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Anatomy & Physiology > Unit 5: Introduction to the Muscular System > Flashcards

Unit 5: Introduction to the Muscular System Flashcards

1
Q

What are the functions of the muscular system? (5)

A
  • Produce movement of the skeleton
  • Maintain posture and body position
  • Support soft tissues
  • Guard entrances and exits
  • Regulate body temperature
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2
Q

How many layers of connective tissue does the skeletal muscle have?

A

3

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3
Q

What are the 3 connective tissue layers in a skeletal muscle?

A
  • epimysium
  • perimysium
  • endomysium
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4
Q

Epimysium (3)

A
  • The outermost layer
  • Separator from surrounding tissues
  • Consist of collagen fibers
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5
Q

Perimysium (2)

A
  • Surrounds bundles of muscle fibers
  • Inside of it are blood vessels, nerves, fibers, collagen, and elastic fibers
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6
Q

What is another name for bundle of muscle fibers?

A

fascicles

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7
Q

Endomysium (2)

A
  • Surrounds the individual muscle fiber
  • Has stem cells
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8
Q

What does the collagen from the 3 connective tissue layers form?

A
  • tendons
  • aponeurosis
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9
Q

Tendon

A

attach muscle to bone

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10
Q

Aponeurosis (sheets)

A

connect muscles

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11
Q

Sarcolemma

A

plasma membrane

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12
Q

Sarcoplasm

A

cytoplasm

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13
Q

Transverse Tubules

A

transmit nerve impulses thru entire fiber

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14
Q

Sarcoplasmic Reticulum (2)

A
  • surrounds each myofibril
  • stores Ca2+
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15
Q

Myofibrils

A

bundles of protein filaments called myofilaments

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16
Q

How many myofilaments are there?

A

2

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17
Q

What are the two types of myofilaments?

A
  • actin (thin filaments)
  • myosin (thick filaments)
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18
Q

Sarcomere

A

Smallest functional unit

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19
Q

Striations

A

alternating thick & thin filaments

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20
Q

Z-line

A

boundary of a sarcomere

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21
Q

I-Band

A

thin filaments and the proteins that bind them together

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22
Q

A-Band

A

contains the entirety of the thick filaments as well as the intertwining of them with thin filaments

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23
Q

H-Band

A

thick filaments only

24
Q

M-Line

A

attachment sites for thick filaments

25
Q

What characteristics distinguish skeletal muscle cells from “typical cells?” (4)

A
  • striated
  • multinucleated
  • tubular
  • voluntary
26
Q

What happens during muscle contraction? (4)

A

1) Sarcoplasmic reticulum releases Ca2+ in response to action potential from neuron
2) Ca2+ bind to troponin, causes shape change and allows tropomyosin to swing sway from actin proteins, exposing active sites
3) Myosin head attaches to active site of actin forming a cross bridge
4) Power Stroke: myosin heads pivot toward center of sarcomeres using energy from hydrolyzed ATP

27
Q

What is the structure and function of the neuromuscular junction? (4)

A

1) Action potential (electrical signal) arrives
2) Neurotransmitter acetylcholine (Ach) is released into synaptic cleft
3) Ach binds to muscle cell at motor end plate → influx of Na+
4) Action potential travels across sarcolemma & down T tubules

28
Q

Where does the striated appearance of skeletal muscles come from?

A

the alternating between thick and thin filaments

29
Q

The all or none principle

A

a muscle fiber is either contracted or relaxed

30
Q

How does muscle tension vary? (2)

A
  • frequency of stimulation
  • Number of muscle fibers stimulated
31
Q

Muscle Tone

A

tension at rest 🡪 stabilizes bones & joints

32
Q

Isotonic Contraction

A

tension rises & muscle changes length

33
Q

Isometric contraction

A

develops tension but does NOT change length

34
Q

How is glucose stored in muscles?

A

as glycogen

35
Q

What is the role of creatine phosphate? (2)

A
  • stores excess ATP in resting muscle
  • can provide E for ~15 sec
36
Q

Aerobic Metabolism (5)

A
  • happens in mitochondria
  • resting fibers use ATP to form glycogen & creatine phosphate
  • Contracting fibers use glycogen 1st, then fat for ATP production
  • provides 95% of ATP in resting cell
  • yields ~34 ATP
37
Q

Anaerobic Metabolism (3)

A
  • breakdown of glucose in sarcoplasm primary energy source for peak activity
  • results in lactic acid formation if no O2 is present
  • yields 2 ATP
38
Q

What causes muscle fatigue? (2)

A
  • Depletion of energy reserves
  • build up of lactic acid
39
Q

Recovery Period

A

Liver converts lactic acid to pyruvic acid & releases glucose into blood to recharge muscle glycogen reserves

40
Q

Oxygen Debt

A

additional O2 is needed

41
Q

Fast Twitch Fibers (5)

A
  • strong, quick contractions
  • large diameter
  • few mitochondria
  • fatigue quickly
  • large glycogen reserves
42
Q

Slow Twitch Fibers (5)

A
  • slow to contract
  • small diameter
  • more mitochondria
  • high O2 supply
  • contain myoglobin (red pigment that stores O2)
43
Q

Why would there be oxygen debt after exercise?

A

additional O2 would be needed to bring levels back to normal

44
Q

Which activity are fast fibers associated with?

A

anaerobic activity

45
Q

Which activity are slow fibers associated with?

A

aerobic activity

46
Q

Hypertrophy (2)

A
  • muscle growth
  • ↑’s mitochondria & glycogen reserves due to increase in muscle fiber diameter
47
Q

Atrophy (2)

A
  • fibers become small & weak due to lack of stimulation
  • ↓’s muscle size & tone
48
Q

Which type(s) of muscle is/are found in the walls of hollow organs and blood vessels?

A

Smooth Muscle

49
Q

What is the primary function of smooth muscle tissue?

A

To line the insides of organs and tracts and regulate the movement of materials

50
Q

What are some characteristics of cardiac muscle? (5)

A
  • branched
  • connected by intercalated discs
  • contain gap junctions
  • Automaticity
  • Aerobic metabolism only
51
Q

Gap Junctions (2)

A
  • allow ion movement between cells
  • pass action potentials from cell to cell
52
Q

What are the 3 muscles and their striations and voluntariness?

A
  • Skeletal Muscle: striated and voluntary
  • Cardiac Muscle: striated and involuntary
  • Smooth Muscle: nonstriated and involuntary
52
Q

What effects do aging have on the muscular system? (4)

A
  • smaller in diameter
  • less ecstatic
  • decreased tolerance for exercise
  • decreased ability to recover from injury
53
Q

What entails muscles becoming smaller diameter with aging? (5)

A

fewer…
- myofibrils
- myoglobin
- glycogen
- ATP
- Creatine Phosphate

54
Q

What entails muscles becoming less elastic?

A
  • increasing amounts of fibrous tissue, restricts movement & circulation
55
Q

What entails muscles having decreased tolerance for exercise?

A
  • Slower delivery of blood to muscles during exercise, faster fatigue
  • Impaired ability to eliminate heat, causes overheating

Anatomy & Physiology (9 decks)

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