structure of nerves

Question 1

neurons

Answer 1

• structural units of nervous system
• can function for a lifetime in the right conditions
• can not undergo mitosis

Question 2

neuroglia

Answer 2

• glial cells produce myelin

- nerve cell; glue

Question 3

structure of neuron

Answer 3

• membrane, cytoplasm, cell organelles and nucleus

- long thing processes (fibres of cytoplasm)

Question 4

motor neuron

Answer 4

• cell body (Nissl body, cell membrane, nucleus and neuroplasm)
• dendrites (collects informations and passes it on)
• node of Ranvier (rapid conduction of pulses)
• Schwann cell (wrapped around axon, secretes the myelin sheath)
• axon (carries impulses away from cell body)
• myelin sheath (electrical insulation)
• terminal branches (carry impulses to synaptic knob)
• synaptic knob (forms synapse with another neuron)

Question 5

sensory neuron

Answer 5

• afferent neurons carrying impulses from receptors to CNS

- unipolar (one fibre attached to cell body

Question 6

connector neuron

Answer 6

• relay neurons / association neurons / interneurons
• multipolar (many fibres attached to cell body)
• ## receive impulses from sensory neurons and pass them on to other neurons

Question 7

motor neurons

Answer 7

• efferent neurons carrying impulses away from CNS to effectors
• brings about the appropriate response

Question 8

nerves

Answer 8

• neron fibres
• tracts in CNS, nerves in PNS
• bound together by bundles of connective tissue (perineurium)
• inside bundles surrounded by delicate connective tissues (endoneurium)
• entire nerve surrounded by connective tissue (epineurium)
• artery and vein between bundles
• carry impulses

Question 9

nerve impulses

Answer 9

• resting potential
• polarized membrane when resting
• resting potential is the difference in charge across the cell membrane
• active potential
• conduction of nerve impulses
• once stimulated there is a rapid reversal of charge in a cell (depolarisation)
• stimulus is strong enough it becomes a burst of electrical activity (nerve impulses)
• all-or-nothing response (if the threshold potential is not reached no impulses will be generated
• refractory potential
• recovery stage where a membrane becomes repolarised once an impulse has passed along
• by carrier molecules actively transporting ions back to their original positions