HAP Senses

somatic sense

touch, pressure, temperature, pain

special senses

smell, taste, vision, hearing, equilibrium (within ear)

sensory receptors

detect environmental changes and trigger nerve impulses

eyes, ears

large complex organs

taste buds and olfactory epithelium

localized clusters of receptors

chemoreceptors

detect chemical changes

pain receptors

detect pain

thermoreceptors

detect temperature changes

mechanoreceptors

detect touch

photoreceptors

detect light

somatic sense

senses are associated with receptors in the skin, muscles, joints, and viscera (organs of the body)

heat receptors

respond to warmer temperature (29-45C or 82-113F). discharge most vigorously at 45C (113F) above this range, pain receptors are stimulated burning sensation.

cold receptors

respond to colder temperature (5C=40C or 41-104F) discharge most vigorously at 25C(77F). below this, pain receptors stimulate freezing sensation (you feel pain)

visceral pain

occurs in visceral tissues such as the heart, lungs, intestine

referred pain

feels as though it is coming from a different part (heart pain may be felt as pain in the arm or the shoulder)

acute pain

originates from skin, usually stops when stimulus stops (needle prick)

chronic pain

dull aching sensation

phantom limb pain

feels like it’s coming from a body part that’s no longer there. originates in the brain and spinal cord.

regulation of pain impulses

awareness of pain arises when impulses reach the thalamus

cerebral cortex

determine pain intensity, locates pain source , and mediates emotional and motor responses

enkephalins

suppress acute and chronic pain, relieve severe pain

serotonin

stimulates other neurons to release enkephalines

endorphins

extreme pain and natural pain control

sensation

feeling that occur when a brain interprets a sensory impulse

projection

process where the cerebral cortex causes a feeling to stem from a source

sensory adaptation

sensory receptors stop sending signals when they are repeatedly stimulated

adaptation

frequency of the receptor potential decreases over time in response to a continuous stimulus

small elevated projections on the tongue called papillae

where are taste buds located

olfactory receptors

yellowish brown masses- covers upper parts of the naval cavity the superior nasal conchae, and portion of the nasal septum

10,000

how many on tongue

1,000

how many on roof of mouth

sweet, sour, salty, bitter, and umami

what are the five basic tastes

very bitter

PAV-PAV = TT

somewhat bitter

PAV-AVI = Tt

nontaster

AVI-AVI=tt

70% tasters and 30% nontasters

general population of PTC tasting

thiocynate compounds

(bitter taste) found in broccoli, cauliflowers, mustard family

europeans

all 3 alleles (PAV, AVI, AAV)

asians

AAV allele rare

native americans

98% have PAV allele only

auricle (pinna)

flap on the side of the head

external auditory meatus

ear canal, which leads from the auricle, through temporal bone, into the ear canal

tympanic membrane (eardrum)

stretches across the inner end of the auditory canal, separating it from the middle ear

malleus, incus, stapes

3 very small bones named for their shape (hammer, anvil, stirrup); amplify sound

oval window

vibrates as stapes hit against it; passes vibration to fluid in cochlea

round window

acts as a “pressure valve” and allows oval window to continue to transmit vibrations in cochlear fluid

eustachian tube

passage leading from the pharynx to the cavity of the middle ear, permitting the equalization of pressure on each side of the eardrum

inner ear

has structures that help to produce both hearing and balance

static equilibrium

sense the position of the head, maintain stability and posture

dynamic equilibrium

(semicircular canals)- balance the head during sudden movement

cerebellum

interprets impulses from the semicircular canals and maintains overall balance

eye

the ___ is the sense organ for vision and converts light into electrical impulses/action potentials

sclera

white of the eye; protects

choroid

becomes the iris in front

retina

incomplete innermost layer of the eyeball (no anterior portion)

optic disk aka blind spot

where axons of sensory neurons leave the eye as the optic nerve

rods

rhodopsin

cones

erythrolable (red), chlorolable (green), cyanolable (blue)

astigmatism

cornea i

cataracts

protein in the lens clumps together and starts to cloud the lens

colorblindness

inability to distinguish certain colors due to photopigment defect in cone cells

vitamin A deficiency blindness

leading cause of preventable childhood blindness