Sensation, Perception, General and Special Senses (Vision, Olfaction, Gustation) and Pain Pathways

A set of vocabulary flashcards covering sensation, perception, photoreception, taste and smell, somatic senses, general vs. special senses, and key eye anatomy terms as described in the notes.

Sensation

The conscious or unconscious awareness of incoming sensory information.

Perception

Awareness of a sensation; the brain's interpretation or awareness of that sensation.

Projection

The process by which the brain refers a sensation back to its source.

Adaptation

A decrease in sensitivity to a constant stimulus over time.

General senses

Somatic senses with receptors widely distributed in the body (e.g., pain, touch, temperature, proprioception).

Special senses

Senses housed in specific organs: taste, smell, sight, hearing, and balance.

Nociceptors

Pain receptors; free nerve endings that respond to tissue injury or damage.

Phantom pain

Pain sensation perceived in a body part that has been amputated, due to signaling from nerve endings.

Ischemia

Deficiency of blood (and thus oxygen) to tissue, which can cause pain.

Referred pain

Pain perceived at a location other than the site of the actual tissue injury.

Spinothalamic tract

Nerve pathway that carries pain and temperature signals to the thalamus and then to the cortex.

Mechanoreceptors

Receptors that respond to mechanical forces such as touch, pressure, and vibration.

Tactile receptors

Touch receptors in the skin, especially concentrated in lips and fingertips.

Thermoreceptors

Receptors that detect changes in temperature (heat and cold).

Proprioception

Sense of body position and movement; awareness of limb location without looking.

Proprioceptors

Sensory receptors in muscles, tendons, joints, and the inner ear that provide proprioceptive input.

Olfactory receptors

Chemoreceptors in the nasal mucosa that detect odors; transmitted via the olfactory nerve (CN I).

Olfaction

Sense of smell.

Gustatory sense

Sense of taste (gustation); detected by taste buds on the tongue.

Taste buds

Taste-receptive organs mainly on the tongue (also on tonsils); contain receptors for taste.

Rods

Photoreceptors highly sensitive to light, provide black-and-white (monochromatic) vision and function in dim light; distributed more peripherally in the retina.

Cones

Photoreceptors responsible for color and detail vision; active in bright light; concentrated in the macula lutea, especially the fovea.

Macula lutea

Central retina region with high visual acuity; contains the fovea centralis.

Optic disc

Blind spot; location where the optic nerve exits the retina; contains no photoreceptors.

Vitreous humor

Gel-like substance filling the posterior eye cavity; helps press the retina against the choroid.

Aqueous humor

Watery fluid in the anterior eye chamber; produced by the ciliary body and maintains eye shape; drains via the canal of Schlemm.

Glaucoma

Elevated intraocular pressure due to impaired drainage of aqueous humor, risking optic nerve damage.

Sclera

Outer, tough, fibrous protective layer of the eye; gives the eye its shape.

Choroid

Middle vascular layer of the eye; supplies the retina with blood and absorbs excess light; part of the uvea.

Iris

Colored part of the eye containing radial (dilator) and circular (sphincter) muscles that regulate pupil size.

Pupil

Openings in the center of the iris through which light enters; size controlled by iris muscles.

Ciliary body

Structure that secretes aqueous humor and houses the ciliary muscles that adjust lens shape.

Ciliary muscles

Intrinsic eye muscles that alter lens shape by pulling on suspensory ligaments.

Extrinsic eye muscles

Six external skeletal muscles that move the eyeball and eyelids.

Pheromones

Chemical signals that influence behavior or physiology of others of the same species.

Olfactory nerve (CN I)

Cranial nerve that transmits smell information from the nose to the brain.