Anatomy Chapter 12 Final Exam

Senses

Maintain homeostasis by providing information about the internal and external environment

General (somatic) senses

Widely distributed receptors in skin

Special senses

Specialized receptors located in the head that detect vision

Sensory receptor

Structure that detects stimuli and transmits information to the CNS

Sensory transduction

Conversion of a stimulus into a graded receptor potential

Sensory transmission

Passage of action potentials along sensory neurons to the CNS

Sensory interpretation

Processing of sensory information in the brain or spinal cord

Sensation

Awareness of sensory stimuli

Perception

Brain’s interpretation and understanding of sensory information

Projection

Process in which the brain interprets sensation as coming from a specific location

Chemoreceptors

Respond to changes in chemical concentrations

Photoreceptors

Respond to light intensity

Thermoreceptors

Respond to temperature changes

Mechanoreceptors

Respond to mechanical forces such as touch and pressure

Nociceptors

Pain receptors that respond to tissue damage

Sensory adaptation

Decreased sensitivity to continuous or repetitive stimuli

Exteroceptors

Receptors associated with the body surface

Interoceptors

Receptors that detect changes in internal organs

Proprioceptors

Receptors that detect body position and muscle tension

Free nerve endings

Simplest receptors that detect pain

Tactile (Meissner’s) corpuscles

Detect fine touch and texture

Lamellated (Pacinian) corpuscles

Detect deep pressure and vibration

Warm receptors

Thermoreceptors sensitive to temperatures above 25°C

Cold receptors

Thermoreceptors sensitive to temperatures between 10°C and 20°C

Pain threshold

Intensity of a stimulus required to produce pain

Fast pain fibers

Myelinated fibers that transmit sharp localized pain

Slow pain fibers

Unmyelinated fibers that transmit dull aching pain

Referred pain

Pain perceived in a location different from its source

Enkephalins

Natural pain-inhibiting neurotransmitters

Endorphins

Chemicals that reduce pain perception

Serotonin

Neurotransmitter involved in pain inhibition

Visceral pain

Pain originating from internal organs

Proprioception

Awareness of body position and movement

Special senses

Senses associated with complex sensory organs in the head

Olfaction

Sense of smell

Gustation

Sense of taste

Olfactory receptors

Chemoreceptors that detect odor molecules

Olfactory bulb

Brain structure that processes smell information

Anosmia

Loss or absence of the sense of smell

Taste buds

Sensory organs that contain taste receptors

Taste cells

Modified epithelial cells that detect taste

Sweet taste

Stimulated by carbohydrates

Sour taste

Stimulated by acids

Salty taste

Stimulated by sodium or potassium ions

Bitter taste

Stimulated by many organic compounds

Umami taste

Stimulated by amino acids such as MSG

Ear

Organ of hearing and equilibrium

Outer ear

Collects sound waves

Middle ear

Amplifies sound vibrations

Inner ear

Contains receptors for hearing and balance

Tympanic membrane

Eardrum that vibrates in response to sound

Auditory ossicles

Three bones that amplify sound vibrations

Malleus

Ossicle attached to tympanic membrane

Incus

Ossicle between malleus and stapes

Stapes

Ossicle that vibrates against the oval window

Tympanic reflex

Muscle contraction that protects inner ear from loud sounds

Auditory tube

Connects middle ear to throat and equalizes pressure

Cochlea

Spiral structure of inner ear involved in hearing

Spiral organ (organ of Corti)

Hearing receptor organ within the cochlea

Hair cells

Receptors for hearing with stereocilia

Basilar membrane

Vibrates in response to sound waves

Conductive deafness

Hearing loss caused by impaired sound conduction

Sensorineural deafness

Hearing loss due to damage to receptors or nerves

Static equilibrium

Sense of head position when body is not moving

Dynamic equilibrium

Sense of motion and rotation

Macula

Sensory organ for static equilibrium

Crista ampullaris

Sensory organ for dynamic equilibrium

Eye

Organ of vision

Cornea

Transparent anterior portion that refracts light

Sclera

White outer layer of the eye

Choroid coat

Vascular layer that absorbs excess light

Iris

Colored part of the eye that controls pupil size

Pupil

Opening through which light enters the eye

Lens

Transparent structure that focuses light

Accommodation

Change in lens shape for near vision

Retina

Inner layer of eye containing photoreceptors

Rods

Photoreceptors for dim light and black-and-white vision

Cones

Photoreceptors for color and sharp vision

Fovea centralis

Area of sharpest vision in the retina

Optic disc

Blind spot where optic nerve exits the eye

Rhodopsin

Light-sensitive pigment in rods

Iodopsins

Light-sensitive pigments in cones

Visual acuity

Sharpness of vision

Myopia

Nearsightedness caused by elongated eyeball

Hyperopia

Farsightedness caused by shortened eyeball

Astigmatism

Distorted vision due to uneven curvature of cornea or lens

Presbyopia

Age-related loss of accommodation