BECOM Exam #5 (Week 3) Flashcards
(126 cards)
1
Q
Lower motor neuron:
Alpha motor neurons
Gamma motor neurons
INNERVATE was fibers
A
Lower motor neuron:
Alpha motor fibers -> innervate extrafusal fibers
Gamma motor fibers -> innervate intrafusal fibers (polar ends)
2
Q
Alpha motor neurons consist of two types and what they innervate (large vs small)
A
Large motor neuron = fast twitch muscles (high force/velocity)
Small motor neuron = slow twitch muscles (postural, endurance)
3
Q
intrafusal fiber types and afferent neuron type
A
Nuclear bag fibers: Large number of nuclei packed in middle portion
-Type Ia afferent -> faster response
Nuclear chain fibers
-Type Ia and type II afferent -> slower response
4
Q
stretch reflex pathwaw
A
intrafusal fibers stretched –> Type Ia or type II afferent fiber to spinal cord –>
Efferent response:
- Alpha -> all muscel fibers
- Gamma -> tip (polar regions of fiber)
- contract polar part of intrafusal fibers causes stretch of fibers -> keeps sensitivity
AND
alpha efferent inhibition to antagonist muscle
5
Q
Dynamic myotatic reflex vs. Static (tonic) myotatic reflex
- define
- afferent fibers
A
Dynamic myotatic reflex: strong, fast reaction causing sudden contraction of the whole muscle and opposes sudden lengthening of the muscles
-type Ia afferent fibers
Static (tonic) myotatic reflex: slower and weaker than dynamic stretch important for posture and muscle tone
-type Ia and type II afferent fibers
6
Q
Inverse myotatic reflex (Glogi tendon reflex)
- normal situation
- extreme situation
A
Stretching of golgi tendon -> inhibition to same muscle that got stretched and excitation of opposite muscle
-allows find control
In extreme cases (caring something heavy) Golgi tendon will cause relaxation of entire muscle to protect the muscle from tearing
7
Q
Flexor withdrawal reflex
A
Harmful stimulus
Ipsilateral side:
Flexion activate
extension inhibited
Contralateral side:
flexion inhibited
extension activated
-also used in walking
8
Q
Afterdischarge
A
keep muscle contraction for a little bit longer time
-cross extension lasts longer than flexion -> keep balance
9
Q
Central pattern generator
A
produces the alternating contractions of limb flexors and extensors even with the connection to brain cut
- response must be located in spinal cord
- sensory input is important for fine tuning of motion but not for gross movement
- important in infants and paraplegic individuals
10
Q
Supplementary motor area (SMA) use
A
- bimanual tasks
- skilled movements
- responsible for planning movements
- together with the premotor areas -> complicated movement program
11
Q
Premotor cortex
A
- contains MIRROR neurons
- together with the SMA -> complicated movement program
12
Q
Motor apraxia
A
- disorder of the execution of learned movements, not due to weakness, loss or coordination, or sensory loss.
- can lead to inability to organize actions (example putting clothes on wrong part of body)
13
Q
Unilateral lesions in corticobulbar tract
A
VII unilateral lesion -> opposite side lower face
XI unilateral lesion > tongue pulls towards side of lesion
14
Q
Posterior limb of internal capsule lesion
A
- area where corticospinal tract runs through brain
- loss of contralateral fine motor control
15
Q
Pyramidal tract (upper motor neurons from corticospinal tract or corticobulbar) control
A
- open and close the spinal reflex arc
- pyramidal tract controls the flexors
- in paraplegia, exaggerated planterflexion (foot it extended bc flexion is lost from corticospinal tract)
16
Q
Corticorubrospinal tract
A
Serves as alternative pathway for transmitting cortical signals to the spinal cord that causes contraction of muscle groups (gross movement)
- cortex -> red nucleus -> spinal cord
- lacks fine control
17
Q
Reticulospinal tract tract pontine vs medullary control
A
Posture
Pontine: PEM
-excitatory
-lateral
Medullary: MIL
- inhibitory
- lateral
18
Q
Tectospinal tract (inferior and superior colliculus)
A
superior colliculus receives input from retina and the frontal eye field -> conjugate eye movements and reflex movement towards moving object
Auditory stimuli reach the superior colliculus via the inferior colliculus -> auditory reflex towards source of stimulus
19
Q
Head angular acceleration (head rotation) is detected by
A
semicircular canals (ampula)
20
Q
Head linear acceleration (translational motion and gravity)
- forward/backward acceleration
- nodding up and down
- GRAVITY
A
saccule and utricle (macula)
21
Q
initial movement vs. sudden stop in ampulla
A
initial movement: depolarization
sudden stop: hyperpolarization
*slightly depolarized at rest
22
Q
Horizontal canals
LARP (left anterior right canal and right posterior canal)
RALP (right anterior canal and left posterior canal)
-corresponding muscles
A
Horizontal canals: lateral and medial recti.
