Nervous and stimuli response

Question 1

Stimulus

Answer 1

Detectable change in the
environment
detected by cells called
receptors

Question 2

Nervous system
structure

Answer 2

Central nervous system = brain
and spinal cord
peripheral nervous system =
receptors, sensory and motor
neurones

Question 3

Simple reflex
arc

Answer 3

Stimulus (touching hot object)
-> receptor
-> sensory neurone
-> coordinator (CNS / relay neurone
-> motor neurone
-> effector (muscle)
-> response (contraction)

Question 4

Importance of
simple reflexes

Answer 4

Rapid - short pathway
only three neurones & few
synapses
autonomic
conscious thought not
involved - spinal cord
coordination
protect from harmful stimuli
e.g., burning

Question 5

Receptors

Answer 5

Cells that responds to specific
stimuli
stimulation of receptor leads to
establishment of a generator
potential - causing a response
pacinian corpuscle
rods
cones

Question 6

Pacinian
corpuscle

Answer 6

Receptor responds to pressure
changes
occur deep in skin mainly in
fingers and feet
sensory neurone wrapped with
layers of lamellae

Question 7

Pacinian
corpuscle
structure

Answer 7

• Outer capsule
• lamellae ( looks like rings of membrane)
• sensory neuron ( thin long structure)
• schawnn cell

Question 8

How pacinian
corpuscle
detects pressure

Answer 8

When pressure is applied,
stretch-mediated sodium ion
channels are deformed
sodium ions diffuse into
sensory neurone
influx increases membrane
potential - establishment of
generator potential