Exam I Flashcards

1
Q

Describe the mechanism of muscle contraction

A
  1. nerve impulse triggers release of ACH into synaptic cleft - initiates muscular impulse
  2. as muscle impulse spreads to T-tubulues, Calcium ions are released
  3. Calcium ions bind to troponin - troponin changes shape, moving tropomyosin and exposing actin binding sites
  4. Myosin binds to exposed actin sites
  5. Myosin heads pivot, moving thin filaments toward the sarcomere center. ATP binds myosin and is broken down into ADP. Myosin detach from thin filaments and return to original position.
  6. Repeat of step 5 results in sliding of thick and thin filaments past one another (contraction)
  7. When impulse stops, calcium ions are transported into sarcoplasmic reticulum, tropomyosin reverts back, and filaments relax
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2
Q

Understand compartmentalization of body fluids

A

Total Body Water: 60%
ICF: 40%
ECF: 20%

ECF split:

  • -ISF: 15%
  • -Plasma: 5 %

transcellular fluid: CSF, digestive secretions, synovial fluid, etc.

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3
Q

Know types and examples of membrane transport especially passive vs. active transport

A
  1. Active transport: against gradient & requires ATP
    A. Primary: Na/K+ ATPase
    B. Secondary: carrier mediated; uphill (SGLT glucose)
  2. Passive transport: with gradient; no energy
    A. Facilitated diffusion: GLUTS
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4
Q

Discuss difference between electrical and chemical gradients

A

Electrical gradient: electrical force

Concentration gradient: chemical force

  • at equilibrium: no net movement of ions
  • determined by ion conc. gradients
  • ***K+ (leak)
  • ***Na/K+ pump (low intracell. Na; High intracell. K+)
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5
Q

What is the normal resting membrane potential across the membrane?

A

-70 to -80 mV

  • established by diffusion potentials
  • K+
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6
Q

Know everything about each stage of an action potential

A
  1. Upstroke: Depolarization (less neg.)
    - -open voltage gated Na channels
    - -Na influx
  2. Overshoot
    - -influx of sodium
    - -potential very +
  3. Falling: Repolarization
    - Voltage gated K+ channels open
    - Na channels close
  4. Undershoot (Hyperpolarization)
    - slow closure of K+ channels
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7
Q

Fiber types

A

A-fast (somatic sensory)
B-Fast (pre-ganglionic ANS)
C-slow (pain, temp; post-ganglionic)

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8
Q

Describe Skeletal Muscle activation

A
  1. action potential
  2. Depol along T-tubules
  3. Ca2+ release
  4. Ca2+ binds troponin C
  5. expose myosin binding site
  6. cross-links
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9
Q

Describe SM activation

A
  1. stimulus for Ca2+ entry into cell
  2. Inc. intracellular calcium
  3. Binding of Ca2+ to calmodulin
  4. myosin light chain kinase
  5. phosphorylation of light chain kinase
  6. Inc. myosine ATPase
  7. myosin-actin binding
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10
Q

Autonomic regulation is coordinated by

A

hypothalamus and brain stem

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11
Q

The nervous system is split into somatic and visceral. Describe visceral

A

Afferent: Viscerosensory
Pain (e.g., ischemia,
distension, cramping)
& REFLEX

Efferent: SM & CM and glands

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12
Q

Describe origins of sympathetic vs. parasympathetic

A

Sympathetic:
– “Thoracolumbar”
Intermediolateral cell column T1-L2 (IML) of SC
Intermediate gray: sympathetic pre-ganglionic neurons

Parasympathetic

  • “Craniosacral”
  • CN’s 3,7,9,10 *
  • S2-S4
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13
Q

The adrenal medulla is a specialized ganglion in the sympathetic division of the autonomic nervous system. The cell bodies of its pre-ganglionic neurons are located in the thoracic spinal cord. They travel to the greater splanchnic nerve where they synapse and release

A

Ach on nicotinic receptors

  • secretes mainly epinephrine
  • -PMNT
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14
Q

Sympathetic have ___ pre- and ___ post ganglionic cells. Parasympathetic have ___ pre and ___ post.

A

Sympathetic:

  • Pre = short; Ach to nicotinic
  • Long post = Norepinephrine; adrenergic receptors

Parasympathetic:

  • Pre = long (Ach, nicotinic)
  • Post = short (Ach, muscarinic)
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15
Q

Sympathetic pre-ganglionic and post-ganglionic info

A

Pre:
T1-L2 lateral horn

Post:

  • paravertebrl ganglia (sympathetic chain)
  • pre-vertebral ganglia (celiac)
  • adrenal (chromaffin)
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16
Q

Parasympathetic pre-ganglionic vs. post-ganglionic

A

Pre: CN 3, 5, 7, 9

Post: wall/effector organs; associated with CN

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17
Q

Adrenoreceptors (Sympathetic)

