Question:

What happens when the pacemaker becomes is non-functional?

Updated On: Jul 7, 2022

Only auricles contract rhythmically
Only ventricles contract rhythmically
Cardiac muscles do not undergo co-ordinated rhythmic movements
Auricles and ventricles contract rhythmically

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The Correct Option is C

Solution and Explanation

The $SA$ node possesses a unique property of self excitation, which enables it to act as the pacemaker of heart. It spontaneously generates a wave of contraction which spreads over both the auricles more or less simultaneously along the muscle fibres that fan out from the pacemaker. The pacemaker establishes the basic rhythm at which the heart beats. Thus, if the pacemaker becomes nonfunctional, then the cardiac muscles do not undergo co-ordinated rhythmic movements.

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List I	List II
A	P wave	I	Heart muscles are electrically silent.
B	QRS complex	II	Depolarisation of ventricles.
C	T wave	III	Depolarisation of atria.
D	T-P gap	IV	Repolarisation of ventricles.

Notes on body fluids and circulation

Concepts Used:

Body Fluids and Circulation

Liquid substances in the animal or human body are known as body fluids. The human body consists of about 60-67% body fluids. The chief components of the human body fluids are blood and lymph. Blood comprises a matrix called plasma with blood corpuscles floating in it. The blood cells are white blood cells, red blood cells, and platelets. Lymph consists of lymph cells.

Read More: Body Fluids and Circulation

Types of Body Fluids:

The different types of body fluids:

Blood

The main components of blood involve;

Plasma
Red Blood Cells
White Blood Cells
Platelets

Lymph

A colorless fluid present in the interstitial tissues is lymph. It circulates all over the lymphatic system. It can be described as blood without the RBCs. The exchange of hormones, nutrients, and gases occurs via this fluid. It contains lymphocytes that play a major function in the immune responses of the body.

The movement of blood across the vessels of the body that carries nutrients and gases along with it and removes waste from the different parts of the body is circulation.

Types of Circulatory Systems:

There are two types of circulatory systems:

Open Circulatory system
Closed circulatory system