Chapter 6

Question 1

Stimulus

Answer 1

changes in the surroundings of an organism

Question 2

Response

Answer 2

reaction by an organism to a stimulus

Question 3

Receptor

Answer 3

cell or organ that detects a stimulus

Question 4

Effector

Answer 4

organ that brings about a response (muscle/gland)

Question 5

Nerve impulses

Answer 5

tiny electrical signals, pass down nerve cell. Caused by movements of ions in/out of axon

Question 6

Neurone

Answer 6

nerve cell

Question 7

Sensory neurone

Answer 7

nerve cell carries impulses from receptor to CNS

Question 8

Central nervous system (CNS)

Answer 8

brain and spinal cord

Question 9

Motor neurone

Answer 9

nerve cell that transmits impulses from CNS to effector organ

Question 10

Dendron

Answer 10

extension of neurone cytoplasm, carries impulses towards cells

Question 11

Dendrite

Answer 11

fine extensions of the dendrons of a neurone

Question 12

Synapse

Answer 12

junction between two neurons

Question 13

Axon

Answer 13

long extension of a neurone, carries nerve impulses away from the cell body

Question 14

Neuromuscular junction

Answer 14

synapse of nerve cell on muscle

Question 15

Myelin sheath

Answer 15

covering made of lipid material, surrounds axon (cells with them are myelinated)

Question 16

Sclera

Answer 16

tough outer coat of eye

Question 17

Cornea

Answer 17

transparent front of eye that allows light to enter and refracts it

Question 18

Iris

Answer 18

coloured part of eye, muscles in iris change size of pupil

Question 19

Pupil

Answer 19

hole in centre of iris, allows light into eye

Question 20

Choroid

Answer 20

dark layer of tissue below sclera, contains blood vessels and pigment cells

Question 21

Retina

Answer 21

inner, light sensitive layer at back of eye

Question 22

Rods

Answer 22

light sensitive cell in retina, detects light (works well in dim light)

Question 23

Cones

Answer 23

cell in retina of eye which detects different wavelengths of light (sees colour)

Question 24

Optic nerve

Answer 24

nerve carrying impulses from the retina to brain

Question 25

Fovea

Answer 25

region in centre of retina, high concentration of light sensitive receptor cells

Question 26

Reflex action

Answer 26

rapid automatic involuntary response to stimulus

Question 27

Blind spot

Answer 27

area of retina where optic nerve leaves eye, cannot detect an image

Question 28

Accommodation

Answer 28

changes in eye, allows it to focus on objects at different distances

Question 29

Suspensory ligaments

Answer 29

fibres between lens and ciliary body of eye, holds lens in position

Question 30

Ciliary muscle

Answer 30

ring of muscle around lens of eye that alters the shape of the lens

Question 31

Reflex arc

Answer 31

nerve pathway of a reflex action

Question 32

Dorsal root

Answer 32

part of a spinal nerve that emerges from the dorsal part of spinal cord

Question 33

Relay neurones

Answer 33

short neurone, connects sensory neurone with motor neurone

Question 34

Ventral root

Answer 34

part of spinal nerve, emerges from ventral side of spinal cord

Question 35

Grey matter

Answer 35

tissue in middle of spinal cord and outer part of brain. Consists mainly of nerve cells

Question 36

White matter

Answer 36

tissue in outer part of spinal cord and middle of brain. Consists mainly of nerve axons

Question 37

Dorsal root ganglion

Answer 37

swelling in the spinal nerve that contains the cells of sensory neurones