  • Inc. heart
  • Constricts SM vessels
  • Dilates SK (SM) vessels
  • Dec. GI motlity
  • Bronchodilator
  • Ejaculation
  • Relax bladder wall; constrict sphincter
  • Inc. sweating (M sympathetic)
  • Dilates pupil (eye)
  • Inc. renin
  • Inc. lipolysis
A

a1:
- vascular SM
- GI, sphincters
- bladder
- iris (radial muscle)

a2:
- GI
- adrenergic neurons

B1:

  • heart
  • salivary
  • adipose
  • kidney

B2:

  • cronchioles
  • skeletal muscle SM (vascular)
  • GI
  • bladder
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18
Q

G-proteins and their receptors

A

GI: inhibition of cAMP
–A2, D2, M2

Gs: Inc. cAMP, adenylyl cyclase
–B1, 2, 3 & D1

Gq: Phospholipase C, IP2, DAG; Ca2+
-M1, M3, A1

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19
Q

Spinal cord arrangement

A

Inner: gray (neuronal cell bodies)
Outer: white matter (tracts; myelin)

Dorsal: sensory
Ventral: Motor

DRG: all sensory info from periphery and CNS (pseudounipolar)

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20
Q

Somatotropic organization: the lateral cortex controls

A

Face and arms

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21
Q

Somatotropic organization: the central gyrus is split into pre and post. What neurons are in these sections?

A

Pre: primary motor

post-primary sensory

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22
Q

PCMl detects

A

discriminative touch, pressure, vibration, two point discrimination, proprioception

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23
Q

ALS detects

A

pain, temp, light touch

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24
Q

PCML lower extremity signals travel through what fasciculus? Upper?

