Anatomy Exam 4 lecture 1

stimuli

sensory information

sensation

conscious awareness of the stimuli

What are stimuli detected by?

sensory receptors

general senses

temperature, pain, touch, stretch and pressure and are distributed throughout skin and organs

Special senses

gustation, olfaction, vision, equilibrium, and hearing and are housed in complex organs of the head

Transduction

conversion of stimuli into an impulse

perception

CNS assigning meaning

Chemoreceptors

detect specific molecules dissolved in fluid

thermoreceptors

detect changes in temperature

photoreceptors

detect changes in intensity, color, and position of light

mechanoreceptors

detect touch, pressure, vibration, and stretch

Baroreceptors

detect pressure changes within body structures(blood vessels) and are mechanoreceptors

Nociceptors

detect painful stimuli

phantom pain

sensation associated with a part of the body that has been removed

referred pain

impulses from certain viscera are perceived as originating not from the organ but from the skin(ie. heart attack—> feeling pain down the arm)

tactile receptors

a type of mechanoreceptor that reacts to touch, pressure and vibration that is the most numerous

Where are tactile receptors located

In the dermis and subcutaneous layer

Gustation

sense of taste

gustatory cells

detect tastants in food and is housed in specialized organs(taste buds)

Papillae

epithelial and connective tissue elevations

5 taste sensations

sweet, salt, sour, bitter, umami

Taste buds on anterior 2/3 of tongue

conduct gustatory information to CNS through facial nerve

Taste buds on posterior 1/3 of tongue

conduct gustatory information to CNS through glossopharyngeal nerve

What is taste interpreted by?

Insula

Olfaction

sense of smell

Odorants

are dissolved in mucus of nasal cavity and detected. More sensitive in animals.

Olfactory epithelium

lines superior nasal cavity

Olfactory nerves

bundle of axons of olfactory receptor cells

What enters olfactory bulbs

axons from neurons foramina of cribriform plate

What do olfactory bulbs project?

axon bundles called olfactory tracts to the temporal lobe

conjunctiva

lining of eyelids over the anterior surface of eye, does not cover cornea

what is lacrimal fluid

tears

where is the anterior cavity of the eye and what does it contain?

it is in front of the lens and contains circulating aqueous humor

where is the posterior cavity of the eye and what does it contain

it is behind the lens and contains vitreous humor

what are the three eye wall layers

fibrous tunic, vascular tunic and retina

vitreous humor

gelatenous, helps maintain shape

glaucoma

pressure buildup within an eye because of high amounts of aqueous humor

cornea

clear anterior portion of the eye, continuous with sclera

sclera

white part of eye

vascular tunic

deep(brownish)

choroid

vast network of capillaries supplying nutrients and oxygen to the retina (region with blood vessels)

cilliary body

changes lens shape, anterior expansion with ligaments attached to the lens

iris

pigmented part of anterior eye; defines pupil

pupil

controls amount of light entering eye

circular sphincter pupillae

immediately around, makes pupil smaller when there is a bright light

radial dilator pupillae

makes pupil larger when theres less light

retina

internal layer of eye

neural layer

houses photoreceptors and associated neurons. It receives light; converts energy into nerve impulses

Bipolar cells

synapse with photoreceptor and ganglion cells

photoreceptor cells

outermost layer composed of rods and cones

rods

important for dim light, 120 million/retina, more numerous, night vision, low acuity, vision in shades of grey

cones

important for precise vision and color, 6 million/retina, concentrated in fovea, day vision, high acuity

ganglion cells

innermost layer of retina; axons of these cells leave the retina and form the optic nerve

optic disc

blind spot of retina lacking photoreceptors

where is the optic disc located

where ganglion cell axons exit the retina to form the optic nerve and blood vessels enter and exit the retina

fovea centralis

depression in retina containing the highest proportion of cones and almost no rods. Has the sharpest vision

where is the fovea centralis located

within the macula lutea(lateral to optic disc)

Lens

transparent structure, suspensory ligaments attach to outer capsule of lens

accommodation

change shape of lens to focus image

optic chiasm

where optic nerves cross over each other

optic tracts

extend laterally, posteriorly from chiasm

optic radiation

extends from thalamus to occipital lobe

visual acuity

the ability to distinguish fine detail

nearsightedness(myopia)

cant see far away because eye is too long, can add width to correct. Treatment is surgery or glasses(thin in middle)

farsightedness(hyperopia)

cant see short distances because eye is to short, add length. Glasses are thick in the middle.

Presbyopia

age related not eye changes

astigmatism

irregularity on lens or cornea. Treatment is glasses(varies for each case)

conjunctivitis

pink eye. Virus or bacteria, inflammation of conjunctivity

cataracts

clouding of lens—>age(older people)

glaucoma

increase in pressure in eye because of aqueous humor

diabetic retinopathy

small unstable vessels develop in eye and can rupture

strabismus

misalignment of eyes, one side of extrensic muscles stronger than the other

Part of external ear

auricle, external acoustic meatus, and tympanic membrane

auricle

external funnel

external acoustic meatus

ear cannel

tympanic membrane

ear drum, amplifys sound waves

auditory tube

connects middle ear to nasopharynx

auditory ossicles(small bones)

transmit sound waves to inner ear

equilibrium

awareness of head position

maculae

contains hair cells