Phys Lab 4

sensation

awareness and localization of stimulis

where does perception occur

central nervous system (brain assigns meaning to sensation)

does sensation always result in perception

no

phasic receptor

can show adaptation

what happens during adaptation

there is sensation but no perception

(tune out)

tonic receptor

dont show adaptation

what caused the ‘ring’ in your eyes

stimulation of photoreceptors by mechanical pressure

do receptors perceive different stimulus as different? Mechanical vs light?

no, all percevied as same

von frey fillament was used for

touch sensation

aesthesiometer used for

2 point discrimination

snellen eye chart used for

testing vision

20/20 vision means

you can see from 20 feet what a normal person can see from 20 feet

20/200 vision means

you can see from 20 feet away from what others can see from 200 feet

Astigmatism

unequal curvature of the cornea or lens of eye, which results in some areas of the retina not being stimulated

if astigmatism is present what will the chart look like

some spokes blurred and some sharp

ishiharas colour plates test for

colour blindness

what are the 3 colours of cones

RGB

you can test convergence and nystagmus to test for

lazy eye

concussions

convergence

medial movment of eyes to maintain partial overlap

nystagmus

involuntary, rapid rythmic movement of 1 or 2 eyeballs

what causes nystagmus

damage to branch of cranial nerve that innervates extrinsic (rectus) eye muscle.

what are most muscles that move the eye around innervated by

cranial nerve III (oculomotor nerve)

2 exceptions of eye muscle innervation are innervated by

abducens (cranial nerve VI)

trochlear nerve (cranial nerve IV)

what muscle is innervated by abducens

lateral recutus

how can damage to eye muscles be tested

tracking an object

if convergance is compromised what happens

1 or both eyes may be misaligned when focusing on close object

if nystagmus is present what happens (pen side to side)

eyes appear to shake as they track objects

Weber test

tests for hearing loss due to middle ear deafness or nerve defects

middle ear deafness also called

conductive hearing loss

hearing loss due to nerve defects also called

sensorineural hearing loss

if hearing is normal what should happen during Weber test

sounds equal on both sides

with Conductive hearing loss the ear that is effective will have _____ sound

louder

with sensorineural hearing loss the effective ear will have _____ sound

quieter

does the Weber test distinguish between conductive and sensirineural hearing loss

no

what test can be combined to distinguish between conductive and sensirineural hearing loss

Rinne and Weber

Rinne test compares

air and bone conduction of sound

when does air conduction occur

soundwaves pass from auricle to inner ear via tympanic membrane and ossicles

when does bone conduction occur

vibrations passed through skull to the inner ear

is bone or air conduction more sensitive

air

during Rinne test if the bone conduction is better then air conduction what can be said

impairment of fuction of external ear (wax)

conductive hearing loss

if hearing loss was due to nerve defects what would happen during rinne test

sound not perceived by bone or air

light pupillary reflex is _______ (auto/somatic)

autonomic

what is the light pupillary refelex

regulates the amount of light entering the eye

light pupillary reflex is (ipsi/contralateral)

ipsillateral

path of light pupillary reflex

photoreceptors stimulated

signal travels to brain via optic nerve

signal integrates in midbrain and relays to pre and postganglionic neurons within oculomotor nerve

oculomotor nerve innervates smooth muscle in iris that constricts

what can light pupillary response asses

sensory function of optic nerve (CN 2)

parasympathetic function of oculomotor nerve (CN 3)

function of brianstem

what can cause changes in light puppillary reflex

head injuries (change of intercranial pressure)

use of stimulants

consensual light reflex

light shown into one eye causes the other pupil to constrict

consensual light reflex is (ipsi/contralalteral)

contralateral

ciliospinal reflex

tests the function of sympathetic pathways involved in pupill dilation

ciliospinal reflex pathway

stimulating neck, face, shoulder

pressure is relayed through 1st order sensory neurons to spinal cord

interneurons send signal to pre/post ganglionic sympathetic neurons that innervate dilator pupillae muscle

ciliospinal reflex is (ipsi/contralateral)

ispilateral

what changes with a sensory neuron during somatic reflex

sensory neuron signals directly the lower motor neuron without input from the voluntary movement center in brain

corneal reflex

response to cornea or sclera being touched (blink)

what is the function of corneal reflex

protect the eye and clear dust

corneal reflex is used to asses the function of which nerves

V and VII

what is cranial nerve V called and what does it do

trigeminal, caries sensory info from cornea to brain

what is cranial nerve VII, and function

facial nerve, controls contraction of effector

what can abnormal responses to corneal reflex indicate

brain stem injury
depth of anaesthesia

does corneal reflex happen in both or 1 eye

both

patellar reflex is a ____ reflex

stretch

what does the patellar reflex do

protect quad from overstretching

maintain muscle tone

patellar reflex pathway

stretch detected by muscle spindles

sensory info relayed to dorsal horn and transmited to lower motor neuron that innervates quads.

what is patellar reflex used to asses

spinal cord injury in lumbar area

UMN and LMN damage

if UMN damage what happens to patellar reflex

hyperreflexia

if LMN damage what happens to patellar reflex

hypoflexia or areflexia

what is the jendrassik manoeuvre

pulling hands apart to distract

how does fatigue effect patellar reflex

decreases

achilles tendon reflex is a ____ reflex

stretch

achilles tendon reflex

stretch happens in gastrocemius (calf) to maintain muscle tone and posture, protect overstretching

achilles tendon reflex used to asses

pathways with sacral spinal cord

function of UMN and LMN

monitor progresion of neurological conditions

achilles tendon reflex results in _____ of the foot

plantar flexion

plantar reflex is a _____ reflex

elicited reflex (not stretch)

what is a normal plantar reflex response

toes curl

what is abnormal planter reflex, why does it happen?

toes flare out (babinski reflex)

after seizure or damage to corticospinal tract

what is normal planter reflex in babies, why?

babinski sign

tracts not fully mylenated

what did the coin / rubber band test show

adaptation

is light pupillary reflex somatic or autonomic

autonomic (para)

is ciliospinal reflex somatic or autonomic

autonomic (symp)

corneal reflex somatic or autonomic

somatic

what are the only cranial reflexs looked at

light pupillary

consenual

corneal reflexs

(others all spinal)