LARP: left vertical recti, right obliques.
RALP: right vertical recti, left obliques.
23
Q
Physiological nystagmus
A
rapid movement of eyes from one object to another
24
Q
Vestibulo-ocular reflex
A
keep the eyes still in space when the head moves (extremely fast, bisynaptic).
25
Vestibulo-collic reflex
keeps the head still in space – or on a level plane when body is moving
26
Vestibular-spinal reflex
maintain posture during rapid cages in position
27
lateral vestobulospinal tract
- Ipsilateral
- Allows the legs to adjust for head movements.(EXTENSORS)
- Provides excitatory tone to extensor muscles -> leads to rigidity when corticospinal tract is lesions (inhibition)
28
Medial Vestibulospinal Tract
Keeps the head still in space – mediating the vestibulo-colic reflex.
29
vestibular nucleus combines visual and vestibular signals
- Initial recognition of movement is by the vestibular system but this does not give constant stimulation if movement continues
- Retinal motion by head movement compensates
30
Benign positional vertigo
debris from the otoconia in the utricle float into the posterior canal, causing interference with cupula function, brought out by motion in the plane of the affected posterior cana
31
Phase I Reactions
1. Oxidations
- Flavin monooxygenase
- Amine oxidase
2. Reductions
3. Hydrolysis
32
Phase II Reactions
```
GLUCURONIDATION
AcetylatioN
GLUTATHIONE CONJUGATION
Glycine conjugation
Sulfation
Methylation
Water conjugation
```
*cyp independent*
33
cyp associated with acetaminophen break down?
cyp2E1
34
most drugs are metabolized by?
Cyp 3A4/5 or UGT
35
drugs that are enzyme inducers
Carbamazepine
Rifampin
*Warfarin (Coumarin) not an inducer just influenced by a bunch of other inducers*
36
drugs that are inhibitors
Cimetidine
Ethanol
Grapefruit juice
37
Enterohepatic Circulation
-highly lipophilic drugs
| Bile in GI tract -> Hepatic Portal Vein -> Liver -> Bile -> Bile released to GI tract
38
zero order vs. first order elimination
Zero order: half life is changing but elimination rate is staying the same
-linear
First order: elimination rate is changing but half life is staying the same
- exponential
- 95% of drug is gone after 5 half lives
39
increase vs decrease Vd
Increase Vd: more drug in peripheral compartment (lipophilic)
- dec clearance
- dec elimination
- inc half life
Decrease Vd: less drug in peripheral compartment
- inc clearance
- inc elimination
- dec half life
40
Maintenance Dose Rate =
Desired Drug plasma con x CL (clearance) x Dose interval / F (bioavailability)
41
Loading Dose =
Desired Drug plasma con x Vd / F
42
half life =
0.7 x Vd / CL
43
clearance =
Vd x Ke (elimination constant)
44
pharmacodynamics
is the study of the relationship between drug concentration in the body and the physiological response to that concentration of drug
45
pharmacokinetics
d
46
Partial agonist
Partial agonist: bind to both inactive state and active conformation
-A partial agonist serves as an agonist in the absence of a full agonist but decreases the response of full agonist when given together
47
Potency
Dose of a drug necessary to produce 50% of drug’s total response, expressed as an ED50 value
48
Efficacy
total response produced by a drug
| -clinical effectiveness of a drug depends on its maximal efficacy (Emax) and not the potency (ED50/KD)
49
Inverse Agonist
- Antagonists that measurably decrease spontaneous receptor activity
- bind to receptors that are constantly on at base level with the absence of ligand and turn them all the way off
50
Chemical Antagonism
Binding of one drug to another and making it unavailable for binding to its receptor
51
Physiological (Functional) Antagonism
Two drugs having opposite physiological effect/response through completely different mechanisms, for example, glucocorticoids increase blood glucose levels whereas insulin decreases it
52
Allosteric Modulation
When a drug binds to a receptor at a completely different site and modifies the response of the receptor to the agonist binding
53
tracts into superior cerebellar peduncle
Anterior spinocerebellar tract
-Information coming from ipsilateral side
54
tracts into middle cerebellar peduncle
Pontocerebellar tract
-Information coming from ipsilateral side
