1-6 Muscle Physiology Flashcards
A: _______ and _______ muscle are both STRIATED but _______ is a Single-Unit while _______ is Multi-Unit.
B: Single-Unit = Functional _______ & _______
C: _______ muscle which is Multi-Unit requires Motor Nerve innervation
D: _______ muscle can be either Single-Unit OR Multi-Unit
E: 3 Functions of Muscle
A: Cardiac and Skeletal muscle are both STRIATED but Cardiac is a Single-Unit while Skeletal is Multi-Unit.
B: Single-Unit = Functional Synchrony & Automaticity
C: Skeletal muscle which is Multi-Unit requires Motor Nerve innervation
D: SMOOTH muscle can be either Single-Unit OR Multi-Unit
E: Functions of Muscle
- Motion
- Posture
- Heat
What are the 7 Layers of Muscle [Superficial—-> DEEP] ending with [Myofiber Muscle Cells]
B: [Myofiber Muscle Cell] EACH have _______ NERVE ENDING! and contain _______ membrane, _______ and _______
C: Muscle is made of _______, which each contain [Myofiber Muscle cells]. Each [Myofiber Muscle cell] contains _______ which has the Sarcomere in it. Arrangement of _______ in the Sarcomere give muscle STRIATED appearance!
Layers of a Muscle [Superficial—-> DEEP]
1st: Periosteum covering Bone
2nd: Tendon
3rd: ACTUAL SKELETAL MUSCLE
4th: EPImysium
5th: Perimysium
6th: Endomysium
7th: [Myofiber Muscle Cell]
B: [Myofiber Muscle Cell] EACH have ONE NERVE ENDING! and contain Sarcolemma membrane, Sarcoplasm and Myofibrils
C: Muscle is made of Fascicles, which each contain [Myofiber Muscle cells]. Each [Myofiber Muscle cell] contains Myofibrils which has the Sarcomere in it. Arrangement of myofilaments in the Sarcomere give muscle STRIATED appearance!
1.Myofibrils are made of __#__ repeating ⬜ , which itself contain ⬜ and ⬜
Connective tissue sheaths of muscle
2.Endomysium surrounds ⬜ and contain ⬜
3.Perimysium surrounds ⬜ and contains ⬜ and ⬜
4.EPI, Peri and Endomysium all come together = ⬜
- Myofibrils are made of 50 repeating Sarcomeres, which Sarcomeres itself contain [Myofilaments: Myosin & Actin]
- *Connective tissue sheaths of muscle**
2. Endomysium surrounds individual [Myofiber Muscle Cells] and contain Capillaries
- Perimysium surrounds fascicle and contains blood vessels and Nerves
- EPI, Peri and Endomysium all come together = TENDON
A: Sarcomeres boundaries are from _______ to _______
B: [Dark A-Band] contains MOSTLY _______ (and some _______) and are anchored by the _______
vs.
C: [liight ii-Band] contains ONLY _______ and is anchored by the _______
D: The ___-line is what’s connected to Collage ECM
E: Actin has a _______ structure that contains _______ USED only in Skeletal muscle and OFTEN causes ALLERGIC RXNS!
A: Sarcomeres boundaries are from Z-line to Z-line
B: [Dark A-Band] contains the [Myosin Thick filaments] (and some actin thin filaments) and are anchored by the M-Line.
vs.
C: [liight ii-Band] contains ONLY [actin thin filaments] and is anchored by the Z-liine.
D: The Z-liiine is what’s connected to Collagen ECM
E: Actin has a helical structure that contains Tropomyosin which is USED only in Skeletal muscle and OFTEN causes ALLERGIC RXNS!
A: _______ filaments BINDS to _______ & has ATPase activity via its _______ head. Although there are TWO Globular heads only 1 attaches to _______ via _______ _______
B: Each pair of heads is oriented ___º from the next pair which will give _______filaments 3-D Coverage
A: [Myosin Thick filaments] BINDS Actin & has ATPase activity via its Globular head. Although there are TWO Globular heads only 1 attaches to Actin via cross bridges
B: Each pair of heads is oriented 120º from the next pair —>gives [Myosin Thick filaments] a 3-D Coverage
A: Describe Actin
B: Name the 3 Major components of Actin
C: There is ONE _______ and _______ per every 7
[G-Actin monomers]
D:
How does Myosin bind to Actin if Actin is “protected”?
On the ⬜ , Ca+ binds to ⬜ which moves ⬜ into the [ ⬜ groove ]. This exposes the Myosin binding site on ⬜ so Myosin can bind for contraction!
