B10 - The Nervous System

Question 1

define:

homeostasis

Answer 1

keeping conditions inside the body constant

Question 2

list 4:

conditions inside the body that are controlled

Answer 2

• body temperature
• water content
• CO₂ levels
• blood glucose levels

Question 3

name:

the 3 parts of automatic control systems

Answer 3

1. receptors - receives information from stimuli
2. coordination centres - interprets change and determines response
3. effectors - carry out a response

Question 4

define:

stimulus

Answer 4

a change in external or internal environment

Question 5

role of hypothalamus

Answer 5

coordinates responses to change in temperature

Question 6

role of pituitary gland

Answer 6

coordinates responses to changes in water content in the blood

Question 7

role of pancreas

Answer 7

coordinates responses to changes in blood glucose levels

Question 8

How does the nervous system send information?

Answer 8

through electrochemical (electrical) signals

impulses

Question 9

define:

CNS and PNS

Answer 9

central nervous system and peripheral nervous system

Question 10

name:

3 neurons that are part of the nervous system and their function

Answer 10

1. sensory neuron - receptor (PNS)
2. relay neuron - coordination centre (CNS)
3. motor neurone - effector (PNS)

Question 11

list 2:

organs in the CNS

Answer 11

• brain
• spinal chord

Question 12

define:

reflex action

Answer 12

an involuntary action which doesnt require conscious thought

Question 13

define:

reflex arc

Answer 13

the nerve path followed by a reflex action

Question 14

define:

synapse

Answer 14

a location where neurons connect and communicate with each other

where the gap is betwen the neurons

Question 15

How is informations transmitted over a synapse?

Answer 15

1. vesicles (on the pre-synaptic neuron) release neurotransmitters
2. receptors (on the post-synaptic neuron) absorb neurotransmitters

neurotransmitters are chemicals

Question 16

list 3:

regions in the brain

Answer 16

• cerebral cortex
• cerebellum
• medulla

Question 17

role of the cerebral cortex

Answer 17

consciousness, intelligence, memory and language

Question 18

role of the cerebellum

Answer 18

coordinating muscular activity and balance

Question 19

role of the medulla

Answer 19

controlling unconscious activities

e.g. heartbeat and breathing

Question 20

define:

MRI

Answer 20

Magnetic Resonance Imaging - scan for viewing the brain

Question 21

name:

2 light receptors and their purpose

Answer 21

• rods - night vision
• cones - colour vision

Question 22

draw:

diagram of the eye

8 parts

Answer 22

image

IGNORE fovea and pupil

Question 23

define:

accomodation

in the eye

Answer 23

process of changing the shape of the lens to focus on near or distant objects

Question 24

define:

myopia

Answer 24

short sightedness where light rays don’t focus onto the retina

Question 25

define:

hyperopia

Answer 25

long sightedness where light rays don’t focus onto the retina

Question 26

list 2:

eye defect treatments

Answer 26

• lenses (glasses / contacts)
• laser eye surgery

Question 27

function:

Cornea

Answer 27

Refracts light - bends it as it enters the eye

Question 28

function:

Iris

Answer 28

Controls how much light enters the pupil

Question 29

function:

Lens

Answer 29

Further refracts light to focus it onto the retina

Question 30

function:

Retina

Answer 30

Contains the light receptors

Question 31

function:

Optic nerve

Answer 31

Carries impulses between the eye and the brain

Question 32

function:

Sclera

Answer 32

Tough white outer layer of the eye. It helps protect the eye from injury

Question 33

describe:

accomodation with near objects

Answer 33

• the ciliary muscles contract
• the suspensory ligaments loosen
• the lens is then thicker and refracts light rays strongly

Question 34

describe:

accomodation with far objects

Answer 34

• the ciliary muscles relax
• the suspensory ligaments are pulled tight
• the lens is then thinner and refracts light rays slightly