Reflexes and Reflex Arc

Gag Reflex

A normal reflex mechanism that causes retching; activated by touching the soft palate or the back of the throat. TESTS THE SOMATIC MOTOR RESPONSES OF CRANIAL NERVES IX AND X. WHEN THE ORAL MUCOSA IS STROKED EACH SIDE OF THE UVULA SHOULD RISE.

Ipsilateral Response

A reflex occurring on the same side stimulated.

Reflex Arc

A relatively direct connection between a sensory neuron and a motor neuron that allows an extremely rapid response to a stimulus, often without conscious brain involvement.

Somatic Reflexes

Activate skeletal muscle

Consensual Reflex

Allows both eyes to respond when you shine a light in one eye

Corneal Reflex

Closure of eyelids resulting from direct corneal irritation MEDIATED THROUGH THE TRIGEMINAL NERVE (CRANIAL NERVE V)

Integration center

Decodes signal

Ciliospinal

Handle of hammer to back of neck reaction of pupil on same side.

Plantar Flexion

Handle of mallet to bottom of foot.

Learned reflexes

Or Acquired reflexes Come from experience

Innate reflexes

Or Intrinsic reflexes A super fast motor response to a startling stimuli

Pupillary

Pen light in pupil, look at opposing pupil as well.

Cross-Extension

Pin prick arm, opposing hand, or Lift one leg observe the other.

Autonomic Reflexes

Pupillary Reflexes Ciliospinal Reflex Contraction of smooth or cardiac muscles or secretion of glands

Reflex

Rapid, predictable involuntary response to stimuli.

Superficial Cord Reflex

Reflexes that result from pain and temperature changes

Effector

Respond by contracting or secreting

Patellar/ Knee-Jerk

Rubber Mallet to Patellar ligament, crossed leg.

Achilles/ Ankle-jerk

Rubber mallet to Achilles tendon

Motor neuron

Sends directions back to site of stimulus

Receptor

Senses a stimulus (EX: Step on tack)

Spinal Reflexes

Stretch reflexes, Patellar, Achilles(activity 1, L2-L4 of the spinal cord), Reciprocal Inhibition. Crossed extensor reflexes (activity 2, at spinal cord level) Plantar reflexes: (activity 3, pyramidal tract). Babinski's Sign- Toes flaring or spreading, abnormal, except in babies.

Reciprocal Inhibition

The relaxation of the antagonist muscle in response to an agonist contraction is known as

Contralateral Response

The response observed on one side of the body when the opposite side has been stimulated.

Stretch Reflex

What reflex is initiated by stretching of muscle spindles and causes a contraction of the stimulated muscle and inhibits its antagonist

Cranial Nerve Reflex

corneal & lacrimation (ipsilateral CN V1 → bilateral CN VII), jaw jerk (CN V3 → V3), pupillary (ipsilateral CN II -LGN-to-pretectal-to-EW nucleus→ bilateral CN III), gag (CN IX → CN X)

Ciliospinal Reflex

dilation of the pupil on the painful side of stimulation. if absent there may be a lesion of the cervical sympathetics

Cremaster Reflex

male reflex in which brushing the skin in the superior aspect of the upper thigh causes the cremaster muscle to contract, causing the scrotum to elevate.

Abdominal Reflex

reflex that checks the integrity of the spinal cord and ventral rami from T8 to T12 brush along abs & umbilicus deviates toward stimulus = abnormal response (positive reflex)

Polysynaptic reflex arc

sensory neuron may fire onto a motor neuron as well as interneurons that fire onto other motor neurons

Monosynaptic reflex arc

single synapse between the sensory neuron that receives the stimulus and the motor neuron that responds to it Knee jerk reflex

Salivary Reflex

stimulate saliva production

Sensory neuron

transmits signal up to PNS