function Flashcards
what are the functional subdivisions of the nervous system
the somatic nervous system and the autonomic nervous system
where does the somatic nervous system supply
the soma (body wall)
- head and neck walls
- chest walls
- back
- the diaphragm (its internal wall)
- abdominal wall
- pelvic wall
- limbs
and the external environment
- skin
- fascia
- skeletal muscle
- skeleton
- internal lining of the body cavity
where does the autonomic nervous system supply
visceral motor system and the internal environment
- viscera
- glands
- smooth and cardiac muscle
- external lining of organs
in what direction do motor nerve signals travel
motor (effernt):
action potential towards the body wall, body cavity or organ
in what direction do sensory nerve signals travel
sensory (afferent):
action potential towards brain
what is the sensory supply of the soma (body wall) and the motor supply
somatic sensory
somatic motor
what is the sensory and motor supply of the organs
visceral afferent and motor supply is sympathetic and parasympathetic
what is the sensory supply and the motor supply of the special sense organs (eg. eyes)
special sensory and the motor supply is sympathetic and parasympathetic
describe the somatic sensation from the L2 dermatome to the cerebral cortex
- somatic sensory mechanoreceptors in L2 dermatome are stimulated
- APs conducted along axons within the L2 anterior ramus
- the same L2 axons weave their way through the lumbar plexus to the L2 spinal nerve
- APs conducted via the same axons which pass through the dorsal root ganglion, the posterior roots
and posterior rootlets - APs arrive at the posterior horn of the L2 spinal cord segment
- AP’s synapse in posterior horn onto 2nd sensory neurone
- AP’s cross over the midline and then ascend towards the thalamus and cerebral cortex
describe the somatic motor innervation to move the lower limb
- somatic motor axons from cerebral cortex cross over in brainstem then descend to the anterior horn
- APs conducted along axons within anterior rootlets, then anterior roots, then into spinal nerves
- APs conducted along axons in named nerves of lumbar plexus
- Synapse onto skeletal muscle of lower limb
- skeletal muscles contract and move the lower limb
what is the motor pathology of the upper and lower motor neuron
upper motor neurone
- opposite side from movement
- axons cross over at brainstem
- upper motor neurone lesion
lower motor neurone
- same side as movement
- connect to skeletal muscle
- lower motor neurone lesion
what is muscle papalysis and how is it caused
A muscle without a functioning lower motor neuron is paralysed, and this muscle cannot contract. on examination the muscle would have reduced tone
what is muscle spasticity and how is it caused
the muscle has an intact and functioning lower motor neuron, it is the descending controls from the brain that are not working (upper motor neuron damage). on examination the muscle would have increased tone.
what is the sympathetic division of the ANS and what does it supply
it is the ‘fight or flight’ response, where pupils dilate, HR increases, adrenaline is released etc
it suppys all internal organs and body wall organs and arterioles
describe the autonomic sympathetic outflow from the autonomic centres in the brain to the organs etc
originates from the autonomic centres in the brain, passes down the spinal chord, exits the spinal chordwith T1-L2 spinal nerves. then travels to sympathetic chains running the length of the vertebral column.
pass to anterior and posterior rami to then supply the body wall structures (skin etc) or travel via splanchnic nerves to reach organs
