spinal tracts

Question 1

what do gray commissures contain?

Answer 1

decussating neurons- if you touch with left side then right side of brain will light up

Question 2

what the difference between dorsal horns and ventral horns

Answer 2

dorsal contains somatic and autonomic sensory nuclei
-ventral has somatic motor nuclei

Question 3

lateral horns

Answer 3

only present from T1-L2/L3
have cell bodies of preganglionic sympathetic neurons

Question 4

what is the somatic nervous system main functions

Answer 4

conscious awareness (senses) and control (movement)

Question 5

where are the sensory receptors in the somatic NS located

Answer 5

skin, muscles and joints

Question 6

what are the effector organ in the somatic NS

Answer 6

skeletal muscle

Question 7

somatic sensory pathway for fine touch, pressure or proprioception

Answer 7

start at sensory receptor(1st order neuron)-> decussates and synapses in medulla oblongata(2nd order neuron)-> synapse in thalamus (relays and sorts info so that you are aware of the nature of stimulus and location) (3rd order neuron)-> end at primary somatosensory cortex

Question 8

anterior tract (spinothalamic)

Answer 8

crude and pressure:
starts at sensory receptor-> decussates and synapses at spinal cord at level of entry-> synapses in thalamus-> end at primary somatosensory cortex

Question 9

lateral tract (spinothalamic tract)

Answer 9

pain and extreme temp:
starts at sensory receptor-> decussates and synapses at spinal cord at level of entry-> synapses in thalamus-> end at primary somatosensory cortex

Question 10

spinocerebellar sensory tract (enters spinal cord ends and cerebelum)

Answer 10

processes proprioceptive sensations(coordination of body movements)
-doesnt reach thalamus

Question 11

somatic sensory vs motor

Answer 11

somatic sensory:
- transmits sensations that we are conscious of
-3 order neurons
somatic motor:
-transmits info to skeletal muscle
-2 motor neurons

Question 11

lateral corticospinal tract

Answer 11

start primary motor cortex-> decussates in pyramids of medulla oblongata-> synapses w lower motor neuron in ant horns of sc-> innervates most skeletal muscles in limbs

Question 11

anterior corticospinal tract

Answer 11

starts primary motor cortex->decussates at ant white commissure-> synapses w lower motor neuron in ant horn of sc-> innervates mostly neck, should and trunk (skeletal m)

Question 12

corticobulbar tract

Answer 12

starts primary motor cortex-> decussates at brainstem-> synapses w lower motor neuron in motor nuclei of some of cranial nerves

Question 13

what happens when there’s a spinal cord injury

Answer 13

• inhibits passage of electrical impulses in both directions at level of injury