55
tracts into inferior cerebellar peduncle
Posterior spinocerebellar tract
Olivocerebellar tract
-Information coming from ipsilateral side
56
tracts out of superior cerebellar peduncle
Dentothalamic pathway
| Dentorubrothalamic pathway
57
tracts out of inferior cerebellar peduncle
Cerebelloreticular
58
Anterior lobe syndrome of cerebellum
staggering gate and ataxia in the legs
| -Broad based, staggering gait
59
Neocerebellar Syndrome of cerebellum
effects lateral hemisphere of the cerebellum
- Changes in muscle tone, reflexes, and coordination of voluntary movements all ipsilateral to side of damage
- have trouble pointing at objects
- have trouble touching nose
60
purkinje fibers
Successive inhibitory feed -> damping of the DCN excitatory output -> prevents overshooting/ oscillation
61
Deep cerebellar nucleus control
Inhibitory influence arise from Purkinje cells, excitatory from afferent input to the cerebellum
-afferent: climbing fibers and mossy fibers
62
Climbing fibers
communicate directly with 10-20 purkinje fibers as well as the deep cerebellar nucleus
- route through the INFERIOR OLIVE nucleus then to the cerebellum
* when learning a new task the climbing fibers are the many fibers used (complex spikes)*
63
Mossy fibers
communicate with he granular cell which then send thousands of fiber to communicate with thousands of purkinje cell
64
Basket cells
Stellate cells
Golgi cells
in cerebellum
```
Basket cells (receives input granule cells): inhibit Purkinje fibers
Stellate cells (receives input from granule cells/paralell fibers): inhibit Purkinje cells
Golgi cells: inhibit granule cells
```
*Important for lateral inhibition (sharpening of the signal) to modulate signal from purkinje fibers
65
Vestibulocerebellum controls
Important in controlling balance between agonist and antagonist muscles of the spine, hips and shoulders during rapid changes in body position
- keeping balance while swinging a bat
- predictive balance before a movement occurs
- sends DIRECT projections to vestibular nuclei
66
Spinocerebellum receives and controls
Receives input from:
1. Copy efferent: From cerebral motor cortex, descending tracks or interneurons (intended sequential plan)
2. Feedback from peripheral receptors: Reafferent fibers from M spindles, GTO, and proprioceptors (actual movement input)
* Important for feedback control of distal limb movements*
67
Cerebellar functions on movements
1. Prevents overshooting
2. Prevents back and forth oscillation of movements (intention tremors)
3. Facilitates rapidly alternating movements and bilateral coordination (supination and pronation with both hands opposite -> hard)
68
Cerebrocerebellum arises from and controls
-Arises from the LATERAL zones of the cerebellum
-Planning of sequential movements (ability to progress smoothly from one movement to another)
Timing of sequential movements (ability to progress in timely order)
-wide wobbly gate
69
Dysdiadochokinesia caused by
lesion of cerebellum --> can't supinate and pronate both hands at same time
70
inhibition of vestibuloocular reflex (eyes staying fix on target while moving head)
inhibited by vestibulocerebellar
71
Potency equation
1 / Kd
72
Spare receptors
are receptors that exist in excess of those required to produce a full effect
-dont need to bind to all receptors to get max response
73
Quantal Dose-Response Curve
determines the drug dose required to produce a specified magnitude of effect in a large number of individual patients or experimental animals
-At what dosage can the most people get the most effect
74
Therapeutic Window
Therapeutic window is the range of steady-state concentrations of drug that provides therapeutic efficacy with minimal toxicity (range from minimum effective dose to minimum toxic dose)
75
ED50 definition
the dose where half of the population tested will respond to the drug
76
lethal dose (LD50) or median toxic dose (TD50) definition
the dose where half of the animals tested will not survive
77
certain safety factor (CSF) equation
TD1 / ED99
78
therapeutic index (TI) equation and definition
TD50 / ED50
| -the safety of a drug
79
Specificity
If a drug has one effect, and only one effect on all biological systems.
