Circulatory System Archives

11. The oxygenated blood from the lungs is received by the

The oxygenated blood from the lungs is received by the

left auricle

left ventricle

right auricle

right ventricle

This question was previously asked in

UPSC NDA-2 – 2018

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Oxygenated blood from the lungs returns to the heart through the pulmonary veins and is received by the left atrium (also known as the left auricle).

– The circulatory system involves the heart pumping blood to the lungs for oxygenation and then distributing the oxygenated blood to the rest of the body.
– Deoxygenated blood from the body enters the right atrium, goes to the right ventricle, and is pumped to the lungs via the pulmonary artery.
– Oxygenated blood from the lungs enters the left atrium, goes to the left ventricle, and is pumped to the body via the aorta.

The heart has four chambers: the right atrium and right ventricle (handling deoxygenated blood) and the left atrium and left ventricle (handling oxygenated blood). The atria (auricles) are the receiving chambers, and the ventricles are the pumping chambers.

12. In Egypt, ancient mummies can be found to have their arteries intact d

In Egypt, ancient mummies can be found to have their arteries intact due to well-preserved:

mineralized blood

fibroblasts fibre

elastic fibre

brown fat

This question was previously asked in

UPSC NDA-2 – 2015

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Ancient Egyptian mummification involved sophisticated techniques to preserve soft tissues. The structure and elasticity of arteries are largely due to the presence of elastic fibers within their walls. Effective embalming methods that preserved the protein structure of these elastic fibers would contribute significantly to the intactness of the arteries over millennia.

The structural integrity of arteries, including their elasticity, is primarily attributed to the presence of elastic fibers. Preservation of these fibers through mummification techniques helps keep the arteries intact.

Fibroblasts produce collagen and other matrix components, including the precursors of elastic fibers, but the mature elastic fiber itself provides the elasticity. Mineralized blood might refer to calcification or remnants within the vessel lumen, but it doesn’t explain the preservation of the vessel wall structure. Brown fat is a type of adipose tissue involved in thermogenesis and is not a structural component of arteries. Mummification processes often involved the removal of organs and treatment of tissues with various salts and resins to dehydrate them and inhibit microbial decay, preserving their structural components like elastic fibers.

13. In blood, platelets are required for:

In blood, platelets are required for:

transporting oxygen

transporting carbon dioxide

initiating blood clotting

initiating degradation of urea

This question was previously asked in

UPSC NDA-2 – 2015

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The correct option is C, initiating blood clotting.

Platelets, also known as thrombocytes, are small, anucleated cell fragments in the blood that play a crucial role in hemostasis, the process by which bleeding is stopped. When a blood vessel is injured, platelets aggregate at the site of injury, forming a platelet plug. They also release factors that activate the coagulation cascade, a complex series of reactions leading to the formation of a fibrin clot, which reinforces the platelet plug and seals the damaged vessel. Red blood cells (erythrocytes) are responsible for transporting oxygen. Carbon dioxide is transported in the blood in various forms (dissolved in plasma, bound to hemoglobin, or as bicarbonate ions). Urea is a waste product transported by the blood to the kidneys for excretion; its degradation primarily occurs in the liver during its formation from ammonia.

Deficiency or dysfunction of platelets can lead to bleeding disorders, such as thrombocytopenia. Conversely, excessive platelet activation can contribute to the formation of blood clots (thrombosis) within blood vessels, which can lead to serious conditions like heart attacks or strokes.

14. Which one of the following statements regarding Electrocardiogram is c

Which one of the following statements regarding Electrocardiogram is correct ?

Electrocardiogram is graphical representation of electrical activity of cornea

Electrocardiogram is graphical representation of activity of kidney

Electrocardiogram is graphical representation of activity of brain

Electrocardiogram is graphical representation of electrical activity of heart

This question was previously asked in

UPSC NDA-1 – 2019

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Electrocardiogram (ECG) is a graphical representation of the electrical activity of the heart.

An ECG machine records the electrical signals generated by the heart as it beats.

ECGs are used to diagnose various heart conditions, such as arrhythmias, myocardial infarction (heart attack), and heart failure by analyzing the patterns of electrical waves. It does not measure activity of the cornea, kidney, or brain (which is typically measured by EEG).

15. The Poisonous nature of Carbon monoxide (CO) is due to its

The Poisonous nature of Carbon monoxide (CO) is due to its

insolubility in water

ability to form a complex with haemoglobin

ability to reduce some metal oxides

property of having one sigma bond

This question was previously asked in

UPSC NDA-1 – 2018

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The poisonous nature of carbon monoxide (CO) is primarily due to its ability to bind strongly to haemoglobin in red blood cells.

Carbon monoxide has a much higher affinity for haemoglobin (about 200-250 times greater) than oxygen. When inhaled, CO binds to haemoglobin forming carboxyhaemoglobin (COHb), effectively reducing the capacity of the blood to transport oxygen. This leads to oxygen deprivation in the body’s tissues and organs.

