sensation
any stimuli or change the body is aware of
perception
conscious awareness and interpretation of a sensation
sensory organs
extensions of the central nervous system; stimulus generates nerve impulses to brain which interprets sensation
general senses
sense overall body conditions; visceral, touch, temperature, pain, proprioception
visceral sense
sense of internal body sensations; hunger and thirst
touch sense
sense of feeling; an awareness of something touching the body
temperature sense
sense of heat and cold inside and out
pain sense
sense of physical irritation that alerts nervous system of potentially harmful stimuli
proprioception sense
sense of body position; keeps the body in an upright position
special senses
specific sensory organs and structures located in the head; gustatory, olfactory, auditory, equilibrium, vision
gustatory sense
taste buds located in the mouth; cats more sensitive than dogs
olfactory sense
sense for smelling odor with receptors located high in both nasal passages; stronger in animals than humans
auditory sense
sense for hearing sound with receptors located in ear
equilibrium
sense for balance with receptors located in portions of the inner ear that helps animals maintain balance by keeping track of position and movement of the head
vision sense
sense for sight with receptors located in the retina of the eyes
ophthalmology
study of the eyes; most ocular structures exist to help form images not detect them
ocular/ophthalm
term and prefix that are used in reference to the eyes
canthus
site where the eyelids come together
nictitans
third" eyelid located in the medial canthus of the eye; usually not noticeable unless prolapsed
conjunctiva
mucous membrane associated with the eye
palpebral conjunctiva
inner lining of the eyes; eye lids
bulbar conjunctiva
outer lining of the eye; eye ball
lacrimal glands
create tears to lubricate the eyeball
nasolacrimal ducts
connects with the nasal cavity that functions as a drainage system for tears
meibomian glands
located at the eyelid margins and produce a waxy substance that helps prevent tears from overflowing onto an animal's face
eye muscles
skeletal muscles that attach to the sclera of the eye that hold the eye in place as well as allow it to move
outer fibrous layer
contains structures that admit light to the interior of the eye and give strength and shape the eyeball; cornea and sclera
cornea
clear outer layer of the eye where light comes through
sclera
whites of the eye that light cannot come through; covered by a thin layer of conjunctiva
middle vascular layer
the uvea; where major blood and nerve supply to the eye is located; iris, pupil, lens, ciliary, choroid
iris
sphincter muscle that regulates light coming into the eye
pupil
opening to the iris that constricts to limit light entering the eye or dilate to allow more light to enter eye
lens
located posterior to the pupil; that bends light rays to focus them on inner layer of eye
ciliary
tiny muscles located immediately behind the iris; helps change the shape of the lens to allow both close up and distant vision
choroid
located between the sclera and retina and provides blood flow to the retina
inner nervous layer
aka retina; lines the back of the eye and contains two sensory photoreceptors that generate nerve impulses for vision; where the actual visual image is formed
cornea, aqueous humor, lens, vitreous humor
4 structures in the eye that help form a clear image in the retina
dichromatic vision
ability to see blue, yellow and purple but not red; dogs, cats, horses, cattle. birds can see red as well
cones
receptors that see color; works best in light rather than dark conditions
rods
receptors that see mainly gray, black and white; allows dim light vision. nocturnal animals have more of these than cones
aqueous compartment
aqueous humor filled compartment located in front of the lens and ciliary body
anterior chamber
portion of aqueous compartment located in front of the iris
posterior chamber
portion of aqueous compartment located behind the iris
cells of ciliary body
produce aqueous humor
canal of schlemm
drains away aqueous humor
vitreous compartment
vitreous humor filled compartment located behind the lens and ciliary body
aural
refers to ears
hearing
mechanical sense that converts vibrations of air molecules into nerve impulses that are interpreted by the brain as sound
external ear
funnel for sound wave vibration
pinna
ear flap; part of external ear
external ear canal
right angle canal that leads to and protects the ear drum; part of external ear
ceruminous glands
type of sweat gland located in external ear canal that produces waxy substance called cerumen
tympanic membrane
ear drum; part of external ear
middle ear
sound wave transmitter
tympanic bulla
thin bone in skull that surrounds and protects middle and inner ear
auditory bones
aka ossicles; 3 small bones that link the tympanic membrane with the cochlea of the inner ear and transmit sound wave vibrations
hammer/malleus, anvil/incus, stirrup/stapes
three auditory bones
eustachian tube
aka auditory tube; connects the middle ear to the pharynx and function is to equalize air pressure inside the ear drum
inner ear
sensory reception for hearing and equilibrium
cochlea
site where mechanical noises are changed into electrical impulses that go to the brain; part of inner ear
vestibule
located between the cochlea and the semi-circular canals and generates nerve impulses to the brain via movement of the head; part of inner ear
semi-circular canals
site of sensory receptors for balance located on the other side of the vestibule from the cochlea; part of inner ear
heatstroke
significantly elevated body temperature; can result from prolonged exposure to high environmental temperatures
esthesiology
the study of the sensory system
anesthesia
the loss of esthesia, or the complete loss of sensation
general anesthesia
complete loss of sensory perception accompanied by loss of consciousness
local anesthesia
loss of sensation from a specific, localized area without affecting consciousness
analgesia
state in which the perception of pain is decreased but not completely absent
windup
the exaggerated pain response caused by the neurons of the spinal cord being bombarded with painful stimuli during surgery; can be prevented with analgesic or local anesthetic drugs
ear hematoma
abnormal accumulation of free blood in the pinna; can cause cauliflower ear
glaucoma
characterized by increased intraocular pressure that causes pain and can lead to blindness; most often caused by insufficient drainage of aqueous humor rather than over production
cataract
abnormal condition of the eye where the lens becomes opaque