80
Selectivity
Most drugs act on more than one receptor site once they reach an appropriately high concentration
81
most common drugs with Narrow Therapeutic Index Drugs
warfarin, levothyroxine
| -ED50 is high or LD50 is really low
82
Cytokine receptor
receptor does not phosphorylate like ligand receptor but rather recruits a other protein when activated to phosphorylate
- JAK/STAT = inc gene expression
- long lasting compared to ligand enzyme receptors
83
Pharmacodynamic Tolerance
A decreased responsiveness to a drug or hormone stimulation that occurs slowly over time i.e. cellular adaptation
84
striatum includes
1. putamen
2. caudate nucleus
3. nucleus accumbens
85
Hemiballismus
- Uncontrolled flailing of one arm and leg
- lesion in contralateral subthalamic nuclei
- STN usually excites the GPi which inhibits the thalamus, when it is injured, the Gpi is not excited and inhibition of the thalamus is reduced creating unwanted movements
86
Huntington’s disease
- Caused by neural degeneration that is severe in striatum
| - C shows MRI reconstructions from 20 patients to show the pattern of degeneration of the caudate nucleus and putamen
87
Parkinson’s Disease
Parkinson’s usually has a decrease in pigmentation of the substantia nigra
decrease in dopamine levels. Treatment was proposed to administer doses of L-dopa
-inhibition of wanted muscle movements and inc in unwanted movements (tremors)
88
Association cortex primarily projects to
Sensorimotor cortex primarily projects to
Limbic area primarily projects to
Association cortex primarily projects to caudate nucleus
Sensorimotor cortex primarily projects to the putamen
Limbic area primarily projects to nucleus accumbens
89
Basal ganglia function
- Selection of the more important moves (action selection)
| - Operational learning (deciding favored actions based on outcomes, based on timing)
90
Default status of basal ganglia
suppress all movements
91
Lead-pipe rigidity
| Cogwheel rigidity
Lead-pipe rigidity (BG lesion)
-Continuous resistive tone throughout stretch
Cogwheel rigidity (PD and related disorders)
-Rigidity with superimposed tremor
92
left eye right and up muscle
inf oblique
93
(SO4LR6)
Sup. oblique - trochlear
Lateral rectus - abducens
Everything else - oculomotor
94
loss of oculomotor nerve (III)
eye turned down and out
ptosis (drooping of eyelid)
mydriasis (constant dilated pupil)
95
loss of trochlear nerve (IV)
diplopia (double vision)
| distortion of eye (eye turns away from nose)
96
loss of abducens (VI)
diplopia
| medial deviation of eye
97
Saccadic movements
conjugate eye movement rapidly from one target to another
98
control of horizontal gaze and pathway
pons (paramedian pontine reticular formation)
- left frontal eye field (cortex) --decussate--> paramedian pontine reticular formation -> abducens nucleus ->
1. lateral rectus
2. medial longitudinal fasciculus oculomotor nucleus -> oculomotor nerve -> medial rectus
99
control of vertical gaze (up, down)
midbrain (rostral interstitial nucleus of the medial longitudinal fasciculus)
- up - dorsal aspect
- down - ventral aspect
100
cant look up, down issues
- pineal gland tumor
| - dilation of cerebral aqueduct
101
optokinetic movements
combination of saccade and smooth pursuit movement
102
angular gyrus
- role
- lesion
role: makes out meaning of visually perceived words
lesion: cant understand written language but can understand spoken language
103
prefrontal lobotomy effects
- Inability to solve complex problems
- Inability to string together sequential tasks to reach complex goals
- Inability to learn to do several parallel tasks at the same time
- Placid
- Inappropriate social responses (loss of morals and increase sexual activity)
- Mood swings
104
prosopagnosia
