Circulation Biology Class 11
Notes for kpk
Q.2 i) How the interstitial fluid is formed?
Answer:
Interstitial fluid (tissue fluid, or intercellular fluid):
When blood passes through the arteries (with pressure), veins, and capillaries the water
along with salts, some plasma proteins, etc. ooze out in tissue spaces. This fluid is called
interstitial fluid.
Formation of tissue fluid:
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Interstitial fluid is simply blood plasma minus most of the proteins. Interstitial fluid bathes
the cell in the tissue space and substances in it can enter the cells by diffusion or active
transport. Substances like carbon dioxide can diffuse out of the cells and into the interstitial
fluid.
Q.2 ii) Why does the normal value of BP increase in
old age? Explain your answer.
Answer:
The increase in blood pressure with age is mostly associated with structural changes in the
arteries and especially with large artery stiffness which leads to atherosclerosis and
arteriosclerosis. In elderly people, the most powerful predictor of risk is increased pulse
pressure due to decreased diastolic and increased systolic blood pressure. Although blood
pressure does increase with age, it is still clearly detrimental to cardiovascular health. There
is a direct link between high blood pressure and the risk of stroke, heart failure, kidney
failure, and coronary artery disease.
Q.2 iii) If the baroreceptors are removed from an
artery what would be the effect?
Answer:
Baroreceptors are a type of nerve endings which are located in the blood vessels of the
human body which detect the pressure of blood flowing through them and send messages
to the central nervous system to increase or decrease total peripheral resistance and cardiac
output. If these baroreceptors are removed from the artery, baroreflex failure occurs which
results in the change of blood pressure with episodes of severe hypertension (high blood
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, pressure). There can be an increased heart rate during stress and hypotension (low blood
pressure) with normal or reduced heart rate during rest.
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Symptoms:
Headache
Excessive sweating
Extremely high or volatile blood pressure and heart rate with spikes in blood
pressure in response to stress, with periods of normal or even low blood pressure
during rest
The heart rate that does not respond to medications intended to improve it
Q.2 iv) What changes occur in BP and cardiac
output during a strenuous exercise?
Answer:
During exercise, the human body needs three or four times more than normal
cardiac output, because body muscles need more oxygen.
Exercising makes the heart pump more blood to the muscles. This will increase blood
flow, which is beneficial for the brain so cardiac output increases.
Most of the increase in cardiac output goes to the exercising muscles. There is an
increase in blood flow to the skin (dissipation of heat) and the heart (increased work
performed by the heart).
In both skeletal and cardiac muscles, vasodilation is mediated by local metabolic
factors
Exercise also stimulates the growth of new blood vessels, causing blood pressure to
decrease in fit people.
Simultaneously with vasodilation in these three regions, vasoconstriction occurs in
the kidneys and gastrointestinal organs, due to an increase in activity of sympathetic
neurons supplying them.
Q.2 v) If we don’t take water the whole day in June,
what would be the effect on the volume of lymph?
Answer:
If we don’t take water the whole day in June, dehydration occurs and the body will become
water-deficient due to sweating or urination. This will lead to decreased blood volume, and
less lymph will be secreted out into tissue spaces resulting in decreased lymph volume.
Lymph fluid is composed of 95% water and interacts with every cell in the body. It helps get
nutrients to different parts of the body and cleanses internally continually to restore balance
in cells. It also carries waste products and bacteria away for disposal, ensuring that the body
processes stay in equilibrium. When it stops flowing properly, waste and bacteria get stuck,
the immune system struggles to cope and the body becomes sick.
2|Page Perfect24u.com
Notes for kpk
Q.2 i) How the interstitial fluid is formed?
Answer:
Interstitial fluid (tissue fluid, or intercellular fluid):
When blood passes through the arteries (with pressure), veins, and capillaries the water
along with salts, some plasma proteins, etc. ooze out in tissue spaces. This fluid is called
interstitial fluid.
Formation of tissue fluid:
Advertisements
Interstitial fluid is simply blood plasma minus most of the proteins. Interstitial fluid bathes
the cell in the tissue space and substances in it can enter the cells by diffusion or active
transport. Substances like carbon dioxide can diffuse out of the cells and into the interstitial
fluid.
Q.2 ii) Why does the normal value of BP increase in
old age? Explain your answer.
Answer:
The increase in blood pressure with age is mostly associated with structural changes in the
arteries and especially with large artery stiffness which leads to atherosclerosis and
arteriosclerosis. In elderly people, the most powerful predictor of risk is increased pulse
pressure due to decreased diastolic and increased systolic blood pressure. Although blood
pressure does increase with age, it is still clearly detrimental to cardiovascular health. There
is a direct link between high blood pressure and the risk of stroke, heart failure, kidney
failure, and coronary artery disease.
Q.2 iii) If the baroreceptors are removed from an
artery what would be the effect?
Answer:
Baroreceptors are a type of nerve endings which are located in the blood vessels of the
human body which detect the pressure of blood flowing through them and send messages
to the central nervous system to increase or decrease total peripheral resistance and cardiac
output. If these baroreceptors are removed from the artery, baroreflex failure occurs which
results in the change of blood pressure with episodes of severe hypertension (high blood
1|Page Perfect24u.com
, pressure). There can be an increased heart rate during stress and hypotension (low blood
pressure) with normal or reduced heart rate during rest.
Advertisements
Symptoms:
Headache
Excessive sweating
Extremely high or volatile blood pressure and heart rate with spikes in blood
pressure in response to stress, with periods of normal or even low blood pressure
during rest
The heart rate that does not respond to medications intended to improve it
Q.2 iv) What changes occur in BP and cardiac
output during a strenuous exercise?
Answer:
During exercise, the human body needs three or four times more than normal
cardiac output, because body muscles need more oxygen.
Exercising makes the heart pump more blood to the muscles. This will increase blood
flow, which is beneficial for the brain so cardiac output increases.
Most of the increase in cardiac output goes to the exercising muscles. There is an
increase in blood flow to the skin (dissipation of heat) and the heart (increased work
performed by the heart).
In both skeletal and cardiac muscles, vasodilation is mediated by local metabolic
factors
Exercise also stimulates the growth of new blood vessels, causing blood pressure to
decrease in fit people.
Simultaneously with vasodilation in these three regions, vasoconstriction occurs in
the kidneys and gastrointestinal organs, due to an increase in activity of sympathetic
neurons supplying them.
Q.2 v) If we don’t take water the whole day in June,
what would be the effect on the volume of lymph?
Answer:
If we don’t take water the whole day in June, dehydration occurs and the body will become
water-deficient due to sweating or urination. This will lead to decreased blood volume, and
less lymph will be secreted out into tissue spaces resulting in decreased lymph volume.
Lymph fluid is composed of 95% water and interacts with every cell in the body. It helps get
nutrients to different parts of the body and cleanses internally continually to restore balance
in cells. It also carries waste products and bacteria away for disposal, ensuring that the body
processes stay in equilibrium. When it stops flowing properly, waste and bacteria get stuck,
the immune system struggles to cope and the body becomes sick.
2|Page Perfect24u.com