A

Lower: Midline: grascilis fasciculus

Upper: cuneatus fasciculus

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25
How are images viewed?
Inverted vertically Reversed horizontally
26
Describe vision pathway
``` Nerve Chasm Tract Last. Geniculate body Cenuculo Cerebral cortex ```
27
Describe what occurs when you cut parts of the eye
1. Optic nerve: ypsilateral blndness (same eye) 2. Optic chiasm: bitemporal hemianopia —both eyes; bitemporal loss 3. Tract: contralateral hemianopia - loss of temporal in one eye, loss of nasal in the other
28
Cones of the eye are responsible for
Color 3types: iodopsin R,B,G 20/20 vision
29
Rods of the eye are responsible for
Black/white vision Rhodopsin: purple/blue
30
Phototransduction:
1. Light closes Na gated channels 2. Dec. influx; dec. dark current 3. Hyperpolarize 4. Dec. glutamate 5. Inhibit retinal nerves 6. Excitation
31
Flow of CSF
1. Lateral ventricle 2. Interventricular foramen 3. 3rd ventricle 4. Cerebral aqueduct 5. 4th ventricle 6. —branch either to foramen lunches OR to Median aperture 7. subarachnoid space 8. Arachnoid villi 9. Superior Sagittal sinus
32
Hydrocephalus
Block cerebral aqueduct
33
Choroid plexus
Lines ventricles - where CSF is made - infections (meningitis)
34
Ependymoma
Cancer of 4th ventricle (CSF flow)
35
CST: cortisol spinal tract steps - motor - 2 neuron pathway
(Primary/upper motor neuron) 1. Primary motor cortex 2. Midbrain 3. Cerebral peduncles 4. Pons 5. Medulla Desiccates (secondary/lower motor neuron) 6. Cervicomedullary junction (lateral cortico spinal tract; LCST) 7. Synapse at anterior horn cells 8. Skeletal muscle
36
Basal ganglia is part of The limbic system. Describe
Areas: Substantia Nigra Nucleus accumbens: addiction ``` Functions: -motor movement -blocks unwanted movements Habit -cognition -emotion ``` Dysfunction: huntington’s; Parkinson’s,s
37
Describe cortico-basal-ganglia-loop
Dopamine-dependent D1: direct - wanted movements (excitatory) - dysfunction leads to hypokinesia (ex: parkinson’s) D2: indirect - inhibits unwanted movements - dysfunction: hyperkinesis (ex: huntington’s Choreoform or turrets)
38
Cerebellum
Fine tunes motor movements - Purkinje: GABA-ergic to deep cerebellum nuclei - Disinhibition for motor learning - interconnected with vestibular system Damage: clumsy motor movements (tremors)
39
Broca’s area
Speech formation | Broca’s aphasia: comprehend but can’t make correct sounds/words Slurring
40
Wernicke’s area
Language comprehension Wernicke’s aphasia: difficulty understanding language and their speech doesn’t make sense
41
Disinhibition
Inhibit the inhibitor thus causing excitation
42
Glial cells
Support cells - Microglia: macrophages - Ependymal: choroid plexus; CSF - Astrocytes: BBB tight junctions & reactive gliosis - oligodendrocytes- myelin Post-mitotic **tumors
43
Taste innervation
CN: 7 (anterior; chordates tympani) CN 9, 10 (posterior 1/3 of tongue) -gag; epiglottis Synapses: nucleus solitaris, medial meniscus Thalamus
44
Taste is controlled by what parts of the brain
Frontal cortex: perception Hypothalamus/Amygdala: motivation/emotion Hippocampus: memory
45
Smell is controlled by what parts of the brain
Frontal cortex: perception of smell Hypothalamus/Amygdala: motivation/emotion Hippocampus: memory
46
Smell is innervated by
CN I (olfactory nerve) - olfactory receptor neurons - to olfactory bulb
47
Alpha motor neurons
From anterior horn to muscle
48
Brown Sequard syndroms
1) Lesion below medulla 1) PCML: ypisilateral symptos 2) ALS: contralateral 3) LCST (motor): loss of motor function (ypsilateraL
49
B12 deficiency
1) Subacute combined degeneration of the spinal cord 2) Demyelination of PCML 3) LCST: muscle weakness, spastic paralysis 4) + Romberg test 5) + Babinsky
50
Lesion above the dessucation
1) PCML: contralateral symptoms | 2) ALS: contralateral symptoms
51
UMN vs LMN lesions
UMN: Weakness, Inc. atrophy & reflexes, tone, **Babinsky LMN: Weakness, Dec. atrophy and reflexes, tone, **Fasciculations
52
Know what constitutes an UMN vs. LMN and know characteristics signs if they’re damaged
1) Upper motor neuron lesion: spastic paralysis; everything goes up 2) Lower motor neuron lesion: flaccid paralysis (everything goes down) 3) Babinsky: 1) present in upper motor neuron: toes point up 2) Absent in lower motor neuron: toes don’t point up
53
Anterolateral system
2) Anterolateral system (Spinothalamic tract): 1) Pain 2) termperature 3) light touch 4) Information travels: 1) A-delta and C-fibers: slow, small diameter, unmyelinated 5) Direction: 1) First order neurons decussate immediately at anterior commissure of spinal cord (primary afferent) 2) 2nd order neurons in thalamus 3) Third order neuron in somatosensory 4) 4th order neuron in * *first order neurons have cell bodies in DRG (substantia gelatinosa) * *synapse at level of pain or travel via Lissauer’s tract * lose info on contralateral side * Lesion in DCS: results in loss of ypsilateral fine touch and proprioception * Lesion in ALS: contralateral loss of pain and temp
54
PCML system
1) Dorsal column system (PCML): 1) fine touch (mechanoreceptors) 2) pressure, 3) two point discrimination, 4) vibration (Tuning fork test) 5) proprioception (Romberg test) Information travels: 6) Lower extremity: gracilis fasciculis; 7) Upper extremity: cuneatus fasciculus 8) A-Beta fibers Direction: 9) Ascend ypsilaterally – decussate contra-laterally at lower medulla 1) Crosses midline in the brainstem 2) 1st order neurons: ypsilateral to brainstem (past spinal cord) 3) 2nd order neurons: thalamus 4) 3rd order neurons: sensory cortex
55
Types of sensory receptors
1) Mechanoreceptors – pressure/changes in pressure (Pacinian corpuscles; baroreceptors) 2) Photoreceptors (light/vision) 3) Chemoreceptors (chemicals – olfaction, taste, detect O2 and CO2) (carotid body) 4) Thermoreceptors – temperature (TRPV1) 5) Nociceptors –pain; extremes of pressure, termperature, noxious chemicals
56
Sensory transduction vs. receptor potential
3) *Sensory transduction: environmental stimulus (light, pressure) activates a receptor and converts it into electrical energy (ex: TRPV1 – responds to heat/capsaicin) 4) Receptor potential: inc. or dec. likelihiodd that action potential happens
57
Hearing is controlled by what cranial nerve?
CN 8 (vestibulocochlear) 1. external ear: Pinna (sound waves) 2. Tympanic membrane (eardrum) between external and internal 3. Middle ear: Malleus, stapes, incus (sound amplification) 4. Oval windown 5. Inner Ear: cochlea (hearing and equilibrium)
58
Sound amplification
- mechanoreceptors - Eardrum vibrates -- causes malleus to vibrate increasing vibration in incus and stapes - Hair cells: vibrations/sound waves
59
Hair cells in the organ of corti transduce sound signals. How?
Organ of corti: sensory organ for sound -K+ enters -- depolarizes -- transduction
60
Hearing muscles
stapedius: CN 7 (stapedial branch) | Tensory tympani: CN 5 (V3)
61
Vestibular system is involved with balance. What are structures?
Semicircular canals: rotary movements Endolymph: motion sensors Saccules: tilt vertical; gravity Utricles: tilt horizontal
62
Describe pupillary light reflex
1. Light enters 2. Into optic nerve (CN 2) 3. to Occipital lobe - -pre-tectal area - -lateral geniculate nucleus - -**Eddinger westfall nucleus (both eyes) Out: 1. CN 3 oculomotor 2. pre-ganglionic to cilia to post-ganglionic * sphincter papillary muscle - -constriction/dilation