Tag: cardiac cycle

Questions Related to cardiac cycle

Pulmonary artery originates from the:

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

  1. right ventricle

  2. left ventricle

  3. right auricle

  4. left auricle

Show answer
Correct Option: A
Explanation:

Pulmonary artery and the Pulmonary vein are a set of blood vessels that are related to the lungs. The Pulmonary artery carries deoxygenated blood from the right ventricle to the lungs for oxygenation, this oxygenated blood is carried back to the heart by the Pulmonary vein for systemic circulation i.e. for ​circulation to different parts of the body.

So, the correct option is 'Right Ventricle'.

Choose the correct answer from the alternatives given.
The typical lub-dub sounds heard in the heart beat of a healthy person are due to:

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

  1. closing of the semilunar valves

  2. closing of the tricuspid and bicuspid valves

  3. closing of the tricuspid and bicuspid valves followed by the closing of the semilunar valves

  4. blood flow through the aorta

Show answer
Correct Option: C
Explanation:

Heart sounds are noises generated by the closing and opening of the heart valves. In a healthy individual, there are two normal heart sounds called lub and dub. Lub is the first heart sound. It is associated with the closure of the tricuspid and bicuspid valves at the beginning of systole. The second heart sound dub is associated with the closure of the semilunar valves at the beginning of diastole.

So, the correct option is 'closing of the tricuspid and bicuspid valves followed by the closing of the semilunar valves'.

Go through the statements
Statement (I): The AV node and the bundle of His constitute the only electrical link between the atria and the ventricles.
Statement (II): The Bundle of His is a bundle of electrical nodes which allow the ventricles to contract.
Statement (III): The bundle of His is a group of fibres that carry electrical impulses through the centre of the heart
Statement (IV) : The bundle of His is located in the proximal intraventricular septum
How many of the above statements are correct? 

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

  1. One

  2. Two

  3. Four

  4. Three

Show answer
Correct Option: A
Explanation:
  • The AV node is located at the inferior end of the inter-atrial septum and the Bundle of His help in transmission of electrical impulses from the AV node to the ventricles. So, they constitute the electrical link between the atria and the ventricles.
  • The Purkinje fibres carry the electrical impulses from the left and the right bundle of his (in the ventricles) to the contractile cells of the myocardium and cause contraction of the ventricles.
  • The bundle of his is a bundle of cardiac muscle fibres that carry the electrical impulses from the AV node located at the inferior end of the inter-atrial septum (near the bottom of the right atrium) into the right and the left ventricles. They, therefore, do not carry impulses through the centre and are not located only at the proximal end of the interventricular septum.
So, the correct option is 'One'.

The cardiac impulse is initiated and conducted further upto ventricle. The correct sequence of conduction of impulse is 

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

  1. SA Node, AV node, Purkinje fibre, AV Bundle

  2. SA Node, Purkinje fibre, AV Node, AV Bundle

  3. SA Node, AV node, AV Bundle, Purkinjee fibre

  4. SA Node, Punkinje fibre, AV Bundle, AV Node

Show answer
Correct Option: C
Explanation:
The nerve impulses produced by the SA node travel to the AV node and cause the initiation of the articular depolarization. From here, the impulse travels to the AV bundle and then to the Purkinje fibres.
Thus, the correct answer is 'SA Node, AV node, AV Bundle, Purkinje fibre.'

Read the following statements and choose the correct option.
Statement 1: Atrial receives blood from all parts of the body which subsequently flows to ventricles.
Statement 2: Action potential generated at sino-atrial node passes from atria to ventricles.

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

  1. Action mentioned in Statement 1 is dependent on action mentioned in Statement 2.

  2. Action mentioned in Statement 2 is dependent on action mentioned in Statement 1.

  3. Actions mentioned in Statements 1 and 2 are independent of each other.

  4. Actions mentioned in Statements 1 and 2 are synchronous.

Show answer
Correct Option: D
Explanation:

Atria receive blood from all parts of the body which subsequently flows to the ventricles. Action potential generated at sinoatrial node passes from the atria to the ventricles. Both these events take place at the same time.

Thus, the correct answer is 'Actions mentioned in Statements 1 and 2 are synchronous.'

The atrio-ventricular node is situated

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

  1. Near the bicuspid valve

  2. In between the atrium

  3. At the base of inter-auricular septum

  4. In the interventricular septum

Show answer
Correct Option: C
Explanation:

The heart beat originates at SA node and passes to the AV node which finally conducts it to the bundle of His. The AV node is placed between the atria and the ventricles of the heart, specifically in the posteroinferior region of the interatrial septum near the opening of the coronary sinus, which conducts the normal electrical impulse from the atria to the ventricles.

So, the correct answer is option C.

In which the following has the ability to generate action potentials without any external stimuli? 

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

  1. Sino-atrial node(SAN)

  2. Atrio-ventricular node (AVN)

  3. Purkinje fibers

  4. All of the above

Show answer
Correct Option: A
Explanation:

Sino-atrial node(SAN)  is known as a pacemaker and has the ability to generate action potentials without any external stimuli. 

When the right ventricle of heart of man contracts then blood is pumped into

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

  1. Superior vena cava

  2. Dorsal aorta

  3. Pulmonary artery

  4. Pulmonary vein

Show answer
Correct Option: C
Explanation:

The pulmonary artery is the vessel transporting de-oxygenated blood from the right ventricle to the lungs. Deoxygenated blood from the systemic circulation enters the right atrium from the superior and inferior venae cavae and passes to the right ventricle. From here it is pumped into the pulmonary circulation through the pulmonary artery, to the lungs where it receives oxygen and gives off carbon dioxide. 

So, the correct answer is option C.

Choose correct alternative in the following statements:
The only artery which carries deoxygenated blood is called

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

  1. Hepatic artery

  2. Pulmonary artery

  3. Aorta

  4. Renal artery

Show answer
Correct Option: B
Explanation:

  • The only artery which carries deoxygenated blood is called the pulmonary artery. It carries deoxygenated blood from the right ventricle into the lungs for oxygenation. 
  • Hepatic artery is a short blood vessel that supplies oxygenated blood to the liver.
  • Aorta is the largest artery in the body. It carries oxygenated blood from left ventricle to the other parts of the body.
  • Renal artery carries oxygenated blood to kidneys.
Hence, the correct answer is 'Pulmonary artery'.

What happens when the pacemaker becomes non-functional?

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

  1. Only auricles contract rhythmically

  2. Only ventricles contract rhythmically

  3. Cardiac muscles do not undergo coordinated rhythmic movements

  4. Cardiac muscles contract in coordinated manner rhythmically

  5. Auricles and ventricles contract rhythmically.

Show answer
Correct Option: C
Explanation:

The natural (SA node) or artificial pacemaker has a function to send electrical impulses from atrium for contraction and pumping action into the ventricles. The impulses get transferred in the following route :

SA node(pacemaker) $\rightarrow$ Interatrial cardiac fibre $\rightarrow$ AV node(pacesetter) $\rightarrow$ Bundle of his $\rightarrow$ Bundle branch $\rightarrow$Purkinje fibres.
Thus, the rhythmic contraction of the heart is made by SA node.
So, if the pacemaker becomes non-functional then, cardiac muscles do not undergo coordinated rhythmic movement.