Q9 of 95 Page 94

Study the following diagram carefully and then answer the questions that follow:

(a) Name the cell labelled 1.


(b) Identify the phenomenon occurring in A.


(c) Mention two structural differences between 1 and 2.


(d) Name the process occurring in B and C and state the importance of this process in the human body.

(a) The cell labelled 1 is Red blood cells (as it is circular, disc-like and biconcave).


(b) The phenomenon occurring in A is diapedesis as the white blood cells are shown squeezing out through the walls of capillaries.


(c) Two structural difference between 1 (RBC) & 2 (WBC) are :




















White Blood Cells



Red Blood Cells



a) White blood cells have a nucleus.



a) Red blood cells do not contain nucleus.



b) White blood cells do not contain haemoglobin.



b) Red blood cells contain haemoglobin.



c) White blood cells are irregular in shape with lots of extensions.



c) Red blood cells are circular and biconcave in shape.



(d) The process occurring in B & C is phagocytosis. During this process White blood cells, neutrophils engulf particle-like solid substances especially bacteria. This is a defensive mechanism against disease germs.



More from this chapter

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5

The following simplified diagram refers to the outline plan of the circulation of blood in a mammal. Study the diagram and write the number and the name of the blood vessel in each case as mentioned ahead.


(a) Several hours after a meal containing a lot of protein, which vessel will contain the highest concentration of urea?


(b) Which vessel would contain the highest concentration of amino acids and glucose soon after a meal?,

 6

The figures given below show diagrammatic cross sections of three kinds of blood vessels.


(a) Identify the blood vessels A, B and C.


(b) Name the parts labelled 1-4.


(c) Mention two structural differences between A and B.


(d) Name the kinds of blood that flow through A and through B respectively


(e) In which one of the above vessels referred to in (a) above does the exchange of gases actually take place?

 7

The diagram given alongside represents the human heart in one phase of its activity. Study the same and then answer the questions that follow:


(a) Name the phase.


(b) Which part of the heart is contracting in this phase? Give a reason to support your answer.


(c) Name the parts numbered 1 to 6.


(d) What type of blood flows through the parts marked ‘1’ and ‘2’ respectively?


(e) How many valves are closed in this phase?

 8

Given below is a diagrammatic representation of certain types of blood vessels in human body.


(a) Identify the types of blood vessels numbered 1 to 5.


(b) Where can such an arrangement be found as an example -in lungs or in heart walls?