Neurosensory Systems and Tests
- Neuron - nerve cell -
- axons carry away
- dentrites bring to
- neurotransmitters - help conduct impulses across the synapse
- acetylcholine
- seotonin
- dopamine
- endorphins
- gamma-aminobutyric acid
- norepinephrine
- CNS - central nervous system - brain and spinal cord
- Cerebrum - largest part of the brain
- hemispheres - right and left opposite control because motor impulses cross in the deulla
- fissures divide cerebrum into 4 lobes
- frontal - personality, memory, reasoning, concetration and motor control of speech
- parietal - sensation, integration of sensory information and spatial relationships
- temporal - hearing, speech, memory, and emotion
- occipital - vision and involuntary eye movements
- Thalamus - 2 oval shaped parts deep in the brain, the relay station - recieves input form all senses except smell, analyses input and transmits to other parts of the brain.
- Hypothalamus - beneath the thalamus - control sleep and wakefulness, temperature, respiration, BP, sexual arousal , fluid balance, and emotioal response.
- Cerebellum - base of the brain - coordinates muscle movements, maintains balance and controls posture
- Brain Stem - connects brain and spinal cord has 3 sections
- midbrain - pupillary relexes and eye movements; relfex center of the 3rd and 4th cranial nerves
- pons - helps regulate respiration, mediates chewing, tasting, saliva and equilibruim; reflex center for the 5th, 6th, 7th and 8th cranial nerve
- medulla oblongata - vomiting, vasomotor, respiratory and cardiac centers
- Spinal cord - 2 way conduction system between brain and peripheral nervous system (PNS)
- gray matter - cell bodies and dendrites and axons
- white matter ascending (sensory) sends signalsto the brain and desending (motor) tracts send signals out to the muscles
- PNS - Periperal Nervous System - delivers messages (like the post office) main nerves grouped
- 31 pairs of spinal nerves - carry mixed impulses (motor and sensory)
- 12 pairs of cranial nerves -
- olfactory
- optic
- oculomotor
- trochlear
- trigeminal
- abducen
- facial
- acoustic
- glossopharyngeal
- vagus
- spinal accessory
- hypoglossal
- Autonomic nervous system - subdividsion of PNS - controls involuntary body functions
- digestion
- respiration
- cardiovascular
- 2 cooperating systems
- sypathetic - fight or flight
- parasympathetic - conserves and restores energy
- Eyes -
- external -
- eyelids
- conjuctivae (thin transparent membrane that line the lids)
- lacrimal apparatuses,extraocular muscles, and the eyeballs
- internal -
- iris
- cornea
- pupil
- lens
- vitreous humor
- retina
- retinal cones - visual acuity and color discrimination under bright lights
- retinal rods - peripheral vision under decreased light conditions
- optic nerve - 2nd cranial nerve
- Ears
- External - pinna (auricle) and external auditory canal separated by the tympanic membrane
- Middle - AKA tympanum - air filled cavity in the temporal bone - 3 small bones - malleus, incus, and stapes
- Inner - AKA Labyrinth - cochlea, vestibule and semicircular canals
Most Important Tests
- Electroencephalogram (EEG) electrical graph of brain activty
- Computer tomography (CT) - cross scetion veiws of brain images
- Magnetic Resonance Imaging (MRI) - magnetic snapshot - contraindications - pacemaker
- Cerebral Angiogram - upstairs artery exam blood flow using dye
- check site for bleeding
- assess distal pulses
- assess neuro status
- encourage fluids
- Lumbar Puncture L(P) - reveals pressure also used to inject dye for myelogram *contra indicated with increase intracranial pressur (ICP)
- keep flat
- monitor neuro status
- monitor site for leakage or bleeding
- encourage fluids
- Cerebrospinal fluid (CFS) analysis - LAB
- Electromypgraphy (EMG) - electrical acitivity of a muscle at rest and contraction
- Myelography - see the spine - subarachnoid space, spinal cord and verebrae contraindicated with seafood or iodine allergies
- keep flat after
- check site for leakage or bleeding
- encourage fluids
- Skull x-ray
- Positron emission tomography (PET) injection of radioisotope after visulaization of the brain's oxygen uptake, blood flow and glucose metabolism
- no tobacco, alcohol, or caffeine 24 hours before
- Blood Chemestry Test - checking levels of potassium, sodium, calcium, phoshorus, protein, osmolality, glucose, bicarbonate, blood urea nitrogen and creatinine
- Hematologic study - WBCs, RBCs, erythrocyte sedimentation rate, platelets, hemoglobin, hematocrit.
- Coagulation study
- Visual Acuity
- Extraocular eye muscle testing - checks for parallet alignment of the eyes, muscle strength and cranial nerve function
- Visual field examinaitn
- Tonometry test - measures intra ocular pressure
- Tick-tock test is an auditory acuity test checking ability to hear a whispered phrase or a ticking watch
- Otoscopic examination to visulize the tympanic membrane
- Audiometry - measures degree of deafness
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