exam review - quiz 6 Flashcards

1
Q

name: types of propagation (2)

A
  1. unmyelinated axon
    - continuous conduction
    - AP at one spot + propagate by stim. adjacent regions
    - AP in 1 direction only
  2. myelinated axons
    - saltatory conduction
    - voltage gated Na+ channels at nodes
    - faster AP flow
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2
Q

explain: continuous conduction

A
  • unmyelinated axon
  • mvt. of ions = local current
  • only one direction because absolute refractory period desensitizes region
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3
Q

explain: saltatory conduction

A
  • myelinated axon
  • depol. at small regions at nodes of ranvier
  • less ATP needed bc don’t need to reestablishb resting potential as much
  • only one direction
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4
Q

name: factors affecting propagation speed (3)

A
  1. axon diameter
    - more SA = more voltage gated Na+ channels = faster local current = faster propagation
  2. amount of myelination
    - heavy > lighter
  3. temperature
    - cool - slower
    ⤷ bc channels = prot. and prot. affected by temp.
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5
Q

name + describe: nerve fiber types (3)

A

Type A
- large diameter (fast)
- myelinated (fast)
- conduct at 15 - 20m/s
- motor neurons supplying skeletal and most sensory neurons

Type B
- medium diameter
- lightly myelinated
- conduct at 3 - 15m/s
- part of ANS

Type C
- small diameter (slower)
- unmyelinated (slower)
- conduct at 2m/s or less
- part of ANS

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6
Q

define: synapse

A
  • junction between cells that allow comm.
  • 2 types = elec. and chem.
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7
Q

explain: electrical synapse

A
  • junction between 2 cells
  • important for coordinated conditions
    ⤷ ex. cardiac musc., smooth musc.
    -
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8
Q

explain: chemical synapse

A
  1. AP arrives at presyn. term. causing voltage gated Ca2+ channels to open 2. Ca2+ diffuses into cell stimulating exocytosis of synaptic vesicles
    ⤷ releases neurotransmitter
  2. neurotransmitter diffuses from presynaptic term across synaptic cleft
  3. neurotransmitters combine w/ receptor sites causing ligand gated Na+ channels to open
  4. Na+ diffuses into cell and depol.
  • no direct transfer of ATP
    ⤷ relies on neurotransmitters
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9
Q

explain: methods of removal of neurotransmitters (3)

A
  1. diffusion
    - down conc. gradient
  2. enz. degradation
    - acetylcholine
    - acetylcholinesterase = receptor
    ⤷ breaks down acetylcholine into acetic A and choline
  3. uptake by neurons or glial cells
    - neurotransmitter transporters
    - prozac = serotonin reuptake inhibitor
    ⤷ lets serotonin stay in syn. cleft for longer (used as depression treatment)
    - neurotransmitter transported takes norepinephrine back to presynaptic term. to reuse or degrade
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10
Q

explain: types of postsynaptic potentials (2)

A
  1. excitatory postsynaptic potential (EPSP)
    - depol.
    - may reach threshold to prod. AP
  2. inhibitory postsynaptic potential (IPSP)
    - hyperpol.
    - inhibits resp.
    - decreases AP (moves away from threshold)

**summation = adding signals
⤷ spatial = several axons releasing neurotrans. to same cell body
⤷ temporal = same area releasing many times

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11
Q

define: vertebral column, vertebral foramen, vertebral canal, intervertebral foramina

A
  • vert. column = stack bone
  • vert. foramen = openings in vertebrae
    ⤷ creates vertebral canal
  • vertebral canal = canal housing spinal cord
  • intervertebral foramina
    ⤷ spaces between vertebrae
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12
Q

explain: shape of spinal cord

A
  • not uniform, 2 enlargements
    1. cervical (upper)
    2. lumbosacral (lower)
  • conus medullaris = inferior end (tapered)
  • filum terminale = anchors spinal cord to vertebral cord
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13
Q

explain: inside of spinal cord

A
  • white matter = 2 halves (inside), 2 columns in half
    ⤷ each column subdivided into nerve tracts (fasciculi)
  • up and down
  • myelinated
  • gray matter = 4 categories
    1. post horns = sensory nerves
    2. anterior horns = motor neurons to skeletal musc.
    3. lat. horns = ANS

**commisure = axons cross

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14
Q

name: regions of spinal cord (nerve numbers not plexuses)

A
  • cervical = C1 - C8
  • thorasic = T1 - T12
  • lumbar = L1 - L5
  • sacral = S1 - S5
  • coccygeal = Co
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15
Q

question: how many pairs exit through each region in/around vertebral column?

