Senses

What is synesthesia?

condition in which one sense being triggered causes the triggering of another (etc. “smelling” colors or “seeing” music)

Where do general senses originate from? Special senses?

General senses = receptors found throughout the body

special senses = specialized receptors found in the head (eyes, ear, nose, mouth)

Where in the nervous system are receptor cells found?

in the peripheral nervous system (the nerves throughout the body)

how are receptor cells classified?

based on their structure, location, and function

what is sensory adaptation?

sensory receptors stop sending signals when they are repeatedly stimulated by the same thing

1. what are free nerve endings?

2. what’re they alternatively called?

3. what do they respond to?

1. dendrites embedded in tissue as recievers

2. nociceptors

3. pain and temperature

1. what are encapsulated receptors?

2. what do they do

3. what are they alternatively called?

1. receptors embedded in connective tissue

2. increase sensitivity to pressure and touch

3. mechanoreceptors

where are specialized receptors found?

retina of the eye

where are exteroreceptors found?

near the external environment (skin)

where do interoreceptors do?

interpret stimuli from internal organs

where are proprioceptors found and what do they do?

near moving body parts

interprets position

what are chemoreceptors and where are they found?

chemicals

nose/mouth

what do osmoreceptors do?

respond to solutes in body fluids

what do thermoreceptors do?

maintain temperature and detect changes t it

where does visceral pain occur?

in heart, lungs, intestine

what is referred pain?

feels as though it is coming from a different part (ex. heart attack may be detected by pain in the shoulder)

where does acute pain originate and when is it felt?

skin

when the stimulus stops (ex. after getting a shot)

what is chronic pain?

a dull, aching ongoing sensation

what is the universal pain assessment tool?

ask patient to describe their pain from 0-10 to understand their pain level through self-assessment

what is the FLACC scale?

face, legs, activity, cry, consolability scale

used for children by monitoring how they act to determine how bad the problem is

what is gustatory?

sense of taste

what are papillae?

taste buds

what are the five taste sensations?

sweet, sour, salty, bitter, savory (umami)

what is olfaction?

sense of smell

how does a smell travel through the body?

smell → receptor cells → olfactory epithelium → olfactory tract

why do smells trigger memories?

the stimuli of a smell travels to the brain and goes through the hippocampus, where memories are stored

what is the auricle and what is another name for it?

the outer ear

pinna

what is the opening of the ear called?

auditory canal

why can some people wiggle their ears?

they have the trait that allows the use of auricular muscles, which allows them to wiggle the outer ear

what is the tympanic cavity?

the middle ear

what is the tympanum?

eardrum

what are the three auditory ossicles and what do they do?

malleus, incus, stapes

transmit vibrations and amplify signals

what does the Eustachian tube do and what is another term for it?

connects the middle ear to the throat and maintains air pressure

auditory tube

why do children get recurrent ear infections?

how do doctors treat them?

children have more horizontal Eustachian tubes, which means that the fluid in their throat can travel to the ear and cause fluid buildup there, often causing an infection

insert a small tube in the eardrum to allow for ventilation between the ear and the throat, preventing fluid buildup

what is another term for the inner ear?

labyrinth

what is the function of the semicircular canals?

sense of equilibrium and balance

what makes up the vestibule?

semicircular canals, utricle, saccule, and cochlea

what is in the cochlea and what does it contain?

organ of corti

hearing receptors (hair-like cells)

what are the steps in hearing?

1. sound waves enter auditory canal

2. eardrum vibrates

3. auditory ossicles amplify vibrations

4. the stereocilia that are found on top of the hair-like auditory receptors (which are found in organs of corti, which are found in the cochlea) are moved by the vibrations

5. hair (stereocilia) bundles turn the movements into electrical impulses

6. impulse is sent to the vestibulocochlear nerve

7. auditory cortex of the temporal lobe interprets the impulse

what causes hearing loss?

loud noise damage the hair-like cells inside the cochlea, which can cause hearing loss over time

what is tinnitus and what causes it?

a ringing in the ear even though there is no actual external sound present; causes phantom noises

caused by hair cells randomly moving, which can be caused by injury or a different underlying problem

how do cochlear implants work?

they receive sound from the outside environment, process it, and create an electrical current that is sent to the auditory nerve since the ear can’t do it itself. the brain learns to recognize this signal over time and can experience it as organic “hearing”

what type of physician works with disorders of the ears, nose, and throat?

otolaryngologists

how many newborns are affected by hereditary deafness?

