The Nervous System

Question 0

Reflex reaction

Answer 0

Involuntary and almost immediate response to a stimulus

Question 1

Types of neurons

Answer 1

Motor Sensory Relay

Question 2

Cell body

Answer 2

The part of a neurone which contains the nucleus

Question 3

Dendrites

Answer 3

Extensions which receive nerve impulses from other cells; the nerve impulses are then transmitted towards the cell body

Question 4

Axon

Answer 4

Carries nerve impulses to an effector organ

Question 5

Myelin sheath

Answer 5

Fatty sheath which insulates the axon (preventing short-circuits of electrical impulses) and speeds up the conduction of nerve impulses

Question 6

Nerve muscle junction

Answer 6

The point between the branches of the axon and the muscle cells

Question 7

Reflex arc

Answer 7

The pathway thought the nervous system that reflex takes

Question 8

Spinal cord

Answer 8

Extension of the CNS from the brain which is enclosed by the vertebral column

Question 9

Summary of the reflex arc

Answer 9

Sense organ receptor senses stimulus Sensory neurone detects and passes to relay (through spinal cord) and to motor neurone which triggers a response from the muscle effector

Question 10

Dorsal root ganglion

Answer 10

Module on dorsal root containing ell bodies

Question 11

Grey matter

Answer 11

Darker tissue of spinal cord

Question 12

Synapse

Answer 12

Tiny gal between two neurones

Question 13

Nerve impulses across synapse

Answer 13

Travels to synapse as electrical impulse They trigger vesicles, containing neurotransmitters, to move to the membrane Neurotransmitters released across synapses then bind to receptors on the next neurone This triggers new nerve impulse

Question 14

Cornea

Answer 14

Clear later at front of eye Helps to refract and focus light

Question 15

Lens

Answer 15

Transparent structure behind pupil Refracts and focuses light

Question 16

Pupil

Answer 16

Hole in centre of iris Controls amount of light entering eye

Question 17

Iris

Answer 17

Pigmented tissue Controls amount of light entering eye

Question 18

Suspensory ligaments

Answer 18

Ligaments in connecting the ciliary muscles and the lens Involved in controlling accommodation (focussing)

Question 19

Ciliary muscles

Answer 19

Ring of muscle connected to lens via suspensory ligaments Controls accusation (focussing)

Question 20

Retina

Answer 20

Inner layer of eye containing rods and cones Responds to light stimulus

Question 21

Optic nerve

Answer 21

Sensory nerve Carries nerve impulses from retina to brain

Question 22

Dark

Answer 22

Pupil dilates Radical muscles contract Circular muscles relax

Question 23

Bright light

Answer 23

Pupil constricts Radical muscle relaxes Circular muscles contract

Question 24

Image formed in the retina

Answer 24

Originally upside down but the brain interprets this image so it appears upright to us

Question 25

What do cones do

Answer 25

Detect colour

Question 26

Optic fibre nerve

Answer 26

Point where the neurones leave the eye

Question 27

Blind spot

Answer 27

Light focusses on the optic nerve and we are unable to detect it

Question 28

Focussing in distant object

Answer 28

Lens less convex (thinner) Rays refract less Clary muscles relax Suspensory ligaments pulled tight

Question 29

Focussing on near object

Answer 29

Lens more convex (rounded) Rays refract less Ciliary muscles contract Suspensory ligaments slack

Question 30

Nervous system

Answer 30

Vast network of nerves in the body

Question 31

Nerve

Answer 31

A bundle of many neurones

Question 32

Neurone

Answer 32

A cell specialised to generate and conduct electrical impulses from one part of the nervous system to another

Question 33

Axon

Answer 33

The extension of a neurone that transmits a signal

Question 34

CNS

Answer 34

Central nervous system- contains brain optic nerve and spinal cord

Question 35

Brain

Answer 35

Control centre of CNS

Question 36

Stimulus

Answer 36

A detectable change in the environment

Question 37

Receptor

Answer 37

A cell that senses a stimulus and starts transmission of the impulse

Question 38

Sense organ

Answer 38

Specialised organ with clusters of receptor cells

Question 39

Nerve impulse

Answer 39

Information in the form of an electrochemical signal that travels through a neurone

Question 40

Spinal cord

Answer 40

A bundle of nerves enclosed in the spine which connects nearly all parts of the body to the brain

Question 41

Light travelling through eye

Answer 41

Conjunction, cornea, aqueous humor, pupil, lens, vitreous humor, fovea

Question 42

Myopia

Answer 42

Short sightedness

Question 43

Hyperopia

Answer 43

Long sightedness

Question 44

Astigmatism

Answer 44

Vision problem caused by an irregularly shaped cornea

Question 45

Form of message in nervous system and hormones

Answer 45

Electrical impulses/chemicals

Question 46

Carried in nervous system and hormones

Answer 46

Neurone/blood streaming

Question 47

Time in nervous system and hormones

Answer 47

Fast with instant effect short lived/slower with longer And act long lasting

Question 48

Area effected in nervous system and hormones

Answer 48

Very localised-individual cells/wide spread in deff went organs

Question 49

Structure of the eye

Answer 49