Cant recognize faces due to lesion
- fusiform gyrus lesion
- superior temporal lobe
105
left vs right hemisphere
Right:
- Specialized for spoken and written language
- Sequential and analytical reasoning (math and science)
- Breaks information into fragments and analyzes it in a linear way
Left:
- Perceives information in a more integrated holistic way
- Seat of imagination and insight
- Musical and artistic skill
*corpus collosum allows communication between two hemispheres
106
non dominant broca area
| non dominant Wernicke's area
non dominant broca area: speech with variable tones
| non dominant Wernicke's area: appreciation of subliminal meanings, humor
107
Tetanic stimulation vs Posttetanic potentiation
Tetanic stimulation: rapid arrival of repetitive signals at a synapse causes Ca2+ accumulation and postsynaptic cell more likely to fire
Posttetanic potentiation:to jog a memory
- Ca2+ level in synaptic knob stays elevated
- Little stimulation needed to recover memory
108
what makes unified long term memories and where are they stored?
hippocampus and are stored in
- superior temporal lobe: faces and vocabulary
- prefrontal cortex: plans and social roles
- amygdala: emotional memory
109
haircell neurotransmitter
glutamate
| aspartate
110
toxins that can cause vestibular dysfunction
streptomycin and gentamycin
111
vestibular nuclei -> ventral thalamus -> parietoinsular cortex
-lesions of parietoinsular cortex causes
difficulty perceiving the vertical: they think vertical lines tilt away from the side of the lesion
112
general area controlling brain activity level
bulboreticular facilitatory area
113
Lateral hypothalamus limbic control
↑general activity, overt rage and fighting
114
Ventromedial nucleus limbic control
tranquility (also satiety)
115
Bilateral lesions of lateral hypothalamus cause
extreme passivity and dramatically reduced eating and drinking
116
Bilateral lesions of ventromedial nucleus
excessive rage upon slightest provocation (sham rage), hyperactivity, excessive drinking and eating
117
PVN to secrete
CRH into portal veins. CRH evokes release of ACTH from the pituitary which evokes release of cortisol from adrenal cortex. Cortisol ↑ glucose levels & amino acid, fat breakdown, release of neutrophils & ↑ memory
118
Reward centers
| Punishment center
Reward centers: medial forebrain bundle (receive treat)
Punishment center: amygdala
-Storage of memories that are associated with good and bad memories
119
Hippocampus and memories
Hippocampus is not were all memory is stored but where new memories are made
- Lesion -> cant make new memories but can remember old memories
120
Amygdala
sex, fear
| -fight or flight (freeze up)
121
Kluver - Bucy Syndrome
-removal of temporal lobe
Pre-op: aggressive, raging
Post-op: docile, orally fixated, increased sexual and compulsive behaviors
122
Cingulotomy (cutting fibers of anterior cingulate) relieves
persistent pain and depression
123
```
Locus ceruleus
Raphe nucleus
Tuberomammilary nucleus
Periaquiductal grey matter
Periofornical area
-neurotransmitters
```
Locus ceruleus -> NE
Raphe nucleus -> serotonin (wakes you up, antiserotonin will put you to sleep)
Tuberomammilary nucleus -> histamine
Periaquiductal grey matter -> dopamine
Periofornical area -> orexin (def. can cause narcolepsy and can promote hunger)
124
ventrolateral preoptic area stimulation
| -what triggers
= sleep
- release of adenosine (coffee binds adenosine receptors)
- IL-1 (inflammation), prostaglandin, insulin (meal)
125
narcolepsy caused by what kind of def.
orexin insufficiency
126
```
Stage 1
Stage 2
Stage 3
Stage 4
REM
waves
```
```
Stage 1: alpha
Stage 2: theta, k complexes, sleep spindles
Stage 3: low freq theta and some delta
Stage 4: delta
REM: sharp theta
```
