Sensory Physiology Lab

Sensation

the process of receiving environmental stimuli by a sensory receptor and converted to action potentials that are sent to the brain

Perception

the brain receiving and interpreting action potentials so we are consciously aware of the situation

Mechanoreceptors

responds to mechanical stimuli such as touch, pressure, and vibration

Proprioceptors

found in muscle, joint, and tendon tissue that detects changes in body position or movement

Thermoreceptors

responds to changes in temperature

Chemoreceptors

responds to chemicals in a solution

Nociceptors

responds to stimuli that is harmful to the body

receptor

responds to a particular type of sensory stimulus, creates action potentials that are sent to the integration center

integration center

interpret the incoming information and send out motor response (brain)

effector organ

carries out the motor response

Intrinsic

when reflex arcs require no experience or learning to be carried out by the body

spinal reflex arc

a intrinsic reflex, associated with very rapid movement of skeletal muscle tissue

pupil

open space at center of iris, allows light to enter the eye and strike the retina

Iris

has two types of muscles that will control the diameter of the pupil, therefore controlling how much light enters the eye

dilater pupillae muscle

contracts → pupil becomes wider

sphincter pupillae muscle

contracts → pupil becomes narrower

consensual reflex

stimulus is applied to only one side of the body but the response is observed on both sides

lens

structures inside the eye that helps focus light directly on the retina by bending light as it enters the eye for clear vision

pupil accommodation

size of the pupil changes according to distance of object

lens accommodation

lens can change shape to change the ability to refract (bend) light to focus it on the retina

more round lens = more refractory power

converge

depending on distance of the object, eyes may need to converge (move inward) to focus on an object

patellar/knee-jerk reflex

stretched patellar tendon tapped by hammer- tests L2-L4 level of spinal cord

Jendrassik’s maneuver

forces individual to focus attention elsewhere than patellar reflex

achilles/ankle-jerk reflex

stretched achilles tendon is tapped

antagonistic muscles

pairs of muscles that work in opposite direction to move and stabilize joints, one contracts, one relaxes (lengthens)

ciliospinal reflex

reflex mediated by the sympathetic nervous system (fight or flight) in response to pain

Babinski’s reflex

big toe up, rest down- seen in babies, if in adults then damaged pyramidal tract fibers

semicircular canals

three fluid-filled tubes in inner ear that help balance and equilibrium while moving by aiding visual fixation on moving objects

nystagmus

reflexive movement of the eyes caused by the semicircular canals

anterior semicircular nystagmus

stimulated by forward and backward head movements (backflip)

posterior semicircular nystagmus

stimulated by movement of head tilting to the side (cartwheel)

lateral semicircular nystagmus

stimulated by movement where head spins or moves side to side (spinning in a circle)

slow phase nystagmus

eyes move slowly in one direction, maintain fixation on a moving target- happens first

fast phase nystagmus

eyes very rapidly move to twitch in the opposite direction- happens second

rotary nystagmus

fluid in semicircular canal moves, stimulating receptors in inner ear

post-rotary nystagmus

eyes continue to move reflexively after fluid movement/ movement has stopped

spatial orientation

the ability to maintain the body’s position and posture in relation to out surroundings

the inner ear

receptors here respond to changes in head position during linear acceleration and rotational movement

two-point threshold

the smallest distance at two points of contact can be felt

sensory adaptation

if a stimulus is applied for a prolonged period without change, the rate of receptor discharge will slow, conscious awareness of the stimulus will decline or is lost

conduction deafness

damage to structures from the tympanic membrane to the auditory ossicles (malleus, incus, stapes)-prevents transmission of sound to inner ear

nerve deafness

(sebsirineural deafness), auditory nerve or brain is damaged, action potentials relating to sound are either not produced by the auditory nerve or cannot be interpreted by the brain

near point

closest point at which an object can be placed from the face and still forma a focused image → demonstrates the elasticity of the lens and its ability to accommodate when viewing an object up close

presbyopia

loss of near focusing ability → lens becomes flexible as we age

optic disc

“blind spot”, area of the back of eye on retina where there are no photoreceptors for visual reception- where the optic nerve and blood vessels enter + leave the eye

visual acuity

the sharpness of vision, ability discern letters or numbers at a given distance according to a fixed standard

Snellen Test

chart with letters of different sizes- letters of diff sizes should be seen clearly at diff distances

myopia

nearsightedness- can see things clear near, but things that are far are blurry

hyperopia

farsightedness, can see things clear far, but things that are near are blurry

Young Helmholtz theory of color vision

trichromatic color vision, one type of photoreceptor, called a cone, allows for color vision- red, blue, green cones allow us to differentiate colors

color blindness

recessive trait on X chromosome, have trouble seeing difference between colors, brightness of colors, and differentiating between shades of colors

red-green color blindness

most common type, person lacks either red or green cones in the retina

Ishihara Test

color blind test, dots with numbers