Tag: cardiac cycle

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Questions Related to cardiac cycle

Multiple choice biology transport in animals cardiac cycle heart, blood vessels and cardiac cycle human heart

'Bundle of His' is a network of

  1. Muscle fibres distributed throughout the heart walls

  2. Muscle fibres found only in the ventricle wall

  3. Nerve fibres distributed in ventricles

  4. Nerve fibres found throughout the heart
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

'Bundle of His' is a network of muscle fibres, found in the walls of ventricles. They originate from AV node and further give rise to Purkinje fibres. This helps in maintaining the rhythmic contraction of the ventricles. 

Multiple choice biology transport in animals cardiac cycle heart, blood vessels and cardiac cycle human heart

The pace-setter in the heart is called as

  1. Purkinje fibres

  2. Sino-atrial node (SAN)

  3. Papillary muscle

  4. Atrio-ventricular node (AVN)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The cardiac impulse is initiated in the sino-atrial node also known as natural pacemaker. It then travels to the atrio-ventricular node. From there through the Purkinje fibres to the ventricles. The atrio-ventricular node regulates the rhythm of the heart rate mainly. The delay in conduction of impulse in this node changes the duration of contraction between the atria and the ventricles. Hence AV node is called as the pace-setter.

Multiple choice biology transport in mammals cardiac cycle heart, blood vessels and cardiac cycle human heart

________ caries blood from right ventricles to lungs.

  1. Superior vena cava

  2. Inferior vena cava

  3. Pulmonary arteries

  4. Pulmonary veins
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The pulmonary artery is a blood vessel which delivers impure blood from right ventricles to lungs for the oxygenation. Pulmonary artery begins from the base of the right ventricle. As it leaves the heart it divides into two branches left and right pulmonary artery. The left and right branches bring their de-oxygenated blood to the corresponding left and right lungs.
So, the correct answer is 'Pulmonary arteries'.
Multiple choice biology transport in animals cardiac cycle heart, blood vessels and cardiac cycle human heart

Heart beat is accelerated by

  1. Sympathetic nerves and noradrenaline

  2. Cranial nerves and adrenaline

  3. Cranial nerves and acetylcholine

  4. Sympathetic nerves and acetylcholine
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A normal heart rate is 60 to 80 beats per minute. However, in certain conditions, the heart beat is accelerated. The major system involved in acceleration of heartbeat is sympathetic nervous system. It releases hormones like adrenaline and noradrenaline during stress or excitement. Exercise also stimulates sympathetic nervous system to accelerate the heartbeat. Apart from heartbeat, sympathetic nervous system and noradrenaline constricts blood vessels, goose bumps, sweating, increased blood pressure, dilation of pupil.

Thus, the correct answer is 'Sympathetic nerves and noradrenaline.'

Multiple choice biology transport in animals cardiac cycle heart, blood vessels and cardiac cycle human heart

Bundle of His is

  1. Nervous tissue supplying ventricles

  2. Nervous tissue supplying heart

  3. Muscular tissue supplying atria

  4. Muscular tissue supplying ventricles
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A) Bundle of His is a muscular tissue.

B) Bundle of His is a muscular tissue that carries electrical impulses to the ventricles.
C) Bundle of His supplies to the ventricles.
D) The bundle of His is an important part of the electrical conduction system of the heart, as it transmits impulses from the atrioventricular node, located at the inferior end of the interatrial septum, to the ventricles of the heart. It is a muscular tissue.
So the correct answer is 'Muscular tissue supplying ventricles'.

Multiple choice biology transport in animals cardiac cycle heart, blood vessels and cardiac cycle human heart

Which of the following can't be taken as an example of parasympathetic stimulation:

  1. Increase in the intestinal peristalsis

  2. Increased secretion of gastric juice

  3. Contraction of the detrusor muscles of urinary bladder.

  4. Increase in ventricular force of contraction.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Increase in vertricular force of contraction is not an example of Parasympathetic stimulation because its function is to slow the heart rate of person.
Multiple choice biology transport in animals cardiac cycle heart, blood vessels and cardiac cycle human heart

When does the blood enter in Atria. Choose the correct:-
(a) During generation of impulse from SAN
(b) Atrial relaxation
(c) As the tricuspid and bicuspid valves are open 
(d)Joint diastole

  1. a,b

  2. a, b, c

  3. b, c, d

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

Heart has two ventricles and two atria, left and right respectively. Deoxygenated blood enters the left atrium through superior & inferior vena cava, when the atria relaxes, blood enters into it, whereas impulse from SA node causes contraction of atria which leads to the flow of blood into ventricles.

Thus, the correct answer is 'a,b.'