Sense Organs Ch 14 Flashcards
What are 4 general types of stimuli that can trigger a response from sensory receptors?
mechanical stimuli
thermal stimuli
electromagnetic stimuli
chemical stimuli
What is mechanical stimuli?
touch, hearing, balance
What is thermal stimuli?
hot and cold
What is electromagnetic stimuli?
vision
What is chemical stimuli?
taste and smell
What are visceral senses?
They make up a somewhat miscellaneous category of interior body sensations
- most are vague and poorly localized
- sensations of hunger and thirst
- visceral stretch receptors in GI tract and urinary system
What do the visceral senses do?
indicate deficits in the body so the body can maintain homeostasis in the body
What are the general senses?
visceral sensations, touch, temperature, pain, proprioception
How many senses are there?
10
With the visceral sensations sense what are sensed and what type of stimulus is it?
- hunger, thirst, hollow-organ fullness
- chemical, mechanical
At the heart of all sense organs are various kinds of specialty modified nerve endings what are they called?
dendrites or sensory receptors
With the touch sense what are sensed and what type of stimulus is it?
- touch and pressure
- mechanical
With the temperature sense what are sensed and what type of stimulus is it?
- heat and cold
- thermal
With the pain sense what are sensed and what type of stimulus is it?
- intense stimuli of any type
- mechanical, chemical, or thermal
With the proprioception sense what are sensed and what type of stimulus is it?
- body position and movement
- mechanical
Touch and pressure means?
- tactile sense - sensation of something touching surface of body
- pressure - sensation of something pressing on body surface
- different touch and pressure receptors produce sensations of light contact, deep pressure, vibration, or hair movement
Temperature means?
- superficial temperature receptors - in skin - detect upward or downward changes in skin temp.
- central temperature receptors - in hypothalamus - monitor the temperature of blood
- CNS can activate mechanisms (sweating, piloerection) to correct hypothermia or hyperthermia
What is nocieptors?
pain receptors - most common and widely distributed sensory receptor inside and on the surface of the body
Pain receptors or nociceptors may be free nerve endings or more specialized structures that detect ________ forces and ________.
mechanical
temperature
Where in the body is the only place where pain receptors are not found?
brain
What is the process of experiencing pain?
nociception
What are the 4 processes that contribute to nociception?
transduction
transmission
modulation
perception
What is transduction?
conversion of painful stimulus into nerve impulse - occurs at the sensory nerve ending
What is transmission?
conduction of nerve impulse to the spinal cord
What is modulation?
changes the sensory nerve impulse (occurs in spinal cord) - can amplify or suppress sensory impulses
What is perception?
conscious awareness of painful stimuli
What is proprioception?
- sense of body position and movement
- stretch receptors in skeletal muscles, tendons, ligaments, and joint capsules sense movements of limbs, positions of joints, the state of contraction of muscles, and the amount of tension being exerted on tendons and ligaments
What are the special senses?
taste, smell, hearing, equilibrium, vision
Taste is ?
- gustatory sense - sense of taste - chemical sense
- chemical receptors: taste buds in oral cavity - back portion of tongue
- papillae - small elevated structures on the tongue - where taste buds are located
- taste buds also found in the lining of the mouth and pharynx
What is the sense of smell also called?
olfactory sense
Olfactory sense is?
very important in most nonhuman animals
It is a chemical sense
The sense of smell is organized in two patches. Olfactory cells are mixed with _______ cells in epithelial patches in nasal passages
supporting
_______ processes project up from olfactory cells into the mucous layer that covers the nasal epithelium.
hairlike
______ molecules dissolve in the mucus of nasal passages and contact the _______ processes.
Odor
sensory
______ impulses are generated, travel to the brain, and are interpreted as particular smells.
nerve
Hearing is also called the?
auditory sense
Hearing is a ______ sense that converts _____ of air molecules into nerve impulses.
mechanical
vibrations
Most structures of the ear are located in the ______ bone of the skull.
temporal
The ear, the organ of hearing can be divided into 3 physical and functional areas. What are they?
external ear
middle ear
inner ear
What is the external ear?
acts as a funnel to collect sound wave vibrations and direct them to the eardrum
What is the middle ear?
amplifies and transmits the vibrations from the eardrum to the inner ear
What is the inner ear?
contains the sensory receptors that convert the mechanical vibrations to nerve impulses, along with receptors for the equilibrium sense
What is the pinna?
it is the part of the ear that we can see from outside and is a funnel-like structure
What is the pinna composed of?
elastic cartilage and skin
What does the funnel-like structure of the pinna do?
it collects sound wave vibrations and directs them into the external auditory canal (membrane-lined tube)
The tympanic membrane is commonly called?
