unit 14

Question 1

what do electrical impulses travel through?

Answer 1

electrical impulses travel along
neurones (axon - dendrite)

Question 2

describe the mammalian nervous system

Answer 2

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

Question 3

what is the role of the nervous system as
coordination and regulation of body functions

Answer 3

Your nervous system’s main function is to send messages from various parts of your body to your brain, and from your brain back out to your body to tell your body what to do - googled

Question 4

Describe a simple reflex arc

Answer 4

receptor,
sensory neurone, relay neurone, motor neurone
and effector

Question 5

what is 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

what is a synapse

Answer 6

a junction between two
neurones

Question 7

what is the strcuture of a synapse?

Answer 7

vesicles containing neurotransmitter
molecules, the synaptic gap and receptor
proteins

Question 8

what happens at a synapse?

Answer 8

a) an impulse stimulates the release of
neurotransmitter molecules from vesicles
into the synaptic gap
(b) the neurotransmitter molecules diffuse
across the gap
(c) neurotransmitter molecules bind with
receptor proteins on the next neurone
(d) an impulse is then stimulated in the next
neurone

Question 9

what do synapses ensure?

Answer 9

synapses ensure that impulses travel in
one direction only (this si ecause axon terminals contain vesicles, not dendrite)

Question 10

what are sense organs?

Answer 10

groups of receptor cells responding to specific stimuli

Question 11

what are the specific stimuli sense organs react to?

Answer 11

light, sound, touch, temperature and chemicals

Question 12

what is the function of the cornea?

Answer 12

to refract light

Question 13

what is the function of the iris?

Answer 13

to control how much light enters the pupil

Question 14

what is the function of the lens?

Answer 14

focuses light on the retina

Question 15

what is the function of the retina?

Answer 15

contains light receptors, some sensitive to light of different colours

Question 16

what is the function of the optic nerve?

Answer 16

carries impulses to the brain

Question 17

what happens in low lighting? (pupil reflex)

Answer 17

Radial muscles contract, so the pupil will appear bigger

Question 18

what happens in bright lighting? (pupil reflex)

Answer 18

Cordial muscles contract, so the pupil will appear smaller

Question 19

what does the eye do to view near objects?

Answer 19

ciliary muscle contract. suspensory ligaments slacken. lens becomes fatter.

Question 20

what does the eye do to view far away objects?

Answer 20

ciliary muscle relaxes. suspensory ligaments contract / stretch thin. lens become thinner.

Question 21

Describe the distribution of rods and cones in the retina of a human

Answer 21

ummmm?

Question 22

what is the function of rods?

Answer 22

greater sensitivity for night vision

Question 23

what is the function of cones?

Answer 23

three different kinds of cones, absorbing light of different colours, for colour vision

Question 24

what is a hormone?

Answer 24

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

Question 25

what hormones do adrenal glands secrete?

Answer 25

adrenaline

Question 26

what hormones does the pancreas secrete?

Answer 26

insulin and glucagon

Question 27

what hormones do the testes secrete?

Answer 27

testosterone

Question 28

what hormones do the ovaries secrete?

Answer 28

oestrogen

Question 29

what is adrenaline?

Answer 29

the hormone secreted in ‘fight or flight’ situations

Question 30

what are the effects of adrenaline?

Answer 30

increased breathing rate, heart rate, pupil diameter, blood glucose concentration

Question 31

what is the difference between nerve signals and hormones’ signals?

Answer 31

nerve signals are fast through neurons but the effect is short-term. (e.g: dodging a ball. immediate, not needing to be repeated) hormones send signals slowly through bloodstream. (e.g: hips widening) -> meant to stay for years and slowly happen.