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Co-ordination. Electrical messenger Chemical messenger. Nervous System. Neuron. dendron. cytoplasm. nucleus. cell membrane. direction of nerve impulses. axon. nucleus of cell which makes the myelin sheath. Nerve fiber. Myelin Sheath. Protection of nerve fiber
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Co-ordination Electrical messenger Chemical messenger
dendron cytoplasm nucleus cell membrane direction of nerve impulses axon nucleus of cell which makes the myelin sheath
Myelin Sheath Protection of nerve fiber Speed up impulse transfer
- - + + + Rest Potential • More + ion outside the nerone • Na K pump • K channel • Big - ions
Action potential mechanism • Depolarization • Stimulus to threshold • Na channel open • Inside nerone turn +ve. • Repolarization • Potential rise inside nerone to max • Na channel close • More k channel open so hyperpolarised • Rest potential established by na k pump.
Na open Refractory period K open Na close
synapse • 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
SynapticCleft Neurotransmitter in vesicle release to cleft. It diffuse to another side and attach on surface receptor. Enzyme next to receptor break down. Transmitter
dorsal root ganglion sensory neurone receptor (pain) dorsal root (sensory nerve) association neurone effector(muscle) spinal cord motor neurone ventral root (motor nerve) Reflex arc :sensory,association,motor neurones
white matter grey matter spinal nerve central canal spinal cord
cranial nerve spinal nerve Peripheral Nervous System • consist of cranial nerves and spinal nerves • these nerves leave CNS and run out to every part of the body
Endocrine System Hormone concept Steroid 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.
Feedback mechanism Negative feedback reduce hormone production when effect of hormone expressed
Endocrine and Exocrine Blood vessel Secretary duct
Adrenal gland Adrenalin
Pancreas Islet of langerhans
Control of endocrine system Hormone control hormone Nerve control hormone
Posterior Anterior Anterior and Posterior Pituitary gland