Tag: heart, blood vessels and cardiac cycle

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Questions Related to heart, blood vessels and cardiac cycle

Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

Which of the following statements is false?

  1. $Mg^{2+}$ ions form a complex with ATP
  2. $Ca^{2+}$ ions are important in blood clotting
  3. $Ca^{2+}$ ions are not important in maintaining the regular beating of the heart
  4. $Mg^{2+}$ ions are important in the green parts of plants.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Calcium is important for heart because the movement of calcium ions help the heart muscles to contract. This occurs because: calmodulin, a protein binds to the sodium channel, helps keep it open. Calcium ions regulate the connection between the protein and the channel by causing the protein to hook up to the channel. This in turn, keeps it open and allows sodium ions to pass through. In the absence of Ca$^2$$^+$ the heart beat will be irregular. 

So the correct answer is ' Ca2+ ions are not important in maintaining the regular beating of the heart'.

Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

The first heart sound is

  1. DUP

  2. LUBB

  3. LUPP

  4. BUD
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The first heart sound 'lubb' is made by the closing of the mitral valve and tricuspid valve (atrioventricular valves). The second heart sound is 'dub' and is caused by the closure of the aortic valve and the pulmonary valve. 

So, the correct option is 'LUBB'.

Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

In human beings heart beat is initiated by

  1. Purkinje fibres

  2. AV node

  3. SA node

  4. Bundles
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sinoatrial node is a cluster of cells present in the right atria just below the opening of  Vena cava. It autonomously generates electrical impulses that initiate the muscle contraction in the atria.

It is called the natural pacemaker of the heart.
So, the correct answer is 'SA node'.

Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

First heart sound is called?

  1. Lubb

  2. Dub

  3. Murmur

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • The heart produces a characteristic sound at the beginning g of ventricular systole or contraction. 
  • These sounds are a result of the closure of the atrioventricular valves, the mitral valve and the tricuspid valve. 
  • The sounds produced are “lubb-dub”, lubb being the first of the two. 
  • So, the correct answer is 'Lubb'.

Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

An artifical pacemaker is implanted sub-cutaneously and connected to heart in patients.

  1. having high B.P

  2. having irregularity in heartbeat

  3. having blockage in heart

  4. suffering from arteriosclerosis.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A pacemaker insertion is the implantation of a small electronic device that is usually placed in the chest (just below the collarbone) to help regulate slow electrical problems with the heart. A pacemaker may be recommended to ensure that the heartbeat does not slow to a dangerously low rate.


So, the Correct option is B.

Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

Human heart is myogenic and it is supplied with sympathetic and vagus nerve branches that are acceleratory  and inhibitory in nature respectively.Which one of the following statement is incorrect w.r.t the heart beat?

  1. In foetal heart the heart rate is $140-130$ beats per minutes

  2. Mental status such as depression and grief decrease heart rate
  3. An excess of $Ca^{++}$ ion decreases heart beat rate
  4. High levels of $Na^+$ and $K^+$ decreases the strength of contraction
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Heartbeat rate is the number of the beating of the heart per minute.

  • It is found that in normal humans, the rate of heartbeat is about 70 - 72 times per minute but in feotus or babies it is found much higher about 140 - 130 times per minute or may even up to 160 per minute. 
  • At the time of mental disorders like depression, grief or sadness body releases stress hormone, these stress hormone tightens the blood vessels, thus increases the heart rate.
  • Calcium ions play a major role in cardiac activity as well in muscle contraction when they are present in high amount then causes a lower heartbeat.
  • Sodium-potassium pumps are the ion channels or proton pumps that regulate the activity of contraction in the heart muscles. Excess of these ions dilates the blood vessels, thus lowers the heart rate and strength of the contraction of the heart muscles.
So, the correct option is 'Mental status such as depression and grief decrease heart rate'.

Multiple choice biology transportation in plants and circulation in animals heart beat cardiac cycle heart, blood vessels and cardiac cycle

What happen on heart beating if the parasym-pathetic nerve going towards heart is cut down?

  1. Increases

  2. Decreases

  3. Normal

  4. Stopped
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The parasympathetic nervous system (via the vagus nerve) acts to slow down the heart rate. If this nerve is cut, the inhibitory effect is removed, leading to an increase in heart rate.