sensory system

exam 4 content

sensation definition

any stimulus the animal body is aware of

perception definition

conscious awareness and interpretation of a sensation

4 general types of stimuli

mechanical

thermal

electromagnetic

chemical

list of visceral sensations

hunger, thirst, hollow-organ fullness

chemical and mechanical stimulus

what type of sensation do stretch receptors in hollow organs sense?

stretch

what is tactile sense?

sensation of something in contact with the surface of the body (ex.whiskers)

how are changes in skin temperature monitored?

superficial receptors (in the skin)

how are changes in blood temperature monitored?

central receptors (in the hypothalamus)

pain definition

an unpleasant sensory and emotional experience associated with actual or potential tissue damage

what are nocieptors and what is their significance?

pain receptors

protect the body from damage

4 steps of pain sensation

transduction, transmission, modulation, perception

what is proprioception?

sense of body position and movement

how does acute pain differ from chronic pain?

acute: adavptive, nocieptive or inflammatory, varies in severity, caused by a disease/injury, serves biological purpose (ex.wound)

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chronic: maladaptive/pathalogical, neuropathic or functional, no biological purpose, no clear end point, affects physical wellbeing

list the 5 special senses, what is sensed, and the type of stimulus

taste: senses tastes, chemical stimulus

smell: senses odors, chemical stimulus

hearing: senses sounds, mechanical stimulus

equilibrium: senses balance/head position, mechanical stimulus

vision: senses light, electromagnetic stimulus

list the 5 general senses, what is sensed, and the type of stimulus

visceral: hunger/thirst/hollow-organ fullness, chemical/mechanical stimulus

touch: touch and pressure, mechanical stimulus

temperature: heat and cold, thermal stimulus

pain: intense stimuli of any type, mechanical/chemical/thermal stimulus

proprioception: body position/movement, mechanical movement

what is the gustatory sense?

taste

chemical receptors are taste buds

papillae (small elevated structures on tongue)

found on lining of mouth/pharynx

what is the olfactory sense?

smell

cranial nerve

olfactory cells in epithelial patches in nasal passages

what cranial nerve is associated with olfaction?

the first cranial nerve

what is the vomeronasal organ and another name for it?

2 narrow/parallel ducts embedded in the heard palate (one on each side of its junction with nasal septum)

AKA Jacobsons organ

what is the function of the vomeronasal organ?

involved in sexual activity (ex.lip curl)

flehmen reaction in male animals

not present in adult humans

what is the flehmen response?

the lip curl in male animals

associated with sexual activityand the vomeronasal organ (olfaction)

what is the auditory sense?

hearing

converts vibrations of air molecules into nerve impulses

impulses interpreted by brain as sound

which skull bone contains most ear structures?

temporal bones of skull

what are the 3 division of the ear and the functions of each division?

external ear: funnel to collect sound wave vibrations and direct them to eardrum

middle ear: amplifies/transmits vibrations from eardrum to inner ear

inner ear: has sensory receptors that convert mechanical vibrations to nerve impulses, with receptors for equilibrium sense

which portion of the ear contains the structures that contribute to equilibrium?

the inner ear

which portion of the ear contains the eardrum?

the middle ear

which portion of the ear contains the external auditory canal?

the external ear

which portion of the ear contains ossicles?

the middle ear

what is another name for the auditory canal?

the acoustic meatus

which portion of the ear contains the auditory canal?

the external ear

what is the function of the pinna? (picture)

elastic cartilage and skin in the external ear

connects sound waves

what is the function of the external auditory canal? (picture)

membrane-lined tube in the external ear

L-shaped

what is the function of the tympanic membrane? (picture)

AKA eardrum

thin connective tissue membrane

stretched across opening between external auditory canal and middle ear cavity

sound wave vibrations strike tympanic membrane and cause it to vibrate

what is another name for the eardrum?

the tympanic membrane

where is the eardrum located?

in the external ear

stretched across the opening between the external auditory canal and the middle ear cavity

where is the eustachian tube located?

in the middle ear

connects middle ear cavity with pharynx

AKA auditory tube

which structures does the eustachian tube connect?

connects the middle ear cavity with pharynx

what is the function of the eustachian tube?

equalizes air pressure on the 2 sides of the tympanic membrane

slit opening into pharynx stretches during yawning/swallowing

what is the shape of the external auditory canal in animals and what are the parts called?

L-shaped

pinna, external auditory meatus, eustachian tube, tympanic membrane, cochlea

what structures do the middle ear ossicles link?

link the tympanic membrane with the cochlea of the inner ear

what is the function of the middle ear ossicles?

system of levers that transmit sound wave vibrations from tympanic membrane to cochlea

list the 3 middle ear ossicles (outer to medial)

malleas (hammer)

incus (anvil)

stapes (stirrup)

what is another name for the malleus?

the hammer

outermost bone

what is the malleus attached to?

attached to tympanic membrane

what is another name for the incus?

the anvil

middle bone

what is the incus attached to?

attached to the malleus and oval window

what is another name for the stapes?

the stirrup

medial-most bone

what is the stapes attached to?

attached to membrane that covers oval window of cochlea

what is the cochlea and where is it found?

shell-shaped spiral cavity

found in the temporal bone

what is the Organ of Corti and where is it found?