eardrum
What is the tympanic membrane made of and where is it located?
thin connective tissue that is stretched tightly across the opening between the external auditory canal and the middle ear cavity
What happens when sound waves vibrations strike the tympanic membrane?
causes the tympanic membrane to vibrate
Where is the middle ear located?
behind the ear drum
What are the 3 small bones in the middle ear called?
ossicles
What do the ossicles do?
link the tympanic membrane with the cochlea of the inner ear
What connects the middle ear cavity with the pharynx?
eustachian tube
What does the eustachian tube do?
equalizes air pressure on the two sides of the tympanic membrane
What are the 3 small ossicles that link the tympanic membrane with the cochlea of the inner ear, where receptors for hearing are located?
malleus, incus, stapes
What is the malleus?
outermost bone attached to tympanic membrane
What is the incus?
middle bone
What is the stapes?
middle-most bone attached to membrane that covers the oval window of the cochlea
What is the cochlea?
shell-shaped cavity in the temporal bone
What is the hearing portion of the inner ear?
cochlea
What structures are in the inner ear?
cochlea, organ of Corti
What is the organ of Corti?
is within the cochlea, is soft, multilayered, and has fluid-filled portion that contains receptor cells of hearing
Where does the organ of Corti run?
along the cochlear duct on the basilar membrane
What are the main parts of the organ of Corti?
hair cells (hearing receptors), supporting cells, and the tectorial membrane
What causes the tympanic membrane and ossicles in the middle ear to vibrate?
sound wave vibrations
What else does sound wave vibrations cause?
vibrations of fluid around the cochlear duct
What does fluid vibration cause?
the cochlear duct to move
The inner ear is made up of structures that contribute to both…?
hearing and equilibrium
What are the effects of sound waves on cochlear structures?
Sound waves cause lympanic membrane and ossicles to vibrate, As the stapes vibrates back and forth, it pushes and pulls on the membrane covering the oval window of the cochlea. This sets fluid in the cochlea in motion, which causes hair cells and tectorial membrane to rub against each other. This bends sensory hairs, generating nerve impulses that are transmitted to the brain and interpreted as sound
Different frequencies of _____ wave vibrations stimulate different areas along the length of the organ of _______.
sound
Corti
What is equilibrium?
a mechanical sense that helps maintain balance by keeping track of the position and movements of the head.
Where are the equilibrium receptors located?
located in the portions of the inner ear called vestibule and semicircular canals
Maintaining balance involves?
information from the equilibrium receptors, from the eyes, and the proprioceptors around the body
Where is the vestibule located?
between the cochlea and semicircular canals
What is the vestibule composed of?
two sacklike spaces called utricle and saccule surrounded by perilymph
In each utricle and saccule is a patch of sensory epithelium called?
macula
What does macula consist of?
hair cells and supporting cells covered by a gelatinous matrix that contains crystals of calcium carbonate (otoliths)
What are otoliths?
crystals of calcium carbonate
What causes otoliths and the gelatinous matrix to put pressure on the hairs on the vestibule?
gravity
What bends sensory hairs on the vestibule?
movement of the head
What does the vestibule do?
generates nerve impulses that give the brain information about position of the head
Where are semicircular canals located?
opposite the vestibule from the cochlea
What do semicircular canals contain?
fluid-filled membranous tubes
What is an ampulla?
enlarged area near the utricle end of each semicircular canal
The ampulla contains?
the receptor structure called crista ampullaris or crista
What does crista contain?
supporting cells and hair cells with modified dendrites sticking up into gelatinous structure called the cupula
What is the cupula?
gelatinous structure in the crista
When the head moves in the plane of one of the semicircular canals, what happens?
inertia causes the endolymph to lag behind the movement of the canal itself
The relative movement of the endolymph in the semicircular canals pulls on the cupula which…?
bends the hairs
The movement of the endolymph generates what?
nerve impulses that give the brain information about motion of the head - particularly rotary motion
Most components of the eye function to help form an…?
accurate visual image, not detect it
Photoreceptors that detect the image and generate visual nerve impulses are?
in a single layer of cells in the retina
Two general terms refer to the eye, what are they?
ocular and the combining form ophthalm
The eye consists of 3 major layers, what are they?
outer fibrous layer, middle vascular layer, inner nervous layer
What is the fibrous layer of the eye?
admits light to its interior and gives strength and shape to the eyeball
Components of the fibrous layer are?
cornea, sclera, and limbus
What is the cornea?
transparent; admits light to interior of the eye
In the cornea there is an arrangement of _____ fibers; no ______ vessels.
collagen
blood
What is the sclera?
