Sensory Physiology Lecture Flashcards

These vocabulary flashcards cover the general principles of sensory physiology, specific receptor types, cranial nerves, and the mechanisms of somatosensation, vision, audition, olfaction, and gustation as presented in the lecture.

Sensation

The conscious awareness of stimuli.

Receptor potential

A change in membrane potential that generates action potentials in the receptor cell or causes the release of a neurotransmitter.

Chemoreceptors

Functional types of receptors that detect specific molecules dissolved in fluid.

Thermoreceptors

Functional types of receptors that detect changes in temperature.

Photoreceptors

Functional types of receptors that detect changes in light intensity, color, and the movement of light.

Mechanoreceptors

Functional types of receptors that detect physical deformation due to touch, pressure, vibration, and stretch.

Nociceptors

Functional types of receptors that detect tissue damage and pain.

Ionotropic receptor proteins

Sensory receptor proteins that are ion channels themselves or directly affect ion channels, such as those found in mechanoreceptors and thermoreceptors.

Metabotropic receptor proteins

Sensory receptor proteins that affect ion channels through G proteins and second messengers, such as those in chemoreceptors and photoreceptors.

Coding

The conversion of a stimulus into a signal that is conveyed to the central nervous system.

Adaptation

The diminishing response of sensory cells to repeated stimulation, enabling animals to ignore background conditions.

Receptive Field (RF)

The specific area monitored by a sensory neuron; smaller fields generally correlate with higher resolution in cortical representation.

Merkel's discs

Mechanoreceptors in the skin that adapt slowly and provide continuous information.

Meissner's corpuscles

Mechanoreceptors in the skin that adapt quickly and provide information about change.

Ruffini endings

Deep mechanoreceptors that adapt slowly and react to low frequency vibrations.

Pacinian corpuscles

Deep mechanoreceptors that adapt rapidly and react to high frequency vibrations.

Kinesthesis

The sense of posture and movement initiated by somatic receptors.

Golgi tendon organ

A receptor located in tendons and ligaments that provides information about the force generated by muscle to prevent muscle tearing.

Dermatomes

Specific areas of skin usually innervated by a single spinal nerve, providing a "map" of affected areas if a nerve is damaged.

Referred pain

Pain that is perceived to occur at a site other than where the stimulus actually occurs.

Hyperalgesia

An increased sensitivity to painful stimuli that can last for hours after the original stimulus is over.

Analgesia

The selective suppression of pain without effects on consciousness or other sensations.

Rhodopsin

A photopigment consisting of the protein opsin and the light-absorbing group $11\text{-cis-retinal}$.

Transducin

The G protein activated when rhodopsin absorbs a photon of light in rod cells.

Rod cells

Photoreceptors responsible for night vision (Black & White) that hyperpolarize when light causes $Na^+$ channels to close.

Fovea

The area of the retina with the highest density of cone cells.

Accommodation

The process by which the lens changes shape to focus an image on the retina.

Horizontal cells

Cells in the retina that form synapses between photoreceptor cells to sharpen contrast between light and dark.

Amacrine cells

Retinal cells that form local interconnections between bipolar and ganglion cells, sensitive to changing illumination and motion.

Optic Nerve (II)

The cranial nerve responsible for vision and the detection of light by the pupil.

Oculomotor Nerve (III)

The "eye mover nerve" responsible for upward, downward, and inward eye movement, as well as pupil constriction.

Trochlear Nerve (IV)

The cranial nerve that innervates the superior oblique muscle for downward and inward eye movement.

Abducens Nerve (VI)

The cranial nerve that innervates the lateral rectus muscle for side-to-side eye movement.

Red-green color blindness

The most common form of color blindness, resulting from a recessive mutation in genes encoding cone pigments, affecting $1$ out of $12$ men.

Eustachian tube

A tube that opens to the throat and equilibrates air pressure between the middle ear and the outside.

Ossicles

The three bones of the middle ear (malleus, incus, and stapes) that transmit vibrations from the tympanic membrane to the oval window.

Organ of Corti

The structure sitting on the basilar membrane that transduces pressure waves into action potentials using hair cells.

Conduction deafness

Hearing loss resulting from the loss of function of the tympanic membrane or the ossicles.

Vestibulocochlear Nerve (VIII)

The auditory nerve consisting of vestibular and cochlear branches, responsible for hearing and equilibrium.

Wernicke’s area

A region located in the auditory association area of the temporal lobe responsible for the understanding of words and speech comprehension.

Umami

A savory, meaty taste produced by receptors for amino acids.

Facial Nerve (VII)

The major motor nerve of facial expression that also carries taste information from the anterior $\frac{2}{3}$ of the tongue.

Glossopharyngeal Nerve (IX)

The cranial nerve responsible for taste in the posterior $\frac{1}{3}$ of the tongue, swallowing, salivation, and the gag reflex.

Odorant

A molecule that binds to a receptor protein on the olfactory cilia.

Glomeruli

Clusters in the olfactory bulb where axons from neurons with the same receptors converge.

Primary Gustatory Cortex

The area located in the Insula responsible for the sense of taste.