Final Exam Flashcards
(107 cards)
1
Q
Peripheral Chemoreceptors
A
O2, CO2 levels, H+ ions, blood glucose, electrolyte concentrations. In carotid and aortic bodies, responds to stomach, taste buds, and olfactory bulbs
2
Q
Mechanoreceptors
A
Pressure and stretch
3
Q
Nociceptors
A
Stretch, ischemia
4
Q
Thermoreceptors
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Skin and blood temperatures
5
Q
Central chemoreceptors
A
Medulla
-Respond to H+, CO2
Hypothalamus
-Respond to BG levels, electrolyte concentrations
6
Q
Peripheral cutaneous thermoreceptors
A
respond to changes in external temperature
7
Q
Central thermoreceptors
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in hypothalamus, respond to small changes in blood temperature
8
Q
Somatic motor efferent system
A
Under voluntary control, Cannot be exerted by hormones, Act on musculoskeletal structures, Directly under control of brain, Consist of 1 neuron in peripheral pathway
9
Q
Autonomic efferent system
A
Automatic, nonconscious, Can be exerted by hormones, Act on musculature of internal organs, Under control of lower centers, or local nervous system, eg, enteric system of GI tract, Usually consist of 2 neurons that synapse outside CNS
10
Q
Sympathetic efferents to UE, thoracic viscera, trunk functions
A
Regulate tone in arteries of UE/trunk, increase HR/contractility, dilate bronchi, nerves travel along peripheral nerves
11
Q
Sympathetic control in the head
A
Regulate tone in blood vessels tone and sweating - same as rest of body
12
Q
Sympathetic efferents to abdominal and pelvic organs
A
Regulate tone in arteries of LE/trunk, contract GI sphincters, decrease peristalsis, decrease GI blood flow, decrease GI secretions, inhibits bladder/bowel movements, elicit ejaculation
13
Q
Atropine
A
blocks parasympathetic activity by blocking acetylcholine release
14
Q
Beta 1 adrenergic receptors in heart
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increase in heart rate and contractility
15
Q
Beta 2 adrenergic receptors in bronchial tree
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dilation of bronchioles
16
Q
β1 blocker (Metoprolol)
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decreases HR and BP w/o affecting airways
17
Q
β2 agonist (Albuterol)
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keep airways dilated in COPD, asthma, but has side effects as B2 is also present in heart
18
Q
α adrenergic blockers (Cardura, Minipress)
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reduce high BP by blocking alpha receptors, cause vasodilation
19
Q
Fibers in CN VII and IX innervate…
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salivary glands
20
Q
Fibers in CN VII innervate…
A
lacrimal glands
21
Q
Fibers in CN X innervate…
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almost all thoracic and GI organs
22
Q
CN X activity…
A
slows HR/contractility, causes bronchoconstriction, increases peristalsis, increases GI secretions
23
Q
Sacral parasympathetic efferents…
A
empty bladder/bowel, cause penile erection, vaginal lubrication
24
Q
CRPS (complex regional pain syndrome)
A
Pain in arm –thought to be due to sympathetic overactivity
Treatment by stellate ganglion block, decrease sympathetic stimulation of the sensitized autonomic nociceptors in skin
But side effect is Horner’s syndrome
25
Clinical correlations of phrenic nerve
Irritation – Hiccups
Referred pain – clavicle area, shoulder
Paralysis - thoracic surgery, chest tubes or SCI
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CN I
Olfactory Nerve,
sense of smell
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CN II
Optic nerve,
Ability to see
28
Accommodation reflex (Near Triad)
To keep viewing an object that is coming closer to eyes, or to move from viewing a far object to a near object
29
Right CN 3 palsy
R eye abducted due to medial rectus weakness, eyelids drooped, pupil dilated
30
Right CN 4 palsy
R eye pulled inward and upward due to SO weakness
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Lateral Rectus
Abducts eyeball
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Inferior rectus
depresses, adducts, and laterally rotates eyeball
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Inferior oblique
abducts, elevates, and laterally rotates eyeball
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Medial rectus
Adducts eyeball
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Levator palpebrae superioris
raises upper eyelid
36
Superior rectus
elevates, adducts, and medially rotates eyeball
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superior oblique
abducts, depresses, and medially rotates eyeball
38
