Write the differences between: (a) Blood and Lymph (b) Open and Closed system of circulation (c) Systole and Diastole (d) P-wave and T-wave | NCERT solution | Class 11 Biology | Unit-18 Body Fluids and Circulation



Q.7:- Write the differences between:
(a) Blood and Lymph
(b) Open and Closed system of circulation
(c) Systole and Diastole
(d) P-wave and T-wave

 

Answer:- 

(a) Blood and Lymph

Lymph
Blood
It is a colourless fluid. It is red-coloured fluid.
It contains plasma and lesser number of WBCs and platelets. It contains plasma, RBCs, WBCs, and platelets.
It transports nutrients from the tissue cells to the blood, through lymphatic vessels. It transports nutrients and oxygen from one organ to another.
It helps in body defence and is a part of the immune system. It helps in the circulation of oxygen and carbon dioxide.

 

 

(b) Open and Closed system of circulation

Open system of circulation Closed system of circulation
In this system, blood is pumped by the heart, through large vessels, into body cavities called sinuses. In this system, blood is pumped by the heart, through a closed network of vessels.
The body tissues are in direct contact with blood.
The body tissues are in indirect contact with blood.
Blood flows at low pressure. Blood flows at high pressure.
Blood flow cannot be regulated.
Blood flow can be regulated
This is present in arthropods and molluscs. This is present in annelids, echinoderms, and vertebrates.

OR



The organs are directly bathed in blood in case of open circulatory system. In case of closed circulatory system, the blood is channelized through closed vessels.

(c) Systole and Diastole

Systole
Diastole
It is the contraction of the heart chambers to drive blood into the aorta and the pulmonary artery. It is the relaxation of the heart chambers between two contractions.
Systole decreases the volume of the heart chambers and forces the blood out of them. Diastole brings the heart chambers back into their original sizes to receive more blood

OR

Contraction of heart muscles is called systole, while dilatation is called diastole.

(d) P-wave and T-wave

Systole
Diastole
In an electrocardiogram (ECG), the P-wave indicates the activation of the Sino-atrial node. In an electrocardiogram (ECG), the T-wave represents ventricular relaxation.
During this phase, the impulse of contraction is generated by the SA node, causing atrial depolarisation. During this phase, the ventricles relax and return to their normal state.
It is of atrial origin. It is of ventricular origin.

OR

P-wave marks the depolarization of atria, while T-wave marks the return of ventricles to repolarised state.