Tag: cardiac cycle

Questions Related to 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?

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

  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

Show answer
Correct Option: B
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'.

Time interval between DUP and LUBB is ______ coincide with _____

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

  1. $0.3$ sec, ventricular systole

  2. $0.5$ sec, joint diastole and atrial systole

  3. $0.4$ sec, joint diastole

  4. $0.1$ sec, atrial systole

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Correct Option: A

A moderate increase in the concentration of which of the following ions speeds up the heart rate and strengthens the heart beat?

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

  1. Na$^+$ ions

  2. Ca$^{2+}$ ions

  3. $K^+$ ions

  4. All of these

Show answer
Correct Option: A

State whether the following statement is true or false. If false rewrite the correct form of the statement by changing the last word.
The sound produced when the atrioventricular valves close in the heart is called dub.

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

  1. True

  2. False

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Correct Option: A

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

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

  1. Increases

  2. Decreases

  3. Normal

  4. Stopped

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Correct Option: A

The volume of blood pumped by heart in one minute is called?

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

  1. Heart rate

  2. Systole

  3. Cardiac output

  4. Diastoles

Show answer
Correct Option: C
Explanation:

Cardiac output is the blood volume pumped in a minute by the core. It is equivalent to the rate of heart multiplied by the quantity of the stroke. So if there are 70 beats per minute and with each heart beat 70 ml of blood is drawn, the power production is 4900 ml / minute. This value is typical of an average resting adult, although during intense practice, cardiac production can achieve up to 30 liters / minute.

The first heart sound is semilunar valves

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

  1. Closure of the tricuspid and Biscuspid valves

  2. Closure of the tricuspid and biuspid valves

  3. Opening of the semilunar valves

  4. Opening of the eustachian valve

Show answer
Correct Option: A
Explanation:

The first heart sound which we hear is produced by the simultaneous closure of both the atrioventricular valves namely, the bicuspid (mitral) valve and the tricuspid valve.

It resembles the word "LUBB" and is produced due to the isometric contraction period and the earlier part of ejection period.

The volume of blood pumped by heart in one minute is called?

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

  1. Heart rate

  2. Systole

  3. Cardiac output

  4. Diastols

Show answer
Correct Option: A
Explanation:

Cardiac output is the blood volume pumped in a minute by the core. It is equivalent to the rate of heart multiplied by the quantity of the stroke. So if there are 70 beats per minute and with each heart beat 70 ml of blood is drawn, the power production is 4900 ml / minute. This value is typical of an average resting adult, although during intense practice, cardiac output can reach  upto 30 liters / minute.

So, the correct answer is 'Heart rate'

The heart rate is increased by

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

  1. An increase in the activity of the sympathetic nerves that supply the heart

  2. A decrease in the activity of the parasympathetic (vagus) system

  3. An increase in the level of adrenalin in the circulation

  4. All of the above

Show answer
Correct Option: D
Explanation:

A special neural centre in the medulla oblangata can moderate the cardiac function through autonomic nervous system (ANS). Neural signals through the sympathetic nerves (part of ANS) can increase the rate of heart beat, the strength of ventricular contraction and thereby the cardiac output. On the other hand, parasympathetic neural signals (another component of ANS) decrease the rate of heart beat, speed of conduction of action potential and thereby the cardiac output. Adrenal medullary hormones (adrenaline, noradrenaline) can also increase the cardiac output.

Heart rate is accelerated by

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

  1. Cranial nerves and acetylcholine

  2. Sympathetic nerves and acetycholine

  3. Cranial nerves and adrenalin

  4. Sympathetic nerves and epinephrine

Show answer
Correct Option: D
Explanation:

Normal activities of the heart are regulated intrinsically, i.e., auto regulated by specialised muscles (nodal tissue), hence, the heart is called myogenic. A special neural centre in the medulla oblangata can moderate the cardiac function through autonomic nervous system (ANS). Neural signals through the sympathetic nerves (part of ANS) can increase the rate of heart beat, the strength of ventricular contraction and thereby the cardiac output. On the other hand, parasympathetic neural signals (another component of ANS) decrease the rate of heart beat, speed of conduction of action potential and thereby the cardiac output. Adrenal medullary hormones can also increase the cardiac output. Epinephrine / adrenaline increases the heart rate.