Unit 14

Question 1

what to electrical impulses travel along

Answer 1

neurones

Question 2

what is a bundle of neurones called

Answer 2

nerves

Question 3

what does hte central nervous system consist of

Answer 3

the brain and spinal cord

Question 4

what does the peripheral nervous system consist of

Answer 4

the nerves outside the brain and spinal cord

Question 5

what is the role of the nervous system in the body

Answer 5

coordination and regulation of body functions
the ability to respond to our surroundings

Question 6

what is the purpose of sensory neurones

Answer 6

they carry impulses from sense organs to the CNS

Question 7

structure of sensory neurones

Answer 7

long and have a cell body in the middle of the axon

Question 8

purpose of relay neurones

Answer 8

they are found inside the CNS and connect sensory and motor neurones

Question 9

structure of relay neurones

Answer 9

they are short and have a small cell body with many dendrites branching off

Question 10

purpose of motor neurones

Answer 10

they carry impulses from the CNS to the effectors

Question 11

structure of motor neurones

Answer 11

they are long and have a large cell body with long dendrites

Question 12

what are effectors

Answer 12

muscles or glands that produce a response

Question 13

describe a reflex arc

Answer 13

receptor sends a signal through a sensory neurone where it goes through a relay neurone and is passed on to a motor neurone. the impulse produces a response through the effector

Question 14

what is a reflex action

Answer 14

it is a means of automatically and rapidly integrating and coordinating stimuli with the responses of effectors

Question 15

advantages of reflex actions

Answer 15

they are quicker than any other type of response and help minimise damage to the body

Question 16

what is a synapse

Answer 16

a junction where two neurones meet

Question 17

what are the parts of a synapse

Answer 17

vesicles containing neurotransmitter molecules
the synaptic gap
receptor proteins

Question 18

describe the events at a synapse

Answer 18

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

Question 19

what is the purpose of synapses

Answer 19

to ensure that impulses travel in one direction only

Question 20

what are sense organs

Answer 20

groups of receptor cells responding to specific stimuli( such as light,sound,touch,temperature,chemicals)

Question 21

what does the cornea do

Answer 21

refract light

Question 22

what does the iris do

Answer 22

control how much light enters the pupil

Question 23

what does the lens do

Answer 23

focuses light onto the retina

Question 24

what does the retina do

Answer 24

contains light receptors ( rod and cone cells)

Question 25

what does the optic nerve do

Answer 25

carry impulses to the brain

Question 26

what is the blind spot and why is it created

Answer 26

it is where nothing can be seen because there are no rod or cone cells. it i found where the optic nerve joins the retina

Question 27

what happens to the pupils in dim light

Answer 27

pupils dilate to allow as much light in as possible

Question 28

what happens to the pupils in bright light

Answer 28

they constrict to allow less light in to protect the retina

Question 29

how do the pupils dilate

Answer 29

radial muscles contract and circular muscles relax

Question 30

how do the pupils constrict

Answer 30

radial muscles relax and circular muscles contract

Question 31

what is accomodation

Answer 31

the eye focusing on near or far objects

Question 32

what happens when objects are close

Answer 32

ciliary muscles contract suspensory ligaments loosen lens becomes fatter light is refracted more

Question 33

what happens when objects are far from the eye

Answer 33

ciliary muscles relax suspensory ligaments tighten lens becomes thinner light is refracted less

Question 34

where are cone cells found

Answer 34

in the fovea, near the centre of the eye

Question 35

what do rod cells do

Answer 35

they are sensitive to dim light

Question 36

what do cone cells do

Answer 36

they see color

Question 37

how many different types of cone cells are there

Answer 37

3, they absorb light for different colors

Question 38

what is a hormone

Answer 38

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

Question 39

what do the adrenal glands produce

Answer 39

adrenaline

Question 40

where are the adrenal glands found

Answer 40

next to the kidneys

Question 41

what do the pancreas secrete

Answer 41

insulin

Question 42

what do the testes secrete

Answer 42

testosterone

Question 43

what do the ovaries secrete

Answer 43

oestrogen

Question 44

when is adrenaline secreted

Answer 44

its secreted in 'fight or flight' situations

Question 45

what is the affect of adrenaline

Answer 45

increased breathing rate increased heart rate increased pupil diameter increased blood glucose concentration diverts blood supply away from unneeded areas

Question 46

what are the differences between nervous and hormonal control

Answer 46

nervous control is very fast and duration of effect is short hormonal control is slower and length of effect is longer

Question 47

where is glucagon secreted from

Answer 47

the pancreas

Question 48

what is homeostasis

Answer 48

the maintenance of a constant internal environment

Question 49

what does insulin do

Answer 49

decrease the blood glucose concentration

Question 50

what is negative feedback

Answer 50

when conditions change from an ideal or set point and these conditions need to be returned to the set point

Question 51

how does insulin achieve its purpose

Answer 51

it converts extra glucose into glycogen in the liver

Question 52

what does glucagon do and when is it released?

Answer 52

it increases blood glucose concentration by converting the glycogen back into glucose. happens when blood glucose concentration is low

Question 53

what is the treatment of diabetes

Answer 53

insulin injections to decrease blood glucose concentration because the body is unable to produce enough insulin on its own

Question 54

how does the body insulate itself to maintain a constant body temperature

Answer 54

fatty tissue under the skin acts as a layer of insulation to prevent too much body heat being lost

Question 55

why do we sweat

Answer 55

when its too hot, sweat is secreted by sweat glands to cool the skin. hairs lie flat against the skin allowing air to frelly circulate and increase heat transfer

Question 56

why do we shiver

Answer 56

when its cold, skeletal muscles contracts and we shiver which leads to energy being released as heat erect hairs trap a layer of air around the skin preventing heat loss

Question 57

what is vasoconstriction

Answer 57

when its cold ,skin capillaries get narrower to reduce heat loss

Question 58

what is vasodilation

Answer 58

when its hot, skin capillaries get wider to increase heat loss

Question 59

what is gravitropism

Answer 59

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

Question 60

what is phototropism

Answer 60

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

Question 61

what are the tropic responses of the shoots of a plant

Answer 61

shoots have a positive phototropic response and a negative gravitropic response

Question 62

what are the tropic response of the roots of a plant

Answer 62

they have a negative phototropic response and positive gravitropic response

Question 63

what does auxin do

Answer 63

hormone that causes cell elongation wherever its concentrated

Question 64

how does auxin work

Answer 64

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