Special senses definitions Flashcards
Reflex
Rapid, predictable, involuntary motor responses to stimuli
Reflex arc
Neural pathway that mediates reflexes
Patellar reflex
Tap the patellar ligament sharply with the reflex hammer just below the knee between the patella and the tibial tuberosity.
Simple reflex arc
Two-neuron, monosynaptic reflex arc. patellar/knee jerk reflex
Polysynaptic reflex arc
Reflex arc involving participation of one or more interneurons in the reflex arc pathway. i.e. flexor reflex
Stretch reflexes
Important postural reflexes, normally acting to maintain posture, balance, and locomotion. Initiated by tapping a tendon or ligament, which stretches the muscle to which the tendon is attached
Crossed-extensor reflex
More complex than stretch reflex. Consists of a flexor, or withdrawal, reflex followed by extension of opposite limb.
Pupillary light reflex
Shine a light in persons eye while covering opposite eye.
Contralateral response
Consensual response, or any reflex observed on one side of the body when the other side has been stimulated
Ipsilateral response
The pupillary light response, or any reflex occurring on the same side stimulated
Ciliospinal reflex
Stroke hairs on neck lightly, watch pupils dilate
Proprioceptors
Respond to internal stimuli but are restricted to skeletal muscles, tendons, joints, ligaments and connective tissue coverings of bones and muscles. Provide info about body movements and position by monitoring degree of stretch of those structures
Exteroreceptors
cutaneous receptors in the skin and special senses. react to stimuli in external environment
Interoceptors
respond to stimuli arising within the body. found in the internal visceral organs and include stretch receptors in walls of hollow organs, chemoreceptors, and others
Tactile corpuscle (merkel disc)
touch, light pressure. found in dermal papillae of hairless skin
free nerve endings
pain, temperature. found widespread in the skin
bulbous corpuscle
deep continuous pressure and stretch stimuli. found in dermis
hair follicle receptor
hair movement, light touch. found entwining hair follicles
lamellar corpuscle
deep pressure. found deepest in dermis
Two point discrimination test
Use calipers to test the ability to differentiate two distinct sensations when skin is touched simultaneously
Tactile localization
Ability to determine which portion of the skin has been touched. use marker to touch body with eyes closed and person marks with another pen.
Adaptation of touch sensory receptors
Use pennies. stack one on top of the other each time person can’t feel them again.
purpose of palpebrae
eyelids, protect eye
purpose of lacrimal caruncle
produces a whitish oily secretion
purpose of conjunctiva
secretes mucus to lubricate eyeball
Action of lateral rectus
moves eye laterally
action of medial rectus
moves eye medially
action of superior rectus
elevates eye and turns it medially
action of inferior rectus
depresses eye and turns it medially
action of inferior oblique
elevates eye and turns it laterally
action of superior oblique
depresses eye and turns it laterally
Extrinsic muscles of the eye
Origins of muscles are outside the eye (in the orbit) and insertion is outside the sclera
Blind spot
hold spot test away from eyes. close one eye and focus on X. move figure toward face until the dot disappears
Refraction
When light rays pass from one medium to another, their velocity, or speed of transmission, changes, and the rays are bent.
Accommodation
The ability of the eye to focus differentially for objects of near vision (less than 6m or 20 ft)
emmetropia
Normal vision (eye) that can accommodate properly
Myopia
The image normally focuses in front of the retina (nearsightedness). can see close objects but difficulty with far.
Correction for myopia?
Requires a concave lens which causes the light to diverge
Hyperopia
The image focuses behind the retina (farsightedness). can see far but problems with close.
Correction for hyperopia?
Requires convex lenses to augment converging power of lens
Astigmatism
Irregularities in the curvatures of the lens and/or the cornea lead to blurred vision problem
Correction for astigmatism?
cylindrically ground lenses, which compensate for inequalities in the curvatures of refracting surfaces.
Presbyopia
Old vision, when the elasticity of the lens decreases resulting in difficulty in focusing for near or close vision.
Purpose of weber test?
localization of sound
Purpose of rinne test?
Air and bone conduction
Olfaction
smell
Gustation
taste
Olfactory adaptation
the temporary, normal inability to distinguish a particular odor after a prolonged exposure to that airborne compound
