Common misconceptions
5 min read

Body Fluids And Circulation

- Clear the fog of misconceptions and get a clarity of concepts.
1
Pressure in blood capillaries must be greater than the pressure in arteries or veins. We know that the cross-section area of a pipe is inversely proportional to the pressure of the fluid flowing through it. Fluid flowing through a broad pipe will be at lower pressure and the fluid passing through a narrow pipe would be at a very high pressure. If we apply the same principle to the blood vessels of the circulatory system, then the pressure of blood inside the capillaries should be greater than the blood pressure inside the arteries. But, it is not so. This is because the number of capillaries is very high as compared to the arteries and thus the total area of capillaries is way more than the area of an artery. So, the pressure of blood in capillaries gets distributed and is thus very less as compared.
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The blood pressure is high in:
A
Arteries
B
Vein
C
Capillaries
D
Veins portal system
Which of the following statement is incorrect?
A
Walls of the arteries are elastic enabling them to stretch and contract with changes in blood pressure.
B
Blood pressure in the veins is normally too low for blood to return to the heart without the action of skeletal muscles.
C
Because of their small size, the blood in capillaries moves more quickly than in other parts of the circulatory system.
D
Veins are typically larger in diameter than the arteries.
2
Is deoxygenated blood blue in colour? Human blood is red. It gets its colour due to haemoglobin, a metallo-protein compound containing iron in the form of heme, to which oxygen binds. There exists a popular misconception that deoxygenated blood is blue and that blood only becomes red when it comes in contact with oxygen. In humans, blood is never blue; veins appear blue because blue light is scattered more than the red light through the skin. Moreover, the blood inside the veins is dark red and exhibits poor light reflection. The blood flowing in arteries is bright red. From a physiological perspective, veins and arteries appear similar when skin is removed and are seen directly. Watch the given video to clarify this popular myth.
Your blood is red, so why are your veins blue?
2 mins
Generally, the blood flowing in the vein is:
A
Red and Deoxygenated
B
Blue and Oxygenated
C
Blue and Deoxygenated
D
Red and Oxygenated
3
Arteries carry oxygenated blood and all veins carry deoxygenated blood We always hear that arteries are the blood vessels that carry oxygenated blood and veins are the one's which carry deoxygenated blood. But the truth is that there are exceptions to this perception of arteries and veins. For example, pulmonary artery, carries deoxygenated blood from the right ventricle to the lungs and pulmonary veins carry oxygenated blood from the lungs to the left atrium. So, a general definition for arteries and veins can be that arteries are the blood vessels which transport blood away from the heart and veins are the blood vessels which transport blood towards the heart.
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Oxygenated blood flows in:
A
Pulmonary arteries
B
Right ventricle
C
Right atrium
D
Pulmonary veins
4
Atrium and Auricle - Are They Same? We always use atrium and auricle interchangeably, but it's a misconception. Atrium is the upper chamber of the heart and auricle (means "ear" in Latin) is the conical muscular appendage of the atrium. It is an appendage which serves by increasing blood holding capacity and blood pumping capacity.
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5
Atherosclerosis vs Arteriosclerosis There are two conditions of the cardiovascular system that are very confusing - Arteriosclerosis and Atherosclerosis. Arteriosclerosis is the thickening, hardening, and loss of elasticity of the walls of arteries. This can be due to age factor. Atherosclerosis is a disorder in which plaque builds up inside your arteries. Plaque is made up of fat, cholesterol, calcium, and other substances found in the blood. With time, the plaque hardens and narrows the arteries. This limits the flow of oxygen-rich blood to the organs. Check out this image to break this misconception.
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The thickening of walls of arteries is called:
A
Aneurysm
B
Arteriosclerosis
C
Arthritis
D
Both A and B
Thickening of arteries due to cholesterol deposition is known as: 
A
Arteriosclerosis
B
Rheumatic heart disease
C
Blood pressure
D
Cardiac arrest