GCSE Nervous System

Question 1

Define homeostasis

Answer 1

The maintenance of a constant internal environment

Question 2

Define negative feedback

Answer 2

When a change from normal conditions is detected and prompts a response to return to normal

Question 3

Give three procedures that homeostasis maintains

Answer 3

Temperature, blood glucose levels, water balance

Question 4

What are the two communication systems in the body?

Answer 4

Hormonal and nervous systems

Question 5

How does the nervous system send signals?

Answer 5

Via electrical impulses in neurones

Question 6

Define stimulus

Answer 6

A signal to which an organism responds

Question 7

Give the stimulus for smells

Answer 7

Chemicals

Question 8

Describe the coordination pathway

Answer 8

Stimulus —> receptor (PNS) —> coordinator (CNS) —> effector

Question 9

Give examples of stimuli

Answer 9

Pressure, temperature, sounds light, chemicals

Question 10

Give examples of receptors

Answer 10

Skin, eyes, ears, nose, tongue

Question 11

Give examples of coordinators

Answer 11

Brain, spinal cord

Question 12

Give examples of effectors

Answer 12

Muscles and glands

Question 13

What are nerves?

Answer 13

Bundles of neurones in the PNS

Question 14

Where are electrical impulses generated?

Answer 14

Receptors

Question 15

What are the three types of neurones?

Answer 15

Sensory, relay and motor

Question 16

Where are the sensory neurones found?

Answer 16

From receptors to CNS

Question 17

Where are relay neurones found?

Answer 17

CNS

Question 18

Where are motor neurones found?

Answer 18

CNS to effectors

Question 19

What does the reflex arc do?

Answer 19

Rapid, automatic responses to stimuli to protect the body

Question 20

What part of the CNS do reflexes go through

Answer 20

Spinal cord (usually closer than brain)

Question 21

What is a synapse?

Answer 21

The gap between neurones

Question 22

How do synapses work?

Answer 22

The nerve signal is transferred by neurotransmitters which diffuse across the gap and set off a new electrical impulse in the next neurone

Question 23

Describe how electrical impulses are transmitted across synapses

Answer 23

When the electrical impulses reaches the end of a neurone, vesicles move to join the cell membrane to release neurotransmitters into the synapse, which diffuse across the synapse and bind to receptors on the next neurone to begin a new impulse

Question 24

Give an identifying feature of a sensory neurone

Answer 24

Cell body sticking out of axon

Question 25

Give an identifying feature of a relay neurone

Answer 25

Short

Question 26

Give an identifying feature of a motor neurone

Answer 26

Cell body attached to dendrites + effector on one end

Question 27

What is the eye?

Answer 27

A sensory organ that detects light and converts light energy into electrical impulses

Question 28

What are the rods responsible for?

Answer 28

Black and white vision in low light

Question 29

What are the cones responsible for?

Answer 29

Coloured vision in high light

Question 30

What do radial and circular muscles do?

Answer 30

radial muscles contract, circular muscles relax

Question 31

What is accommodation?

Answer 31

The process by which the eye's lens changes shape to focus near or far objects on the retina

Question 32

How does accommodation work for distant images?

Answer 32

Ciliary muscles relax, suspensory ligaments contract, lens is long and thin (less refraction needed)

Question 33

How does accommodation work for close images?

Answer 33

Ciliary muscles contract (bulge), suspensory ligaments relax, lens is short and fat (more refraction needed)

Question 34

Why does the lens become fatter to see close objects?

Answer 34

The divergent rays are shining on the ends of the lens, so it makes it bulgy to focus the rays into the retina

Question 35

What is myopia?

Answer 35

Short sightedness - unable to see distant objects - eye is too long / lens is too convex - image forms in front of retina

Question 36

What is hyperopia?

Answer 36

Long sightedness - unable

Question 37

What are the treatments for myopia and hyperopia?

Answer 37

Concave lens for myopia, convex lens for hyperopia

Question 38

What part of the brain controls homeostasis?

Answer 38

The hypothalamus

Question 39

What is the thermoregulatory system made up of?

Answer 39

Receptors that monitor blood temperature

Question 40

What is negative feedback?

Answer 40

A response to a change in the body that reverses the change

Question 41

What effectors does the thermoregulatory system use?

Answer 41

Sweat glands. blood vessels in skin and skeletal muscles

Question 42

What is the body's negative feedback loop to being too cold?

Answer 42

stimulus: too cold / receptor: thermoreceptors in the skin / coordinator: hypothalamus / effector + response: vasoconstriction, shivering, sweat production stops, piloerection / core body temperature rises.

Question 43

Why does the body use vasoconstriction/dialation?

Answer 43

Vasodialation allows heat to be lost by radiation. Vasoconstriction stops heat from being radiated

Question 44

Why does the body shiver?

Answer 44

Rapid skeletal muscle contraction causes high rates of respiration, which is an exothermic reaction

Question 45

Why does the body use piloerection when cold?

Answer 45

To trap warm air between hairs