“white” of the eye
What is the sclera composed of?
dense fibrous connective tissue
Where is the limbus located?
junction of the cornea and the sclera
What is the middle vascular layer also called?
uvea
The middle vascular layer has several parts, what are they?
choroid
iris
ciliary body
The choroid is?
in most animals it forms the tapetum - highly reflective area in the rear o the eye
What is the choroid composed of?
pigment and blood vessels
Where is the choroid located?
between the sclera and the retina
What is the iris?
pigmented muscular diaphragm
What does iris do?
controls the amount of light that enters the posterior part of the eyeball
What is the pupil?
opening at the center of iris
What is the ciliary body?
surrounds the eye and is ring-shaped structure behind the iris and have muscles that adjust shape of the lens to allow near and far vision
What is the retina?
lines the back of the eye
What does the retina contain?
the sensory receptors for vision, the rods and cones
A compartment of the eyeball is aqueous compartment which is subdivided by…?
the iris into anterior and posterior chambers
The aqueous compartment contains?
clear watery fluid; aqueous humor
The aqueous compartment is produced?
in the posterior chamber by cells of the ciliary body
The vitreous compartment contains?
a clear gelatinous fluid called vitreous humor - gives eye its spherical shape
The viterous humor fills?
the whole back of the eyeball behind the lens and ciliary body
The interior of the eye is made up of two fluid-filled compartments what are they?
The aqueous compartment - is in front of the lens and ciliary body
The vitreous compartment - is behind the lens and ciliary body
The lens of the eye is a?
soft, transparent structure
The lens of the eye is made up of?
layers of fibers
The lens of the eye is elastic and?
biconvex (bulges out on both sides)
The front surface of the lens of the eye is?
in contact with aqueous humor
The back surface of the lens of the eye is?
in contact with vitreous humor
The main role of the lens is to?
help focus a clear image on the retina regardless of whether the image is being view close up or far away
What does accommodation mean in relation to the lens?
it is the process by which the shape of the lens is changed to allow close-up and distant vision
What happens when the ciliary muscles in the lens relaxes?
it causes tension on suspensory ligaments; flattens the lens
What happens when the ciliary muscles in the lens contracts?
releases tenson on the suspensory ligaments; lens assumes its natural, more rounded shape
Close up vision requires ______ contractions in the ciliary body, but distant vision _____ ____.
muscle
does not
What is the retina?
- it is multilayered
- lines most of the vitreous compartment
What are the layers of the retina?
From outside in, the layers are - a thin pigment layer - the photoreceptor layer - the bipolar cell layer - the ganglion cell layer - a nerve fiber layer that proceeds to the optic nerve deepest layer
What is the optic disc of the retina?
site where nerve fibers on the inside surface of the retina converge and leave the eye to form the optic nerve - back of eye - no photoreceptors
What is the photoreceptor cells?
neurons with modified dendrites
Two receptors with different shapes and characteristics are found among the photoreceptor cells, what are they called?
rods and cones
What are rods?
What are cones?
- more sensitive to light
- more sensitive to color and detail
Extraocular structures are not part of the eye itself but play an important role in its _______ and ____.
protection and functioning
The structures of the extraocular are?
conjunctiva, eyelids, the tear-production and drainage system, and the muscles that delicately move and position the eyeballs
What is conjunctiva?
thin transparent membrane that covers the front portion of the eyeball and lines the interior surfaces of the eyelids
What is the conjunctival sac?
the space between the bulbar and palpebral portions of the conjunctiva
What are the eyelids?
upper and lower folds of skin lined by the thin, moist conjunctiva
What are the lateral and medial canthus?
corners where the eyelids come together
What are the tarsal glands?
produce waxy substance that helps prevent tears from overflowing onto the face
What is the nictitating membrane?
third eyelid of domestic animals located medially between eyelids and eyeball - it is T-shaped plate of cartilage covered by conjunctiva
What is the lacimal apparatus?
structures that produce and secrete tears and drain them away from the surface of the eye
Two small openings, one each in the upper and lower eyelid margins, drain tears away from the surface of each eye, what are the openings called?
lacrimal puncta
From the lacrimal puncta on each side, the tears flow down two small ducts to the?
lacrimal sac
The tears go from the lacimal sac to a single duct called the?
nasolacrimal duct
Eye muscles attach to the?
sclera of the eye
The eye is capable of?
a wide range of movements
The eye has 6 extraocular muscles, what are they?
4 straight muscles and 2 oblique muscles
The straight muscles in the eye are called rectus muscles, they include?
dorsal, ventral, medial, and lateral rectus muscles - the names indicate where they attach to the eyeball
The two oblique muscles in the eye are?
dorsal and ventral oblique muscles
