Co-ordination Electrical messenger Chemical messenger

Co-ordination

Electrical messenger

Chemical messenger

Nervous System

Neuron

cytoplasm dendron

cell membrane

nucleus

nucleus of cell which makes the myelin sheath

axon

direction of nerve

impulses

Nerve fiber

Myelin Sheath

•Protection of nerve fiber•Speed up impulse transfer

Rest Potential- - +

+

+

More + ion outside the nerone

1. Na K pump

2. K channel

3. Big - ions

Action potential

Action potential mechanism

• DepolarizationStimulus to thresholdNa channel openInside nerone turn +ve.• RepolarizationPotential rise inside nerone to maxNa channel closeMore k channel open so hyperpolarisedRest potential established by na k pump.

Na open

K open

Na close

Refractory period

ending of axon secretes a chemical which diffuses into synapse and stimulates the next neurone to pass on the impulse

the chemical is unstable and will be destroyed later

synapse

Synapse

Synapse mechanism

Go

SynapticCleft

Neurotransmitter in vesicle release to cleft. It diffuse to another side and attach on surface receptor. Enzyme next to receptor break down. Transmitter

Brain

dorsal root ganglion

dorsal root (sensory nerve)

associationneurone

spinal cord

ventral root (motor nerve)motor neurone

sensory neurone

effector(muscle)

receptor(pain)

Reflex arc : sensory, association, motor neurones

white matter grey matt

er central canal

spinal cord

spinal nerve

Peripheral Nervous SystemPeripheral Nervous System

consist of cranial nerves and spinal nerves

these nerves leave CNS and run out to every part of the body

spinal nerve

cranial nerve

Spinal Cell

Endocrine System

Hormone conceptSteroid concept

Endocrine organs

Hormone concept

Hormone is chemical messenger.It required a fitted receptor.Hormone attaching to receptor calls response.

Hormone concept 2

Hormone required blood vessel to transport to whole

body.

Water soluble hormone

Water soluble hormone only attach to membrane receptor.

Fat soluble hormone (steroid)

Steroid can penetrate cell membrane and bind to internal receptor.

Example of steroids

Feedback mechanism

Negative feedback reduce hormone production when effect of hormone

expressed

Endocrine and Exocrine

Blood vessel

Secretary duct

Endocrine organs

Adrenal gland

Adrenalin

Photo of adrenal gland

Pancreas

Islet of langerhans

Thyroid gland

Pituitary gland

Control of endocrine system

Hormone control hormone Nerve control hormone

Anterior and Posterior Pituitary gland

AnteriorPosterior

Photo of pituitary gland