lab 13

what are the 2 classes of general senses? what does each include

somatic

• tactile sensation

• thermal

• pain

• proptioreception

visceral

• located in the skin (vutaneous sesnations)

• found in tendons, ligaments and muscles

• detet stretching of the internal organs

Tactile Sensations

• Tactile corpuscles function

• found in the dermal paillae

• detcts the onset sensation of touch + low frequency vibrations

• more sensitive in hairless areas of the skin

Tactile Sensations

• hair root plexuses function

• free nerve ending wrapped around a hair follicle

• detects movement that disturbs the hair

Tactile Sensations

• Nonencapsulated sensory corpuscles

• merkel discs or tactile discs

• found in the stratum basale, associated with tactile epithelium

• detect pressure + continuous touch

• more numerous on hairless areas of the skin (fingertips, hand, lips)

Tactile Sensations

• Bulbous corpuscles

• found deep in the dermis

• located in tendons and ligaments

• detects stretching and steady pressure

Tactile Sensations

• Lamellar corpuscles

• located in the dermis and subcutaneous regions

• detects frequency vibrations + steady pressure

Tactile Sensations

• Free nerve endings

• stimulated by certain chemicals to create the tickle and itch sensations, also temp

Results of Testing for Two-Point Touch Threshold

• Which area(s) tested appeared to be the most and least sensitive?

• What does this tell you about the distribution of touch receptors in the areas of the body

  tested?

  Which type of touch receptor(s) responded to the stimuli in this experiment

most sensitive = fingertips

least sensitive = upper forearm

• this shows that touch receptors are not evenly distributed across the body, places like the fingertips have a high denity of touch receptors, whereas the upperforearm has a lower density of touch receptors

• tactile corpuscles + merkle discs

Thermal Receptor Distribution

• Briefly explain your results in terms of the specificity and distribution of hot and cold receptors.

• Why might warm receptors be less abundant than cold receptors

• warm and cold sensations are detected by different receptors, these recpetors are not easily distributed thorughout the skin

• cold receptors are more abundant because a drop in temp is more critical to survival

hat structure detects pain

free nerve endings called nociceptors

where are propioreceptors found? what aprt of the brain recieves information about propiorecrtion?

senses body postiton

found in synovial joints, tendons and skeletal muscle

the cerebrum and cerebllum recives input from porpiorecptors

Procedure 5: Proprioception

• why is the dominant hand more accurate than the non-dominant hand?

the dominant hand has better motor control and coordination due to more frequent use and practice

where are sensory receptors for olfaction located? what are they classified as?

located in in the olfactory epithelium

• classified as chemoreceptors because they respond to chemicals in a solution

olfactory tract and bulb function

recvies smell information and tramsits it to the brain for processing

ethmoid bone function

form part of the skull, contains the cribriform plate, assists the olfactory region

cribriform plate function

allows olfactory nerve fibres to pass from the nasal cavity to the brain

nasal cavity function

warms, filters, and humidifies inhaled air

olfactory gland and mucus

olfactory gland = secretes mucus

mucus= dissolves odour molecules to stimulate the olfactory receptors

olfacotry sensory neuron function

detects odour molecule and generates a nerve impulse

dendrite of olfacotry sensory neuron function

recieves smell stimuli from the nasal cavity

axon of olfacotry sensory neuron function

transmits the nerve impulse to the olfactory bulb

olfactory cilia/ hair function

binds odor molecules to initiate a nrrve impulse

odour molecule function

a chemical substance that dissolved in mucus that stimulates the olfacotry receptors

Procedure 6: Olfactory Adaptation

• explain what happened in terms of adaptation and smell

• When does olfactory adaptation occur in real life?

sensory receptors adapted to the first smell (peppermint), so it faded. the new smell (clove) was detected because it was a new stimulus.

• in real life it occurs when you stop smelling a constant smell like ones body odour or perfume

is olfactory adaptation desirable?

yes, becuause it allows you to ignore constant, bacground smell and detect new, important smells like fire or a gas leak

where are sensory recceptors for gustation located?

located in taste buds of the tongue, pharynx, epiglottis, + soft palate

what are lingual papillae

elevated structures on the tongue that contain taste buds

function of gustatory epithelial cells

receptor cells that detect dissolved food molecules and initite taste signals

gustatory microilli

hair like projections that come into contact with dissolved food molecules and detect taste

taste pore function

opening through which dissolved food molecules reach the gustatory microvilli

saliva function

dissolves food molecules so they can stimulate taste receptors

Name three cranial nerves that transmit sensory information from the taste buds to the brain.

VII (7)

• facial nerve

IX (9)

• glossopharyngeal

X (10)

• vagus

Which sense, taste or smell, appears to be more important in the proper identification of a strong substance? Explain

smell is more important for identifying tatse becuase most of our taste perception relies heavily on olfaction

What conclusions can you draw about chemoreception and gustation?

chemoreception in gustation depends on chemicals being dissolved in saliva, taste is detected much quick when there is saliva in the mouth

lacrimal gland function

produces tears that lubrictae and protect the eye

lacrimal sac

collects + drains tears into the nasolacrimal duct

eyelid

protects the eyes from foreign particles and keeps the eyeball moist by spreading tears while blinking

pupil funcion

structures that allows light to enter the eye

iris function

constricts the pupil to control the amount of light that enters the eye

sclera function

tough, outer layer of the eyeball that maintains it’s shape and provides protection

superior rectus vs inferior rectus

• innervating nerve

• function

superior rectus

• oculomotor nerve (III)

