The Nervous System 2 Flashcards
What is the sensory supply to the organs?
Including arterioles, sweat glands etc
Visceral afferent
What is sensed by mechanoreceptors?
Coarse and fine touch
Vibration
Proprioception
What is felt by nociceptors?
Pain - sharp, stabbing, well localised
Roughly describe the route along which a somatic sensation would take back to the CNS?
Stimulation if the specific dermatome
AP continues along the anterior rams
AP continues to the spinal cord of that level
AP continues along axons to posterior roots and rootlets of same level
AP continues into the posterior horn of spinal cord and synapses onto a 2nd neurone
AP cross over the mud lone and ascend towards the thalamus and synapse onto a 3rd neurone
AP continues to the cerebral cortex
What happens in the left parietal lobe in the primary somatosensory area?
Sensory AP’s arrive here from the RIGHT side of the body wall
Describe upper motor neurone?
Originates opposite side form the movement
axons cross over at brainstem
Describe lower motor neurone?
Originates same side as the movement
Connects to skeletal muscle
What is in the frontal lobe?
The primary somatomotor area
What happens when a right sided skeletal muscle is moved?
The left frontal lobe in the primary somatomotor area is where the AP originated from
Roughly describe the route along which a motor sensation would take from the CNS to the muscle?
AP generated by voluntary intention in the LEFT primary somatosensory cortex
AP conducted via upper motor neurone axons cross in brainstem and reach the anterior horn of the spinal cord
The upper motor neurone synapses with the lower motor neurone stimulating an AP
The AP continues along the axons of the same level spinal nerve
AP continues to either anterior rams
AP anterior rami weave through the plexus via a named nerve
AP then reaches the neuromuscular junction of the supplied muscle
What is the spinal reflex and what does it miss out?
It is very rapid and it misses out the pathway to the brain
It is a protective involuntary response
What is paralysis?
a muscle without a functioning lower motor neurone is “paralysed”
a paralysed muscle cannot contract
on examination the muscle would have reduced tone
What is spasticity?
the muscle has an intact and functioning lower motor neurone
the descending controls from the brain are not working
on examination the muscle would have increased tone
What would the pain felt from visceral afferents be like?
Dull, achy, poorly located can be referred pain too
Describe some actions of the sympathetic nervous system?
Increased HR
Decreased motility
increased release of adrenaline