Right CN 6 palsy
R eye does not abduct due to LR weakness
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Right internuclear ophthamoplegia
Due R MLF lesion, R eye does not adduct on voluntary gaze towards L
40
Tropia
deviation of one eye from forward gaze when both eyes are open, deviation always present, large deviations can be detected with plain eye exam (primary gaze or H test), small deviations can be tested with cover-uncover test
41
Phoria
more subtle deviation, not always present, double-vision comes when fatigued and when binocular vision is broken due to fatigue, can be ‘exposed’ when both eyes are not allowed to synchronously look at one object, can be tested with crosscover/alternating cover test
42
Optokinetic nystagmus
Normal, purpose is to adjust eye position to keep image stable on retina during slow sustained head movements, structures involved are pretectal area, vestibular nuclei, oculomotor nuclei
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Saccades
Purpose - Fast eye movements to switch gaze from one object to another
Can be elicited by visual, tactile, auditory, nociceptive stimuli
2 types – reflexive saccades, voluntary saccades
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Structures involved with reflexive saccades
superior colliculus -> cranial nerve nuclei
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Structures involved with voluntary saccades
visual cortex -> info from perception and action streams, info from frontal eye fields, info from basal ganglia ocular loop pathways -> superior colliculus -> reticular formation -> cranial nerve nuclei
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Smooth pursuit
Purpose is to follow a moving object, mostly voluntary. Elicited by visual information of moving object in visual cortex.
Structures involved – perception and action centers, cerebellum, vestibular nuclei, reticular formation
47
CN V
Trigeminal nerve,
Biggest CN, 3 branches are Ophthalmic (V1), Maxillary (V2), Mandibular (V3). light touch, proprioceptive info from TMJ, nociceptive and temperature info, pain info but not taste from anterior 2/3rd of tongue, controls muscles of mastication, afferent limb of corneal blink reflex
48
CN VII – Facial nerve
controls muscles of facial expression, taste from anterior 2/3 of tongue, parasympathetic component (lacrimal, nasal, salivary glands), general sensations, efferent arm of corneal reflex
49
CN VIII – Vestibulocochlear nerve
Vestibular – info about head position/movement with respect to gravity
Cochlear – hearing
50
Sensory organs for vestibular info
crista ampullaris in semicircular canals and otolithic organs in utricle and saccule
51
Sensory organ for hearing
Organ of Corti
52
Vestibulo-ocular reflex (VOR)
Purpose - Stabilize the visual world and prevents it from appearing to bounce/jump during head movements, e.g, when walking
Initiated by vestibular receptors in the 3 fluid-filled semicircular canals in inner ears – info carried by CN VIII to vestibular nuclei
53
Problems with gaze stabilization is...
impaired VOR
54
Nystagmus
Abnormal oscillating movements of the eyes
Can by spontaneous or gazed-evoked
Due to problems in the CN VIII or central vestibular system
Could also be normal physiologic
55
CN IX – Glossopharyngeal nerve
General sensations from posterior 1/3rd of tongue, soft palate, pharynx. Taste from posterior 1/3 of tongue, controls stylopharyngeus muscle, efferent arm by vagus nerve, gag reflex, swallowing reflex
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Parasympathetic efferent (GVE) of CN IX
parotid gland
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Autonomic afferent (GVA) of CN IX
from carotid sinus/body – BP/HR and O2/CO2 concentration
58
CN X – Vagus nerve
General sensations from pharynx, larynx (GSA)
Taste from epiglottis/root of tongue (SVA)
Motor (SVE) – ms of pharynx, larynx
Efferent arm of gag and swallowing reflex
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Parasympathetic efferent (GVE) of CN X
to digestive glands in pharynx, larynx, thoracic and abdominal viscera (except lower intestine)
60
Autonomic afferent (GVA) of CN X
stretch, visceral pain (referred at times to somatic areas)
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CN XI – Spinal accessory nerve
Spinal component provides innervation to SCM and trapezius (GSE)
Cranial component provides innervation to muscles of the soft palate, larynx and pharynx (SVE)
62
CN XII – Hypoglossal nerve
Innervation to intrinsic and extrinsic ms (genioglossus, hyoglossus, styloglossus) of the ipsi side of tongue
Complete lesion of hypoglossal causes atrophy of ipsi tongue muscles.
