exam review - quiz 6 Flashcards
(32 cards)
1
Q
name: types of propagation (2)
A
- unmyelinated axon
- continuous conduction
- AP at one spot + propagate by stim. adjacent regions
- AP in 1 direction only - myelinated axons
- saltatory conduction
- voltage gated Na+ channels at nodes
- faster AP flow
2
Q
explain: continuous conduction
A
- unmyelinated axon
- mvt. of ions = local current
- only one direction because absolute refractory period desensitizes region
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
4
Q
name: factors affecting propagation speed (3)
A
- axon diameter
- more SA = more voltage gated Na+ channels = faster local current = faster propagation - amount of myelination
- heavy > lighter - temperature
- cool - slower
⤷ bc channels = prot. and prot. affected by temp.
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
6
Q
define: synapse
A
- junction between cells that allow comm.
- 2 types = elec. and chem.
7
Q
explain: electrical synapse
A
- junction between 2 cells
- important for coordinated conditions
⤷ ex. cardiac musc., smooth musc.
-
8
Q
explain: chemical synapse
A
- AP arrives at presyn. term. causing voltage gated Ca2+ channels to open 2. Ca2+ diffuses into cell stimulating exocytosis of synaptic vesicles
⤷ releases neurotransmitter - neurotransmitter diffuses from presynaptic term across synaptic cleft
- neurotransmitters combine w/ receptor sites causing ligand gated Na+ channels to open
- Na+ diffuses into cell and depol.
- no direct transfer of ATP
⤷ relies on neurotransmitters
9
Q
explain: methods of removal of neurotransmitters (3)
A
- diffusion
- down conc. gradient - enz. degradation
- acetylcholine
- acetylcholinesterase = receptor
⤷ breaks down acetylcholine into acetic A and choline - 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
10
Q
explain: types of postsynaptic potentials (2)
A
- excitatory postsynaptic potential (EPSP)
- depol.
- may reach threshold to prod. AP - 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
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
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
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
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
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
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
- cervical plexus = C1 - C4
- innervates superficial neck structures, skin of neck, posterior part of head
- phrenic nerve = C3 - C5, innervates diaphragm (important for breathing) - brachial plexus = C5 - T1
- 3 trunks, 6 divisions, 3 cords, 5 branches
- nerves: axillary, radial, musculocutaneous, ulnar, median
- supplies shoulders and upper limbs - lumbar plexus = L1 - L4
- 2 major nerves = obturator and femoral
- supplies part of lower limbs - sacral plexus = L4 = S4
- 2 major nerves = tibial and common fibular
- bind to become sciatic nerve
- supplies large portion of lower limbs - 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
- cell body in CNS
⤷ motor nuclei for cran. nerves
⤷ anterior horn of spinal cord - skeletal muscle
⤷ target tissue
22
Q
explain: pathway of AP in autonomic motor system
A
- 2 neuron system
- preganglionic neuron (always myelinated)
⤷ cell body in CNS
⤷ autonomic nuclei of cran. nerves
⤷ lateral horn of spinal cord) - postganglionic neuron (always unmyelinated)
⤷ from synapse to target tissue
23
Q
name: divisions of autonomic motor nervous system from PNS (2.5)
A
- sympathetic
- parasympathetic
- both innervate most organs (dual innervation -> opposing effects) - 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
- neurons exit lateral horn via ventral root
- join at spinal nerve
- enter at sympathetic ganglia (chain/trunk)
- can take several paths after
⤷ synapse at same level
⤷ move through to collateral and synapse there
⤷ travel up or down chain/trunk ganglia
25
explain: routes of sympathetic axons (4)
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
explain: parasympathetic NS
- craniosacral division
- cran. nerves 3, 7, 9, 10
- S2 - S4
- reaches pelvis splanchnic nerves (smooth muscles + glands of colon, bladder, rep. organs)
27
explain: mneumonics for PNS and SNS
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
name: which neurotransmitters are cholinergic and adrenergic in ANS + which neurons are cholinergic and adrenergic in SNS and PNS
ANS neurotransmitters
- acetylcholine = cholinergic
- norepinephrine = adrenergic
SNS neurons
- preganglionic = cholinergic
- postganglionic = adrenergic
PNS neurons
- preganglionic = cholinergic
- postganglionic = cholinergic
29
explain: cholinergic receptors
- for acetylcholine
- 2 classes
1. nicotinic = excitatory, open Na+
⤷ on postganglionic neurons in autonomic ganglia, muscles, cell membrane
2. muscarinic = excitatory or inhibitory, triggers G-protein signaling pathway
⤷ on effector cells that respond to acetylcholine from postganglionic neurons
30
explain: adrenergic receptors
- for norepinephrine
- 2 classes
1. alpha (A1 and A2)
2. beta (B1 and B2)
- depend on receptor and tissue
31
explain: regulation of ANS
- homeostasis
- autonomic reflexes
- baroreceptors
32
name: generalizations about ANS (generalized/localized effect, rest vs activity)
- generalized = sympathetic
- localized = parasympathetic
- rest = parasympathetic
- activity = sympathetic
