*Lab Quiz 5 Flashcards
Receptor organ
One that detects changes in the external or internal environment such as the eye which serves vision
Effector organ
Muscles and glands that become active in response to stimulation and cause an effect in response to directions from the nervous system
Communications network
Input (sensory) stimulus
Any event or object that is received by the senses and elicits a response from a person. Ex.: light, heat, sound, touch
Output (motor) response
Information that is sent out to the skeletal muscles that control movement
Innate
An automatic, instinctive, and unlearned reaction to a stimulus
Spinal reflexes
Require transmission from the periphery to the spinal cord and then back to the appropriate effector organ. Ex.: spinal reflex immediately causes withdrawal of the finger from the offending object
Consensual reflex
Light that is directed in one eye produces pupil constriction in both eyes
When the sphincter muscles of the iris contract,
Pupil size decreases (constricts)
When the dilator muscles of the iris contract,
Pupil size increases (dilates)
Pupil accommodation
The pupil constricts or dilates based on the distance of the image requiring focus. To increase the depth of focus, the pupil will constrict, blocking the light scattered by the periphery of the cornea.
Lens accommodation
The eye’s ability to modify the focal length of the lens by changing the curvature of the eye lens. If the object is close, ciliary muscles contract, decreases tension on lens which increases its curvature. If the object is far, ciliary muscles relax, increases tension on lens which decreases its curvature.
Convergence in accommodation
When an individual shifts their view from a far object to a nearby object, the eyes converge to keep the image focused.
Tendon (stretch) reflexes
Patellar (knee-jerk) reflex
Kicking-like motion produced by the extension of the knee joint upon the ipsilateral stimulation of the patellar tendon
Achilles (ankle-jerk) reflex
Occurs when the achilles tendon is tapped while the foot is dorsiflexed
Palpate
A method of feeling with the fingers or hands during a physical examination
Antagonistic muscles
One muscle contracts as the other relaxes. Important for maintaining body and limb position as well as for controlling rapid movement of a limb.
Ciliospinal reflex
A response mediated over the sympathetic nervous system in response to a painful stimulus
Plantar reflex
A downward response of the hallux (flexion). Seen in healthy adults.
Babinski reflex
An upward response (extension) of the hallux. Seen in healthy children under 1 year old. If present in child older than 1 or in an adult, it is often a sign of a CNS disorder. It is an abnormal response often associated with damage to the pyramidal tract fibers.
Labyrinthine reflex
Function of semicircular canal mechanism
To aid visual fixation on moving objects
Nystagmus
A movement of the eyes resulting from a reflex response
Rotary nystagmus
Caused by the acceleration of fluid in the semicircular canals which stimulates the crustal in the ampullae and produces the sensation of turning
Proprioception
Your body’s ability to sense movement, action, and location.
Spatial orientation
Our natural ability to maintain our body orientation and/or posture in relation to the surrounding environment (physical space) at rest and during motion
Mechanoreceptors
Specialized sensory receptors located in specific areas of the skin
Receptive fields
The areas in which mechanoreceptors respond to external stimuli
Two-point threshold
The smallest distance at which two points of contact can be felt
Sensory adaptation
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).
Weber test
Used to establish a diagnosis in patient with unilateral healing loss to distinguish between conductive and sensorineural hearing loss
Rinne test
Used to evaluate hearing loss in one ear
Near point for accommodation
The limit to our binocular vision and refers to the distance between your near vision and your distant vision
Presbyopia
A refractive error that makes it hard for middle-aged and older adults to see things up close due to a loss of flexibility in the lens
Myopia
Refers to an individual’s inability to focus light properly on the retina resulting in nearsightedness
Blind spot (optic disc)
An area on the retina where the optic nerve and blood vessels enter and leave the retina and hence there are no rods/cones for visual reception
The formula used to state a person’s visual acuity
V= d/D, where “d” is the distance at which the patient can read the letters, and “D” is the distance at which a normal eye can read the letters
Young-Helmholtz Theory of Color Vision
Theory that there are tiny cells in the eyes that receive different wavelengths of light and translate them into red (longest wavelength= 560nm), blue (shortest wavelength= 420nm), and green colors (mid-length wavelength= 530nm)
Ishihara test
A color vision test for detection of red-green color deficiencies
