1

2

c

de

3

4

axon

Cell body

dendron

5

f

6

Node of Ranvier

White fat from Schwann cell

7

Myelin sheath:

Faster nerve impulse,

Protection, Insulation

axon

8Sensory neuroneSensory neurone

Motor neuroneMotor neurone

Relay neuroneRelay neurone

11

33

22

CNS

9

11

33

22

10

Cell body

11

12Na-K pumpFacilitated diffusion

13

-ve

bb

cc

dd

14Action Potential: change of membrane permeability to Na & K

channel opens = permeability increases

15

K Na=0

(K outflux)

K Na (Na influx) K

Na=0 (K

outflux)

K Na=0

(too much K outflux)

K Na=0

(K outflux)

16

K Na=0

K Na K

Na=0

K ,Na=0

K Na=0

depolarizationrepolarization

hyperpolarization

polarization

17

Na perNa per K perK per

potential potential differencedifference

K per>Na per

Na per>>K per

K per >>Na per

K per> Na per

18

freq. only

19

Wave of negativity

along axon

surface

20

depolarization

polarization

repolarization

Pump out Na & prepare for next

impulse

p.d

21

22

1. Axon Diameter (thicker > faster)

2. Myelin Sheath (faster)

3. Temperature (higher > faster)

1. Axon Diameter (thicker > faster)

2. Myelin Sheath (faster)

3. Temperature (higher > faster)

23

postsynapticpostsynaptic

presynapticpresynaptic

presynapticpresynaptic

24

Synaptic knob

Cell body

Nucleus of cell body

axon

25

Synaptic vesicle

Presynaptic membrane

Postsynaptic membrane

Synaptic cleft

Synaptic knob mitochondria

26

postsynapticpostsynaptic

presynapticpresynaptica

b

c

depolarization

d) Na influx, depolarizarion

27

28

29a b

c d

e f

30

1.Ensure impulse to pass in one direction

2.Prevent damage of effectors due to over stimulation

3.Act as junctions for dividing up and merging of neurones

1.Ensure impulse to pass in one direction

2.Prevent damage of effectors due to over stimulation

3.Act as junctions for dividing up and merging of neurones

31