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40 Cards in this Set
- Front
- Back
Peripheral Nervous System (PNS)
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all parts of ns that are not brain and spinal cord
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Ganglia
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collections of neuronal cell bodies
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Nerve
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hundreds to thousands of PNS axons plus associated connective tissue & blood vessels bundled into functional organ
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A nerve consists of
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bundles of myelinated axons
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Endoneurium
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surrounds each axon
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Fascicles
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bundles of axons
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Perineureum
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surrounds the fascicles
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Epineureum
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surrounds the whole nerve
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Sensory receptors
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respond to enviornmental changes called stimuli
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Mechanoreceptors
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touch, pressure, vibration, or stretch
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Thermoreceptors
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temperature
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Chemoreceptors
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chemicals
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Nociceptors
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pain
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Receptors can be classified by
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location or location of active stimulus
overall structural complexity |
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Exteroreceptors
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sensitive to external stimuli (ex. pain, pressure, temp.)
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Interoreceptors
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responds to internal stimuli (ex. chemicals, stretch, temp.)
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Proprioceptors
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respond to position; found in muscles, tendons, joints, ligaments
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Meissner’s corpuscles
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receptors for discriminatory and light touch in hairless areas of the body
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Pacinian, or lamellated, corpuscles
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stimulated when deep pressure is first applied
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Ruffini’s corpuscles
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responds to deep and continuos pressure
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Muscle spindles
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detects when a muscle is being stretched and initiate a reflex that resists the stretch.
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Golgi tendon organs
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stimulated when the associated muscle stretches the tendon.
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Joint kinesthetic receptors
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monitors the stretch in the articular capsules of synovial joints.
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Cranial nerves
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emerges from brain
12 pairs |
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Spinal nerves
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emerges from spinal cord
31 pairs |
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Cranial Nerve I
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Olfactory
Sensory Smell receptors in olfactory epithelium; nerves pass through cribriform plate of the ethmoid to the olfactory bulb; fracture of ethmoid can result in anosmia |
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Cranial Nerve II
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Optic
Sensory Vision receptors in retina of eye; optic nerves pass through optic foramen, partially cross over at the optic chiasma; visual defects are called anopsias |
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Cranial Nerve III
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Oculomotor
Mixed - Sensory, Somatic, Autonomic Proprioception, Movement of upper eyelid & eyeball, alters lens for near vision chiefly motor nerves to 4 of the 6 eye muscles,the eyelid, iris, and lens; nerves pass through the superior orbital fissure of the ethmoid; |
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Ptosis
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eyelid droops (oculofactory)
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External strabismus
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focusing becomes difficult (oculofactory)
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Cranial nerve IV
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Trochlear
mixed - sensory & somatic Proprioception, movement of eyeball primary motor nerves to the superior oblique muscle of the eye; damage results in inability to rotate eye inferiolaterally |
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Cranial nerve V
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Trigeminal
mixed - sensory & somatic conveys impulses for touch, pain & temp. sensations, chewing largest cranial nerve with 3 divisions; opthalmic maxillary mandibular |
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Ophthalmic division
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passes through the superior orbital fissure;
fibers from nasal cavity, cornea, lacrimal gland; tested by attempting to elicit corneal reflex |
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Maxillary division
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passes through the foramen rotundum;
fibers from nasal cavity, palate, upper teeth, cheeks, lower eyelid; tested with pin pricks and hot and cold objects |
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Mandibular division
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passes through the foramen ovale; to/from tongue lower teeth, chin;
tested by strength of jaw opening and closing, and lateral jaw movement |
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Tic doulereux
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inflammation of the trigeminal;
results in severe pain from slight stimuli; partly treatable with drugs; in severe cases, the nerve is severed to relieve pain |
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Cranial Nerve VI
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Abducens
mixed - Sensory & Somatic Proprioception & movement of eyeball primarily motor to lateral rectus muscle of eye |
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Internal strabismus
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eye can't move laterally (Abducen)
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Cranial Nerve VII
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Facial
Mixed - Sensory, Somatic, Autonomic Taste, facial expression, secretion of tears & saliva somatic motor nerves run through internal acoustic meatus then stylomastoid foramen of temporal to muscles of facial expression, palate, tongue, salivary glands parasympathetic motor nerves to lacrimal, nasal, salivary glands; sensory nerves from anterior part of tongue; damage results in loss of taste, inability to tear, asymmetry of face; |
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Bell’s palsy
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paralysis of facial muscles, usually on 1 side, eyelid droop;
it is the result of a Herpes virus infection of the facial nerve |