filled with endolymph and has hair cells (hearing receptors)/supporting cells/tectorial membrane

found along the length of cochlear duct on basilar membrane

what fluid fills the Organ of Corti?

the endolymph

what is equilibrium?

maintains balance by keeping track of head position and movement

uses information from eyes/proprioceptors around the body

where are the equilibrium receptors found in the inner ear?

in the vestibule and semicircular canals

what structures is the vestible located between?

between the cochlea and semicircular canals

which structures comprise the vestibule?

made of the utricle and saccule

where are the otoliths found in the ear?

in the vestibule

hair cells covered by a gelatinous matrix that contains crystals of calcium carbonate

what is the function of otoliths?

puts constant pressure on the hair by gravity and gelatinous matrix

generated nerve impulses give brain info about head position

head movement bends sensory hairs

where are the semicircular canals located?

located on the other side of the vestibule from the cochlea

have fluid-filled membranous tubes

which structures comprise the semicircular canals?

the ampulla, crista amullaris, capula

which cranial nerve is responsible for vision?

the optic nerve (CN II)

where are the photoreceptors in the eye located and what is their function?

in a single layer of cells in the retina

detect the image and generate visual nerve impulses

what are the 3 layers of the eyeball (outer to inner)?

outer fibrous layer (cornea, sclera)

middle vascular layer (choroid, iris, ciliary body)

inner nervous layer (retina)

list the ocular structures located in the fibrous layer of the eye

cornea and sclera

what is another name for the vascular layer of the eye?

the iris

list the ocular structures located in the vascular layer of the eye

choroid

iris

ciliary body

list the ocular structures located in the nervous layer of the eye

retina, fundus

where is the tapetum lucidum located in the eye?

in the middle vascular layer

which portion of the eye contains the sensory receptors for vision?

the inner nervous layer- retina

rods and cones

what structures comprise the fundus of the eye?

retina

optic disc

macula

what is the optic disc and where is it located?

in the retina

the blind spot of the eye

nerve fibers on the inside of the retina converge and leave eye to form optic nerve

what are the 2 types of photoreceptor cells in the retina and what are their functions?

neurons with modified dendritic sensory receptors

rods: more sensitive to light

cones: more sensitive to color/detail

list the layers of the retina

pigment

photoreceptor

bipolar cell

ganglion cell

layer of nerve fibers

what are the 2 compartments of the eyeball?

aqueous compartment

vitreous compartment

where is the aqueous compartment of the eye?

in front of the lens

subdivided by the iris (anterior and posterior chamber)

what type of fluid does the aqueous compartment contain?

aqueous humor

clear and watery fluid

produced in posterior chamber by cells of ciliary body

drained by canal of Schlemm

which structure produces aqueous humor?

produced in the posterior chamber by cells of ciliary body

how is aqueous humor drained?

drained by canal of Schlemm

what are the divisions of the aqueous compartment of the eye?

the anterior chamber and the posterior chamber subdivided by the iris

what structure divides the aqueous compartment into chambers?

the iris

what structures are in the anterior chamber of the aqueous compartment?

cornea

iris

ciliary body

lens

what structures are in the posterior chamber of the aqueous compartment?

aqueous humor

where is the vitreous compartment of the eye?

fills the back of the eyeball behind lens and ciliary body

what type of fluid does the vitreous compartment contain?

vitreous humor

clear and gelatinous fluid

what structures are in the vitreous compartment?

the optic nerve

describe the composition of the lens of the eye

soft/translucent layers of fibers

elastic and biconvex

front surface contact aqueous humor

back surface contacts vitreous humor

what does the front surface of the lens contact?

contacts aqueous humor

what does the back surface of the lens contact?

contacts vitreous humor

what is the function of the lens?

helps focus clear image on retina through accommodation process

what is lens accomodation?

process where the shape of the lens is changed to allow close-up and distant vision

list the 4 refractive media in the eye that help form a clear upside-down image on the retina

cornea, aqueous humor, lens, vitreous humor

brain inverts image

conscious mind sees everything right-side up

what is the conjunctiva?

extraocular structure

thin/moist/transparent membrane

bulbar conjunctive covers front of eyeball

palpebral conjunctiva lines interior surfaces of eyelids

what is the conjunctival sac?

extraocular structures

space between bulbar and palpebral conjunctiva

what is the upper/lower eyelid?

folds of skin lined by conjunctiva

what is the lateral canthus?

corner where the eyelids come together (outer)

extraocular structure

what is the medial canthus?

corner where eyelid comes together (inner)

extraocular structure

what are the tarsal glands?

meibomian glands

tiny openings found along eyelid margin

produce waxy substance to prevent tears from overflowing onto face

extraocular structure

what are eyelashes?

prominent on upper lid of most animals

extraocular structure

what is the third eyelid?

nictitating membrane

T-shaped plate of cartilage covered by conjunctiva

located medially between eyelids and eyeball

no muscle attachment (passive movements)

lymph nodules/accessory lacrimal gland on ocular surface

extraocular surface

where is the palpebral conjuctiva found?

lining the interior surface of eyelids

extraocular structure

wher is the bulbar conjunctiva found?

covering the front of the eyeball

extraocular structure