The Hardest Quiz On The Human Heart You'll Ever Attempt

1.

_____ are the anchors of the inter-ventricular valves.
- A.
  
  Leaflets
- B.
  
  Chordae tendineae
- C.
  
  Ventricular muscle fibers
- D.
  
  Atrial muscle fibers
Correct Answer
B. Chordae tendineae

Explanation
Chordae tendineae are the anchors of the inter-ventricular valves. These fibrous cords connect the valves to the papillary muscles in the ventricles of the heart. When the ventricles contract, the papillary muscles also contract, pulling on the chordae tendineae and preventing the valves from inverting into the atria. This helps to ensure that blood flows in the correct direction through the heart.

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2.

Nor-epinephrine is released from _______ nerves, causing heart rate to _______ :
- A.
  
  Sympathetic, reduce
- B.
  
  Para-Sympathetic, increase
- C.
  
  Para-Sympathetic, reduce
- D.
  
  Sympathetic, increase
Correct Answer
D. Sympathetic, increase

Explanation
Nor-epinephrine is a neurotransmitter that is released from sympathetic nerves. The sympathetic nervous system is responsible for the "fight or flight" response, which increases heart rate and prepares the body for action. Therefore, the release of nor-epinephrine from sympathetic nerves would cause an increase in heart rate.

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3.

Which of the following about heart sounds is incorrect :
- A.
  
  The first heart sound is LUP
- B.
  
  The second heart sound is DUB
- C.
  
  The second Heart sound is LUP
- D.
  
  Heart sounds occur due to valve closure
Correct Answer
C. The second Heart sound is LUP

Explanation
The second Heart sound is not LUP. The second heart sound is actually DUB. Heart sounds occur due to valve closure, and the first heart sound is LUP.

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4.

Intra alveolar pressure will be _____ during normal inspiration and _____ during normal expiration :
- A.
  
  +1,-1
- B.
  
  -1, 0
- C.
  
  -1, +1
- D.
  
  0, +1
Correct Answer
C. -1, +1

Explanation
During normal inspiration, the diaphragm contracts and the intercostal muscles expand the ribcage, causing an increase in the volume of the thoracic cavity. This increase in volume leads to a decrease in intra-alveolar pressure, creating a pressure gradient that allows air to flow into the lungs. On the other hand, during normal expiration, the diaphragm and intercostal muscles relax, causing a decrease in the volume of the thoracic cavity. This decrease in volume leads to an increase in intra-alveolar pressure, creating a pressure gradient that allows air to flow out of the lungs. Therefore, the intra-alveolar pressure is -1 (decreased) during normal inspiration and +1 (increased) during normal expiration.

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5.

After forceful expiration and glottis is closed :
- A.
  
  IAP=Positive and IPP = Positive
- B.
  
  IAP=Negative and IPP = Negative
- C.
  
  IAP=0 and IPP = 0
- D.
  
  IAP=0 and IPP = Negative
Correct Answer
A. IAP=Positive and IPP = Positive

Explanation
After forceful expiration, the glottis is closed, which means that the air pressure inside the thoracic cavity increases. This increase in pressure leads to a positive intra-abdominal pressure (IAP) and a positive intra-pulmonary pressure (IPP).

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6.

Plateau in cardiac muscles action potential will occur due to :
- A.
  
  Inward diffusion of Na+
- B.
  
  Inward diffusion of K+
- C.
  
  Inward diffusion of Ca²+
- D.
  
  Inward diffusion of H+
Correct Answer
C. Inward diffusion of Ca²+

Explanation
During the plateau phase of the cardiac muscle action potential, there is a sustained inward diffusion of Ca²+. This influx of calcium ions prolongs the depolarization phase and helps to maintain the plateau, which is important for the contraction of the cardiac muscles. The influx of calcium ions also triggers the release of more calcium ions from the sarcoplasmic reticulum, leading to further contraction of the cardiac muscles. Therefore, the inward diffusion of Ca²+ is responsible for the plateau in the cardiac muscle action potential.

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7.

The pressure in pleural space :
- A.
  
  More than atmospheric pressure
- B.
  
  Positive in valvular pneumothorax
- C.
  
  Equal to atmospheric pressure
- D.
  
  Negative in valvualr pneumothorax
Correct Answer
B. Positive in valvular pneumothorax

Explanation
In valvular pneumothorax, air enters the pleural space but cannot escape, leading to an increase in pressure within the pleural space. This increased pressure causes the lung to collapse further and compresses the mediastinal structures. Therefore, the pressure in the pleural space is positive in valvular pneumothorax.

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8.

Which one of the following parts of the circulation has the highest compliance :
- A.
  
  Veins
- B.
  
  Arteries
- C.
  
  Arterioles
- D.
  
