Chapter 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 (muscle and glands - effectors)

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 thins fibre of cyptoplasm 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

central nervous system

Answer 11

the brain and the spinal cord

Question 12

peripheral nervous system

Answer 12

the nerves outside the brain and the 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 transmits 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

fovea

Answer 17

the part of the retina when cone cells are very tightly packed

Question 18

rods

Answer 18

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

Question 19

cones

Answer 19

receptor cells in the retina that are sensitive to the light of different colours

Question 20

iris

Answer 20

the coloured part of the eye

Question 21

pupil

Answer 21

a circular gap in the middle of the iris through which light can pass

Question 22

iris reflex

Answer 22

an automati response to a change in light intensity

Question 23

antagonistic muscles

Answer 23

a pair of muscles whose contraction has opposite effects

Question 24

refraction

Answer 24

bending light rays

Question 25

cornea

Answer 25

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

Question 26

lens

Answer 26

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

Question 27

accomodation

Answer 27

changing the shape of the lens to focus on objects at different distances from the eye

Question 28

suspensory ligaments

Answer 28

strong, inelastic fibres that hold the lens in position

Question 29

cilliary muscles

Answer 29

A circle of muscles that surround the lens and joined to it by the suspensory ligaments

Question 30

hormones

Answer 30

chemicals that are produced by a gland and carried in the blood which alter the activites of a specific organ

Question 31

endocrine glands

Answer 31

glands that secrete organs

Question 32

adrenaline

Answer 32

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

Question 33

tropism

Answer 33

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

Question 34

phototropism

Answer 34

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

Question 35

gravitropism

Answer 35

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

Question 36

auxin

Answer 36

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