Reflexes Flashcards
What is a reflex arc consist of?
an afferent neuron, spinal cord segment, efferent neuron and motor unit
Is the menace response, a reaction or reflex?
Reaction
What characterizes a reaction?
- cortical awareness
* voluntary behavior
Monosynaptic spinal reflex
involves signal to a single efferent nerve
Polysynaptic spinal reflex
- associated with an interneuron
* signals many efferent nerves, inhibitory or stimulatory
Upper Motor neuron
cell bodies in the brain, terminate at the spinal cord (synapse with a LMN)
Lower Motor Neuron
cell bodies in the spinal cord, terminate at teh target organ (muscle or gland)
Pupillary light reflex
afferent: CN2
efferent: CN3`
Corneal Reflex
Afferent: opthalmic br. of trigeminal (V)
Efferent: VII (for blink), VI ( retraction of globe and passive movement of 3rd eyelid)
Palpebral Reflex
Afferent: maxillary br. of V (lateral canthus)
opthalmic br of V (medial canthus)
Efferent: VII
Menace Response
afferent: CN2
Efferent: VII –> orbicularis occuli
Is pain a reflex or response?
response
Panniculus reflex tests the integrity of
afferent n, spinal cord segments, lateral thoracic nerve and cutaneous trunci m
How to test the Panniculus reflex?
pinch the skin over the dermatomal area in dorsal thoracolumbar area (T2-L4)
What are the components of the panniculus reflex?
afferent n: superficial pain receptors
spinal segment: thoracic nerve locate (C8-T1)
Efferent n: lateral thoracic n
Motor Unit: Contractin of cutaneous trunci mm
Withdrawal reflex is testing
withdrawal of limb being stimulated
What are the components of the withdrawal reflex (at teh pes)
Stimulation of plantar surface of pes (tibial n) to lumbosacral intumescence (L4-S2), interneuron excites efferent LMN’s to activate flexors of teh limb and inhibit extensors)
What is the crossed- extensor reflex?
extension of teh limb opposite a withdrawal stimulus
When is the crossed-extensor reflex normal?
Is is normal in teh standing patient only!!!!!!
***not normal in recumbant patient
If crossed extensor reflex occurs while an animal is recumbant, you know the lesion is located where
The defect is located in the spinal cord cranial to the reflex
Perineal Reflex tests the integrity of
segments S1-3 and the pudendal n
What is the efferent and afferent in the Perineal reflex?
Afferent: caudal rectal and perineal br. of pudendal n.
Efferent: cadual rectal br of pudendal n
The myotatic reflex is also known as the
muscle spindle reflex, tendon tap reflex, stretch reflex
The myotatic reflex is a protective reflex by
preventing over stretch of a ligament, by increasing tone to the muscle being stretched
Patellar reflex is an example of what kind of reflex?
myotatic
What two different types of stretch can be used to induce the myotatic reflex?
tonic and phasic stretch reflex
Tonic stretch reflex
manipulate limbs to determine resistance to passive movement
Phasic stretch reflex
use reflex hammer to strike tendon and rapidly stretch muscle
Is clonus normal in a myotatic reflex?
no
What is clonus?
When a reflex is repeated, after the initial reflex is over
What does the circuit of the pain response involve?
intact nociceptive afferent fibers, spinal segment, ascending UMN tract from initial afferent neuron to the brain and normal parietal lobe in the brain
