0 Running head: BIOSCIENCE
Name of the Student
Name of the University
A1. a. The normal range of body temper …
0 Running head: BIOSCIENCE
Name of the Student
Name of the University
A1. a. The normal range of body temperature is between 97F (36.1C) to 99F (37.2 C). Body
temperature usually fluctuates according to the circadian rhythm of any person. It is
necessary for the temperature of the body to be within the normal range for the biochemical
processes to occur and for ensuring that the normal physiological processes of the body are
not disrupted (Petersen, 2019) .This is so because the functioning of the body is based on the
biochemical reactions that occur in the body cells. These reactions occur with the help of
various enzymes that are stored in the cells of the body. The characteristic of enzymes is that
they have an optimum range of temperature where enzymes show maximum enzymatic
activity. In the human body, the optimum range of temperature at which enzymes function is
76.7F- 98.3F (Grodzinsky & Levander, 2019).
The human temperature being around 98F is therefore best suited for enzyme-catalyzed
reactions to occur. Beyond this temperature range, the activity of enzymes declines owing to
denaturation and enzymes are therefore rendered incapable of catalyzing biochemical
reactions of the body. Thus, at high temperatures, the active site and enzymatic shape is
disrupted, whereas at low temperature the molecular movements slow down that delay the
reactions. This makes maintenance of normal body temperature essential otherwise the
biochemical reactions in the body will not occur and life will cease to persist (Marieb &
Hoehn, 2019) .
b. Homeostasis is the tendency of the body to ensure maintenance of arelatively stable and a
constant internal environment. For homeostasis to be maintained, the body involves negative
feedback loops that resist the stimulus which triggers them. This can be explained with an
example when the body is exposed to low temperatures (Madden & Morrison, 2019).
When the body is exposed to cold external temperature such as 10C, it activates the
homeostatic feedback system which starts acting to restore homeostasis. First, the brain â€™s
temperature center starts receiving triggering responses. This causes vasoconstriction where
the blood flow to the skin is lowered and aresult, shivering is promoted. The muscles also
result in heat generation followed by piloerection where the body hair stands so as to trap a
layer of air near the surface of the skin which keeps the body warm. Lastly, hormones are
also secreted with increase heat production. All these steps retain heat and cause the body
temperature to rise, thereby restoring homeostasis (Madden & Morrison, 2019).
A2. Hormone released by the body when blood calcium levels decrease is the parathyroid
hormone (Goltzman, 2018).
Parathyroid hormone or PTH is secreted by the parathyroid glands. The parathyroid cells
contain receptors located in its plasma membrane which detect blood calcium levels and
thereby get activated. Upon activation, the synthesis and release of parathyroid hormone is
inhibited. However when blood calcium levels are low, then this inhibition effect is removed
and release of PTH is triggered (Goltzman, 2018). PTH acts by targeting the cells of the bone
which after binding to osteoblasts causes release of cytokines. This increases increases
osteoclast activity thereby enhancing the bone turnover. As aresult, net bone loss occurs and
levels of calcium therefore rises in blood. PTH also causes stimulation of kidneys and
promotion of calcium reabsorption. It also promotes increased absorption of calcium from
food in the digestive tract and thereby causes levels of calcium in blood to rise (Goltzman,
A3. Internal respiration and external respiration are processes where oxygen and carbon
dioxide is exchanged. These two processes however differ in many aspects. Firstly, internal
respiration is the process where oxygen diffuses from blood into the tissues. In this process,
oxygen also binds with haemoglobin in alveolar tissues and is transported to tissues of the
body. External respiration, on the other hand, also known as breathing, is the process where
gaseous exchange occurs across the lung â€™srespiratory membrane where lungs take up oxygen
(as inhalation), and release carbon dioxide into the external environment (exhalation). Apart
from this difference, in internal respiration, diffusion of oxygen occurs from the blood into
the tissues in comparison to external respiration where oxygen is diffused into the blood from
the alveolar air (Scanlon & Sanders, 2019).
