Exam 4 Stuffs Flashcards
Receptive Field
the area served by that neuron; some areas in the body have a higher density of recepters
Two Point Discrimination Test
used to dtermine a cude map of the density of tactile receptors ; areas that have the greatest density of tactile recptors have a heightened ability to “feel”— these areas correspond to areas that receive the greatest motor innervation; thus they are tpyically areas of fine motor control
What do you do in the Two point Discrimination Test?
use calipers and start with them together and then slowly adjust them out and measure when the person says they can feel two discriminate points; the smallest distance at which two points of contact can be felt is the two point threshold
What area has the smallest two-point threshold?
fingertip
LIGHT travels through…
ganglion–> bipolar neurons–> photorecpters
NERVE IMPULSE travels…
photoreceptors–> bipolar neurons—> ganglion—> optic nerve—> etc
If the left optic nerve is damaged…
vision is lost only in the left eye
If the right optic nerve is damaged…
vision is lost only in the right eye
If the optic chiasma is damaged…
the outer part of the visual field in both eyes is lost
If the visual pathway from the left optic track to the left primary visual cortex is damaged…
vision is lost in the right visual fields of both eyes
If the visual pathway from the right optic track to the right primary visual cortex is damaged…
vision is lost in the left visual fields of both eyes
Demonstrating the Blind Spot Test
the blind spot is the site where the optic nerve exits the eyeball; you use the paper with the X and O and slowly move it toward you while covering one eye and at somepoint the dot will dissappear and this is your blind spot
Accomodation
the ability of the eye to focus differentially for object of close vision (less than 6m or 20 ft)
Emmetropic Eye
normal
Myopic Eye
nearsighted; eyeball too long
Hyperopic Eye
farsighted; eyeball too short
Presbyopia
the elasticity of the lens decreases dramatically with age, resulting in difficulty in forcusing for near or close vision, especially when reading
Near Point Vision Test
test lens elasticity; near point vision is about 10cm from the eye in young adults, closer in children, and farther in old age; use a staright pin and bring it closer to you until it becomes distorted and measure
Visual Acuity Test
or sharpness of vision; is generally tested with a Snellen eye chart (the one with the letters); have someone stand in front of the chart 6m (or 20ft) away and read the lines and check for accuracy and test twice if they have glasses
20/20 Vision means…
persons vision for that eye is normal
20/40 vision means…
or any ratio less than one (basically a bigger number on bottom) they have less than normal visual acuity; they are myopic
20/15 vision means…
their vision is better than normal bc they can stand at 6m (20 ft) from the chart and read the letters that are discernible by the normal eye at only 15 ft; if bottom number is less than 20 their vision is better than normal
Astigmatism Test
tests for unequal curvatures of the lens and/or cornea; if all the radiating lines appear equally dark and distinct there is no distortion of the refracting surface; if some lines are blurred or appear less dark than others, at least some degree of astigmatism is present C
Color Blindness Tests
tests for deficiencies in the color photoreceptors (the cones); cones are either red, blue, or green absorbing; you look at the little cards and if you can not read the numbers or have difficulty colorblindness may be present
Testing for Depth Perception
demonstrates that there is a slightly different view seen by each eye; ADDDDDD
Intrinsic Muscles
controlled by the autonomic nervous system; ciliary body (which alters the lends curvature in focusing) and the sphincter pupillae and dilator pupillae muscles of the iris (which controls pupil size and thus regulate the amount of light entering the eye)
Pupillary Light Reflex
sudden illumination of the retina by a bright light causes the pupil to constrict reflexively in direct proportion to light intensity; this protective response prevents damage to the delicate photoreceptor cells
Accommodation Pupillary Reflex
have someone gaze off at something away from them and then hold some printed material in front of them and have them direct their focus on to it; results are lens thiceking, pupillary constriction, and inward rotation of the eyes (eye convergence)
Convergence Reflex
do the same thing as the accommodation reflex but use a pen instead of printed material; results in the eyes moving inward
ADD EYE TERMS
Sound Localization Test
holding a timer/ticking sound around the persons head and determine at which point they hear it best; the sound is less easily heard at the back
What tuning fork is heard the least well?
the smallest/highest frequency (4096 Hz)
Weber Test
determines conduction of sensorineural deafness; evaluates whether the sound remains centralized (normal) or lateralizes to one side; place a striked tuning fork medially on top of head; if heard eaqually on both sides it is normal; if hearing laterilizes to one side it is indictive of some degree of conduction or sensorineural deafness
Rine Test
compare bone conduction and air conduction; strike tuning fork ad place it on mastoid process; when no longer heard move to ear; if they hear sound again (by air conduction) hearing is not impaired and the result is positive; repeat except start with air conduction first then move to mastoid process; if heard again (by bone coduction) there is some conduction deafness and the result is negative
Conduction Deafness
occurs when soemthing prevents sound waves from reaching the fluids of the inner ear; such as compacted ear wax
Nystagmus
the involuntary rolling of the eyes in any direction or the trailing of the eye slowly in one direction (slow phase) followed by their rapid movement in the opposite direction (rapid pahse); during rotation the slow drift of the eyes is related to the backflow of endolymph in the semicircular ducts and after rotation, abnormal other wise
Vertigo
typically an accompinant of nystagmus; a sensation of dizziness and rotational movement when such movement is not occuring or has ceased
Balance Tests
the ability to walk with balance and without dizziness, unless subject to rotational forces, indicates normal function of equilibrium apparatus
Barany Test
induction of nystegmus and vertigo; evaluates the semicirular canals; if the semicircular canals are operating normally, the subject will experience a sensation that the stool is still rotating immediately after it has stopped and WILL demonstrate nystagmus; ADD
Romberg Test
determines the intergrity of the dorsal white column of the spinal cord; having someone stand against a whiteboard and seeing how much they sway; they sway more with their eyes closed
What happened when something was tasted with the nose closed?
unable to determine what the flavor is because taste is 80% determined by smell
Vallate Papillae
taste papllae arranged in a V formation on the posterior surface of the tongue
Foliate Papillae
in the side walls
Fungiform Papillae
mushroom shaped; more numerious;
