1-6 Muscle Physiology Flashcards Preview

PHYSIOLOGY Exam 1 > 1-6 Muscle Physiology > Flashcards

Flashcards in 1-6 Muscle Physiology Deck (25):
1

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
1. Motion
2. Posture
3. Heat

2

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!

3

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 = _______

1. 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

3. Perimysium surrounds fascicle and contains blood vessels and Nerves

4. EPI, Peri and Endomysium all come together = TENDON

4

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!

5

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

6

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"?

Ca+ binds to _______ which moves _______ into the [_______ groove]. This exposes the Myosin binding site on _______ so Myosin can Bind for _______!

A: Describe Actin= F-actin is a double stranded helix made of many G-actin monomers!

B: Contains several interacting proteins:
1. F-actin itself
2. Tropomyosin

3. Troponin Group-
T-Tropomyosin bound
I- Inhibitory
C- calcium binding

C: There is ONE [Tropomyosin band] and [Troponin Group] per every 7 [G-Actin monomers]

D: Ca+ binds to [Troponin-C] which moves [Troponin-T] into the [actin groove]. This exposes the Myosin binding site on [G-actin monomers] so Myosin can Bind for contraction!

7

[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

8

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

9

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

10

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

11

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

3. ____-binding allows myosin to RELEASE _______ so it can resent on another _______
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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

2.ADP + Pi release causes actual shift and Actin filaments slide toward H-zone pulling Z lines inward

3. ATP-binding allows myosin to RELEASE G-actin monomer so it can reset on another monomer

B: Cross-bridign in muscles is NOT SYNCHRONOUS for each sarcomere and happens in Waves!

12

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
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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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

13

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)
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A: [group of muscle fibers] all innervated by 1 Lower Motor Neuron

B: Muscle Fiber THICKNESS matters because more sarcomeres in parallel ADD FORCE!

14

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 [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

15

4 Types of Muscle Contractions

A:
Concentric contractions = muscle actively _______
vs.
ECCENtric contractions = MUSCLE ACTIVELY _______
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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]

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C: What is Isometric Contraction?
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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
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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
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C: Isometric Contraction = isotonic Muscle actively held at fixed length with gradually INC force
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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

16

**ATP usage in Muscle Metabolism**
1. What sources uses the most ATP in muscle metabolism and give percentage?

2. 2nd

3. 3rd

**ATP usage in Muscle Metabolism**
1st: ATPase for Actomyosin cross-bridging = MOST of ATP consumed [50-70%]

2nd: SERCA [20-30%]

3rd: Na/K ATPase pump for establishing gradient [10%]

17

****SOURCES FOR MORE MUSCLE ATP****

A: Creatine Phosphate
•Creatine-P + _______ ----> Creatine + [rapid _______]
•Is the _______ energy store used during 1st few seconds of _______
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B: Oxidative phosphorylation
• _______ process in mitochondria and requires _______.
•Efficient but slow synthesis of 30 _______ per _______

^Myoglobin gives muscle its _______ Color!
^^Muscles with _______[High/low] Oxidative phosphorylation will appear _______ because they have many working _______ and _______
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C: Glycolysis- _______ exercise
•Fast make of _______ but less Efficient and used when only _______[MUCH/little] O2 is available.
•Glycolytic muscle is _______ because there is LESS _______ and LESS _______
•Produces _______
•Uses __ ATP, makes ___ = __ Net ATP

****SOURCES FOR MORE MUSCLE ATP****

A: Creatine Phosphate
•Creatine-P + ADP ----> Creatine + [rapid ATP]
•Is the 1st energy store used during 1st few seconds of intensity
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B: Oxidative phosphorylation
•AEROBIC process in mitochondria and requires O2.
•Efficient but slow synthesis of 30 ATP per glucose

^Myoglobin gives muscle its RED Color!
^^Muscles with HIGH Oxidative phosphorylation will appear red because they have many working Myoglobin and MITOCHONDRIA
--------------------------------------------------------------------------------------
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C: Glycolysis- anaerboic exercise
•Fast make of ATP but less Efficient and used when only little O2 is available.
•Glycolytic muscle is WHITE because there is LESS Myoglobin and LESS Mitochondria
•Produces Lactate
•Uses 2 ATP, makes 8 = 6 Net ATP

18

A: Central Fatigue can be overcome by "_______ up"

B: Muscle Fatigue is caused by _______ buildup from _______---> _______[INC/DEC] pH--->inhibits _______

C: Neuromuscular fatigue is AKA _______ _______ and NOT common in _______ people

A: Central Fatigue can be overcome by "psyching up"

B: Muscle Fatigue is caused by lactate buildup from Glycolysis--->DEC pH--->inhibits enzymes

C: Neuromuscular fatigue is AKA [myasthenia gravis] and NOT common in healthy people

19

Describe the 3 Motor Fiber Types

1.size of its corresponding Motor Neuron
2.Muscle Type
3.White vs. Red fiber?

4.Amount of Mitochondria & Capillaries

5.Fatigue resistance?

