9. somatic nervous system

what is a neurone

nerve cell

- functional unit of nervous system

neurone structure

dendrites

soma

axon

axon terminal

types of neurones

bipolar

pseudonipolar

multipolar

types of neuroglial cells in CNS

astrocytes

microglial cells

ependymal cells

oligodendrocytes

myelin sheath

surrounds axon

lipid and protein layer

increases velocity of impulse conduction

whats the important thing about myotomes

one muscle myotome may include several spinal segments

clinical relevance of dermatomes and myotomes

to test for motor and/or sensory loss of one or more spinal nerves/segments by testing joint movements or an area of skin in neuro disorders

motor end plate

neuromuscular junction

histology of spinal cord

Includes central canal, dorsal horn, ventral horn, site of ventral root, and ventral fissure

histology of peripheral nerve

looks like a finger print

somatic nervous system

motor

- voluntary control

- skeletal muscle

sensory

- pain, touch, temperature, proprioception (SKIN)

visceral nervous system

motor

- involuntary - ANS

sensory

- visceral pain, chemoreception, stretch receptors (ORGANS)

somatic motor fibre

regulates voluntary control of body movements via skeletal muscle

somatic sensory fibre

transmits general sensation - pain, touch temperature, proprioception - to CNS

spinal cord injury

- roots

sensory OR motor loss

- ventral root = MOTOR loss

- dorsal root = SENSORY loss

spinal cord injury

- spinal nerve

motor AND sensory loss

spinal cord injury

- rami

motor AND sensory loss

- ventral ramus - motor and sensory loss of anterolateral trunk and limbs

- dorsal ramus - motor and sensory loss of back

what does the spinal nerve carry

sympathetic fibres

where does the spinal nerve exit

intervertebral foramen

spinal nerve compression

back pain

Where does the spinal cord end?

L1-L2

5 components of somatic reflex arc

1) receptor responds to stimuli

2) afferent neurone carries signal to CNS

3) integrating centre in CNS initiates response

4) efferent neurone carries signal to effector

5) response from effector

wrist drop

damage to radial nerve