5.1.3 neuronal communication

Question 1

Neurone features

Answer 1

Cell body
Dendrons
Axon

Question 2

Cell body

Answer 2

Contains organelles found in a typical animal cell, including nucleus
Proteins and neurotransmitter chemicals made here

Question 3

Dendron

Answer 3

Carry the action potentials to surrounding cells

Question 4

Axon

Answer 4

Conductive, long fibre that carries nervous impulse bang motor neurone

Question 5

Myelinated neurone

Answer 5

Schwann cells wrap around axon to form myelin sheath - lipid so doesn’t allow charged ions to pass through it
Gaps between myelin sheath called nodes of ranvier

Question 6

Saltatory conduction

Answer 6

Action potential jumps from node to node due to myelin sheath so it travels faster

Question 7

Sensory neurone

Answer 7

Carry electrical impulses from receptor to relay neurone
Has a long dendron so that impulse goes from sensory receptor cell → cell body → axon → next neurone

Question 8

Relay neurone

Answer 8

Impulses from sensory → motor neurone
Multiple short axons and dendrons

Question 9

Motor neurone

Answer 9

Impulses carried from relay or sensory neurone to effector
One long axon and multiple short dendrites

Question 10

Effector

Answer 10

Muscles or glands

Question 11

Sensory receptor

Answer 11

Detect a stimulus
Transducer = converts different types of stimuli into electrical nerve impulses

Question 12

Photoreceptors

Answer 12

Detect light

Question 13

Thermoreceptors

Answer 13

Detect heat

Question 14

Mechanoreceptors

Answer 14

Detect pressure

Question 15

Pacinian corpuscle

Answer 15

Pressure receptors located deep in skin
Sensory neurone in pacinian corpuscle has special channel proteins in its plasma membrane

Question 16

What is a stretch mediated sodium channel in the pacinian corpuscle?

Answer 16

Open and allow sodium ions to enter sensors neurones only when they are stretched and deformed

Question 17

What happens when pressure is applied to the pacinian corpuscle

Answer 17

Deform the neurone plasma membrane, stretches and widens sodium ion channels so sodium ions diffuse in → generator potential established

Question 18

Resting potential

Answer 18

More positive ions like sodium and potassium outside of neurone compared to inside
Inside of neurone more negative = -70 mv

Question 19

How is a resting potential established and maintained

Answer 19

Sodium-potassium pump involving active transport and ATP
Pump moves 2 potassium ions into axon and three sodium ions out
Creates electrochemical gradient causing potassium ions to diffuse out and sodium ions to diffuse in

Question 20

Why do we have a more negative inside compared to outside of neurone

Answer 20

Membrane more permeable to potassium 50 more more out → results in -70mv charge

Question 21

Action potential