B13 Nervous system and homeostasis

Question 1

Function of the nervous system

Answer 1

Enables humans to react to their surroundings and to coordinate their behaviour

Voluntary and involuntary reactions

Question 2

Structure of the nervous system

Answer 2

CNS and Network of Nerves

Question 3

What comprises the CNS?
(Central Nervous System)

Answer 3

Brain and spinal cord

Question 4

How does the nervous system respond to stimuli?

Answer 4

Stimulus is detected by receptors

Information from receptors is passed along neurones to the CNS as electrical impulses

Coordinator- CNS coordinates the body’s response to the stimulus

Effector brings about a response via glands secreting hormones or muscles contracting

Body responds to the stimuluse

Question 5

What are reflex actions?

Answer 5

Responses that do not involve the conscious part of the brain.

Question 6

Give the pathway of a nervous response

Answer 6

Stimulus -> Receptor -> Coordinator -> Effector -> Response

Question 7

Why are reflex actions important?

Answer 7

For survival to prevent damage to the body

Question 8

What are neurones?

Answer 8

They carry electrical impulses around the body

Relay neurones connect sensory neurones to motor neurones

Question 9

What are synapses?

Answer 9

Gaps between neurones, which allow electrical impulses in the nervous system to cross between neurones

Question 10

How does a synapse work?

Answer 10

Impulse arrives at neurone

Chemicals are released in to the gap between the neurone

Chemicals attach to the next surface of the next neurone and set up to a new electrical impulse

Question 11

Cerebral cortex

Answer 11

Outer layer of the brain

Important for consciousness, intelligence memory and language

Question 12

Cerebellum

Answer 12

At the back of the brain

Coordinates muscle activity

Question 13

Medulla oblongata

Answer 13

Above the spinal cord

Controls unconscious activities such as breathing and heart beating

Question 14

Hypothalamus

Answer 14

The hypothalamus in the brain contains the temperature monitoring centre for the body.

Question 15

Pituitary gland

Answer 15

The pituitary gland releases hormones in response to changes detected by the hypothalamus.

Question 16

Why is it difficult to treat brain disorders?

Answer 16

Brain is very complex and delicate

Question 17

What is homeostasis?

Answer 17

Maintenance of a constant internal environment

Question 18

3 internal conditions controlled by homeostasis

Answer 18

Body Temp
Blood glucose concentration
Water levels

Question 19

3 things all control centres include

Answer 19

Receptors
Coordination centres
Effectors

Question 20

Cornea

Answer 20

lets light in and changes directions so light is focused on the retina

Question 21

iris

Answer 21

coloured part of eye
contains muscles that contract to change the size of pupil

lets more/less light in

Question 22

ciliary muscle

Answer 22

contracts and relaxes to change shape of lens

Question 23

retina

Answer 23

layer of receptors at the back of the eye

rods and cones

Question 24

optic nerve

Answer 24

nerve that connects eye to brain

Question 25

lens

Answer 25

sits behind pupil and focuses light on retina

Question 26

how do eyes focus on a NEAR object

Answer 26

ciliary muscles contract so lens becomes thicker and more curved and refracts light rays more strongly

Question 27

how do eyes focus on a DISTANT object

Answer 27

ciliary muscles relax so lens is thinner and flatter and only refracts light rays partially

Question 28

myopia

Answer 28

short sightedness

Question 29

Q what type of lens is used to aid myopia

Answer 29

concave lens

Question 30

hyperopia

Answer 30

long sightedness

Question 31

what type of lens is used to aid hyperopia

Answer 31

convex lens

Question 32

How can eye defects be treated?

Answer 32

-spectacle lenses -contact lenses -laser surgery -replacement lenses in the eye

Question 33

What is accommodation

Answer 33

The process of changing the shape of the lens to focus on objects

Question 34

What part of the brain controls body temperature

Answer 34

hypothalamus

Question 35

What happens if body temperature is too high?

Answer 35

Vasodilation Sweat is produced Hair on body lies flat

Question 36

What happens when body temperature is too low?

Answer 36

Vasoconstriction Sweating stops Shivering Hair on body stands up