Muscle Flashcards
What the type of muscles in body?
Skeletal 40% and smooth + cardiac 10%
What are the muscle properties?
CEEE C- Contract E - Elastic E - Extend E- excited
What are the connective tissue component of a muscle?
- Epimysium
- Endomysium
- Perimysium
How are muscle fiber made?
Myofilament -> Myofibril -> Muscle fiber
Whats an example of muscle fiber?
Myocyte
Whats muscle cell membrane called?
Sacrollemma
Whats a cytoplasm of muscle called?
Sacroplasm
What is a tubule unique to muscle cell?
T tubule
What NMJ?
Neuromusculer junction= in perimysium
What the meeting point tendon and muscle?
myotendinous junction
Whats muscle ER called?
sacroplasmic reticulum
How are skeletal muscles formed?
mesodermal germ layer –> myoblast –> myotube (myogensis) –> myocyte (differentiation)
What help in regeneration?
satellite cell
What are 3 types of skeletal muscle fibers?
Slow oxidative, fast glycolytic oxidative & fast glycolytic.
What of 3 types of skeletal muscle fiber has fewest mitochondria?
Fast glycolytic
True or false- fast glycolytic oxidative is the only one that undergoes anaerobic metabolism.
False- so does fast glycolytic oxidative.
Put skeletal muscle in order of smallest- largest diameter.
Slow oxidative, fast glycolytic oxidative & fast glycolytic
Which is most strongest skeletal muscle?
fast glycolytic
True or false- slow oxidative have little capillary blood supply.
False- it has most blood capillaries
Where is slow oxidative found?
back
Where is fast glycolytic oxidative found?
legs
Where is fast glycolytic found?
limb digits
What are the 2 filaments involved in muscle?
Thick + thin
Whats thick filament?
myosin
What is the composition of myosin
2 heavy (tail) + 4 light (head) + neck hinge
True or false- myosin is in charge of contraction.
True
True or false- myosin tail attaches to other myosin.
True
Whats in thin filament?
Actin, troponin and tropomyosin.
Where is tropomyosin?
Around actin.
What do tropomyosin do at rest and at contraction?
rest: bind at actin in myosin binding site.
Contraction: move away from myosin binding site.
What are the tropnins?
T: tropomyosin- bind tropomyosin to actin
I: inhibitor- inhibit actin + myosin
C: calcium- calcium binds to it allow contraction.
How to check myocardial infraction?
CKMB (most specific) & cardiac troponin 1 (most specific)
What are the cytoskeletal proteins involved in architecture of myofibril?
Actinin: bind actin to z disc
titin: bind myosin via string
dystrophin: anchors to cytoskeleton
nebullin: extend actin
What does lack of dystrophin do?
muscle dystrophy- sacrollema doesnt attach to cytoskeleton
Causes respiratory failure + muscle wasting
True or false- skeletal muscle have striations.
True
Is skeletal muscle a triad or diad?
Triad
What 3 elements cause contraction?
SR + transverse tubular system + calcium
Whats structure of triad and diad?
triad: 2 SR + 2 terminal cisternae
diad: 1 SR + terminal cisternae
True or false- t tubular carries AP
True
True or false- diad is at AI junction and triad at z junction
False- diad at z and triad at AI
How is calcium released in ECC?
- AP is carried along NMJ
- ACh released in synaptic cleft
- Bind to Na channel- depolarizes sacrolemma
- conformation change
- calcium channel activated- depolarize t tubules
- Calcium binds to troponin c
What is stages of contractile cycle?
- attachment
- release
- bending
- force generation
- reattachment
Whats attachment in CC?
Rigor configuration- actin and myosin bind.
Whats release in CC?
ATP bind to myosin
Affinity of actin site to myosin changes (lower)
conformation of actin
Myosin releases
Whats bending in CC?
- Myosin head advances
- ATP becomes ADP and attaches to myosin
- bending
Whats force generstion in CC?
- Phosphate changes affinity of actin + myosin
- affinity increase
- powerstroke = unbent
- ADP lost
- Myosin bind
Whats myasthenia gravis?
Antibodies see that ACh is foreign- NMJ is messed up.
What is symptom of myasthenia gravis?
Limb + respiratory + ocular.
What is treatment of myasthenia?
immunosuppressive drug, ACh inhibitor and thyrectomy
what is the cell in the heart?
Contractile cell
What junctions are there in heart?
G intercalated disc/gap junction
Is heart triad or diad?
diad
True or false- calcium in myocardial cell triggers more release from SR
True
Whats hypertrophic cardiomypathy?
Mutation in myosin heavy chain- growth in heart.
- SCD
- Prone to arrhythmia
True or false- smooth has no stiriation
True
True or false- skeletal has dense bodies
false- smooth
True or false- skeletal has dense bodies
false- smooth
What are the types of smooth muscle?
Multiunit= no coupling or electricity or space
Unitary=gap junction + electricity
What is an example of multiunit muscle?
iris + vas defrens
What is an example of unitary muscle?
uterer + uterus + bladder
True or false- contraction of skeletal + cardiac is the same
True both use Ca2+
How is contraction different in smooth muscle?
- ECC
- Has calmodium not troponin
What 3 factors allow contraction in smooth muscle?
- Depolarization (normal contraction)
- Hormone
- Neurotransmitter
How does depolarization control smooth muscle contraction?
Depolarization –> vgcc open –> ca induced ca release from SR –> calcium rise and bind to CALMODIUM –> myosin light chain kinase reaction (contraction) –> use ATP –> myosin + actin
How do hormones control smooth muscle contraction?
ligand gated channel –> ca induced ca release from SR –> calcium rise and bind to CALMODIUM –> myosin light chain kinase reaction (contraction) –> use ATP –> myosin + actin
How do neurotransmitter control smooth muscle contraction?
IP3 –> ca release from SR –> calcium rise and bind to CALMODIUM –> myosin light chain kinase reaction (contraction) –> use ATP –> myosin + actin
Whats the difference between myosin light chain kinase and myosin light chain phosphate?
Kinase: cross bridge
phosphate: no cross bridge
True or false- SR in triad is more complex than diad
True
True or false- cardiac and smooth arent multinucleated
True
True or false- smooth has T tubules.
False- cardiac + skeletal
True or false- skeletal has junction
false- cardiac- intercalated and smooth- gap
True or false-Calcium in skeletal is in terminal cisternae and in cardiac its in extracellular
true
True or false- Cardiac is the only one that can regenerate
False- CANT
True or false- smooth muscles undergo mitosis
true
What is O2 debt?
exercise= more blood= more dilation= more oxygen= more energy
At one point its not enough- phosphylcreatine make ATP + lactate
Lactate stop enzyme that control pH
Myoglobin used
O2 then collected later and gets rid of lactate
What is O2 debt?
- exercise= more blood= more dilation= more oxygen= more energy
- At one point its not enough- phosphylcreatine make ATP + lactate
- Lactate stop enzyme that control pH
- Myoglobin used
- O2 then collected later and gets rid of lactate