Anat lab quiz 6 sensory physiology Flashcards
The essentials of a reflex mechanism are a…
receptor organ, an effector organ and some type of communications network connecting the two
reflex action is initiated by …. and results in an …..
input(sensory) stimulus
output (motor) response
appropriate response to the stimulus has been built into the nervous system
innate
Example of innate
spinal reflexes
…… requires transmission from periphery to the spinal cord and then back to the appropriate effector organ
spinal reflexes
the pupillary light reflex is a ….
consensual reflex (meaning that normally light that is directed in one eye produces pupil constriction in both eye
when the sphincter muscle of the iris contracts…..
pupil size decreases (constricts)
when the dilator muscle of the iris contract
pupil size increases (Dilates)
Like the pupillary reflex, the pupil constricts or dilates based on the
distance of the image requiring focus
Pupil Accommodation
The ciliary muscles control the tension of the lens and increase its
curvature to increase focusing ability. When an individual views a near object, the ciliary
muscles will contract, which decreases the tension on the lens and increases its curvature
(causes lens to bulge). When an individual views a distant object, the ciliary muscles relax,
which increases the tension on the lens and decreases its curvature (causes lens to flatten)
Lens Accommodation:
When an individual shifts their view from a far object to a
nearby object, the eyes converge to keep the image focused. This convergence requires the
actions of the medial and lateral rectus muscle, which will contract/relax to allow
convergence to occur.
Convergence in Accommodation:
is used in medical settings to illicit a
change in response in tendon reflex activity by forcing the individual to focus their attention on their
arms (by pulling outward) rather than their leg (where the reflex is occurring).
Jendrassik’s Maneuver
reflex assesses the first two sacral segments of the spinal cord
he Achilles, or ankle-jerk,
examine by touch
palpate
as one muscle
contracts, the other muscle relaxes.
antagonistic muscles,
is a response mediated over the sympathetic nervous system in response to a painful stimulus
ciliospinal reflex
is an abnormal response often associated with damage to
the pyramidal tract fibers (normal reflex in infants)
The Babinski Reflex
One of the functions of the semicircular canal mechanism is to….
aid visual fixation on moving objects.
If the
canals are stimulated under experimental conditions, reflex response results in a movement of the eyes called
nystagmus
five senses
sight, hearing, touch, taste, and smell.
specialized sensory receptors
mechanoreceptors
The areas in which mechanoreceptors respond to external stimuli
are known as
receptive fields.
the smallest distance
at which two points of contact can be felt, is the
two-point threshold
. If a stimulus is applied for a prolonged period of time without
movement, the rate of receptor discharge will slow, and conscious awareness of the stimulus will decline or is
lost (until some stimulus change occurs
sensory adaptation.
s an area on the retina where the optic nerve and blood
vessels enter and leave the retina and hence there are no rods or cones for visual reception.
The blind spot (or the optic disc)
the most widely used in the testing of color
blindness.
Ishihara Test.
…. is caused by the acceleration of fluid in the semicircular canals which stimulates the crustal in the ampullae and produces the sensation of turning
rotatory nystagmus
head to tilt upside down such as a backflip
anterior semicircular canal
head to tilt towards the side such as a cartwheel
posterior semicircular canal
side to side movement such as spinning in a circle
lateral semicircular canal
suddenly stopping the spinning person
post rotatory nystagmus
Strike a tuning fork and place the handle of
the vibrating fork medially on top of your partner’s head or on the bridge of their nose where the nasal
bones articulate with the frontal bone.
weber test
The Weber test has been mainly used to establish a diagnosis in patients with unilateral hearing loss to distinguish between conductive and sensorineural hearing loss.
Have the subject plug one ear with a cotton ball and test the open ear as follows: Strike a tuning
fork and place the handle of the vibrating fork on the subject’s mastoid process.
The Rinne test is used to evaluate hearing loss in one ear. The Rinne test differentiates sound transmitted through air conduction from those transmitted through bone conduction via the mastoid bone. By comparing air and bone conduction, it helps detect conductive hearing loss in one ear.
refers to the distance between your near vision and your distant vision.
near point accommodation
A loss of this flexibility over time, usually occurring in older individuals, results in
a loss of near focusing ability
presbyopia.
refers to an individual’s inability to focus light properly on the retina resulting in nearsightedness
myopia
certain sized letters should be seen clearly at
specific distances by eyes having normal acuity.
what’s the equation?
Snellen test
V=d/D (patient reads letter/ normal eye reads letters)