When asked to protrude, tongue deviates towards the lesioned side – ‘lick your lesion’
63
Functions of the vestibular system
Sensory information about head movements and head position relative to gravity
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Labyrinthine Artery
Most often branches off the AICA
Occlusion can cause dizziness and auditory symptoms
May branch directly off of Basilar Artery
Divides into anterior vestibular artery and common cochlear artery
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Anterior Vestibular Artery
Supplies the Vestibular Nerve, Utricle, Horizontal and Anterior Semicircular Canals
Dizziness, but No auditory symptoms
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Common Cochlear Artery
Supplies the Cochlea, Saccule and Posterior Semicircular Canal
Dizziness AND auditory symptoms
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Hair cells in SC canals bend as...
endolymph pushes cupula with angular movements
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Hair cells in Utricle/Saccule bend due to...
gravity or with linear acceleration/deceleration
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Deflection of the hair cell towards the kinocilia
excitatory output
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Deflection of the hair cell away from the kinocilia
inhibitory output
71
Utricular macula
responds to horizontal linear acceleration/deceleration, and also to forward/backward head tilts that begin from head in upright position
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Saccular macula
responds to vertical linear movements, and also to leaning sideways, e.g., from sidelying to standing
73
Dizziness/Vertigo
Illusion of motion/spinning (self or surroundings)
Impaired gaze stability with head movements, blurry vision – due to impaired VOR
Can be associated with nystagmus, which could be
-Spontaneous (without positional changes) – can be seen in primary gaze position of eyes
-Triggered by positional changes
74
Nystagmus is repetitive involuntary beating movements due to...
due to inaccurate signals coming in from peripheral vestibular systems (due to impairments in SC or vestibular nerve) or impairments in central vestibular processing centers (brainstem, cerebellum).
75
Alexander’s Law
the amplitude of the nystagmus increases when the eye moves in the direction of the fast phase.
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Ewald’s Law
movement of the eyes during nystagmus occur in the plane of the stimulated canals
77
Vestibular neuritis
a peripheral lesion in the vestibulocochlear nerve (pathologic spontaneous nystagmus), for example, left side impaired, eye is beating towards right side, will always be opposite.
78
L posterior canal BPPV
a peripheral lesion with otoconia crystals disloged from utricle/saccule that have entered the L posterior canal (pathologic nystagmus with positional changes)
here, the impaired side is the side with the ‘higher firing rate’
79
Peripheral vestibular disorders
Vestibular nerve hypofunction (vestibular neuritis, perilymph fistula, Meniere's disease)
Vestibular apparatus malfunction (BPPV)
Posterior SC
Horizontal SC
Anterior SC
80
Central vestibular disorders
Stroke in brainstem/cerebellum
Cerebellar degeneration
Arnold-Chiari malformation
81
Nystagmus from peripheral lesions
Direction-fixed beating
Follows Alexander’s and Ewald’s laws
-Beating increases as eyes are moved towards the fast phase
-Beating occurs in the plane of impaired canals
Able to fixate with gaze stabilization
Habituates/compensates rapidly with time
Good outcomes with vestibular rehab
Examples of disorders – vestibular neuritis, BPPV
82
Nystagmus from central lesions
-Pure vertical or pure torsional or direction-changing beating depending on gaze
-Does not follow Alexander’s law
-Unable to fixate with gaze stabilization
-Takes longer to habituate/compensate
-Worse (than peripheral) outcomes
Examples of disorders – Stroke in brainstem/cerebellum, medications
83
Cerebellum function
Plans for coordinated movements, adjusts movements …and non-motor functions
Despite its important role in motor coordination, it does not have direct connection to motor neurons
So, after cerebellar damage, there is no muscle paralysis or sensory deficits
84
Vestibulocerebellum
Controls eye movements and controls neck/trunk axial muscles for postural control.