Symptoms of carbon monoxide poisoning include headache, dizziness, nausea, weakness, confusion, and in severe cases, unconsciousness, coma, and death. CO is produced by the incomplete combustion of carbon-containing materials.

16. Red blood cells (RBCs) have

Red blood cells (RBCs) have

no nucleus, no mitochondria and no endoplasmic reticulum

nucleus, mitochondria and endoplasmic reticulum

nucleus, mitochondria but no endoplasmic reticulum

no mitochondria but endoplasmic reticulum is present

This question was previously asked in

UPSC NDA-1 – 2017

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The correct answer is no nucleus, no mitochondria and no endoplasmic reticulum.

Mature mammalian red blood cells (erythrocytes) are unique in that they lack most organelles found in other eukaryotic cells. They are anucleated, meaning they do not have a nucleus. They also lack mitochondria, endoplasmic reticulum, and Golgi apparatus.

The absence of these organelles maximizes the space available for hemoglobin, the protein responsible for oxygen transport. The lack of mitochondria means that RBCs rely on anaerobic respiration (glycolysis) for energy, ensuring that they do not consume the oxygen they carry. Their distinctive biconcave shape provides a large surface area for gas exchange.

17. To prevent heart problems, blood of a normal healthy person should hav

To prevent heart problems, blood of a normal healthy person should have

1. low cholesterol level.
2. high HDL level.
3. high VLDL level.
4. high LDL level.

Select the correct answer using the code given below :

1 and 2 only

1, 2 and 4 only

3 and 4 only

1, 2 and 3 only

This question was previously asked in

UPSC NDA-1 – 2016

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The correct answer is A) 1 and 2 only.

Maintaining good cardiovascular health involves managing blood lipid levels.
1. Low cholesterol level: Generally, lower levels of total cholesterol are desirable. More specifically, low levels of LDL (“bad” cholesterol) are important.
2. High HDL level: High-density lipoprotein (HDL) is often called “good” cholesterol because it helps remove other forms of cholesterol from your bloodstream. High levels of HDL are protective against heart problems.
3. High VLDL level: Very low-density lipoprotein (VLDL) contains a high concentration of triglycerides. High levels of VLDL are associated with an increased risk of heart disease. This is undesirable.
4. High LDL level: Low-density lipoprotein (LDL) is often called “bad” cholesterol because it can contribute to the buildup of plaque in arteries. High levels of LDL are a major risk factor for heart disease. This is undesirable.
Therefore, to prevent heart problems, a normal healthy person should aim for low overall cholesterol (specifically low LDL) and high HDL.

Cholesterol and triglycerides are fats (lipids) that are transported in the blood by lipoproteins. HDL, LDL, and VLDL are types of lipoproteins. A lipid profile test measures levels of total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides, which helps assess the risk of cardiovascular disease.

18. ‘Lub-dup’ sound is produced due to action of

‘Lub-dup’ sound is produced due to action of

Large intestine

Lungs

Heart

Oesophagus

This question was previously asked in

UPSC NDA-1 – 2015

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The ‘lub-dup’ sounds are characteristic heart sounds. The ‘lub’ sound occurs during systole when the atrioventricular valves (mitral and tricuspid) close. The ‘dup’ sound occurs during diastole when the semilunar valves (aortic and pulmonary) close. These sounds are produced by the vibrations of the valves, heart walls, and blood flow.

The ‘lub-dup’ sounds are associated with the closure of heart valves during the cardiac cycle.

These sounds can be heard using a stethoscope. Abnormal heart sounds, called murmurs, can indicate underlying issues with valve function or blood flow.

19. Arteries are the blood vessels which:

Arteries are the blood vessels which:

carry oxygenated blood.

carry deoxygenated blood.

have thin, non-elastic walls.

carry the blood away from the heart.

This question was previously asked in

UPSC Geoscientist – 2021

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The correct answer is D because the defining characteristic of an artery is that it carries blood away from the heart, irrespective of whether the blood is oxygenated or deoxygenated.

Arteries are blood vessels that transport blood from the heart to other parts of the body. Veins carry blood towards the heart. Capillaries are tiny vessels connecting arteries and veins where exchange of substances occurs.

While most arteries carry oxygenated blood (e.g., the aorta and its branches), the pulmonary artery is an exception as it carries deoxygenated blood from the right ventricle of the heart to the lungs. Arteries generally have thick, elastic, and muscular walls to withstand the high pressure of blood pumped from the heart.

20. pH of blood is:

pH of blood is:

7.0

6.8

7.4

6.4

This question was previously asked in

UPSC Geoscientist – 2021

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The pH of human blood is maintained within a narrow range, typically 7.35 to 7.45, which is slightly alkaline. Option C, 7.4, falls within this normal range and is often cited as the average blood pH.

Normal blood pH is slightly alkaline, maintained tightly between 7.35 and 7.45.

Maintaining blood pH within this narrow range is crucial for various physiological processes, such as enzyme activity and oxygen transport. Deviations from this range can lead to serious health problems (acidosis below 7.35 or alkalosis above 7.45).