Senses

Sensory Receptors

Cells that detect stimuli to monitor internal and external conditions.

Sensory Modalities

Different categories of sensory information detected by specific receptors.

General Senses

Senses detected by somatosensory receptors widely distributed throughout the body, including touch, pain, temperature, and proprioception.

Special Senses

Senses detected by receptors within specialized sensory organs, such as vision and hearing.

Vision

The modality of sight where light is the stimulus detected by photoreceptor cells in the retina.

Audition

The modality of hearing where sound is the stimulus detected by hair cell receptors in the cochlea.

Equilibrium

The vestibular sense where acceleration is the stimulus detected by hair cell receptors in the vestibule.

Olfaction

The sense of smell where chemicals dissolved in mucous are detected by olfactory receptor cells.

Gustation

The sense of taste where chemicals dissolved in saliva are detected by gustatory receptor cells.

Receptive Field

The region of the environment that is monitored by a sensory receptor.

Sensory Transduction

A process where a stimulus opens or closes ion channels in the receptor cell membrane to produce receptor potentials.

Mechanoreceptors

Receptors that detect forces such as pressure, vibration, and stretching.

Chemoreceptors

Receptors that detect chemicals dissolved in extracellular fluid, includes olfactory and gustatory receptors.

Thermoreceptors

Receptors that detect changes in temperature.

cAMP

A second messenger molecule produced in olfactory neurons that stimulates opening of ion channels.

Olfactory Tract

A white matter structure that connects to olfactory cortex and contains axons of mitral cells.

Temporal Lobe

The cerebrum region that contains the primary olfactory cortex responsible for odor awareness and identification.

Gustation

The sense of taste, characterized by five distinct tastes identified by physiologists.

Second Messengers

Signals produced inside gustatory receptor cells following activation of G-protein coupled receptors.

Facial Nerve (CN VII)

Cranial nerve containing axons of afferent neurons from taste buds.

Fibrous Layer

The tough fibrous superficial layer of the eye composed of the sclera and cornea.

Vascular Layer

The middle layer of the eye rich in blood vessels, contains the choroid, ciliary body, and iris.

Neural Layer (Retina)

The deepest layer of the eye where an image is formed and includes photoreceptor cells.

Anterior Cavity

The space in front of the lens containing aqueous humor providing nutrients to the lens and cornea.

Posterior Cavity

The space behind the lens filled with vitreous humor that helps hold the retina in place.

Levator Palpebrae Superioris

A skeletal muscle that elevates the superior palpebrae to open the eyes.

Orbicularis Oculi

A skeletal muscle that closes the palpebrae.

Bulbar Conjunctiva

The mucous membrane covering the anterior surface of the sclera.

Conjunctivitis

Inflammation of the conjunctiva, commonly known as pink eye.

Superior Rectus

An extraocular muscle that directs gaze superiorly.

Strabismus

A vision disorder where the eyes do not properly align when looking at an object.

Rods

Photoreceptors sensitive to a broad wavelength range, providing black and white vision.

Rhodopsin

A G protein-coupled receptor found in rods that responds to light.

Photoreceptor Transduction

The process where light leads to hyperpolarization of photoreceptors reducing neurotransmitter release.

Bipolar Cells

Neurons that relay information from photoreceptors to retinal ganglion cells.

Optic Nerve (CN II)

The afferent fiber pathway that carries visual information from the retina to the brain.

Dorsal Stream

The pathway for interpreting motion, answering 'Where is the object' in visual processing.

Ventral Stream

The pathway for processing details like color and shape in visual identification.

Pinna (Auricle)

The outer visible portion of the ear that channels sound waves into the auditory canal.

Malleus (Hammer)

The most lateral ossicle that is attached to the tympanic membrane.

Eustachian Tube

Connects the middle ear to the nasopharynx and equalizes pressure.

Vestibule

Central cavity of the bony labyrinth responsible for the vestibular sense.

Cochlea

A spiral structure of the inner ear that contains the auditory hair cells.

Auditory Hair Cells

Receptor cells in the cochlea that respond to sound vibrations.