A
  • 1st pair exits between skull and first cervical vertebrae
  • 4th pair exits via sacral foramina
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16
Q

explain: peripheral nerves

A
  • 3 layers of connective tissue
    1. deepest = endoneurium
    ⤷ axons grouped into fascicles held by perineurium
    2. perineurium
    3. shallowest = epineurium
    ⤷ continuous w/ brain’s dura mater
17
Q

define: dorsal ramus and ventral ramus (spinal nerve branches)

A
  • dorsal ramus = innervate deep musc. responsible for mvt. of vertebral column
  • ventral ramus = intercostal nerves (thorasic region)
18
Q

list: numbers of plexuses in ventral ramus

A
  • cervical plexus = C1 - C4
  • brachial plexus = C5 - T1
  • lumbar plexus = L1 - L4
  • sacral plexus = S1 - S4
  • coccygeal plexus = S5 - Co
19
Q

explain: each plexuses

A
  1. cervical plexus = C1 - C4
    - innervates superficial neck structures, skin of neck, posterior part of head
    - phrenic nerve = C3 - C5, innervates diaphragm (important for breathing)
  2. brachial plexus = C5 - T1
    - 3 trunks, 6 divisions, 3 cords, 5 branches
    - nerves: axillary, radial, musculocutaneous, ulnar, median
    - supplies shoulders and upper limbs
  3. lumbar plexus = L1 - L4
    - 2 major nerves = obturator and femoral
    - supplies part of lower limbs
  4. sacral plexus = L4 = S4
    - 2 major nerves = tibial and common fibular
    - bind to become sciatic nerve
    - supplies large portion of lower limbs
  5. coccygeal plexus = S5 - Co
    - musc. of pelvis floor
    - sensory into from skin over coccyx (most inferior bone in vertebral column)
20
Q

question: which resp. do the somatic and autonomic motor systems do?

A
  • somatic motor = only excitatory
  • autonomic motor = both excitatory and inhibitory
21
Q

explain: pathway of AP in somatic motor system

A
  • always myelinated, 1 neuron system
  1. cell body in CNS
    ⤷ motor nuclei for cran. nerves
    ⤷ anterior horn of spinal cord
  2. skeletal muscle
    ⤷ target tissue
22
Q

explain: pathway of AP in autonomic motor system

A
  • 2 neuron system
  1. preganglionic neuron (always myelinated)
    ⤷ cell body in CNS
    ⤷ autonomic nuclei of cran. nerves
    ⤷ lateral horn of spinal cord)
  2. postganglionic neuron (always unmyelinated)
    ⤷ from synapse to target tissue
23
Q

name: divisions of autonomic motor nervous system from PNS (2.5)

A
  1. sympathetic
  2. parasympathetic
    - both innervate most organs (dual innervation -> opposing effects)
  3. enteric
    ⤷ innervates digestive system
24
Q

explain: sympathetic division

A
  • thoracolumbar division
  • T1 - L2
  • sympathetic trunk/chain ganglions vertically on side of vertebral column
  • prevertebral/collateral ganglia next to trunk/chain
  1. neurons exit lateral horn via ventral root
  2. join at spinal nerve
  3. enter at sympathetic ganglia (chain/trunk)
  4. can take several paths after
    ⤷ synapse at same level
    ⤷ move through to collateral and synapse there
    ⤷ travel up or down chain/trunk ganglia
25
Q

explain: routes of sympathetic axons (4)

A
  1. synapse in CHAIN ganglion -> exit via spinal nerve
    ⤷ targets skin of neck, trunk, limbs
  2. synapse in CHAIN ganglion -> exit via sympathetic nerve
    ⤷ targets heart and lungs
  3. pass chain, synapse in COLLATERAL ganglion -> exit via splanchic nerve
    ⤷ targets abdominopelvic regions
  4. pass chain, pass collateral, synapse w/ cells in ADRENAL MEDULLA
    ⤷ act as postsynaptic neurons to release epinephrine and norepinephrine
26
Q

explain: parasympathetic NS

A
  • craniosacral division
  • cran. nerves 3, 7, 9, 10
  • S2 - S4
  • reaches pelvis splanchnic nerves (smooth muscles + glands of colon, bladder, rep. organs)
27
Q

explain: mneumonics for PNS and SNS

A

PNS = SLUDD
- salivation
- lacrimation
- urination
- digestion
- defecation
- decreases heart rate, diameter of airway, diameter of pupil

SNS = EEEE
- excitement
- embarassment
- emergency
- exercise
- increases heart rate, blood pressure, pupil contraction

28
Q

name: which neurotransmitters are cholinergic and adrenergic in ANS + which neurons are cholinergic and adrenergic in SNS and PNS

A

ANS neurotransmitters
- acetylcholine = cholinergic
- norepinephrine = adrenergic

SNS neurons
- preganglionic = cholinergic
- postganglionic = adrenergic

PNS neurons
- preganglionic = cholinergic
- postganglionic = cholinergic

29
Q

explain: cholinergic receptors

A
  • for acetylcholine
  • 2 classes
    1. nicotinic = excitatory, open Na+
    ⤷ on postganglionic neurons in autonomic ganglia, muscles, cell membrane
  1. muscarinic = excitatory or inhibitory, triggers G-protein signaling pathway
    ⤷ on effector cells that respond to acetylcholine from postganglionic neurons
30
Q

explain: adrenergic receptors

A
  • for norepinephrine
  • 2 classes
    1. alpha (A1 and A2)
    2. beta (B1 and B2)
  • depend on receptor and tissue
31
Q

explain: regulation of ANS

A
  • homeostasis
  • autonomic reflexes
  • baroreceptors
32
Q

name: generalizations about ANS (generalized/localized effect, rest vs activity)

A
  • generalized = sympathetic
  • localized = parasympathetic
  • rest = parasympathetic
  • activity = sympathetic