Question

a) Draw a labelled diagram of a sectional view of the human heart.
b) Describe double circulation in human beings. Why is it necessary?
c) What would be the consequence of deficiency of haemoglobin in our body?

Answer 1

Hint: Human heart is a four chambered heart it pumps blood throughout the body, it supplies oxygen to the tissues and removes carbon dioxide from the body. The blood circulation system present in human beings is double circulation that has two paths: pulmonary circulation and systemic circulation. In double circulation blood enters the heart twice in a single cycle.

Complete answer:
a) Labelled diagram of a sectional view of the human heart.

b) Humans have a heart that is four chambered heart and the type of blood circulation that is carried out in this is known as double circulation. In this blood is pumped by the right ventricle that enters into the pulmonary artery, whereas the left ventricle pumps blood into the aorta. The deoxygenated blood is oxygenated in the lungs, the deoxygenated blood is pumped into the pulmonary artery from where it gets transferred to the lungs after getting oxygenated in the lungs pulmonary veins carries the oxygenated blood into left atrium. This pathway is pulmonary circulation. Now, we need to provide oxygenated blood to all the body tissues and organs. The blood that is oxygenated enters the aorta and is further transferred to various tissues by a network of arteries, arterioles and capillaries, from the body tissues deoxygenated blood is collected by veins, venules and vena cava and is transferred to right atrium. This is called systemic circulation and from the right atrium it goes to the lung to get oxygenated by pulmonary artery again.
Pulmonary circulation and systemic circulation together forms the double circulation. In this process blood enters the heart two times in a single cycle and doesn’t even get mixed that means oxygenated and deoxygenated blood doesn’t get mixed and hence circulation is maintained properly and so is the body functions, because of this double circulation is necessary in the human beings.

c) Haemoglobin is found in the red blood cells of humans. It is basically a respiratory pigment and this pigment is responsible for the transportation of oxygen to all the cells of the body. In case of deficient haemoglobin levels in the blood it will affect the capacity of oxygen supply to the body cells this will result in deficiency of oxygen in body cells that can cause anaemia at severe level and thus is harmful for our body.

Note:
The four main functions of human heart are as follows;
> To provide nutrients, gases and waste products around in the body.
> To maintain proper body temperature
> It maintains fluid balance in the body.
> Protects body from infection and blood loss.