1 in every 1000-2000

what syndromes are associated with deafness and what do each of them cause?

pendred syndrome - thyroid and deafness

usher syndrome - deafness and vision problems

what prenatal infections can cause deafness?

(ToRCH)

toxoplasmosis

rubella

cytomegalovirus

herpes

what postnatal infections can cause deafness?

meningitis, streptococus, listeria, influenza

what is presbycusis?

age-related hearing loss

what does static equilibrium do and what parts of the ear maintain it?

maintain stability and posture

saccule and utricle

what does dynamic equilibrium do and what parts of the ear maintain it?

maintains balance during sudden movement

semicircular canals

what does the cerebellum do?

interprets impulses from the semicircular canals and maintains overall balance

how did doctors test molly’s vision?

1. response to light (she did not respond)

2. pupil response; constrict in bright light and dilate in low light (her pupils were slow to constrict in bright light)

3. ability to follow target (Molly couldn’t track a toy)

4. ability to navigate obstacles (she would bump into objects)

what was Molly diagnosed with?

Leber Congenital Amaurosis (LCA)

what are the chances that molly’s parents have another kid with the same disorder?

1/4

what is the function of the eyelid?

covers and protects the eye

what is the function of the eyelashes?

protect the eyes from dust and debris

what is conjunctiva?

the covering around the eye and under the eyelids

what is conjunctivitis caused by and what is it? what is it commonly called and is it contagious?

caused by bacteria or viral infection

inflammation and redness of the conjunctiva

pink eye

highly contagious

what is the function of the lacrimal glands?

produce tears

what do tears drain into? via what?

nasal cavity

lacrimal duct

what is the function of tears?

moisten and lubricate the eye surface; has enzymes that kill bacteria

what is the cornea and what is its function?

transparent dome

focuses light coming into the eye

what is keratoconus?

the normally round cornea things, causing a cone-like bulge to develop

where do transplanted corneas come from?

organ donors

what is sclera?

the white of the eye

what is the theory on why humans have white sclera?

we evolved to have it so that we can communicate with others easier by following their gaze

what does the optic nerve transmit info to?

the occipital lobe of the brain

what is optic neuritis?

inflammation of the optic nerve, causing vision loss (can come back)

what is anosmia?

partial or full loss of sense of smell

what is anhidrosis?

inability to sweat

what is congenital analgesia?

inability to feel pain

what parts make up the middle tunic of the eye?

choroid, ciliary body, lens, Iris, pupil, and aqueous humor

what does the choroid contain?

blood vessels

what holds the lens in place?

ciliary body

what is the lens responsible for?

focusing the light that enters the eye

what is the Iris?

the colored portion of the eye

what is the opening for light called

pupil

what is the aqueous humor?

the light surrounding the lens

eye color is the result of what pigment?

melanin

what is the most common eye color?

brown

what is the condition called where the eyes are different colors?

heterochromia

what does the pupil do?

dilate or constrict to adjust to light entering the eye

when does the pupil dilate?

when in the dark

when does the pupil constrict?

in bright light

what causes red eye in photos?

the flash on a camera is bright enough to cause a reflection off the retina- what you see is the red color of the blood vessels

what parts make up the inner tunic of the eye?

retina, fovea Centralis/macula, optic disc, and vitreous humor

what does the retina contain?

visual receptor cells/photoreceptors

what is the region of sharpest vision?

fovea Centralis/macula

what is another term for fovea centralis?

macula

what is the region where nerve fibers leave the eye called?

optic disc

what do the nerve fibers leaving the eye create?

the optic nerve

where is the blind spot located?

at the optic disc

what is the fluid within the eye that supports the internal parts?

vitreous humor

what causes blindness in those w LCA?

the RPE65 protein is expressed in photoreceptor cells. The mutated form of this gene causes the cells to die, resulting in blinfness

what are the two types of photoreceptors?

rods and cones

what is responsible for monochromatic vision?

rods

what is responsible for color vision?

cones

what are the colors of light?

red blue green

how do we see different colors

there are cones for each color of light, and the combinations of those colors are what we see when we see different colors

are dogs colorblind?

they are red-green color blind as they have only yellow and blue cones