Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Z -Biol 151 > Muscular System > Flashcards

Muscular System Flashcards

1
Q

activation gates

A

closed at rest; open with depolarization, allowing Na+ to enter cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

inactivation gates

A

open at rest; block channel once it is open to prevent more Na+ from entering cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

excitation-contraction coupling

A
  • AP from motor end plate to t-tubules to sarcoplasm
  • AP stimulate voltage gates open; linked to Ca channels in terminal cisternae (SR)
  • Ca is released and diffuse out of cytoplasm
  • Ca bind to troponin, cause troponin-tropomyosin to change shape and rest on actin
  • actin activation sites now available to bind to myosin heads and contract
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

cross bridge movement

A

attach: lose P and ADP attaches to myosin head to actin

power stroke: myosin head attached to actin stroke forward from preexisting energy in the heads

release: ATP arrives and removes the myosin head from the actin

recovery: ATP broken into ADP and P; energy released stored in myosin heads

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

relaxation

A
  • Ca back into sarcoplasmic reticulum via active transport (pay w ATP)
  • use ATP to move Ca from troponin-tropomyosin complex
  • troponin-tropomyosin complex reestablishes position and block binding sites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

muscle twitch

A

Muscle contraction in response to a stimulus that causes action potential in one or more muscle fibers
-lag/latent phase
- contraction phase
- relaxation phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

lag (latent) phase

A
  • AP arrive at presynaptic terminal and causes its permeability to increase
  • Ca diffuse in and sends ACh vesicles across synaptic cleft to be received by ACh receptor molecules
    -ACh binding to receptor = open Na ligand channels
  • Na diffuse in > depolarize > conduct AP
  • acetylcholinestrease is working and causes presynaptic AP to cause postsynaptic AP
  • AP in t tubules allows Ca in from SR to sarcoplasm
  • Ca bind to troponin > change shape of troponin-tropomyosin complex > expose actin active sites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

contraction phase

A

cross bridge formation and filament movement (attach, power stroke, release, recovery)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

relaxation phase

A
  • Ca actively transported from sarcoplasm to SR
  • troponin-tropomyosin complex inhibits against cross bridge formation
  • muscle fibers lengthen passively
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

titan

A

a protein the length of a sarcomere that allows muscle fiber to rebound to normal length after being stretched/compressed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

contraction of whole muscle

A
  • Strength of contraction is graded: ranges from weak to strong depending on stimulus strength
  • multiple motor unit summation: strength of contraction depends on recruitment of motor units
    (submaximal stimulus, maximal stimulus, supramaximal stimulus)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

multiple wave summation

A

muscle tension increases as contraction frequencies increase
- incomplete tetanus: muscle fibers relax btwn contractions
- complete tetanus: no relax btwn contractions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

treppe

A

each successive twitch contracts more forcefully than the previous one until all equal after a few stimuli
- occurs in long rested muscle
- Ca in sarcoplasm and not SR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

isometric contraction

A

Muscle contracts but there is no movement, muscle stays the same length (“same” “length”)
- push/pull and hold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

isotonic contraction

A

change in muscle fiber length but tension is constant (“same” “tension”)
- concentric: overcome opposing resistance, muscle shortens
- eccentric: tension maintained but muscle lengthens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

muscle tone

A

the state of balanced muscle tension that makes normal posture, coordination, and movement possible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

multiple wave summation

A

muscle tension increases as contraction frequencies increase
- incomplete tetanus: muscle fibers relax btwn contractions
- complete tetanus: no relax btwn contractions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Tetanus

A

Muscle contractions in smooth/organized way up until complete contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

treppe

A

each successive twitch contracts more forcefully than the previous one until all equal after a few stimuli
- occurs in long rested muscle
- Ca in sarcoplasm and not SR

20
Q

isometric contraction

A

Muscle contracts but there is no movement, muscle stays the same length (“same” “length”)
- push/pull and hold
- postural muscles

21
Q

isotonic contraction

A

no change in length but muscle increases (postural muscles), stays the same

22
Q

muscle tone

A
  • Isotonic: change in length but tension constant, same tone
  • Concentric: overcome opposing resistance and muscle shortens
  • Eccentric: tension maintain but muscle lengthens
23
Q

Muscle Tone

A

Constant tension by muscles for long periods of time (full motor unit recruitment)

24
Q

active tension

A

force applied to an object to be lifted when a muscle contracts
- actively move weight (bicep curl)

