Sensory Receptors and Cranial Nerves Lecture Notes

A comprehensive set of flashcards covering key concepts related to sensory receptors, reflexes, and cranial nerves.

Hyperreflexivity

An overactive or overresponsive reflex.

Hypoactive

Decreased reflex response.

Somatic Reflex

A reflex involving a spinal nerve that targets skeletal muscle.

Spinal Cord Reflex

A reflex that involves spinal nerves with CNS synapses only in the spinal cord.

Stretch Reflex

A spinal cord reflex that helps maintain body position by correcting muscle stretch.

Deep Tendon Reflex

A spinal cord reflex that helps maintain body position by correcting muscle over-contraction.

Acuity

The ability to discriminate between stimuli.

Punctate Distribution

Describes sensory receptors in the skin that are clustered and unevenly distributed.

Rapidly Adapting Receptors

Receptors that respond to a new or changing stimulus but not to a maintained stimulus.

Receptive Field

The particular region of sensory space that triggers the firing of a neuron.

Slowly Adapting Receptors

Receptors that maintain their response to a stimulus.

Two Point Threshold

The smallest separation between two stimuli on the skin that is perceived as two points, indicating a larger receptive field and reduced acuity.

Exteroreceptors

Receptors located on the body surface that receive stimuli from outside the body (e.g. touch, vision).

Interoreceptors

Receptors located within the body that detect internal stimuli (e.g. blood pressure, CSF pH).

Proprioceptors

Receptors that detect stimuli associated with the location and position of the body in space.

Mechanoreceptor

Receptors stimulated by forces that change the shape of tissues (e.g. touch, hearing).

Thermoreceptor

Receptors that detect temperature or temperature changes.

Photoreceptor

Receptors stimulated by light.

Chemoreceptor

Receptors that detect chemicals in a solution (e.g. taste, smell, oxygen).

Nociceptor

Receptors that detect pain.

General Senses

Receptors for general senses that are widely distributed throughout the body (e.g. pain, touch, temperature, proprioception).

Special Senses

Receptors for special senses that are densely located in complex sensory organs within the head (e.g. vision, taste, smell, hearing).

Cranial Nerves

12 pairs of nerves that originate from nuclei in the brain and primarily affect the head and neck.

1. Olfactory Nerve

Cranial nerve responsible for the sense of smell.

2. Optic Nerve

Cranial nerve responsible for vision.

3. Oculomotor Nerve

Cranial nerve responsible for eye movement and pupil constriction.

4. Trochlear Nerve

Cranial nerve that contracts the superior oblique muscles of the eye.

5. Trigeminal Nerve

Mixed cranial nerve responsible for facial sensation and motor functions of the jaw.

6. Abducens Nerve

Cranial nerve that abducts the eye by contracting the lateral rectus muscle.

7. Facial Nerve

Mixed cranial nerve responsible for facial expression and taste from the anterior two-thirds of the tongue.

8. Vestibulocochlear Nerve

Cranial nerve responsible for hearing and balance.

9. Glossopharyngeal Nerve

Mixed cranial nerve responsible for taste from the posterior one-third of the tongue.

10. Vagus Nerve

Mixed cranial nerve responsible for sensory and motor functions to body organs, including heart rate and digestion.

11. Accessory Nerve

Motor cranial nerve that innervates the sternocleidomastoid and trapezius muscles.

12. Hypoglossal Nerve

Motor cranial nerve responsible for tongue movements.