Muscle Tissue Flashcards

0
Q

Functions of muscle tissue - 4

A

Produce body movement
Stabilize body position
Storing and moving substances within body. Store=sphincter
Generating heat

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1
Q

Types of muscle tissue - 3

A

Skeletal - move bones, striated, voluntary
Cardiac - pumps blood, striated, involuntary, pacemaker autorhythmicity
Smooth - hollow internal structures, no striations, involuntary, some have autorhythmicity

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2
Q

Properties of muscle tissue - 4

A

Electrical excitability - action potential, autorhythmic from within muscle, chemical - neurotransmitter
Contractibility - contract when stimulated by action potential
Extensibility - stretch within limits without damage
Elasticity - return to original shape

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3
Q

Muscle proteins 2,2,5

A

Contractile: myosin, actin

Regulatory (switch contraction process on and off)
Tropomyosin, troponin

Structural (keep thick and thin filaments in alignment, give myofibrils elasticity and extensibility, link myofibrils to sarcolemma)
Titin - connect z disc to m line, elastic
(Alpha)actinin - connect z disc to actin to titin
Myomesin - forms m line
Nebulin - wraps around actin, anchor to z disc
Dystrophin - links actin to sarcolemma to connective tissue

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4
Q

Muscle contraction cycle (4)

A

Atp hydrolysis to produce adp and phosphate on myosin head

Attachment of myosin to actin to form cross bridges

Power stroke moves thin fibers

Detachment of myosin from actin, myosin binds new atp

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5
Q

Excitation contraction coupling - 5 steps

A

Muscle action potential along sarcolemma into T tubules
Sarcoplamsic reticulum opens Ca2 release channels
Ca2 flows out of SR onto myofibrils
Ca2 combines with troponin, changes shape, tropomyosin uncovers myosin binding sites on actin.
Myosin heads bind with actin cross bridges, muscle contracts.

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6
Q

Neuromuscular junction terminology

A

Synapse
Synaptic cleft
Neurotransmitter - acetylcholine ACh is one
Axon terminal, synaptic end bulbs, on motor neuron
Synaptic vesicles
Muscle - motor end plate, ACh receptors, junctional folds

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7
Q

Nerve AP to muscle AP - 4 steps

A

Release of ACh by electical potential causing Ca2 channel to open, Ca2 to flow in causing synaptic vesicles to do exocytosis.
Activation of ACh receptor - ACh binds with receptors on motor end plate opening ion channel to let Na into muscle cell
Na makes inside more positive, triggering muscle AP
ACh then broken down by acetylcholinesterase

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8
Q

Twitch contraction, latent period

A

20-200 msec

Latent period 5 msec for AP to propogate, Ca to move out

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9
Q

Refractory period, muscle and nerve

A

Excitability lost just after excited. 5 msec for muscle.

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10
Q

Wave summation

A

Second stim before all relaxed produces larger force
Unfused tetanus 20-30 AP per second. Jagged line force.
Fused tetanus 80-100 AP per second solid high force.

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11
Q

Types of skeletal muscle fibers (3)

A

Slow oxidative SO - lots of myoglobin and mitochondria, so red muscle. ATPAse slow to hydrolyze ATP, slow contraction, slow to fatigue.
Fast oxidative-glycolytic FOG - largest, lots of myoglobin and mitochondria. Fast to hydrolyze ATP. Anaerobic and aerobic.
Fast glycolytic FG - white meat, lots of glycogen, anaerobic. Strong and quick, fast twitch. Fatigue more quickly.

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12
Q

Cardiac muscle

A

Actin myosin bands zones Z discs like skeletal
Intercalated discs to help spread AP with gap junctions and desmosomes.
Endomysium and perimysium but no epimysium
Ca comes from SR and interstitial fluid
Contractions 10-15 times longer
Autorhythmic instead of ACh.
Lots of mitochondria, aerobic. Can make ATP from lactic acid.
Physiological enlarged heart from exercise.

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13
Q

Smooth muscle types 2

A

Visceral single unit, one nerve AP spreads through gap junctions
Multiunit, each fiber needs nerve ending.

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14
Q

Smooth muscle anatomy

A

Filaments thick, thin, intermediate
Caveolae instead of T tubules, contain Ca
Dense bodies instead of Z discs
Contraction causes shortening and twist like helix

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15
Q

Smooth muscle physiology

A

Contraction starts slowly, lasts longer
Can shorten and stretch more than skeletal
Calmodulin enzyme binds ATP, myosin light chain kinase attaches it to myosin head. All more slowly.
Smooth muscle tone maintains pressure long time.
Can contract due to autonomous nervous system, hormone, stretching, change in pH or O2 or CO2, temp, ion concentration.
Stress-relaxation response - stretch causes tension, then relaxes.
Has some capability for regeneration.

16
Q

Filaments, zones, bands, line, disc, unit of contraction in myofibril - 8

A

Thin filament - actin
Thick filament - myosin, 2 thin per thick
Sarcomere - basic functional unit of myofibril, z disc to z disc
Z disc - each end of sarcomere, center if I band
A band - area of thick filament plus thin overlap
I band - thin filament plus z disc
H zone - thick filament only
M line - middle of sarcomere

17
Q

3 ways to get ATP in muscle cell

A

Creatine phosphate - 1 atp
Anaerobic - 2 atp
Aerobic - 30 atp

18
Q

Gluconeogenesis

A

Fats and proteins to glucose

19
Q

Isotonic and isometric contractions

A

Concentric isotonic - move load
Eccentric isotonic - load moves muscle - resist movement, but it is too much
Isometric - pressure but load does not move

20
Q

3 development muscle types embryo

A

Myotome - skeletal muscles
Dermatome - connective tissue, skin
Sclerotome - vertebrae

21
Q

Myasthenia gravis

A

Autoimmune, progressive damage of NMJ, blocks ACh receptors

22
Q

Bell’s palsy

A

Facial paralysis, damage of nerve

23
Q

Strabismus

A

2 eyeballs not aligned. Lazy eye. External is lateral. Internal is medial drift.

24
Q

Mastication, deglutition

A

Chew, swallow

25
Q

Dysphagia

A

Difficulty swallowing

26
Q

Hernia

A

Protrusion of organ through structure that normally contains it. Inguinal common.

27
Q

Impingement syndrome

A

Continual pinching of suprasinatus by repetitive movement causes inflammation. May degenerate and detach.