The Human Nervous System

Question 1

What is the sequence of the nervous system

Answer 1

Stimulus eg pin -> receptor -> sensory neurone (spinal chord) -> coordinator (brain) -> motor neurone -> effector -> response

Question 2

What is a synapse

Answer 2

Synapse is a gap
where 2 neurones meet there is a tiny gap called a synapse
The connection between 2 neurones is called a synapse

Question 3

How do signals cross the gap/synapse?

Answer 3

Signals cross the gap using chemicals released by a neurone
The chemicals move by diffusion across the gap
The chemicals set off a new electrical signal in the next neurone

Question 4

Nerve cells are?

Hormones are ?

Answer 4

Nerve cells are electrical

Hormones are chemical

Question 5

What are the receptors

Answer 5

Receptors detect stimuli
Eyes
Ears
Nose
Tongue
Skin

Question 6

What are the coordination centres

Answer 6

Brain
Spinal chord
Some organs eg pancreas

Question 7

What are the effectors

Answer 7

Muscles and glands

Question 8

What happens when an impulse arrives at the junction between 2 neurones

Answer 8

Chemicals are released that cross the synapse and arrive the receptor sites on the next neurone starting up new electrical impulse in the next neurone

Question 9

What happens when your finger senses something hot

Answer 9

1 stimulus eg touching hot plate
2 sensory receptor in skin of finger
3 sensory neurone transmits through 
4 cell body of neurone
5 relay Neurone
6 synapse
7 motor neurone
8 motor end plate
9 bicep muscle contracts and with draws hand

Question 10

What is a reflex action?

Answer 10

It’s a rapid automatic response of the nervous system that does not involve conscious thought

Eg: The grasp reflex in newborn babies
Knee jerk reflex
Coughing or sneezing
Blinking

Question 11

How do reflexes work?

Answer 11

1. Electrical impulse passes from receptor along sensory neurones to the CNS
2. It then passes along a relay neurone (in spinal cord) and straight back along motor neurone
3. Impulse arrives at effector organ
   This is called a reflex arc
   This is where the impulse bypasses the conscious areas of the brain
   Result = the time between the stimulus and reflex action is as short as possible

Question 12

What is the sequence of the reflex pathway?

Answer 12

Stimulus -> receptor -> sensory neurone -> relay neurone (spinal cord)-> motor neurone -> effector -> response