FINAL EXAM: Unit 3 Flashcards
describe the structure of sympathetic neurons in the autonomic NS. what do they release? where are they located on the spine?
thoracic & lumbar region
-pregang: short, release ACh (N(N), nico)
-autonomic gang: close to SC
-postgang: long, release NE (alpha, beta)
describe the structure of parasympathetic neurons in the autonomic NS. what do they release? where are they located on the spine?
brainstem & sacral
-pregang: long release ACh (N(N), nico)
-autonomic gang: close to effector
-postgang: short, release ACh (musc)
what is the neuroeffector junction? what is the pathway at the neuroeffector junction?
synapse b/w postgang & effector, end in varicosities
1. AP reaches varicosity
2. depolarization
3. Ca2+ release
4. exocytosis
5. NT release
6. postsynapse
what is special about the neurons in the adrenal medulla?
lacks axons, no postganglia
what breaks down NE? what breaks down ACh?
MAO: breaks down NE
acetylcholinesterase: breaks down ACh
what is a direct agonist/antagonist?
mimic/block NT action
what is an indirect agonist/antagonist?
alters secretion, reuptake, or degradation of NT
describe the neurons in the somatic NS
only 1 neuron b/w CNS and effector
-skeletal muscle
what is the neuromuscular junction? what is the pathway at the neuromuscular junction?
synapse b/w motor neuron & muscle
1. AP reaches terminal
2. depolarization
3. Ca2+ entry
4. ACh release
5. binds N(M) receptor
6. net Na+ entry
7. depolarization
8. AP causes muscle contraction
what is the hearts sympathetic NS receptor and effect? parasympathetic receptor and effect?
SYMP: beta 1 -> increased HR
PARASYMP: musc -> decreased HR
what is the blood vessels sympathetic NS receptor and effect? parasympathetic receptor and effect?
SYMP: alpha -> constrict, beta -> dilate
PARASYMP: NONE
what is the bronchioles sympathetic NS receptor and effect? parasympathetic receptor and effect?
SYMP: beta 2 -> dilation
PARASYMP: musc -> constrict
what is the GI tracts sympathetic NS receptor and effect? parasympathetic receptor and effect?
SYMP: alpha 2 -> decrease motility & secretions
PARASYMP: musc -> increase motility & secretions
what is the bladders sympathetic NS receptor and effect? parasympathetic receptor and effect?
SYMP: alpha 1 -> relax (retention)
PARASYMP: musc -> contract (empty)
what is the pupils sympathetic NS receptor and effect? parasympathetic receptor and effect?
SYMP: alpha 1 -> dilate
PARASYMP: musc -> contract
what is the cilliary muscles sympathetic NS receptor and effect? parasympathetic receptor and effect?
SYMP: alpha 1 -> relax (flat lens)
PARASYMP: musc -> contract (round lens)
what is the sweat glands sympathetic NS receptor and effect? parasympathetic receptor and effect?
SYMP: alpha 1 -> increase secretion
PARASYMP: NONE
what is the adipose tissue sympathetic NS receptor and effect? parasympathetic receptor and effect?
SYMP: alpha -> breakdown
PARASYMP: NONE
what is the adrenal medullas sympathetic NS receptor and effect? parasympathetic receptor and effect?
SYMP: no receptor -> secrete E
PARASYMP: NONE
what is insulins sympathetic NS receptor and effect? parasympathetic receptor and effect?
SYMP: alpha 2 -> decrease secretion
PARASYMP: musc -> increase secretion
what is the genitals sympathetic NS receptor and effect? parasympathetic receptor and effect?
SYMP: alpha 1 -> orgasm
PARASYMP: musc -> erection
what are the two fibers in a sarcomere?
myosin: thick, heavy & light chains, ATPase activity
actin: thin, troponin & tropomyosin
what is the Z-disk?
attachment for actin
what is the I-band?
length of ONLY actin, spans into next sarcomere
what is the A band?
entire length of myosin
what is the H zone?
in the middle, length of ONLY myosin
what is the M line?
MIDDLE, myosin attachment site
what is titin?
elastic, stabilizes contractile fibers
what is nebulin?
inelastic, stabilizes actin
what is the process of muscle contraction during the neuromuscular junction phase?
- AP reaches motor neuron
- Ca2+ entry
- exocytosis
- ACh release
- binds nicotinic receptors
- net Na+ entry
what is the process of muscle contraction during the excitation-contraction coupling phase?
- AP reaches T-tubule
- activates DHP receptor -> Ca2+ release
- SR opens RyR channels -> Ca2+ release
- troponin
- tropomyosin moves off myosin binding site
- powerstroke
what is the process of muscle contraction during the powerstroke?
- myosin binds to actin
- ATP binds
- myosin releases
- myosin head cocks
- Ca2+ activates myosin’s powerstroke
- Pi released
- ADP released
- myosin back to rigor state
what is the process of muscle contraction during the contration-relaxation cycle?
