ...............................................................................................................................6
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PART A
1) Homeostatic feedback system in response to decreased temperatures
Homeostasis is the tendency of human body for gaining equilibrium with external
changes in the surroundings. Dynamic equilibrium is maintained by the body internally but when
state of homeostasis is left, a response or feedback system is initiated. In case of elevated or
decreased temperatures in the external environment, the body reacts in the form of sweating or
shivering respectively. The main components of the feedback system are receptors, control
centre and effectors. The stimulus that is sensed by the body is identified by receptors while
control centre or the central nervous system interprets this stimuli (Modell & et. al., 2015).
According to the stimulus, effectors provide a response to the body which is visible in the form
of action and reactions.
The feedback system that is activated in case of homeostasis can be of two types i.e.
negative and positive depending on the type of stimuli. Decreased temperatures is a stimuli
which means that there is a difference in the external surroundings as compared to the internal
body temperature. The feedback system in this kind of stimulus is negative. The receptor in
decreased temperatures is skin. When the body detects that external environment has lower
temperatures, then a message signal is activated from skin and transferred to the control centre.
In case of homeostatic feedback of decreased temperatures, the control centre is hypothalamus.
Thermoreceptors transfer the signal of decreased temperature in external surroundings to
the hypothalamus. Here, the deflection from equilibrium is measured and identified accordingly.
Effectors are skeletal muscles and blood vessels that receive the information of shivering and
vasoconstrict. The effectors make the body shiver and try bringing the balance in equilibrium
that was lost due to difference in temperature of external and internal surroundings. Skeletal
muscles rapidly contract and try generating heat which makes body warm (Johnson, Minson &
Kellogg, 2014). On the other hand, blood vessels undergo vasoconstrict. In this process, the
diameter of blood vessel is decreased and the blood flow beneath the surface of skin is reduced.
This causes the skin to turn pale. Heath generated by muscle contraction is trapped and not lost
to the surface. As a result, the body starts shivering in the stimulus of decreased temperatures.
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The negative feedback system that is activated in this case helps in reaching equilibrium
state by making the body shiver and become warm internally by contraction of muscles and
blood vessels.
PART B
2) Homeostatic feedback system for elevated blood glucose level
The body requires oxygen for maintaining different functions. Cells being the basic unit
of human body require glucose for respiration. It is important to control the level of blood sugar
that is produced in the blood. Different kinds of hormones are involved in regulation of blood
glucose. Insulin and glucagon are the hormones that are responsible for controlling the levels of
blood sugar. Homeostatic feedback is generated in tow conditions i.e. when blood glucose level
is low or high. The increase in concentration of blood glucose after eating, is an action which is
considered as a stimulus for generating insulin (Stanford & et. al. 2013).
The control centre in this feedback system is pancreas and specifically insulin hormone.
Elevated blood glucose is a stimulus that is activated immediately after eating food.
Carbohydrates, proteins, vitamins and minerals are the constituents of this food that begin to
breakdown during digestion. When carbohydrates are being digested in the body, blood glucose
increases. This activates the homeostatic feedback system which has islets of Langerhans or
pancreas is the control centre. Receptors in this system are proteins which are present in the cell
membranes of liver (Vogt & Brüning, 2013). Cells absorb desired quantities of glucose and this
enhances the process of conversion of glucose to glycogen.
Since, it has been realised that blood glucose is essential for maintaining the flow of
internal body functions; it is important to understand the effect elevated blood sugar levels can
have on the body (Holick & et. al. 2012). When too high, pancreas being the control centre of
feedback system will release insulin. Beta cells that are present in the pancreas release insulin in
such conditions. Fat cells become the effectors for maintaining the balance of glucose in normal
blood. The response is provided in the form of consumption of glucose from fat cells. Hence,
excessive fat gets accumulated in different parts of the body (Wei & et. al. 2014). Imbalance in
diet and inappropriate consumption of food can lead to high blood glucose which means increase
in fat cells.
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Once, excess glucose from the body is absorbed by fat cells with help of insulin, the
blood flow is normalised. This type of feedback system is considered as negative feedback
because the equilibrium is disturbed negatively (Reid, Bolland & Grey, 2014). The maintenance
of this blood glucose level in the body is possible with help of rigorous exercises and proper
physical activity of the body.
3) Consequence on bone health
Bones help in providing support and strength to the human body. Calcium and vitamin D
are some important components which enhance the growth and maintenance of bone health. The
main sources of calcium are milk and its products. Skimmed milk, plain or fruit yogurt, all sorts
of cheese, calcium fortified cereals and juices help in inducing calcium ions. On the other hand,
vitamin D is essential because it helps in absorbing calcium by bones. Sun is the greatest source
of vitamin D in the body (Norman, 2017). Egg yolks and fatty fish are also genuine supporters
for enhancing vitamin D.
Inappropriate diet can lead to deficiency of this vitamin and calcium in the body. Severe
deficiency can lead to various consequences on the bone health and may invite diseases.
Cognitive impairment and high risk towards cardiovascular problems are some severe outcomes
which can be experienced by the person who is deficient in vitamin D and calcium ions. In more
extreme cases, the person can also have cancer and severe asthma (Vitamin D Deficiency, 2017).
Hence, it is important to maintain bone health by timely consumption of calcium and vitamin D
rick foods. This will also help in reducing weaknesses for muscles.
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REFERENCES
Books and Journals
Johnson, J. M., Minson, C. T., & Kellogg, D. L. (2014). Cutaneous vasodilator and
vasoconstrictor mechanisms in temperature regulation. Comprehensive physiology.
Modell, H. & et. al. (2015). A physiologist's view of homeostasis. Advances in physiology
education. 39(4). pp. 259-266.
Stanford, K. I. & et. al. (2013). Brown adipose tissue regulates glucose homeostasis and insulin
sensitivity. The Journal of clinical investigation. 123(1). pp.215-223.
Vogt, M. C. & Brüning, J. C. (2013). CNS insulin signaling in the control of energy homeostasis
and glucose metabolism–from embryo to old age. Trends in Endocrinology & Metabolism. 24(2)
pp.76-84.
Wei, J. & et. al. (2014). Bone-specific insulin resistance disrupts whole-body glucose
homeostasis via decreased osteocalcin activation. The Journal of clinical investigation. 124(4).
pp. 1781-1793.
Holick, M. F. & et. al. (2012). Guidelines for preventing and treating vitamin D deficiency and
insufficiency revisited. The Journal of Clinical Endocrinology & Metabolism. 97(4). 1153-1158.
Reid, I. R., Bolland, M. J., & Grey, A. (2014). Effects of vitamin D supplements on bone mineral
density: a systematic review and meta-analysis. The Lancet. 383(9912). pp. 146-155.
Online
Norman, J. (2017). Normal Regulation of Blood Glucose. Retrieved from:
https://www.endocrineweb.com/conditions/diabetes/normal-regulation-blood-glucose. [Accessed
on 23rd March, 2017].
Vitamin D Deficiency. (2017). Retrieved from: http://www.webmd.com/diet/guide/vitamin-d-
deficiency#1. [Accessed on 23rd March, 2017].
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