25
passive tension
tension applied to load when a muscle is stretched but not stimulated - pick up and hold weight (before action)
26
Total Tension
Sum of active and passive tension
27
Fatigue
decreased capacity to work; reduced performance efficiency - psychological: depends on each person - muscular: ATP depletion - synaptic: not enough ACh in NMJ
28
Physiological contracture
State of fatigue where due to lack of ATP neither contraction nor relaxation can occur - muscles cannot relax and stay contracted as not enough ATP is there to remove myosin head
29
Energy Sources
ATP made from: - creatine phosphate: resting condt stores to make ATP - anaerobic respiration: w/o oxygen break glucose down into lactic acid and ATP - aerobic respiration: w oxygen, break glucose into ATP, CO, H2O -oxygen debt
30
Slow twitch fibers
high-oxidative -Lots of mitochondria -Myoglobin stores oxygen in muscles (lots) -Endurance > power -Contract slowly -Lots of blood supply (lots of capillaries) -high aerobic capacity -Postural muscles - small fiber diameter
31
Intermediate Twitch Fibers
- intermediate fiber diameter - medium myoglobin, mitochondria, capillaries, and aerobic capacity - high anaerobic capacity - lower body - endurance activities - traits of both fast and slow twitch fibers
32
fast twitch fibers
low-oxidative - largest fiber diameter - Contractile phase is fast; contract rapid -Low myoglobin and low/fewer mitochondria -Fatigue quickly -Upper limbs for most people - low aerobic capacity - highest anaerobic capacity - fasted ARP breakdown - few capillaries
33
Hypertrophy
increase in: - muscles size - myofibrils - nuclei due to fusion of satellite cells - strength (better coordination) - production of metabolic enzymes - circulation - less restriction by fat
34
Atrophy
decrease in muscle size reverse of Hypertrophy except in severe situations cells die
35
Smooth muscle
-Not striated; small muscle fibers -Spindle shaped; single and central nucleus (not produce a lot of ATP) -no z disks -more actin and less myosin -Dense bodies are the z disk of smooth muscle; noncontractile intermediate filaments
36
Relaxation of Smooth muscle
is caused by enzyme myosin phosphatase (take P of myosin head so smooth muscle can relax)
37
Caveolae
indentations in sarcolemma; act similar to t tubule; electrical signal enter here Ca makes contractions; bind to calmodulin to regulate myosin kinase
38
smooth muscle contraction
- Hormones create action potentials - attach to G-protein + Alpha unit - Alpha unit changes GTP to GDP - Alpha unit w/ GTP opens Ca2+ channel + Ca2+ enters - Ca2+ breaks to Calmodulin - Calmodulin excites myosin kinase - myosin kinase dephosph ATP - P goes to myosin head Myosin phosphatase remove P from myosin so the muscle can relax
39
visceral smooth muscle
-Cells in sheets; function as unit -Digestive system ; respiratory tracts -Work as group with lots of gap junctions -All fire together (autorhythmic)
40
Multiunit smooth muscle
cells or groups of cells act as independent units -Blood vessels (sheets) -Arrector pili or iris (bundles) -Capsule of spleen (single cells) -Partial contractions (autorhythmic)
41
electrical properties of smooth muscle
- not all or none - -60mV (reduced amplitude) - Slow waves of depolarization and repolarization from cell to cell -Depolarization = spontaneous diffusion of Na+ and Ca2+ into cell (none gated leakage channels) -Does not follow all-or-none law -May have pacemaker cells (spontaneous action potential) -Contraction regulated by ANS and by hormones
42
cardiac and skeletal APs
- both have rapid depolarization - both have all-or-none principle skeletal: 2miliseconds long cardiac: 500ms long - slow dispersal of CO2+ to bring it back into repolarization = long plateau phase = causes larger action potential
43
smooth muscle functional properties
- Some visceral muscle show autorhythmic contractions -Tends to contract in response to sudden stretch but not to slow increase in length - constant tension (can maintain contraction for extended amount of period because not all-or-none)
44
smooth muscle regulation
*Innervated by ANS *Neurotransmitters are acetylcholine and norepinephrine *Hormones important are epinephrine and oxytocin *Receptors present on plasma membrane which neurotransmitters or hormones bind determines response
45
cardiac muscle
* Found only in the heart and is striated with one nucleus *Has intercalated disks and gap junctions (can excite adjacent cells) *Autorhythmic cells *Action potentials of longer duration and longer refractory period (500ms) *Ca2+ regulates contraction

Z -Biol 151 (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions