Whales Reflexes

Question 1

Biceps Brachii m.

Muscle Spindle Reflexes

Answer 1

Stimulus: tap tendon of insertion at the bicepis brachii
Primary afferent n.: musculocutaneous n.
Spinal Cord Segments: C6, 7(major), 8
Efferent Limb n.: musculocutaneous n.
Effectors (mm & action): contraction of biceps m, flexion of the elbow

Question 2

Triceps brachii m.

Answer 2

Stimulus: strike the triceps tendon just proximal to the olecranon tuberosity
Primary afferent n.: radial n.
Spinal Cord Segments: C7,8 T1(2)
Efferent Limb n.: (also to evaluate the caudal brachial plexus)
Effectors (mm & action): extension of the elbow, contraction of the m. triceps brachii

Question 3

Thoracic limb withdrawal

Answer 3

Stimulus: pinch web between toes
Primary afferent n.: radial, median, and/orulnar
Spinal Cord Segments: C5 – T1(2)
Efferent Limb n.: brachiocephalicus, axillary, musculocutaneous, median, and ulnar nerves
Effectors (mm & action):

Question 4

Patellar tendon tap

Answer 4

Stimulus: patellar ligament
Primary afferent n.: femoral nerve
Spinal Cord Segments: L4,5,6
Efferent Limb n.:
Effectors (mm & action): contraction of the quadriceps femoris muscle, extension of the stifle

Question 5

Gastrocnemius m. Reflex

Answer 5

Stimulus: tap the tensioned gastrocnemius tendon just proximal to its attachment on the tuber calcaneus.
Primary afferent n.: tibial branch (of the sciatic nerve)
Spinal Cord Segments: L6-S2
Efferent Limb n.:
Effectors (mm & action): rapid contraction of muscle or slight extension of tarsus

Question 6

Pelvic limb withdrawal

Answer 6

Stimulus: squeeze web between digits
Primary afferent n.: sciatic n
Spinal Cord Segments: The sciatic nerve (spinal cord segments L6, L7, & S1 (2)) , femoral nerve (spinal cord segments L4, L5, & L6)
Efferent Limb n.: sciatic and femroal n.
Effectors (mm & action): flex each of the pelvic limb joints in sequence

Question 7

Perineal reflex

Answer 7

Stimulus: Gently pinch the perineum (laterally, dorsally, and ventrally) with a hemostat
Primary afferent n.: pudendal nerve (spinal cord segments S1 – S3)
Spinal Cord Segments:pudendal nerve (spinal cord segments S1 – S3), Constriction of the external anal sphincter is elicited by the caudal rectal branch of the pudendal nerve (S1 – S3). Ventral tail flexion is mediated by the sacral (S1 – S3) and caudal spinal cord segments.
Efferent Limb n.: Constriction of the external anal sphincter is elicited by the caudal rectal branch of the pudendal nerve (S1 – S3). Ventral tail flexion is mediated by the sacral (S1 – S3) and caudal spinal cord segments.
Effectors (mm & action): Noxious stimulation of the perineum should result in constriction of the external anal sphincter and ventral flexion of the tail.

Question 8

Crossed extensor reflex

Answer 8

Stimulus:
Primary afferent n.:
Spinal Cord Segments:
Efferent Limb n.:
Effectors (mm & action):

Question 9

Cutaneous trunci m. Reflex

Answer 9

Stimulus: light pinch of skin lateral to midline
Primary afferent n.:
Spinal Cord Segments: spinal cord damage t3-l3
Efferent Limb n.:
Effectors (mm & action):