12. coordination and response

Question 1

stimuli

Answer 1

changes in the environment that can be detected by organisms

Question 2

receptors

Answer 2

cells or groups of cells that detect stimuli

Question 3

effectors

Answer 3

parts of the body that respond to a stimulus

Question 4

coordination

Answer 4

ensuring that the actions of different parts of the body work together

Question 5

nerve

Answer 5

a group of neurone axons lying together

Question 6

neurone

Answer 6

a cell that is specialised for conducting electrical impulses rapidly

Question 7

motor neurone

Answer 7

a neurone that transmits electrical impulses from the central nervous system to an effector

Question 8

axon

Answer 8

a long thin fibre of cytoplasm that extends from the cell body of a neurone

Question 9

dendrites

Answer 9

short fibres of cytoplasm in a neurone

Question 10

nerve impulse

Answer 10

an electrical signal that passes rapidly along an axon

Question 11

CNS central nervous system

Answer 11

the brain and spinal cord

Question 12

PNS peripheral nervous system

Answer 12

nerves outside the brain and spinal cord

Question 13

sensory neurone

Answer 13

a neurone that transmits electrical impulses from a receptor to the central nervous system

Question 14

relay neurone

Answer 14

a neurone that transmits electrical impulses within the central nervous system

Question 15

reflex arc

Answer 15

a series of neurones that transmit electrical impulses from a receptor to an effector

Question 16

reflex action

Answer 16

a means of automatically and rapidly integrating and coordination stimuli with the responses of effectors

Question 17

synaptic gap

Answer 17

a tiny gap between two neurones at a synapse

Question 18

synapse

Answer 18

a junction between 2 neurones

Question 19

neurotransmitter

Answer 19

a chemical stored in vesicles at the end of neurones which can be released to diffuse across the synaptic gap and set up an electrical impulse in the next neurone

Question 20

receptor proteins

Answer 20

proteins on the membrane of the seconds neurone at a synapse which have a complimentary shape to the molecules of neurotrasmitter

Question 21

sense organ

Answer 21

a group of receptor cells that are able to respond to a specific stimulus

Question 22

retina

Answer 22

a tissue at the back of the eye that contains receptor cells that respond to light

Question 23

optic nerve

Answer 23

the nerve that carries electrical impulses from the retina to the brain

Question 24

blind spot

Answer 24

the part of the retina where the optic nerve leaves and there are no recpetor cells

Question 25

fovea

Answer 25

the part of the retina where cone cells are very tightly packed and light is focused

Question 26

rods

Answer 26

receptor cells in the retina that responf to dim light but do not detect colour

Question 27

cones

Answer 27

receptor cells in the retina that are sensitive to light of different colours but only function in bright light

Question 28

iris

Answer 28

the coloured part of the eye that contains muscles that alter the size of the pupil

Question 29

pupil

Answer 29

a circular gap in the middle of the iris

Question 30

iris reflex

Answer 30

an automatic response to a change in light intensity

Question 31

antagonistic muscles

Answer 31

a pair of muscles whose contraction has opposite effects

Question 32

cornea

Answer 32

a transparent layer near the front of the eye which refracts light rays entering the eye

Question 33

lens

Answer 33

a transparent structure in the eye which changes shape to focus light rays onto the retina

Question 34

accommodation

Answer 34

changing the sha[e of the lens to focus on objects at different distances from the eye

Question 35

suspensory ligament

Answer 35

strong inelastic fibres that hold the lens in position

Question 36

ciliary muscle

Answer 36

a circle of muscle surrounding the lens and joined to it by the suspensory ligament

Question 37

hormones

Answer 37

chemicals that are produced by a gland and carried in the blood, which alter the activities of their specific target organs

Question 38

adrenaline

Answer 38

a hormone secreted by the adrenal glands which prepares the body for fight or flight

Question 39

tropism

Answer 39

a growth response by a plant in which the direction of growth is related to the direction of the stimulus

Question 40

phototropism

Answer 40

a response in which part of a plant grows towards or away from the direction from which light is coming

Question 41

gravitropism

Answer 41

a response in which part of a plant grows towards or away from gravity

Question 42

auxin

Answer 42

a plant hormone made in the tips of shoots which causes cells to elongate