Senses - Biology Chapter 17

Comprehensive vocabulary flashcards covering the study of senses, including receptor types, somatic sensations, taste, smell, vision, hearing, and equilibrium structures.

Sensory receptors

Specialized cells or nerve endings that detect and respond to specific environmental stimuli by converting them into electrical signals (nerve impulses).

Sensory transduction

The process where sensory receptors convert environmental stimuli into nerve impulses.

Exteroceptors

Sensory receptors that respond to external stimuli such as touch, temperature, pain, and special senses.

Interoceptors

Sensory receptors that detect internal body conditions, including blood pressure, chemical levels, and internal pain.

Proprioceptors

Mechanoreceptors located in muscles, tendons, joints, and the inner ear that detect body position and movement to help maintain muscle tone and balance.

Mechanoreceptors

Receptors that detect mechanical forces such as touch, pressure, vibration, stretch, hearing, and balance.

Thermoreceptors

Receptors specialized to detect temperature changes, specifically hot or cold.

Nociceptors

Pain receptors that detect damaging stimuli like extreme temperatures, mechanical force, or chemicals.

Photoreceptors

Sensory receptors found in the retina that detect light for vision.

Chemoreceptors

Receptors that detect chemical stimuli such as smell, taste, blood $pH$, and oxygen levels.

Free nerve endings

Unencapsulated structures that detect pain, temperature, and some touch.

Encapsulated nerve endings

Receptors surrounded by connective tissue designed to enhance sensitivity, such as Pacinian corpuscles for deep pressure.

Specialized receptor cells

Separate cells that synapse with sensory neurons, such as photoreceptors in the eye or hair cells in the ear.

Sensation

The process of detecting, transmitting, and interpreting stimuli from the environment or body leading to conscious awareness.

Perception

The conscious awareness of a sensation created when the cerebral cortex interprets sensory signals.

Sensory adaptation

A decrease in the response of sensory receptors to a constant stimulus over time to prevent sensory overload.

Somatic sensations

Sensory signals associated with the skin, muscles, joints, and internal organs (viscera).

Cutaneous Receptors

Receptors located in the skin that detect touch, pressure, temperature, and pain.

Prostaglandins

Chemicals released by damaged tissues that bind to nociceptors to signal pain.

Gustation

The technical term for the sense of taste.

Olfaction

The technical term for the sense of smell.

Primary Tastes

The five tastes detected by humans: Sweet, Sour, Bitter, Salty, and Umami (savory).

Papillae

The visible bumps on the tongue where taste buds are primarily located.

Olfactory Epithelium

A layer of tissue in the roof of the nasal cavity containing olfactory cells.

Flavor perception

The combined effect of taste and smell, where smell accounts for approximately $80\%$ of what we perceive as taste.

Sclera

The white, fibrous outer layer of the eye that provides protection and support.

Cornea

The clear, front part of the sclera that allows light to enter the eye and refracts light rays.

Choroid

The middle layer of the eye containing dark pigment to absorb stray light and prevent scattering.

Iris

The structure that regulates the amount of light entering the eye by controlling the size of the pupil.

Ciliary body

A structure that holds the lens in place and controls its shape for focusing (accommodation).

Retina

The innermost layer of the eye containing the photoreceptors (rods and cones) for sight.

Aqueous humor

The watery fluid located in the anterior compartment of the eye in front of the lens.

Vitreous humor

The fluid in the posterior compartment of the eye that maintains eye shape and holds the retina in place.

Rods

Photoreceptors that are very sensitive to light and make black-and-white vision possible, especially in low light.

Cones

Photoreceptors that require bright light and are responsible for color vision.

Fovea centralis

The part of the retina that makes acute (sharp) vision possible.

Visual Accommodation

The process of the lens changing shape to focus on objects at different distances; the lens is flat for distant objects and round/thick for near objects.

Blind Spot

The area where the optic nerve exits the eye; it lacks photoreceptors and detects no visual information.

Nearsightedness (Myopia)

A condition where distant objects appear blurry because the eye is elongated, causing light to focus in front of the retina.

Farsightedness (Hyperopia)

A condition where close objects appear blurry because the eye is too short, causing light to focus behind the retina.

Astigmatism

Blurred or distorted vision due to an unevenly shaped cornea or lens that causes improper light refraction.

Pinna / Auricle

The visible part of the outer ear that collects and directs sound waves into the auditory canal.

Tympanic Membrane

The eardrum, which vibrates in response to sound waves and transmits them to the middle ear.

Ossicles

Three small bones in the middle ear (malleus, incus, and stapes) that amplify and transfer sound vibrations.

Eustachian Tube

A tube that equalizes air pressure across the tympanic membrane.

Cochlea

A spiral-shaped, fluid-filled structure in the inner ear that converts sound vibrations into nerve impulses.

Organ of Corti

The structure within the cochlea containing hair cells (sensory receptors) that detect sound vibrations.

Vestibule

The central part of the inner ear containing the utricle and saccule, which detect linear movement and head position for balance.

Semicircular Canals

Three fluid-filled loops oriented along different axes ($x$, $y$, and $z$) that detect rotational (angular) movement.

Crista ampullaris

The sensory structure within each semicircular canal that contains hair cells to detect fluid movement.