  Capillaries
Correct Answer
A. Veins

Explanation
Veins have the highest compliance in the circulation. Compliance refers to the ability of blood vessels to expand and accommodate changes in blood volume. Veins are highly compliant due to their thin and elastic walls, allowing them to stretch and hold a large volume of blood. This high compliance helps veins to store and return blood to the heart, especially during periods of increased blood flow or when there is a need for blood redistribution in the body. Arteries, arterioles, and capillaries have less compliance compared to veins.

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9.

The second heart sound is associated with which one of the following :
- A.
  
  Opening of the pulmonary and aortic valves
- B.
  
  Closing of the pulmonary and aortic valves
- C.
  
  Closing of the mitral and tricuspid valves
- D.
  
  Opening of the mitral and tricuspid valves
Correct Answer
B. Closing of the pulmonary and aortic valves

Explanation
The second heart sound, also known as S2, is produced by the closing of the semilunar valves - the pulmonary and aortic valves. This sound is heard during the diastolic phase of the cardiac cycle when the ventricles are relaxing and filling with blood. As the ventricles relax, the pressure within them decreases, causing the blood to flow back towards the heart. The backflow of blood fills the semilunar valves, causing them to close and produce the second heart sound.

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10.

If the arterial blood pressure is recorded at 132/84, what is the mean arterial pressure :
- A.
  
  110 mm Hg
- B.
  
  100 mm Hg
- C.
  
  120 mm Hg
- D.
  
  90 mm Hg
Correct Answer
B. 100 mm Hg

Explanation
The mean arterial pressure (MAP) is calculated by taking the average of the systolic and diastolic blood pressures, weighted more towards the diastolic pressure. In this case, the systolic pressure is 132 mm Hg and the diastolic pressure is 84 mm Hg. The formula for calculating MAP is (2 * diastolic pressure + systolic pressure) / 3. Plugging in the values, we get (2 * 84 + 132) / 3 = 100 mm Hg. Therefore, the correct answer is 100 mm Hg.

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11.

Cardiac output is equal to :
- A.
  
  Stroke volume / heart rate
- B.
  
  Stroke volume × heart rate
- C.
  
  Systolic pressure - Diastolic pressure
- D.
  
  Diastolic pressure + (pulse pressure/3)
Correct Answer
B. Stroke volume × heart rate

Explanation
Cardiac output refers to the amount of blood pumped by the heart in one minute. It is calculated by multiplying the stroke volume (the amount of blood pumped by the heart in one contraction) by the heart rate (the number of contractions per minute). Therefore, the correct answer is "stroke volume × heart rate."

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12.

The first heart sound is associated with which one of the following :
- A.
  
  Opening of the pulmonary and aortic valves
- B.
  
  Closing of the pulmonary and aortic valves
- C.
  
  Closing of the mitral and tricuspid valves
- D.
  
  Opening of the mitral and tricuspid valves
Correct Answer
C. Closing of the mitral and tricuspid valves

Explanation
The first heart sound is associated with the closing of the mitral and tricuspid valves. This sound, often referred to as "lub," occurs during the isovolumetric contraction phase of the cardiac cycle when the ventricles are contracting and the atrioventricular valves close to prevent blood from flowing back into the atria. This closure of the valves creates the first heart sound that can be heard using a stethoscope.

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The Hardest Quiz On The Human Heart You'll Ever Attempt

_____ are the anchors of the inter-ventricular valves.

Nor-epinephrine is released from _ nerves, causing heart rate to _ :

Which of the following about heart sounds is incorrect :

Intra alveolar pressure will be _ during normal inspiration and _ during normal expiration :

After forceful expiration and glottis is closed :

Plateau in cardiac muscles action potential will occur due to :

The pressure in pleural space :

Which one of the following parts of the circulation has the highest compliance :

The second heart sound is associated with which one of the following :

If the arterial blood pressure is recorded at 132/84, what is the mean arterial pressure :

Cardiac output is equal to :

The first heart sound is associated with which one of the following :

The Hardest Quiz On The Human Heart You'll Ever Attempt

_____ are the anchors of the inter-ventricular valves.

Nor-epinephrine is released from _______ nerves, causing heart rate to _______ :

Which of the following about heart sounds is incorrect :

Intra alveolar pressure will be _____ during normal inspiration and _____ during normal expiration :

After forceful expiration and glottis is closed :

Plateau in cardiac muscles action potential will occur due to :

The pressure in pleural space :

Which one of the following parts of the circulation has the highest compliance :

The second heart sound is associated with which one of the following :

If the arterial blood pressure is recorded at 132/84, what is the mean arterial pressure :

Cardiac output is equal to :

The first heart sound is associated with which one of the following :

Nor-epinephrine is released from _ nerves, causing heart rate to _ :

Intra alveolar pressure will be _ during normal inspiration and _ during normal expiration :