Interactive Questions 06

7/31/2019 Interactive Questions 06

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Human Physiology

INTERACTIVE

MULTIPLE-CHOICEQUESTIONS

The answers are provided.

Explanations of why the alternatives

are unsatisfactory are also offered

D.G. Mackean


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These multiple choice questions are similar to the ones set

by the GCSE and IGCSE Examination Boards except that,in some cases, there may be more than one acceptable

answer.

For this reason, even if you select a correct answer at yourfirst attempt, it is worth looking at all the alternatives

(a) to see if there is a better answer and

(b) to see why some of the alternatives areunacceptable

Question 1


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Question 1

Iron is an important component of a balanced

diet because it is needed mainly by

(a) the blood

(b) the bones

(c) the brain

(d) the nerves

Question 2


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Yes

Iron is an important component ofhaemoglobin,

the red pigment which combines with oxygen in

the red blood cells


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No

Iron is not specifically needed by the bones


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No

Iron is not specifically needed by the nerves


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No

Iron is not specifically needed by the brain


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Question 2

Shortage of vitamin D in the diet of children can

lead to

(a) poor night vision

(b) anaemia

(c) deformed bones

(d) bleeding gums

Question 3


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No

It is shortage ofvitamin A (retinol) which is a cause

of poor night vision, as well as reduced resistance

to disease


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No

A shortage ofiron can be one cause of anaemia


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Yes

A shortage of vitamin D (calciferol) causes defective

incorporation of calcium into the bones, which therefore

remain soft and are easily deformed. This condition isknown as rickets


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No

A shortage ofvitamin C(calciferol) can be one cause

of bleeding gums


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Question 3

The final digestion products of proteins are

(a) sugars

(b) glycerols

(c) fatty acids

(d) amino acids

Question 4


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No

Sugars (e.g. glucose and fructose) are the final digestion

products ofcarbohydrates, such as starch


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No

Glycerol is one of the products offat digestion


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No

Fatty acids are one of the products of digestion offats


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Yes

The final digestion products ofproteins are amino acids


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Question 4

In the small intestine, the villi

(a) speed up digestion

(d) secrete digestive enzymes

(c) increase the absorptive surface

(b) propel food through the intestine

Question 5


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No

The villi speed up absorption


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Food is propelled through the alimentary canal by a

muscular process calledperistalsis

No


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Yes

The numerous, finger-like processes called villi, greatly

increase the absorptive surface of the small intestine

Section of small

intestine opened

to show villi


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No

The villi contain enzymes but they do not secrete them

into the intestine


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Question 5

When the ventricles contract, blood is forced into

(d) the pulmonary artery

(a) the aorta

(b) the vena cava

(c) the pulmonary artery and the aorta

Question 6


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Yes but

Contraction of the left ventricle forces blood into the aorta,

but the right ventricle is contracting at the same time


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No

The vena cava brings blood to the right ventricle


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Yes

Contraction of the left ventricle forces blood into the

aorta. Contraction of the right ventricle forces blood

into the pulmonary artery


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Yes but

Contraction of the right ventricle forces blood into the

pulmonary artery but remember that the left ventricle is

also contracting.


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Question 6

In the lungs, gaseous exchange takes place in

(a) the alveoli

(b) the bronchioles

(c) the bronchi

(d) the trachea

Question 7


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Yes The alveoli are tiny air pockets at the endsof the bronchioles. Oxygen from the air

diffuses into the blood capillaries in theirwalls and carbon dioxide diffuses out

bronchi

trachea

lung

bronchiole

alveoli


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No

The bronchioles are the fine tubes which carry air to the

alveoli but significant gaseous exchange does not take

place here


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No

The bronchi are the wide tubes which branch repeatedly

to form the bronchioles. No significant gaseous

exchange takes place here.


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No

The trachea is the wide tube leading from the

back of the mouth and dividing into bronchi. No

significant gaseous exchange takes place here


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Question 7

Which of the following are excretory organs?

(a) The lungs

(b) The skin

(c) The kidneys

(d) The large intestine

Question 8


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Yes

The lungs excrete carbon dioxide which is a waste

product of cellular respiration.

They also expel water vapour some of which could be a

waste product of respiration, but this is incidental totheir main function and an inevitable consequence of the

moist lining of the alveoli


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No

Sweat, from the sweat glands in the skin, contains salt

(sodium chloride) but this is incidental to the main function

of sweat production (cooling the body). The sweat glands do

not produce sweat in response to an increase in sodiumchloride in the blood and are not, therefore, organs of

excretion.

In fact, loss of salt which results from prolonged sweating

can be harmful.


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Yes

The kidneys excrete, urea, uric acid, excess salts and the

breakdown products of hormones or drugs. These

substances are all waste products of the bodys

metabolism.

The kidneys also excrete excess water, some of which has

been produced in the process of respiration.


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No

The contents of the large intestine are largely made up of

undigested vegetable matter (fibre), bacteria and water.