• move eye superiorly and medially

inferior rectus

• oculomotor nerve (III)

• moves eye inferiorly and medially

lateral rectus

• innervating nerve

• function

trochealr (IV)

• moves eye laterally

medial recuts

• innervating nerve

• function

oculomotor nerve (III)

• move eye medially

superior vs inferior oblique

• innervating nerve

• function

superior oblique

• trochealr (IV)

• moves eye inferiorly and laterally

inferior oblique

• oculomotor nerve (III)
  - moves eye superiorly and laterally

ciliary body

contains structures that change the eye lens and produce aqueous humor

ciliary muscle function

chnages the shape of the lens for focusing

ciliary process function

produces aqeous humor

aqeous humor function

nourishes the cornea and lens, maintains intraocular pressure

anterior chamber function

space between the iris and he cornea, contains aqeous humor

posterior chamber

space between the iris and the lens produces and circulates aqeous humor

cornea function

transparent, anterior portion of the eye that refracts (bend) light entering the eye

lens function

changes shape to direct light onto the retina

zonulnar fibres of lens function

attaches the lens to the cililary body, transmits tension to change the shape o the lens

bulbar conjunctiva

thin membrane that covers the sclera, provides lubrication and protection

retina

converts light into a nerve signal

choroid function

supplies oxygen and nutrients to the retina

macula (macula lutea)

central region of the retina responsible for detailed, sharp central vision

foeva centralis

central region of the retina with the highest visual acuity

optic disc (blind spot) fucntion

where the optic nerve exits the eye, no photoreceptors, no vision

optic nerve

carries visual information from the retina to the brain

posterior segment (viterous chmaber)

space behind the lens that contains viterous humor, which maintains eye shape

viteous humor/body

gel like substance that supports the retina and maintains eye shape

what is visual acuity

the ability to see objects clearly at different distances

what is myopic vision

nearsighted vision

• one is unable to focus distant objects onto the retina, instead the image sits in front of the retina, causing blurry vision

what is hyperopic vision

farsighted vision

• can view distance objects, but bearby objects are focused behind the retina

what is cokourblindess caused by

the deficiency of one or 3 photopigments (red, blue, or green) that are located in cones

what is antangism? effect?

caused by the irregular curvature of the lens or cornea

• images appear blurry because they are not properly focused

intrinsic vs extrinsic eye muscles

intrinsic

• muscles inside the eye control lens shape + pupil size

extrinsic

• muscles outside of the eye that control movement of the eyeball

explain the importance of the puil changing shape for nearsighted vs farsighted vision

the pupil changing shape regulates the amount of the light entering the eye, which helps produce a clearer image on the retina when switicing between near and farsighted vision

what is the vlalue of the convergence reflex?

keeps the image of a near object aligned with both retinas, so that it is viewed as one clear image

helix function

collects sound waves and directs it to the ear canal

temporal bone function

protects the structures of the ear

external acoustic meatus

passage that conducts soundwaves to the eardrum

tymapnic membrane function

vibrates in response to soundwaves and transmits sounwaves to the middle ear

malleus, incus, stapes function

malleus = recieves vibrations from the ear drum, passes it to the incus

incus= receives vibrations fromthe malleus and passes it to the stapes

stapes= receives vibrations from the incus and passes it to the inner ear

vestibular (oval window)

recevies vibrations from the stapes and transmits it to the inner ear fluid

cochlear (round) window function

receives pressure in the cochlea by bulging to in response. tofluid movement

auditory tube (eustachian brach)

eqaulizes pressure between the middle ear and the atmosphere

vestibulocochlear nerve

carries hearing and equilibrium information to the brain

vestibular brach = carries equilibrium info to the brain

cochlear branch= carries hearing info to the brain

semicircular canals

detects rotational movement of the head and maintains balance

ampulla

swollen end on each semiciruclar canal that detects the rotational movement of the head and maintains balance

crista function

receptors located in the ampulla that detect the rotational movement of the head

internal audiotry canal

carries the facial nerve and the vestibulocochlear nerve to the inner ear

cochlea function

contains receptors for hearing, converts sound vibrations into nerve signals

cochlear duct (scala media) fucntion

where sound is converted into a nerve signal

scala vestibuli function

carries sound vibrations from the oval window to the cochlea

scala tympani function

carries pressure waves in the cochlea and relieves pressure at the oval window

vestibular membrane function

separates the scala vestibuli and the cochlear duct

basilar membrane fucntion

supports the spinal organ, vibrates in response to sound, helps concut sound vibrations into nerve signals

spinal organ (organ of coti) function

found in the cochlea, contains hair cells, helps convert sound vibrations into nerve signals

tectorial membrane function

gel like substance that moves in response to sound vibrations, bends hair cells to help produce nerve signals

vestibule function

contains receptors that detect head position and linear movement

urticle function

detetcs head position and linear movement

sacule function

detects head position and verticle movement

macula fucntion

detetcs head position and linear acceleration

otoliths

contains calcium carbonate crystals detects head postiton and linear acceleration

Describe the function of sensory receptors

sensory receptors detct stimuli, concert that stimuli into a nerve signal, then that nerve signal is sent to the brain for processing and interpretation

List three somatic sensations that are detected by free nerve endings

• itch

• tickle

• temp

List three somatic sensations that are detected by encapsulated nerve endings

• pressure

• touch

• vibration

Is there a relationship between the receptor density of an area and the size of the cerebral cortex receiving information from those receptors?

yes, areas with a higheer density od receptors send more detailed information to the cerrebral cortex, therefore areas of rhe cerbral cortex that are devoted to those areas are larger