A: F-actin is a double stranded helix made of many G-actin monomers!
_________________
B: Actin is made of 3 protein groups:
1. [F-actin itself (double stranded helix made of many G-actin monomers)]
2. [Tropomyosin band
- [Troponin TIC Group]
T-Tropomyosin⼀bound
/I- Inhibitory
/C- calcium⼀binding
_________________
C:There is ONE [Tropomyosin band] and ONE [Troponin Group] per every 7 [G-Actin monomers]
_________________
D:
On the [G-actin monomers], Ca+ binds to [Troponin-C] which moves [Troponin-T ( bound to [Tropomyosin band])] into the [actin groove] = consequently moving [Tropomyosin band] out of the myosin-binding groove on [G-actin monomers]. = This exposes the Myosin binding site on [G-actin monomers] so Myosin can Bind for contraction!
[T or F]
All Muscles and Animals contain T-tubules for Action Potential relay
FALSE!
NOT ALL MUSCLES in humans or ANIMALS in general have T-tubules
A: T-tubules are “ditches” inside _______ that dive into muscle _______ and conduct _______ _______. They are located close to _______ _______
B: Dihydropyridine Receptors (DHPR) are ON _______ and (in SKELETAL Muscle), ONLY acts as _______ Sensor for when _______ _______ occurs. _______ _______ causes DHPR conformational change —> activates _______
C: [Sarcoplasmic Reticulum] are _____ muscle ER that store ___ ! [_______ receptors] are ON the SR and when stimulated by _____..releases ___ from SR
D: Muscle doesn’t relax until ___+ is PUMPED BACK INTO SR by ____ and _______ is present to break myosin/actin bond
D: When 1 T-tubule associates with 2 adjacent sacs of SR = _______ _______
A: T-tubules are “ditches” inside Sarcolemma that dive into muscle fibers and conduct ACTION POTENTIALS. They are located close to [Sarcoplasmic Reticulum].
B: Dihydropyridine Receptors (DHPR) are ON T-tubules and ,in Skeletal Muscle, ONLY acts as Voltage Sensor for when AP occurs. AP causes DHPR conformational change —> activates [Ryanodine receptors (RyR)]
C: [Sarcoplasmic Reticulum] are (smooth muscle ER) that store Ca+! [Ryanodine receptors (RyR)] are ON the SR and when stimulated by DHPR..it releases Ca+ from SR
D: Muscle doesn’t relax until Ca+ is PUMPED BACK INTO SR by SERCA and ATP is present to break myosin/actin bond
D: When 1 T-tubule associates with 2 adjacent sacs of SR = Muscle Triad
A: What does SERCA stand for?
B: What does it do?
SERCA (Sarcoplasm Endoplasmic Reticulum Ca+ ATPase) is the Sarcomere pump that PUMPS Ca+ BACK INTO the SR to restore Ca+ gradient
A: Explain How Nerve Impulses get to the Sarcolemma of muscle Cells
*When _______ arrives at end bulb—> _______ is released and diffuses ACROSS the _______ to interact with [_______ _______ receptors] of muscle cell—>this INC ___+ membrane permeability —> ___+ diffuses INTO cell and _____[INC/DEC] [Resting membrane potential] to eventually cause _______ _______. This now will travel down _______ of Sarcolemma
B: Released ACh needs to be quickly hydrolyzed into _______ & _______. This is Done by enzyme [_______ Cholinesterase].
B2: How is this enzyme involved with Biowarfare?
C: The [NICOTINIC ACh receptor] is made of [__ alpha], [__ beta], [__ gamma] and [__ sigma] subunits
D. ___+ is the link between AP Excitation and Muscle Contraction
A: Impulse arrives at end bulb—>ACh is released and diffuses ACROSS cleft to interact with [NICOTINIC ACh receptors] of muscle cell—>this INC Na+ membrane permeability —> Na+ diffuses INTO cell and INC [Resting membrane potential] to eventually cause ACTION POTENTIAL—>travels down T-tubule of Sarcolemma
B: Released ACh needs to be very quickly hydrolyzed into choline & acetate. Done by [Acetyl Cholinesterase].
