Coordination and response

Question 1

Electrical impulses travel along

Answer 1

neurones

Question 2

Mammalian nervous system consist of

Answer 2

The central nervous system (CNS) consisting of the brain and the spinal cord
The peripheral nervous system (PNS) consisting of the nerves outside of the
brain and spinal cord.

Question 3

Role of the nervous system is

Answer 3

coordination and regulation of body functions.

Question 4

Reflex arc:

Answer 4

receptors detect stimulus and generate impulse, it travels to sensory
neurone, then relay neurone, then to motor neutron, then to the effector.

Question 5

A reflex action

Answer 5

a means of automatically and rapidly integrating and coordinating
stimuli with the responses of effectors (muscles and glands).

Question 6

synapse

Answer 6

A junction between two neurones

Question 7

Structure of synapse include:

Answer 7

presence of vesicles containing neurotransmitter molecules
Synaptic gap/cleft
receptor protein

Question 8

Events at a synapse:

Answer 8

An impulse stimulates the release of neurotransmitter molecules from vesicles
into the synaptic gap.
The neurotransmitter molecules move from their region of higher concentration to their region of lower concentration down their concentration gradient across the gap
Neurotransmitter molecules bind with receptor proteins on the next neuron
An impulse is then stimulated in the next neuron.

Question 9

Synapses ensure that

Answer 9

impulses travel in one direction only.

Question 10

Sense organs

Answer 10

groups of receptor cells responding to specific stimuli: light,
sound, touch, temperature and chemicals.

Question 11

cornea function

Answer 11

refracts light

Question 12

iris function

Answer 12

controls how much light enters the pupil

Question 13

lens function

Answer 13

focuses light on to the retina

Question 14

retina function

Answer 14

contains light receptors, some sensitive to light of different colours

Question 15

optic nerve function

Answer 15

carries impulses to the brain

Question 16

As light intensity increase,

Answer 16

diameter of pupil decrease so that less light enters the
eye and prevent damage. The antagonistic muscles, circular muscles contract and
radial muscles relax.

Question 17

As light intensity decrease,

Answer 17

diameter of the pupil increase so that more light enters the
eye and prevents damage. The antagonistic muscles, circular muscles relax and
radial muscles contract.

Question 18

Distant object

Answer 18

Ciliary muscles relax, suspensory ligament pulled tight (tension on
suspensory ligament increase). the lens becomes thin/ less convex.

Question 19

Near object:

Answer 19

Ciliary muscles contract, suspensory ligament slackened (tension on
suspensory ligament decrease). the lens becomes thick/ more convex.

Question 20

There are three different kinds of cone cells

Answer 20

red, green and blue

Question 21

Fovea is almost entirely cones,

Answer 21

packed tightly together

Question 22

Rods

Answer 22

are found further out
on the retina and are less tightly packed.
Rod cells are more sensitive at night

Question 23

hormone

Answer 23

a chemical substance, produced by a gland and carried by the blood,
which alters the activity of one or more specific target organs.

Question 24

Adrenal gland secrete

Answer 24

adrenaline.

Question 25

Pancreas secrete

Answer 25

insulin and glucagon

Question 26

Testes secrete

Answer 26

testosterone

Question 27

Ovaries secrete

Answer 27

estrogen

Question 28

Effect of adrenaline:

Answer 28

increased breathing rate increased heart rate increased pupil diameter increase in blood glucose concentration

Question 29

Speed of action of nervous system is faster than

Answer 29

hormonal control system. Duration of effect of hormonal control system is longer than the nervous system

Question 30

Homeostasis

Answer 30

maintenance of a constant internal environment

Question 31

Insulin decreases

Answer 31

blood glucose concentration.

Question 32

In negative feedback:

Answer 32

There is a set point – a normal level that the system tries to maintain. There is a ‘measuring device’ that keeps track of whether the level is within the range of the set point. If the level goes outside the set point, this triggers events to happen that bring the level back into line again.

Question 33

If blood glucose concentration is too high

Answer 33

it is detected by the pancreas, pancreas release insulin, insulin stimulate liver cells to absorb glucose from blood across the partially permeable membrane. Liver cells convert glucose to glycogen and store glycogen in liver cells, this results in reduction of blood glucose concentration until it reaches the set, normal point.

Question 34

If blood glucose concentration is too low

Answer 34

it is detected by the pancreas, pancreas release glucagon, glucagon stimulate liver cells to convert store glycogen into glucose, and release this glucose into the blood. This results in increase of blood glucose concentration until it reaches the set, normal point.

Question 35

Treatment of type 1 diabetes:

Answer 35

-insulin ; -by injection / insulin pump ; - regular blood glucose tests regular meals and controlled diet

Question 36

If the internal temperature is above normal

Answer 36

it is detected by the brain. Vasodilation of arterioles occur, more blood flows to the skin, so more heat is lost form the blood, decreasing the internal temperature. Sweating occurs which gives a cooling effect and decreases the internal body temperature

Question 37

If the internal temperature is below normal

Answer 37

it is detected by the brain. Vasoconstriction of arterioles occur, less blood flows to the skin, so less heat is lost form the blood, increasing the internal temperature. Adipose tissue in skin act as insulation and reduce heat loss. Shivering produce heat and help to keep the body warm.

Question 38

Gravitropism

Answer 38

a response in which parts of a plant grow towards or away from gravity.

Question 39

Phototropism

Answer 39

response in which parts of a plant grow towards or away from the direction of the light source

Question 40

examples of the chemical control of plant growth

Answer 40

Phototropism and gravitropism

Question 41

How auxin work:

Answer 41

auxin is made in the shoot tip auxin diffuses through the plant from the shoot tip auxin is unequally distributed in response to light and gravity auxin stimulates cell elongation