85
Spinocerebellum
Region that helps to execute coordinated movements using both feedback and feedforward mechanisms. Inputs from spinal cord via spinocerebellar pathways, Outputs adjust motor activity by influencing descending medial tracts (posture, tone) and lateral tracts (fine movements)
86
Cerebrocerebellum
function is to plan for coordinated movements using feedforward mechanism. Receives direct inputs from pontine nuclei and gives off direct outputs to thalamus.
87
Lesions in vestibulocerebellum
nystagmus, difficulty maintaining sitting/standing balance (truncal ataxia)
88
Lesions in spinocerebellum
limb incoordination (DDK, dysmetria (lack of precision in movement when trying to reach for a target)), ataxic gait (wide-based unsteady gait). Also, action/intension tremor, dysarthria
89
Lesions in cerebrocerebellum
difficulty in planning complex movements (mostly fine movements) along with motor areas, Disruption of timing of joint movements
90
Basal Ganglia
plans and executes coordinated motor activity, do not have direct connections to motor neurons. Involved in movement control for goal-directed behavior and helps in judging/decision making by taking into account socially appropriate/inappropriate situations and emotions
91
Goal-directed behavior
Example: deciding whether to run a yellow light when running late to work.
92
Lesion in bilateral caudate
inattention, distractibility, poor concentration. But no movement disorders.
93
Social behavior
Example: deciding whether to run a yellow light with grandma sitting beside you
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Bilateral caudate head lesions
prone to frustration, hypersexual, shoplifting, violent. But no movement disorders
95
Emotional behavior/Limbic circuit
Example: involved with emotional and reward/pleasure seeking behavior, links emotions and motor systems
96
Lesions in ventral striatum
depression, emotional blunting ‘mask-like’ facial expression
97
Oculomotor circuit
To decide whether to use fast eye movements (saccades) to direct attention to visual objects of interest
Lesions in BG can cause impaired saccades
98
Motor circuit
This circuit regulates movements by indirectly controlling activity in voluntary muscles, postural muscles and CPG
This loop up- or down-regulates activity in various motor tracts to promote desired movements and inhibit undesired ones
99
Influence of BG on motor pathways...
Output of motor circuits is always inhibitory on the motor pathways, which can suppress undesired movements or activate suppressed movements by ‘disinhibition’
100
Go (Direct) Pathway
Facilitates desired movements by ‘disinhibiting’ thalamus due to increased inhibitory activity of Striatum on GPi
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No-go (Indirect) Pathway
Suppresses unwanted movements by inhibiting thalamus due to increased inhibitory activity of Striatum on GPe (instead of GPi)
102
Hyperdirect Pathway
Purpose is to inhibit all ongoing movements before initiating voluntary movement
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If the direct pathway becomes less active then...
may cause lack/slowness of desired movements, eg bradykinesia.
104
If the indirect pathway becomes less active then...
may cause increase in unwanted movements, eg dyskinesia, chorea, ballismus
105
Parkinson’s disease
Bradykinesia
Freezing of gait
Tremor
Rigidity – cogwheel type
Non-motor signs – Mask-like facial expression, depression, psychosis, dementia
106
Huntington’s disease
Chorea (a symptom that causes involuntary movement, irregular, or unpredictable muscle movements)
107
Process of nerve tissue movements
With increasing stretch on nerves, first the viscoelastic tubes (endo-, peri- and epineurium) stretch, the axons unfold, the fascicles glide on each other, and finally entire nerve glides relative to surrounding structures. After that tensile stress increases on nerves (nerve stretch)
Process is reverse during shortening
