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1.1.1. Body Logistics > The Muscular System > Flashcards

The Muscular System Flashcards

1
Q

What is atrophy?

A

destruction – loss of protein, reduced fibre diameter, loss of power, 50% loss by 80yrs

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2
Q

What is Hypertrophy?

A

getting bigger, replacement – increase in fibre diameter

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3
Q

What is Hyperplasia?

A

proliferation of more cells, number increases (not size)

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4
Q

What is Myalgia?

A

muscle pain

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5
Q

What is Myasthenia?

A

weakness of muscles

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6
Q

What is Myoclonus?

A

sudden spasm of muscle

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7
Q

What is Sarcolemma?

A

outer membrane of muscle cell

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8
Q

What is Sarcoplasm?

A

cytoplasm of muscle cell

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9
Q

What is Sarcoplasmic reticulum?

A

smooth ER of muscle cell

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10
Q

In skeletal muscle what organelles are abundant?

A

mitochondria

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11
Q

Where are the nuclei placed in skeletal muscle?

A

peripheral, multinucleated

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12
Q

How does skeletal muscle regenerate?

A

via satellite cells

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13
Q

What is the structure of skeletal muscle?

A

epimysium wraps multiple fasicles –> perimysium wraps single fasicle –> endomysium on top of sarcolemma wraps a muscle fibre –> muscle fibre = myofibrils (actin/myosin) + sarcoplasm

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14
Q

Outline the muscle contraction process

A

Nerve impulse travels nerve to neuromuscular junction between axon terminal and muscle fibre, ACh released, 2 bind, nAChRs, depolarises sarcolemma, Na+ channels open, Depolarisation travels down T tubules. Ca2+ released from sarcoplasmic reticulum, Ca2+ binds TnC of troponin on actin moving tropomyosin revealing myosin binding site, ATP –> ADP + P = myosin head extends, Myosin binds forming cross-bridges, Power stroke triggered = myosin pulls actin towards M line (shortening sarcomere) = sliding filament mechanism, ADP + P released during power stroke, ATP binds bringing myosin back to relaxed position

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15
Q

In skeletal muscle where do T tubules lie?

A

A-I band junction

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16
Q

Where are the nuclei in cardiac muscle?

A

Central

17
Q

In cardiac muscle where do T tubules lie?

A

Z band

18
Q

What are the functions of purkinje fibres?

A

Modified muscle cell = Carry action potentials from the AV node to the ventricle muscle, Allow rapid conduction = synchronous contraction

19
Q

How does cardiac muscle regenerate?

A

Incapable of regeneration – damage = fibroblasts invade = lay down scar tissue

20
Q

Which muscle type has no myoglobin?

A

Smooth

21
Q

In smooth muscle where are the T tubules found?

A

Nowhere, they are not present

22
Q

Where are the nuclei placed in cardiac muscle?

A

Central

23
Q

What is the difference between a smooth muscle contraction and a cardiac/skeletal?

A

Smooth = Slower contraction, more sustained, requires less ATP for actin-myosin

24
Q

List muscle injury markers

A

CK: all. Myoglobinuria: myoglobin from muscle secreted in urine, skeletal. Troponin: cardiac ischemia, measure in 20hrs, not proportional to amount of damage. Natriuretic peptide: secreted by atria/ventricles in response to excessive stretching of cardiomyocytes – levels correlate with symptom severity, aim = reduce arterial pressure by decreasing blood volume - ANP: released by atrial myocytes, found during hypovolemic states = congestive heart failure, BNP: released by ventricles

25
Q

Why is muscle striated?

A

Longitudinal nature of actin and myosin

26
Q

What is the H Zone?

A

Section of myosin where there is no overlap of actin

27
Q

Describe a smooth muscle cell

A

Spindle shape, central nucleus

28
Q

What are the 2 cell types present in smooth muscle?

A

Myoepithelial = contraction of glands. Myofibroblasts = wound healing

29
Q

What is the structure of cardiac muscle cell?

A

Striated, central nuclei

30
Q

What is a sarcomere?

A

Contractile unit, from one Z band to another

31
Q

What is the M line?

A

Line that holds myosin fibres together

32
Q

What can happen from the dysfunction of smooth muscle?

A

Asthma, irritable bowel, hypertension

33
Q

What happens when ANP/BNP is released?

A

Na excretion by the kidneys = water travels with = lowers water volume = lowers BP = allows heart to rest when over-stretched

34
Q

What are the 2 different types of muscle fibre?

A

Red = high mitochondria, sustained contraction. White = powerful but easily fatigued

35
Q

What are the markers of muscle damage?

A

CK = all muscle. Myoglobinuria = skeletal muscle. Troponin I = cardiac. ANP/BNP = ventricular stretching

36
Q

What are the different types of atrophy?

A

Disuse - muscle not used = wasting. Denervation = motor neurone lesion - 3 month recovery. Age = 50% loss by 80yrs

37
Q

Outline the banding structure in a sarcomere

A 
A - myosin
I - actin with no myosin overlap
H - myosin with no actin overlap
M - holds myosin together 
Z-Z - sarcomere

A-I - skeletal T tubules
Z - cardiac T tubules

1.1.1. Body Logistics (22 decks)

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