Reflexes and Responses Flashcards
True/False. A conscious integration occurs at the level of the spinal cord and will give us a reflex.
False. Unconscious
A reaction/ response occurring in the cortex of the brain is what kind of integration?
Conscious
What kind of a reflex and response to a stimulus is the withdrawal of a limb?
Unconscious response, somatic reflex
The bladder reflex is what kinda of reflex?
Visceral reflex
Which of the following is false regarding the reflex arc?
a. If any component in the reflex circuit is “broken,” reflex will not happen
b. Can have both somatic and visceral reflexes
c. The reflex requires the cerebral cortex for conscious response
d. All the above are true
c. The reflex requires the cerebral cortex for conscious response
- reflex does NOT require cerebral cortex = unconscious
What sections of the spinal cord are examined for a gait analysis?
Cervicothoracic region C6-T2
Lumbosacral region L4-S2
How will an animal respond if the myotactic/stretch arc is intact?
They will “push back” or kick their legs out
How will an animal respond to a cutaneous stimulation, light pinch, in the limbs if the arc is intact?
Withdrawal the limb (withdrawal/ flexor reflex)
What reflexes can you use the Stretch (Myotactic) Reflex to test?
Patellar reflex
Triceps reflex
Biceps reflex
What is clonus?
When the muscle relaxes after a reflex is over and then joint/ tendon stretches again “cloning” the reflex
Upper brain centers present the clonus via inhibition of ____ activity.
Lower Motor Neuron
What is usually associated with an UMN disorder?
Hyper-reflexive state and/or clonus
What can we use cutaneous stimulation to test?
Autonomous zones of various nerves
Panniculus (cutaneous trunci) reflex
Recumbent withdrawal/crossed extensor reflex
Perineal reflex
What is the Panniculus Reflex useful for?
Locating C8 and T1 spinal cord lesion and their contribution sot the lateral thoracic nerve
When testing the sensory stimulus of the panniculus reflex where do you begin and how far cranially do you progress when compressing the skin?
Begin at L4 and progress cranially to T2
Is the withdrawal (Flexor) Reflex monosynaptic or polysynaptic?
Polysynaptic
What segments of the spinal cord are you testing with the perineal reflex?
S1-S3 and the pudental nerve
What is the normal response of the perineal reflex when you pinch the skin near the anus/perineal region?
Tightening of the external anal sphincter muscle
What are the afferent and efferent nerves of the pupillary light reflex?
Afferent: Optic (CN II)
Efferent: Occulomotor (CN III)
What are the afferent and efferent nerves involved in the corneal reflex?
Afferent: Opthalmic branch of CN V
Efferent: Facial CN VII (blink); Abducens CN VI (retraction of the globe and passive movement of the 3rd eyelid)
What are the afferent and efferent nerves involved in the palpebral reflex?
Afferent: maxillary branch of CN V (lateral canthus) and opthalmic branch of CN V (medial canthus)
Efferent: Facial CN VII
Which two nerves are the main contributors to the micturition reflex?
Pudendal nerve and Pelvic nerve
True/False. The Pudendal nerve is the visceral afferent component that provides stretch receptors in the bladder wall.
False. Pelvic nerve
Which nerve stimulates somatic efferent neuron cells bodies in the sacral spinal cord resulting in the contraction of the external urethral sphincter?
Pudendal nerve
Activity of urine voiding stimulates contraction of ____ muscle and inhibits the contraction of _____.
Detrussor muscle
Internal urethral sphincter
What are the nerves that are involved in the micturition reflex?
Hypogastric nerve
Pelvic nerve
Pudendal nerve
What clinical signs would one see if there was an UMN lesion in the micturition reflex?
Hyperreflexive
Taut bladder
What are the afferent and efferent nerves involved in the menace response?
Afferent: Optic nerve CN II
Efferent: Facial nerve CN VII
Lower motor neurons are ____ neurons whose cell bodies are located in the spinal cord and specific brain nuclei
Somatic efferent neurons
True/False. UMN are both unconscious and conscious regulation
False. LMN
If we have an “inappropriate” reflex (hyper/hyporeflex), does this indicate an UMN lesion or LMN?
UMN
What is the name of the pathway that regulates fine-tuned skilled movements?
Pyramidal pathways
What is the extrapyramidal pathways?
UMN synapse onto interneurons and then onto LMN
What is the role of the extrapyramidal pathways?
Maintain muscle tone and initiate whole limb movements
Where do LMN axons directly synapse onto?
Skeletal muscle in the head and body
True/False. The spinal cord reflex in isolation is a reflexive and unregulated movement.
True
What is somatotopy?
Point-for-point correspondence of a specific body part to a specific region of the CNS
Which somatotopy motor pathway is going to be associated with posture and balance and mainly extensors?
Ventromedial motor systems
What is the dorolateral motor system/ column mainly associated with?
Fine/ precise movements
Distal muscles
Primarily flexors
What system is damaged if the animal produces decreased or absent voluntary movements of the whole limb (mostly extensors) caudal to the site of damage?
Ventromedial motor system
True/False. We will observe LMN signs at the site of the lesion/injury.
True
The GSE cannot stimulate the target tissue and we have no reflexive contraction of the skeletal muscle. Is this a UMN sign or a LMN sign?
LMN sign
If an animal has UMN lesion at C6-T2 will there be a reflex if we were to pinch the pelvic limb?
Yes! However, there will be no response or reflex if we are to pinch the thoracic limb
What are the lower motor neuron signs exhibited at the site of the lesion/injury?
- Paresis to paralysis
- Decreased to absent muscle tone
- Decreased to absent spinal reflexes
- Rapid onset muscle atrophy
