14 Coordination and response

Question 1

what travels along neurons?

Answer 1

electrical impulses

Question 2

What does the CNS consist of?

Answer 2

the brain and spinal cord

Question 3

What does the PNS consist of?

Answer 3

nerves outside of the brain and spinal cord
/
nerve cells that carry information to or from the CNS

Question 4

role of the nervous system

Answer 4

coordination and regulation of body functions

Question 5

reflex action

Answer 5

automatically and rapidly integrating and coordinating stimuli with the responses of effectors

Question 6

reflex arc order

Answer 6

stimulus –> receptor –> sensory neurone –> motor neurone –> effector –> response

Question 7

synapse

Answer 7

a junction between two neurones

Question 8

events at a synapse

Answer 8

1. an impulse stimulates the release of neurotransmitter molecules from vesicles into the synaptic gap
2. the neurotransmitter molecules diffuse across the gap
3. neurotransmitter molecules bind with receptor proteins on the next neurone
4. an impulse is then stimulated in the next neurone

Question 9

how many directions do impulses travel in?

Answer 9

One direction, the synapses ensure that the impulses travel in one direction

Question 10

describe the structure of a synapse

Answer 10

prescence of vesicles containing NT molecules, the synaptic gap and receptor proteins

Question 11

sense organs

Answer 11

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

Question 12

cornea

Answer 12

Clear area of the sclera, it refracts light

Question 13

iris

Answer 13

Muscles which alter the size of the pupil, controlling the amount of light entering the eye

Question 14

lens

Answer 14

focuses light on to the retina

Question 15

retina

Answer 15

contains light receptors, some sensitive to light of different colours

Question 16

optic nerve

Answer 16

Carries impulses between the retina and the brain

Question 17

pupil

Answer 17

Small hole at the centre of the iris through which light enters the eye

Question 18

fovea/yellow spot

Answer 18

a part of the retina that is directly opposite to the pupil and contains only cone cells.
- responsible for good visual acuity (good resolution)

Question 19

blind spot

Answer 19

where the optic nerve leaves the retina so it lacks receptor cells

Question 20

pupil reflex in dim light

Answer 20

radial muscles of the iris contract
circular muscles of the iris relax
pupil is dilated (more light can enter the eye)

Question 21

pupil reflex in bright light

Answer 21

radial muscles of the iris relax
circular muscles of the iris contract
contracted pupil (less light can enter the eye)

Question 22

accomodation to view objects which are near

Answer 22

ciliary muscles: contract
Suspensory ligaments: slackened
Muscle tension on lens: low
Lens shape: thicker and rounder (fat)

Question 23

accomodation to view objects which are distant

Answer 23

ciliary muscles: relax
Suspensory ligaments: stretched
Muscle tension on lens: high
Lens shape: flatter (thin)

Question 24

number of rods and cones in the retina

Answer 24

120 millions rods and 7 million cones

Question 25

where are the rods and cones most concentrated?

Answer 25

rods are most concentrated in the outer edges of the retina
cones are most concentrated in the fovea

Question 26

where do rods and cones work best in?

Answer 26

rods work best in dim light
cones work best in bright light

Question 27

function of rods and cones

Answer 27

• greater sensitivity of rods for night vision
• three different kinds of cones, absorbing light of different colours, for colour vision

Question 28

hormone

Answer 28

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

Question 29

what hormone does the adrenal glands secret?

Answer 29

adrenaline

Question 30

what hormone does the pancreas secret?

Answer 30

insulin

Question 31

what hormone do the testes secrete?

Answer 31

testosterone

Question 32

what hormone do the ovaries secrete?

Answer 32

oestrogen

Question 33

what are the flight or flight reponses during adrenaline secretion?

Answer 33

1. increased breathing rate
2. increased heart rate
3. increased pupil diameter

Question 34

where is glucagon secreted?

Answer 34

pancreas

Question 35

Compare nervous and hormonal control, limited to speed of action and duration of effect

Answer 35

The effects of hormones take longer than the nervous system, but they last longer.

Question 36

role of adrenaline in the control of metabolic activity

Answer 36

a) increasing the blood glucose concentration
b) increasing heart rate

Question 37

what does insulin do

Answer 37

it decreases blood glucose concentration

Question 38

role of rod cells

Answer 38

detect light in low intensity and passes impulse to optic nerve (3)