F4 Bio 2nd Term Test 3 Ch8

F4 Biology Test 3:

Transport in humans

A.     Multiple Choice (10marks)

Q.	1	2	3	4	5	6	7	8	9	10
Answer	B	D	A	B	A	B	A	D	C	C
Wrong no.

B     Conventional questions

1      a      X: tricuspid valve                                                                                                            1

Y: semilunar valve                                                                                                           1

Z: bicuspid valve                                                                                                             1

        b      There will be a backflow of blood into the left atrium when the left ventricle contracts.         1

                The heart will become less efficient in pumping blood to different parts of the body

(except the lungs).                                                                                                           1

2      a      To provide a large surface area for the exchange of materials between the blood and body cells.

                                                                                                                                                        1

        b      The arteriole end of the capillary bed is closer to the heart.                                                     1

                The blood pressure is higher due to the pumping action of the heart.                                      1

                The blood pressure decreases along the length of the capillary as the distance from the heart

increases                                                                                                                          1

and blood flow encounters high resistance of the capillary wall.                                             1

        c      At the arteriole end of the capillary bed, blood pressure in the capillaries is higher than the

pressure of the fluid surrounding the body cells.                                                                     1

Some components of plasma (e.g. water, minerals, sugars, lipids and hormones) are forced out

of the capillaries to form fluid F (tissue fluid).                                                                        1

d      Fluid F provides a relatively constant environment for the normal functions of the body cells.

                                                                                                                                        1

Fluid F serves as a link for the exchange of materials between the blood and body cells.

                                                                                                                                        1

e      Contraction of the skeletal muscles surrounding vessel M drives fluid F forwards.                 1

Valves in vessel M prevent the backflow of fluid F.                                                                1

3      a      P                                                                                                                                      1

                The blood at N receives a greater force from the pumping action of the left ventricle             1                     and thus the blood pressure is higher.                                                                                      1

        b      Valves (1) and (3) are open.                                                                                             1

                Valves (2) and (4) are closed.                                                                                          1