B2: This enzyme is often bound and inhibited by Serun Gas
C: The [NICOTINIC ACh receptor] is made of [2 alpha], [1 beta], [1 gamma] and [1 sigma] subunits
D. Ca+ is the link between AP Excitation and Muscle Contraction
SLIDING FILAMENT CROSS-BRIDGE Cycle
1. Free Energy from ___ cleavage induces _____ head to bend from __º—>___º and bind to _______
2.___ and ___ release causes actual shift and _______ filaments slide toward __-zone pulling ___ lines inward
- ## ____-binding allows myosin to RELEASE _______ so it can resent on another _______B: Cross-bridging in muscles is NOT _______ for each sarcomere and happens in _______!
SLIDING FILAMENT CROSS-BRIDGE Cycle
1. Free Energy from ATP cleavage induces myosin head to bend from 90º—>45º and bind to G-actin monomer
- ADP + Pi release causes actual shift and Actin filaments slide toward H-zone pulling Z lines inward
- ATP-binding allows myosin to RELEASE G-actin monomer so it can reset on another monomer
B: Cross-bridging in muscles is NOT SYNCHRONOUS for each sarcomere and happens in Waves!
4 ways to regulate Muscle Contraction Strength
1. Twitch Summation
2. Recruitment of more motor units
3. Muscle Fiber THICKNESS
4. Length of fiber at Contraction onset (length-tension relationship)
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Describe Twitch Summation
A: Twitch Summation occurs when Multiple _______ _______ fire during a single muscle twitch—> Each _______ releases more __+—->More ___+ makes more G-actin binding sites available for _______!
B:This ALL will eventually lead to _______ until Stimulation ceases or _______ begins
C: Caffeine & Adrenaline causes _______ in the heart —-> INC strength of Heart Contraction
D: Skeletal muscle twitch is ____ or _______ and can only be combined with other twitch (AKA _______) ….UNLIKE Heart muscle which can be _______
4 ways to regulate Muscle Contraction Strength
- Twitch Summation
- Recruitment of more motor units
- Muscle Fiber THICKNESS
- Length of fiber at Contraction onset (length-tension relationship)
- ————————————————————————————
A: Twitch Summation occurs when Multiple ACTION POTENTIALS fire during a single muscle twitch—>Each AP releases more Ca+—->More Ca+ makes more G-actin binding sites available for cross-bridging!
B:This will eventually lead to Tetanus until Stimulation ceases or fatigue begins
C: Caffeine & Adrenaline causes [Ca+ induced Ca+ release] in the heart —-> INC strength of Heart Contraction
D: Skeletal muscle twitch is ALL OR NOTHING and can only be combined with other twitch (AKA Summation) ….UNLIKE Heart muscle which can be modulated
A: What is a Motor Unit?
B: Explain why Muscle Fiber THICKNESS modulates Muscle Contraction Strength
C: What are the 4 ways to regulate Muscle Contraction Strength?
C: 4 ways to regulate Muscle Contraction Strength
1. Twitch Summation
2. Recruitment of more motor units
3. Muscle Fiber THICKNESS
4. Length of fiber at Contraction onset (length-tension relationship)
————————————————————————————–
A: [group of muscle fibers] all innervated by 1 Lower Motor Neuron
B: Muscle Fiber THICKNESS matters because more sarcomeres in parallel ADD FORCE!
4 ways to regulate Muscle Contraction Strength
1. Twitch Summation
2. Recruitment of more motor units
3. Muscle Fiber THICKNESS
4. Length of fiber at Contraction onset (length-tension relationship)
————————————————————————————–
Describe [Length of fiber at contraction onset]
A: If Sarcomere is too short = _______ _______ occurs
vs.
If Sarcomere is tooooooo Loooonng = _______ = ___[INC/DEC] in force
B: What is the Caveat to [Length of fiber at Contraction onset]?
C: Power = _______ x _______
4 ways to regulate Muscle Contraction Strength
1. Twitch Summation
2. Recruitment of more motor units
3. Muscle Fiber THICKNESS
4. Length of fiber at Contraction onset (length-tension relationship)
————————————————————————————–
A: If Sarcomere is too short = steric hindrance
vs.
If Sarcomere is tooooooo Loooonng = not enough [myosin-actin cross bridges] will overlap = DEC in force
B: Caveat: [Length of fiber at Contraction onset] can only modulate Contraction strength in HEART since Skeletal muscle is ALL OR NOTHING contraction event
C: Power = Force x Velocity
4 Types of Muscle Contractions
A:
Concentric contractions = muscle actively _______
vs.
ECCENtric contractions = MUSCLE ACTIVELY _______
————————————————————————————–
B: ECCENtric contractions are physiologically common, has the _______[Most/Least] muscle Force, can ___[INC/DEC] muscle strength but are associated with _______ _______
B2: List 3 Signs of [muscle injury]
C: What is Isometric Contraction?