- crossbridge forms
- I and H bands shorten
- sarcomere overall shortens and contracts
- Ca2+ ATPase pumps Ca2+ back into SR
- tropomyosin binds to myosin binding site
- ACh degraded
what are the three ways ATP is supplied?
phosphocreatine: fastest, donates a phosphate
oxidative phosphorylation: makes the most
anaerobic glycolysis: when O2 is low
what is the difference b/w central and peripheral fatigue?
central: psychological
peripheral: physiological
what are the three types of muscle fibers? what are examples of movements associated with each?
slow-twitch (Type 1): posture
fast-twitch oxidative-glycolytic (Type 2A): standing, walking
fast-twitch glycolytic (Type 2X): jumping, sprinting
which of the fiber types are fatigue resistant?
Type 1 & 2A
which of the fiber types use aerobic? which are anaerobic?
aerobic: Type 1 & 2A
anaerobic: Type 2A & 2X
which fiber type has the highest level of capillaries, mitochondria, and myoglobin?
Type 1
what does it mean when there are more fast motor units? what about more slow motor units?
fast units: more tension
slow units: less tension, endurance
describe the motor units for fine movement
more units
less fibers per neuron
more tension
describe the motor units for gross movement
less units
more fibers per neuron
less tension
what is the difference between isotonic and isometric contractions?
isotonic: force and movement
isometric: force w/o movement
what is the difference between concentric and eccentric movements?
concentric: muscle shortens, flexing
eccentric: muscle lengthens, extending
which of the three muscle types (skeletal, smooth, cardiac) are striated?
skeletal & cardiac
which of the three muscle types (skeletal, smooth, cardiac) has no sarcomeres, t-tubules, or troponin?
smooth
which of the three muscle types (skeletal, smooth, cardiac) gets its Ca2+ from the ECF & SR?
smooth & cardiac
-skeletal gets Ca2+ from just the SR
which of the three muscle types (skeletal, smooth, cardiac) is controlled by the autonomic NS?
smooth & cardiac
-skeletal controlled by somatic NS
describe the contraction pathway for smooth muscle
- Ca2+ entry from ECF
- Ca2+ entry from SR
- Ca2+ binds calmodulin
- activates myosin light chain kinase
- phosphorylation of myosin light chains
- cross-bridge and powerstroke
- contraction
describe the relaxation for smooth muscle
- Ca2+ ATPase pumps Ca2+ into ECF & SR
- dephosphorylation of myosin light chains
what triggers the SR to release Ca2+?
Ca2+ induced (due to ECF Ca2+ release)
IP3 mediated
what triggers ECF Ca2+ release?
Ca2+ channels (voltage, ligand, stretch)
what does histamine and NO do to smooth muscle?
histamine: contract
NO: relax
what are muscle spindles?
respond to stretch
-contain intrafusal fibers
-ENDs: contractile, efferent signals, gamma motor neurons
-MIDDLE: noncontractile, afferent signals, alpha motor neurons
what is the stretch reflex pathway?
- stretch in extrafusal fibers
- detected by muscle spindle
- afferent signal to SC
- alpha neuron goes to extrafusal fibers to contract extensor
- gamma neuron goes to muscle spindle to contract in proportion
what is reciprocal inhibition pathway?
- tap tendon -> spindle -> afferent to SC
- alpha neuron contracts quad (monosynaptic)
- inhibitory alpha neuron relaxes hamstring (polysynaptic)
what is the flexion reflex pathway?
- pain on RIGHT side of body -> spindle -> afferent to SC
- alpha neuron contracts RIGHT flexor
- inhibitory alpha neuron relaxes RIGHT extensor
- alpha neuron contract LEFT extensor
- inhibitory alpha neuron relaxes LEFT flexor
describe the three types of movement (reflex, voluntary, rhythmic)
reflex: external stimuli, integrated in SC
voluntary: external stimuli & will, cerebral cortex
rhythmic: will, SC & cerebral cortex
what does the spinal cord do for movement? what part of movement is it responsible for?
spinal reflexes, CPGs (maintain movement after initation), cross over in corticospinal tract
-executing movement
what does the brainstem do for movement? what part of movement is it responsible for?
posture, hand & eye movements
-executing movement
what does the cerebral cortex do for movement? what part of movement is it responsible for?
planning & coordinating voluntary movement, senses
-decision-making & planning, initiating movement
what does the cerebellum do for movement? what part of movement is it responsible for?
adjusts voluntary movement & monitors, balance
-decision-making & planning, executing movement
what does the thalamus do for movement?
relay station for cerebral cortex
what does the basal ganglia do for movement? what part of movement is it responsible for?
motor planning & feedback to thalamus, releases DA
-decision-making & planning
describe the corticospinal tract pathway
- descending tract
- brainstem
- cross over in medulla pyramids
- alpha motor neurons
- SC
