Chapter 10 - Senses Flashcards
general senses
The senses which are perceived due to receptors scattered throughout the body such as touch, temperature, and hunger, rather than tied to a specific structure, as the special senses vision or hearing are. Often, the general senses are associated with a specific drive; that is, the sensation will cause a change in behavior meant to reduce the sensation.
special senses
the senses that have specialized organs devoted to them, such as vision (the eye) and smell (the nose)
encapsulated receptor cell
a receptor cell that is covered by a capsule of some sort
unencapsulated receptor cell
a receptor cell that is not covered by a capsule
photoreceptors
receptor cells that are sensitive to change in intensity or color of light, as in vision
chemoreceptors
receptor cells that are sensitive to presence of certain chemicals, as in taste or smell
pain receptors
receptor cells that are sensitive to physical injury
thermoreceptors
receptor cells that are sensitive to changes in temperature
mechanoreceptors
receptor cells that are sensitive to mechanical stimuli that change their position or shape
receptor cell
a cell or group of cells that receives stimuli
rods and cones (eye)
Cones and rods are two types of photoreceptors within the retina. This means that they are responsible for receiving signals (or images), processing them, and sending them to the brain.
Rods work at very low levels of light. We use these for night vision because only a few bits of light (photons) can activate a rod. Rods don’t help with color vision, which is why at night, we see everything in a gray scale. The human eye has over 100 million rod cells.
Cones require a lot more light and they are used to see color. We have three types of cones: blue, green, and red. The human eye only has about 6 million cones. Many of these are packed into the fovea.
Organ of Corti
an organ of the inner ear located within the cochlea which contributes to audition (hearing)
crista ampullaris
also spelled cristae ampullares; they are the sensory organ of rotation. They are found in the ampullae of each of the semicircular canals of the inner ear, meaning that there are 3 pairs in total. The function of the crista ampullaris is to sense angular acceleration and deceleration.
macula (macula lutea)
an oval-shaped pigmented area near the center of the retina of the human eye and in other animals
The macula is responsible for the central, high-resolution, color vision that is possible in good light; and this kind of vision is impaired if the macula is damaged, for example in macular degeneration.
retina
the sensory membrane that lines the eye, is composed of several layers including one containing the rods and cones, and functions as the immediate instrument of vision by receiving the image formed by the lens and converting it into chemical and nervous signals which reach the brain by way of the optic nerve
fovea (fovea centralis)
a small pit in the back of the eye that helps with the sharpness or detail of images
lens (eye)
also called the crystalline lens; it is an important part of the eye’s anatomy that allows the eye to focus on objects at varying distances. It is located behind the iris and in front of the vitreous body.
optic nerve
The nerve that carries messages from the retina to the brain.
iris
The colored tissue at the front of the eye that contains the pupil in the center. The iris helps control the size of the pupil to let more or less light into the eye.
vitreous body
also called vitreous humour; the clear colorless transparent jelly that fills the eyeball posterior to the lens and is enclosed by a delicate hyaloid membrane
hyaloid membrane
also called the the vitreous membrane or vitreous cortex; it is a layer of collagen separating the vitreous humour from the rest of the eye. At least two parts have been identified anatomically:
The posterior hyaloid membrane separates the rear of the vitreous from the retina. It is a false anatomical membrane. The anterior hyaloid membrane separates the front of the vitreous from the lens.
pupil (eye)
the circular black area in the center of an eye, through which light enters
ampullae
a dilated portion of a canal or duct, especially of the semicircular canals of the ear.
cochlea
a hollow tube in the inner ear of higher vertebrates that is usually coiled like a snail shell and contains the sensory organ of hearing
proprioceptors
a sensory receptor (such as a muscle spindle) excited by proprioceptive stimuli (such as changes in limb position)
proprioception
also referred to as kinaesthesia (or kinesthesia), it is the sense of self-movement and body position. It is sometimes described as the “sixth sense”.
referred pain
pain that is perceived at a location other than the site of the painful stimulus/origin. It is the result of a network of interconnecting sensory nerves, that supplies many different tissues
cornea
The transparent part of the eye that covers the iris and the pupil and allows light to enter the inside.
sclera
The white layer of the eye that covers most of the outside of the eyeball. It is fibrous and provides support for the eyeball, helping it keep its shape.
choroid
A thin layer of tissue that is part of the middle layer of the wall of the eye, between the sclera (white outer layer of the eye) and the retina (the inner layer of nerve tissue at the back of the eye). It is filled with blood vessels that bring oxygen and nutrients to the eye.
Ciliary muscle
A circular muscle that relaxes or tightens the zonules to enable the lens to change shape for focusing.
zonules
fibers that hold the lens suspended in position and enable it to change shape during accommodation.
accommodation (vision)
the automatic adjustment of the eye for seeing at different distances effected chiefly by changes in the convexity of the crystalline lens
conjunctiva
A mucous membrane that lines the eyelids and covers the fibrous layer in front. The blood vessels you see on the surface of the sclera actually belong to the conjunctiva.
conjunctivitis
inflammation of the conjunctiva, often caused by bacterial or viral infection, allergy, or environmental factors
lacrimal gland
A gland that secretes tears and helps to keep the conjunctiva moist. The lacrimal glands are found in the upper, outer part of each eye socket.
presbyopia
also called age-related farsightedness or oldsightedness; the gradual loss of your eyes’ ability to focus on nearby objects. It’s a natural, often annoying part of aging.
cataract
a medical condition in which the lens of the eye becomes progressively opaque, resulting in blurred vision
visual acuity
The clearness or sharpness of visual perception. Acuity is affected by our focusing ability, the efficiency of the retina, and the proper function of the visual pathway and processing centers in the brain.
