Senses Chap 9

Front 1

sensory pathway

Back 1

the impulses involved in sensations follow precise pathways:
receptors
sensory neurons
sensory tracts
sensory areas

Front 2

receptors

Back 2

*detect changes (stimuli) and generate impulses.
Receptors are VERY SPECIFIC to the kinds of changes they respond to:
EX.
**retina receptors detect light rays
**nasal receptors detect vapors

*ALL generate electrical nerve impulses

Front 3

sensory neurons

Back 3

transmit impulses from the receptors to the CNS.
*FOUND in both cranial & spinal nerves, but ONLY carry impulses from ONE type of receptor

Front 4

sensory tracts

Back 4

white matter in the spinal cord or the brain that transmits the impulses to a specific part of the brain

Front 5

sensory areas

Back 5

most are in the cerebral cortex
**AREAS feel & interpret the sensations.

*learning to interpret sensations begins in infancy and continues throughout life

Front 6

characteristics of sensations

Back 6

how the sensory areas work with information from the receptors:
*projection
*intensity
*contrast
*adaptation
*after-image

Front 7

projection

Back 7

the sensation SEEMS to come from the area where the receptors were stimulated BUT it is actually felt by cerbral cortex.
EX. phantom pain, the person still FEELS that the body part is there after amputation because the nerves continue to generate impulses and PROJECTION of the limb

Front 8

intensity

Back 8

some sensation are felt more distinctly and to a greater degree than others
EX.
a WEAK stimulus (dim light) will affect a small # of receptors, but a STRONGER stimulus (bright sunlight) will stimulate a larger # of receptors

Front 9

contrast

Back 9

the effect of a previous or simultaneous sensation on a current sensation, which MAY be exaggerated or diminished.
**function of the brain, which constantly compared sensations
EX.
HOT day, jump in COLD pool, water feels COLDER than it actually is because the brain senses a significant difference IN temperatures.

Front 10

adaptation

Back 10

becoming unaware of a continuing stimulus
EX.
wearing a watch, at first you feel it on your wrist but cutaneous receptors for touch/pressure adapt quickly to a continuing stimulus, no change=nothing to detect, you become unaware that it is there

Front 11

after-image

Back 11

the sensation remains in the consciousness even after the stimulus has stopped.
EX.
a bright after-image seen after watching a camera flash go off

Front 12

cutaneous senses

Back 12

the dermis and subcutaneous tissue contain sensory receptors

*free nerve endings
*encapsulated nerve endings

Front 13

free nerve endings

Back 13

*respond to ANY intense stimulus

*receptors for HEAT, COLD, ITCH & PAIN

Front 14

encapsulated nerve endings

Back 14

*means there is a cellular structure around the nerve ending

*receptors for TOUCH & PRESSURE

Front 15

referred pain

Back 15

pain that originates in an internal organ may be felt in a cutaneous area.
EX.
*heart attack may be felt in the left arm and shoulder
*gallstones may be felt in the right shoulder

Front 16

muscle sense

Back 16

we do not need to see our muscles to be sure they are working
*conscious
*unconscious

Front 17

conscious muscle sense

Back 17

is felt by the parietal lobes

Front 18

unconscious muscle sense

Back 18

is used by the cerebellum (balance & equilibrium part of brain) to coordinate voluntary movements

Front 19

sense of taste

Back 19

*receptors for taste are found in taste buds
most are on the tongue

*receptors detect CHEMICALS in SOLUTION in the mouth

**chemicals =foods
**solution=saliva

Front 20

taste receptors

Back 20

five (perhaps more) general types of taste receptors:
sweet
sour
salty
bitter
savory (a taste like grilled meat)

Front 21

impulses from taste buds

Back 21

transmitted from the facial & glossopharyngeal (7th & 9th cranial) nerves to the taste areas in the parietals temporal cortex.

*sense of taste important b/c it makes eating enjoyable.

Front 22

interfere with sense of taste

Back 22

medications may interfere with the sense of taste

Front 23

sense of smell

Back 23

gives a great deal of pleasure & practical info

Front 24

receptors for smell (olfaction)

Back 24

receptors are chemoreceptors that detect vaporized chemicals that have been sniffed into the upper nasal cavities

Front 25

olfactory receptors

Back 25

scent receptors (detect vapors) that generate impulses carried by olfactory nerves (1st cranial) thru the ethmoid bone to olfactory bulbs.

* vapors may stimulate many combinations of receptors

**human brain can distinguish between 10,000 scents

Front 26

hunger & thirst

Back 26

called visceral sensations, and both senses (hunger & thirst) are specialized in the hypothalamus

*triggered by internal changes.
EX.
*hunger receptors- detect changes in blood nutrient levels
*thirst receptors- detect changes in the body water content (water-to-salt proportion)

Front 27

the eye

Back 27

contains the receptors for vision and a refraction system that focuses light rays on the receptors in the retina

Front 28

conjunctiva

Back 28

a thin membrane that lines the eyelid

Front 29

conjunctivitus

Back 29

inflammation of the conjunctiva membrane may be caused by allergies, bacteria, or virus
*makes eyes red, itchy, & watery

Front 30

tears

Back 30

*produced by the lacrimal glands
(located at the upper, outer corner of the eyeball)

*tear secretion in constant, & increased by emotional situations & irritating chemicals (onion vapors)

*contains lysozyme (an enzyme) that INHIBITS the growth of most bacteria on surface of wet, warm eye