6.Twitch type

7. Primary Energy Source?

8. Level of Glycolytic Activity

9. Activity Profile

1. S-units = small MN/Type 1/Red Fibers/MOST mitochondria & capillaries/Resistant/[Slow Twitch myosin ATPase] / Oxidative phosphorylation (primary energy)/ low Glycolytic activity / SUSTAINED TONIC
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2A. FR(fatigue Red)-units= small MN/Type 2a/Red Fibers/medium mitochondria & capillaries/Resistant/[FAST Twitch myosin ATPase] / Glycolysis (primary energy)/ medium low Glycolytic activity / Sustained Phasic
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2B. FF(Fat Fatigue)-units=FatLarge MN/Type 2B/WHITE/little mitochon or capillaries/NOT RESISTANT/[FAST Twitch myosin ATPase] / GLYCOLYSIS (primary energy)/ HIGH GLYCOLYTIC ACTIVITY / short term phasic
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20

A: Smooth Muscle can be _______ or _______-unit AND _______ or _______

B: SMOOTH Muscle Examples:
-G.I. tract is ___ unit and _____
- iris m. is ___unit
- Vascular m. is ______


C: SMOOTH Muscle contractile apparatus attaches to [_______ BODIES]

D: SMOOTH Muscle SINGLE Units are interconnected by _______ _______ and uses them to spread _______

A: Smooth Muscle can be SINGLE or MULTI-unit AND [Tonic Continuous] or [Phasic Rhythmic]

B: SMOOTH Muscle Examples:
-Single unit = G.I. tract
-Multi-unit = iris m.
-[Tonic Continuous] = Vascular m.
-[Phasic Rhythmic] = G.I. tract

C: SMOOTH Muscle contractile apparatus attaches to [DENSE BODIES]

D: SMOOTH Muscle SINGLE Units are interconnected by Gap Junctions and uses them to spread depolarization

21

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

22

SMOOTH MUSCLE PATHWAYS that DON'T require membrane depolarization

1. Hormone receptor stimulation ---> IP3 formation --> causes release of __+ from _______

2. Hormone receptor stimulation--->cAMP formation ---> stimulates PKA to 1)phosphorylate _______ and DEC its ___+ sensitivity and 2) INC _______ _______ __+ RETURN pumping

3. Hormone receptor stimulation--->cGMP formation ---> stimulates _____ _______--->REMOVES _______ from Myosin = Relaxation of Smooth Muscle

4. Caffeine & Viagra can _______ the rate of cAMP or cGMP breakdown--->constant smooth muscle _______
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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

2. Hormone receptor stimulation--->cAMP formation ---> stimulates PKA to 1.phosphorylate MLCK and DEC its Ca+ sensitivity and 2. INC SR Ca+ RETURN pumping

3. Hormone receptor stimulation--->cGMP formation ---> stimulates MLC phosphatase--->REMOVES phosphate from Myosin = Relaxation of Smooth Muscle

4. Caffeine & Viagra can reduce the rate of cAMP or cGMP breakdown--->Higher levels of cAMP or cGMP ---> smooth muscle DILATION
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B: 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!

23

1. Moderate depolarizations of resting membrane potential activate _______[small/large] tonic amounts of __+---->which keeps intracellular ___+ tonically high!

2. __+ entry can also be amplified by _______ via [RyR]

1. Moderate depolarizations of resting membrane potential activate small tonic amounts of Ca+---->which keeps intracellular Ca+ tonically high!

2. Ca+ entry can also be amplified by [Ca+ induced Ca+ release] via [RyR]

24

Smooth Muscle Agonist and Drug Modulators

1. NorEpi and Epi from _______ cause _______ MOSTLY but also _______. They use ___ and ____ receptors with _______ and _______ as second messengers

2. ACh from _______ DIRECTLY cause _______ (Muscarinic receptor on _______) but indirectly cause _______ (Muscarinic receptor on _______) .

3. Angiotensin II causes _______ using _______ receptor and _______ as second messenger

4. Adenosine causes _______ using _______ receptor and _______ as second messenger

Smooth Muscle Agonist and Drug Modulators
1. NorEpi and Epi from Sympathetic cause CONTRACTION MOSTLY but also Relaxation. They use a1 and B2 receptors with cAMP and InsP3 as second messengers

2. ACh from PARAsympathetic DIRECTLY cause CONTRACTION (Muscarinic receptor on SMC) but indirectly cause relaxation (Muscarinic receptor on EC) :-O.

3. Angiotensin II causes CONSTRICTION using AT-2 receptor and InsP3 as second messenger

4. Adenosine causes Relaxation using Adenosine receptor and cAMP as second messenger

25

A: _______ muscles source of Ca+ ONLY comes from Sarcoplasmic Reticulum vs. _______ and _______ muscle who gets Ca+ from Outside Cell AND Sarcoplasmic Reticulum

B: _______ and _______ contain NO GAP JUNCTIONS

C: _______ and _______ do NOT exhibit Recruitment abilities

A: Skeletal muscles source of Ca+ comes from Sarcoplasmic Reticulum vs. Smooth and Cardiac which ALSO gets Ca+ from Outside Cell

B: Skeletal and [Smooth m. Multi-unit] contain NO GAP JUNCTIONS

C: Cardiac and [Smooth m. SINGLE unit] do NOT exhibit Recruitment abilities