Exam 2 Study Guide 2 Flashcards
stretch reflex
- monosynaptic
- muscle contraction in response to a quick stretch
stretch reflex aka
- myotatic
- muscle stretch reflex
- deep tendon reflex
cutaneous reflex
- goes along with flexion withdrawal reflex
- If you step on something sharp, you have a cutaneous reflex that causes a flexion withdrawal reflex
flexion withdrawal reflex
movement of a limb away from a stimulus
inverse myotatic reflex
AUTOGENIC INHIBITION
- agonist muscle relaxes after being stretched
- ex. stretching quads causes them to relax
reciprocal inhibition in a stretch reflex
- monosynaptic to agonist
- polysynaptic to antagonist
stretch reflex: decussation?
no
withdrawal reflex: poly/mono
polysynaptic
flexion reflex: decussation
- no decussation
- ipsilateral inhibition of extensors + contraction of flexors
crossed extension portion: decussation
- decussates in SC
- contralateral inhibition of flexors + contraction of extensors for WB
medial CST: direct connection from
cerebral cortex to SC
path of medial CST
motor cortex
» medullary pyramids
» SC
(descends in ventral funiculus)
medial CST: decussation
does not cross
- innervates ipsilateral side of LMN of trunk, neck, and shoulder
Which tract is the most important one controlling voluntary movements?
lateral CST
path of lateral CST
motor cortex (motor planning areas)
» axons through internal capsule in peduncles
» through pons/medulla
» 90% of neurons cross at pyramidal decussation
» travels to SC and synapses with LMN
reticulospinal tract
- begins in reticular formation
- facilitates bilateral LMNs that innervate postural and gross limb movement of muscles throughout the body
rubrospinal tract path
red nucleus
» decussates immediately in brainstem
» travels to cervical cord
» innervates UE (extensors of wrist/fingers)
corticobulbar tracts: purpose
- how we get info through cranial nerves and to the face
- motor homunculus through brainstem
corticobulbar tracts are important for
- expression
- swallowing
- talking
medial CST: synapse between UMN/LMN
cervical spinal cord
medial CST: decussation
no
- ipsilateral only
medial CST: muscles innervated
- back muscles
- shoulder
- neck
medial CST: function
control neck, shoulder, and trunk muscles (posture)
lateral CST: start/finish
start: primary motor, premotor, supplementary motor areas
finish: contralateral innervation of limbs
lateral CST: synapse between UMN/LMN
cervical spinal cord
lateral CST: decussation
some do (lower medulla), some dont
lateral CST: muscles innervated
- distal limbs
- fractionate movements
lateral CST: function
precise control of contralateral movements of limbs, fractionate movements
rubrospinal tract: start/finish
start: red nucleus in midbrain
finish: contralateral upper limb muscles
rubrospinal tract: synapse between UMN/LMN
cervical spinal cord
rubrospinal tract: decussation
yes, midbrain
rubrospinal tract: function
extends wrist and fingers
lateral and medial vestibulospinal tracts (inputs)
receive inputs from vestibular apparatus in the ear
- about head position and movement (medial)
- about gravity (lateral)