*tears, mostly water w/1% sodium chloride

Front 31

orbit

Back 31

most of eyeball is within and protected by

Front 32

chemoreceptors in mouth

Back 32

detect chemical changes in mouth (food) and nasal (vapors)

Front 33

layers of the eyeball

Back 33

**the eyeball has 3 layers
OUTER- sclera
MIDDLE- choroid
INNER- retina

Front 34

sclera

Back 34

OUTER LAYER **is the thickest layer of the eyeball.
*made of fibrous connective tissue that is VISIBLE as the white of the eye

Front 35

cornea

Back 35

*ANTERIOR (front) portion of the eyeball
**differs from the rest of the sclera, in that it is TRANSPARENT
-it has no capillaries
-it covers the IRIS & PUPIL inside eye
-1st part of eye to refract (bend) light rays

Front 36

refraction of light rays

Back 36

the DEFLECTION or BENDING of a ray of LIGHT as it passes through one object and into another if greater or lesser density

Front 37

choroid layer

Back 37

MIDDLE LAYER EYEBALL
*contains blood vessels and a dark blue pigment (from melanin) that absorbs light within the eyeball and prevents glare

**IN anterior portion of choroid
-ciliary body
-iris

Front 38

ciliary body

Back 38

Front 39

lens

Back 39

made up of clear/transparent, elastic protein
*has no capillaries
*looks like an onion peel

Front 40

iris

Back 40

the iris is INFRONT of lens
**the COLORED part of the eye
**pigment is a form of melanin

Front 41

pupil

Back 41

black dot on eye LIGHT RAYS enter through the pupil
**the central opening
**two sets of muscle fibers in the iris change the diameter of the pupil

Front 42

retina

Back 42

lines the POSTERIOR 2/3's of the eyeball and contains VISUAL receptors (rods and cones)

Front 43

rods

Back 43

detect ONLY the presence of light
*rods are abundant toward the edge of retina
*best vision in dim light or @ night depends on rods

Front 44

cones

Back 44

detects color which are the different wavelengths of visible light
*most abundant in the center of the retina

Front 45

two cavitities in eyeball

Back 45

posterior cavity
anterior cavity

Front 46

posterior cavity

Back 46

LARGER of the two cavities
*contains vitreous humor (semisolid substance) which keeps the retina in place

Front 47

anterior cavity

Back 47

contains aqueous humor (the tissue fluid of the eyeball)
*found between the back of the cornea and front of lens

Front 48

occipital lobes

Back 48

are the VISUAL areas of cerebral cortex
*sees images upside down and as left/right

Front 49

binocular vision

Back 49

*EACH eye transmits a slightly different picture
*BRAIN takes images and puts them together, forming a SINGLE IMAGE and interprets them
*BRAIN also turns image right side up (occipital sees images upside down and as left/right)

Front 50

ERRORS of refraction

Back 50

not focusing on images
CORRECTION= contacts/eye glasses

Front 51

the ear physiology

Back 51

OUTER EAR
MIDDLE EAR
INNER EAR

Front 52

OUTER ear consists of

Back 52

auricle (pinna)
ear canal

Front 53

AURICAL (pinna)

Back 53

made of cartilage covered by skin

Front 54

EAR CANAL
(aka)
external auditory meatus (or) auditory canal

Back 54

is lined with skin that contains ceruminous glands

Front 55

MIDDLE ear consists of

Back 55

tympanic membrane (ear drum)
eustacian tube

Front 56

TYMPANIC MEMBRANE

Back 56

*sound waves vibrate
*CONSISTS OF 3 bones AKA *ossicles (smallest bones in body)
***malleus, incus, stapes***

Front 57

EUSTACIAN TUBE (auditory tube)

Back 57

connects throat & ear
*allows AIR to enter or leave the middle ear cavity
*air pressure in middle ear must be the same as atmospheric pressure in order for the eardrum to vibrate properly.

Front 58

INNER ear consists of

Back 58

*cochlea (hearing)
organ of Corti (inside of cochlea)
hearing receptors
*semicircular canals
*saccule
*utricle

**balance & equilibrium

Front 59

cochlea

Back 59

hearing receptors (shaped like a snail shell)
CONTAINS- organ of Corti

Front 60

the two senses of the ear:

Back 60

hearing and equilibrium

Front 61

saccule & utricle (inner ear)

Back 61

membraneous sacs between the cochlea and the semicircular canals
**provides information about the position of the body at REST

Front 62

semicircular canals

Back 62

fluid filled membraneous ovals
**provide info about body in MOTION

Front 63

hearing receptors

Back 63

specialized hair cells or stereocilia contain endings of the cochlear branch of 8th cranial nerve

Front 64

temporal lobes of the cerebral cortex

Back 64

auditory areas of the brain. receives impulses from both ears

Front 65

arterial receptors

Back 65

found in the aorta (*largest artery in the body) & the carotid arteries
*pressoreceptors
*chemoreceptors

Front 66

chemoreceptors in arteries

Back 66

detect changes in OXYGEN, BLOOD pH, & CARBON DIOXIDE

Front 67

pressoreceptors in arteries

Back 67

detect changes in the blood pressure in the carotid and aortic.

Front 68

carotid artery

Back 68

found in the neck (cervicle area)

Front 69

hypoxemia

Back 69

a decrease in oxygen blood level
*HYPO (decrease or low)
*ox (oxygen)
*emia (blood)
**HYPER= increase or high

**sensory to medulla to speed heart rate/speed breathing to increase oxygen intake