In terms of PO2 levels also, in internal respiration the PO2 of blood lowers from 100mm Hg
to 40mm Hg in comparison to external respiration where PO2 levels in blood increase from
40 mmHg to 100 mmHg. The direction and exchange process of carbon dioxide also differs
in the two processes. In internal respiration, carbon dioxide is diffused into the blood from
the tissues, but in external respiration diffusion of carbon dioxide occurs from the blood into
the alveolar air (Peate & Nair, 2017) .The levels of PCO2 also increase in internal respiration
from 40 mmHg to 45 mmHg, but in external respiration PCO2 levels decrease from 45
mmHg to 40 mmHg. Lastly, internal respiration co-relates with the internal environment of
the body since it takes place at the levels of the lungs and in the alveoli. External respiration,
however, relates not only with the internal environment of the body but also with the external
environment since ittakes place between the lungs and the environment (Peate & Nair, 2017).
A4. a. Three roles of cholesterol include involvement in synthesis of sex hormones such as
testosterone and progesterone, maintenance of membrane fluidity and stability, structure and
shape of the cell owing to the amphipathic nature of the molecule, and production of bile in
the liver (Nagpal, 2018).
b. HDL or high- density lipoprotein absorbs excess cholesterol in extra-hepatic tissues and
carries it to the liver. In the liver, LDL or low-density lipoprotein picks up cholesterol and
transports it to peripheral tissues. HDL or â€˜good â€™cholesterol helps in maintaining health of
cardiovascular system by helping the body in getting rid of excess cholesterol levels which
makes it less likely for plaques to develop and accumulate in the arteries. LDL or â€˜bad â€™
cholesterol absorbs cholesterol and deposits in the arteries where itcan lead to atherosclerosis
and thereby increase the risk of develop heart conditions which can be detrimental for the
cardiovascular system health (Nagpal, 2018).
c. Two dietary recommendations to ensure that blood cholesterol levels are optimal include
whole grains and green leafy vegetables. The former can provide soluble fibers that can lower
LDL levels, whereas the latter can bind to bile acids and facilitate increased excretion of
cholesterol, which can maintain the health of the cardiovascular system.
A5. a. Two sources of food rich in iron are organ meats which contain 6.5mg of iron in
100gms, and spinach which contains 2.7mg of 100gms (Pasricha, Tye-Din, Muckenthaler &
b. Two functions of iron include production of haemoglobin, that is aprotein of red blood
cells which carry oxygen to different body parts, and for synthesis of various hormones
(Pasricha, Tye-Din, Muckenthaler & Swinkels, 2021).
c. Iron deficiency can consequences such as iron- deficiency anemia and delayed
development and growth during the period of childhood (Pasricha, Tye-Din, Muckenthaler &
d. Two groups of people who are at an increased risk of having iron deficiency levels are
pregnant woman and women who menstruate. This is because pregnant woman need about
two times more amounts of iron that usual for development and growth of the baby, whereas
women who menstruate lose blood each month and therefore may develop iron deficiency
Goltzman, D. (2018). Physiology of parathyroid hormone. Endocrinology and Metabolism
Clinics ,47 (4), 743-758. https://doi.org/10.1016/j.ecl.2018.07.003
Grodzinsky, E., &Levander, M. S. (Eds.). (2019). Understanding Fever and Body
Temperature: A Cross-disciplinary Approach to Clinical Practice . Springer
Madden, C. J., & Morrison, S. F. (2019). Central nervous system circuits that control body
temperature. Neuroscience letters , 696 , 225-232.
Marieb, E. N., & Hoehn, K. (2019). Human anatomy & physiology. Global edition (11th ed.).
Pearson Education Limited.
Nagpal, M. L. (Ed.). (2018). Cholesterol: Good, Bad and the Heart .BoD â€“Books on Demand.
Pasricha, S. R., Tye-Din, J., Muckenthaler, M. U., & Swinkels, D. W. (2021). Iron
deficiency. The Lancet , 397 (10270), 233-248. https://doi.org/10.1016/S0140-
Peate, I., & Nair, M. (2017). Fundamentals of anatomy and physiology: For nursing and
healthcare students (2nd ed.). John Wiley & Sons, Ltd.
Petersen, O. H. (Ed.). (2019). Lecture notes: Human physiology .John Wiley & Sons.
Rankin, J. (2017). Physiology in Childbearing E-Book: With Anatomy and Related
Biosciences. Elsevier Health Sciences.
Scanlon, V. C., & Sanders, T. (2019). Essentials of anatomy and physiology (8th ed.). F. A.
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