These have not been incorporated into the body or

taken part in chemical changes in the body so they arenot excretory products.

The process of expelling faeces is egestion, not excretion

The break down products of bile pigments, which colourthe faeces, are excretory products but are excreted by the

liver


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Question 8

The graphs represent the relative

concentrations of 3 female

hormones in the blood over a 28day period. In which period is

fertilisation (conception) most

likely to occur?

Days

oestrogen

follicle-stimulating

hormone progesterone

(d) Days 20 - 24

(c) Days 13-16

(b) Days 10 -12

(a) Days 1 - 5

Question 9


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No

This is the period when menstruation is taking place


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Although the concentration of oestrogen is high, there

is unlikely to be an ovum present in the oviduct at this

stage

No


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Yes

Follicle-stimulating hormone is one of the hormones that

triggers the release of an ovum from the ovary (ovulation).

Assuming the ovum can survive for a day, and sperms can

survive for 2 days this is thefertile periodwhen conceptionis most likely


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No

The ovum is unlikely to survive into this period. The

increase in progesterone causes the lining of the uterus

to thicken in preparation for the ovum, if it has been

fertilised


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Question 9

Which of the following are the likely effects of release ofadrenaline from the adrenal gland into the bloodstream?

(d) The heart rate increases

(c) The skeletal muscles relax

(a) The rate and depth of breathing increases

(b) The liver converts glucose in the blood to glycogen

Question 10


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Yes

Adrenaline is the fight or flight hormone and prepares

the body for action. An increase in the rate and depth of

breathing gets more oxygen into the blood. This means

that more prolonged activity can occur.


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No

Adrenaline causes the liver to convert its glycogen store to

glucose which is released into the bloodstream where it

becomes available for rapid muscular contraction.


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No

Adrenaline causes the muscles to tense up in preparation

for flight or fight


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Yes

An increased heart rate helps to supply extra oxygen

and glucose to the muscles for their heightened

activity during flight or fight


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Question 10

Which of the following are reflex actions?

(d) You blink when a particle of sand blows

into your eye

(c) You walk without thinking about it

(b) You automatically move the handlebars of your

bicycle to steer or to keep your balance

(a) You jump in response to a sudden and

unexpected loud noise

Question 11


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Yes

You have no control over whether you jump or not.

This is a reflex action


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Although this happens without your having to think about it,

it is a learned reaction and not a reflex. An acquired skill is

not a reflex

No


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Although this happens without your having to think about it,

it is a learned reaction and not a reflex. An acquired skill is

not a reflex

No


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You have no control over whether you blink or not

Yes


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Question 11

A

B

C

D

The drawing represents the

skeleton and muscles of the leg.When the leg straightens to thrust

the body forwards, which of the

following is the correct sequence?

(a)A contracts, B relaxes,

C relaxes, D contracts

(b) B contracts,A relaxes,

D contracts, C relaxes

(c)A contracts, B relaxes,

C contracts, D relaxes

(d)A contracts, B contracts,

C relaxes, D relaxes

Question 12


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IfD contracts, itflexes the foot at the ankle. The foot

must be extendedif it is to push the body forwards

No


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IfB contracts, it will flex (bend) the leg at the

knee. This will not help to push the body forward

IfD contracts, itflexes the foot at the ankle. The foot

must be extendedif it is to push the body forwards

No


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A

A contracts and extends

(straightens) the leg at

the knee

C contracts and

extends (straightens)

the foot at the ankle

These two movements

make the leg push

against the groundand thrust the body

upwards and forwardsB and D must be relaxed to allow

their antagonistic muscles to

contract

B

C

D

contracts

relaxes

contracts

relaxes

Yes


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IfC and D both relax, there will be nothing to

support the ankle and you will fall flat on your face

No

A and B are antagonistic muscles. If they both tryto contract there will be no movement. However,

the tension in both must be retained in order to

hold the body upright in a standing position


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Question 12

Which of the following is the best definition of

homeostasis in mammals?

(d) Maintaining a constant body mass

(a) Keeping the body temperature constant

(b) Maintaining a constant internal environment

(c) Getting rid of the waste products of metabolism

as fast as they accumulate


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No

Keeping the body temperature within limits is only one aspect

of homeostasis


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Yes

This is the best definition (provided you know what it means)

The internal environment refers mainly to the blood, lymph

and tissue fluid. Homeostasis involves all the processes which

keep the temperature and composition of these fluids within

narrow limitsThe lungs control the levels of oxygen and carbon dioxide. The

kidneys eliminate excretory products and maintain the

concentration.

The skin helps to regulate the temperatureThe liver controls the concentration of glucose

And the brain, nervous system and endocrine system

control them all


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No

This is just one aspect of homeostasis. The kidneys get rid

of the waste products of metabolism as fast as they

accumulate and control the amount of water retained in the

body


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No

Even in a mature animal, the body mass will fluctuate with

the seasons, the activity and the availability of food.

With an immature animal the body mass will increase


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