retinal ganglion cell
a type of neuron located near the inner surface (the ganglion cell layer) of the retina of the eye
ganglion cell layer
also called ganglionic layer; a layer of the retina that consists of retinal ganglion cells and displaced amacrine cells
amacrine cells
interneurons in the retina
aqueous humor
the name of the watery fluid in front of the lens (in the anterior chamber of the eye)
Aqueous humor is constantly being formed, drained, and replaced in the anterior chamber.
glaucoma
Glaucoma is a group of eye conditions that damage the optic nerve, the health of which is vital for good vision. This damage is often caused by an abnormally high pressure in your eye. One thing that can cause such high pressure is a blockage preventing the drainage of aqueous humor.
optic disk
the raised disk on the retina at the point of entry of the optic nerve, lacking visual receptors and so creating a blind spot
refraction
The change in direction of a wave passing from one medium to another or from a gradual change in the medium. Refraction of light is the most commonly observed phenomenon, but other waves such as sound waves and water waves also experience refraction.
macular degeneration
Macular degeneration causes loss in the center of the field of vision. It is a common eye disorder in people over 50. There are two types:
dry macular degeneration–the center of the retina deteriorates
wet macular degeneration–leaky blood vessels grow under the retina
myopia
also called nearsightedness; a vision condition in which close objects appear clearly, but far ones don’t.
hyperopia
also called farsightedness; a vision condition in which nearby objects are blurry, but far ones aren’t
astigmatism
An abnormal eye condition resulting in blurred vision. It is caused by an irregular curvature of the lens.
photopigments
unstable pigments that undergo a chemical change when they absorb light
auricle
also called pinna; the visible portion of the external ear (and what is commonly thought of as the ear)
external acoustic canal
A curving tube about 2.5 cm (1 inch) in length. It starts at the opening of the ear, extends into the temporal bone, and ends at the eardrum.
eardrum
also called the tympanic membrane; a thin flap of skin that is stretched tight like a drum and vibrates when sound hits it. These vibrations move the tiny bones of the middle ear, which send vibrations to the inner ear.
ceruminous glands
glands in the ear that produce cerumen
cerumen
another name for earwax
ossicles
Three bones in either middle ear that are among the smallest bones in the human body. They serve to transmit sounds from the air to the fluid-filled labyrinth (cochlea). The absence of the auditory ossicles would constitute a moderate-to-severe hearing loss. The term “ossicle” literally means “tiny bone”.
The three bones are malleus (Latin: hammer), incus (Latin: anvil), and stapes (Latin: stirrup)
eustachian tube
also called the auditory tube; it is a tube that connects the throat with the middle ear
otitis media
Inflammation or infection located in the middle ear. Otitis media can occur as a result of a cold, sore throat, or respiratory infection.
bony labyrinth
three spaces in the temporal bone, assembled in a complex maze, that make up the inner ear
This odd-shaped bony space is filled with a watery fluid called perilymph and is divided into the following parts: vestibule, semicircular canals, and cochlea.
vestibule
the central cavity of the bony labyrinth of the inner ear or the parts (such as the saccule and utricle) of the membranous labyrinth that it contains
semicircular canals
any of three loop-shaped tubular parts of the inner ear that are filled with a watery fluid, are positioned at nearly right angles to each other, and play a role in the maintenance of balance and stabilization by detecting rotations or angular movements of the head
membranous labyrinth
a balloonlike membranous sac that is suspended in the perilymph and follows the shape of the bony labyrinth much like a “tube within a tube.” It is filled with a thicker fluid called endolymph.
saccule
the smaller chamber of the membranous labyrinth of the ear
utricle
the part of the membranous labyrinth of the inner ear into which the semicircular canals open
cochlear nerve
also known as the acoustic nerve; it is the sensory nerve that transfers auditory information from the cochlea (auditory area of the inner ear) to the brain
presbycusis
The slow loss of hearing in both ears. It’s a common problem linked to aging. It results from degeneration of sensory nerve tissue in the ear and the vestibulocochlear nerve.
vestibulocochlear nerve
A nerve that is responsible for the sense of hearing and that is also pertinent to the senses of balance and body position. It is made up of the cochlear and vestibular nerves
vestibular nerve
the part of the auditory nerve in the inner ear that carries sensory information related to body equilibrium
cupula
a dome-shaped structure, especially the sensory structure within the semicircular canals of the ear
external otitis
also called swimmer’s ear; a common infection of the external ear in swimmers. It can be bacterial or fungal in origin and is usually associated with prolonged exposure to water. The infection generally involves, at least to some extent, the auditory canal and auricle. The ear as a whole is tender, red, and swollen. Treatment of swimmer’s ear usually involves antibiotic therapy and prescription analgesics.
gustation
the sense of taste
taste buds
The sense organs of taste. They contain both supporting cells and chemoreceptors called gustatory cells
gustatory cells
cells that create the nervous impulses ultimately interpreted by the brain as taste
papilla
one of certain small bodily protuberances concerned with the senses of touch, taste, and smell:
olfaction
the sense of smell
adaptation (olfaction)
The fact that olfactory receptors are extremely sensitive and respond quickly to even very slight odors. However, after a short time they develop a kind of fatigue and lose their ability to respond. This loss is called adaptation.
tonsils
fleshy pads located at each side of the back of the throat
The tonsils are part of the lymphatic system, which helps to fight infections.
circumvallate papillae
papilla in the back of the tongue that contain the most taste buds