————————————————————————————–
D: Passive Stretch = muscle PASSIVELY _______ usually as a result of the _______, found in muscle fibers to attach _______ to Z-lines
4 Types of Muscle Contractions
A:concentric contractions = muscle actively shortening
vs.
ECCENtric contractions = MUSCLE ACTIVELY LENGTHENING
————————————————————————————–
B: ECCENtric contractions are physiologically common, has the MOST muscle Force, can INC muscle strength but are associated with [muscle injury]
B2: Signs of [muscle injury]
ºZ-disk misalignment
ºCytoskeletal Desmin protein loss
ºElevated Serum Creatine Kinase
————————————————————————————–
C: Isometric Contraction = isotonic Muscle actively held at fixed length with gradually INC force
————————————————————————————–
D: Passive Stretch = muscle PASSIVELY lengthening usually as a result of the Giant Protein “Titin”, found in muscle fibers to attach [Myosin Thick] to Z-lines
A:
- Smooth Muscle does NOT have _______
- Smooth Muscle Sarcolemma contains [_______] = Gap Junctions for _______ _______—>USED IN SMOOTH MUSCLE _______ UNITS
B: How does Cross-bridge contractions occur in Smooth Muscle??
Smooth Muscle \______ \______ occurs—-> \_______gated Ca+ channels Open—>Ca+ INC and binds to _______ —->[Ca+-_______] go to activate * _______*
–>phosphorylates Myosin, and with outer addition of _______, enables Cross-bridge Tension!
C: How does Smooth Muscle Relax?
{D:Name 3 Other ways Ca+ enters smooth muscle }
E: _______ Tone VARIES in different smooth muscle types
A:
- Smooth Muscle does NOT have T-Tubules
- Smooth Muscle Sarcolemma contains [Caveolae] = Gap Junctions for electrical coupling—>USED IN SMOOTH MUSCLE SINGLE UNITS
B: Smooth Muscle ACTION POTENTIAL occurs—->Voltage-gated Ca+ channels Open—>Ca+ INC and binds to Calmodulin —->[Ca+-Calmodulin] go to activate MLCK [myosin-light chain kinase]—>phosphorylates Myosin, and with outer addition of ATP, enables Cross-bridge Tension!
C: Smooth Muscle is Relaxxed when [myosin-light-chain phosphatase] REMOVES phosphate from Myosin
{D: Other ways Ca+ enters smooth muscle }
- Ligand-gated Ca+ channel w/ hormone
- [IP3-gated Ca+ Channel] w/hormone
- Sarcoplasmic Reticulum
E: Basal Tone VARIES in different smooth muscle types
SMOOTH MUSCLE PATHWAYS that DON’T require membrane depolarization
- Hormone receptor stimulation —> IP3 formation –> causes release of __+ from _______
- Hormone receptor stimulation—>cAMP formation —> stimulates PKA to 1)phosphorylate _______ and DEC its ___+ sensitivity and 2) INC _______ _______ __+ RETURN pumping
- Hormone receptor stimulation—>cGMP formation —> stimulates _____ _______—>REMOVES _______ from Myosin = Relaxation of Smooth Muscle
- ## Caffeine & Viagra can _______ the rate of cAMP or cGMP breakdown—>constant smooth muscle _______B: Nitric Oxide in vascular smooth muscle is released by _______ cells in response to _______ and illicits _______. _______ plays a role and Nitric Oxides ability. If no endothelial cells are present, _______ will act DIRECTLY and cause contraction!
SMOOTH MUSCLE PATHWAYS that DON’T require membrane depolarization
1. Hormone receptor stimulation —> IP3 formation –> causes release of Ca+ from SR
- Hormone receptor stimulation—>cAMP formation —> stimulates PKA to 1.phosphorylate MLCK and DEC its Ca+ sensitivity and 2. INC SR Ca+ RETURN pumping
- Hormone receptor stimulation—>cGMP formation —> stimulates MLC phosphatase—>REMOVES phosphate from Myosin = Relaxation of Smooth Muscle
- ## Caffeine & Viagra can reduce the rate of cAMP or cGMP breakdown—>Higher levels of cAMP or cGMP —> smooth muscle DILATIONB: Nitric Oxide in vascular smooth muscle is released by endothelial cells in response to ACh and illicits RELAXATION. cGMP plays a role and Nitric Oxides ability. If no endothelial cells are present, ACh will act DIRECTLY and cause constriction!
