8: Muscle Tissue Flashcards

1
Q

What are the 3 kinds of muscle tissue?

A

Skeletal, cardiac, smooth

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2
Q

What are the 4 properties of muscle tissue?

A

Excitability, contractability, elasticity, extensibility

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3
Q

What is unique about cardiac fibers?

A

“Y” shaped/branched fibers

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4
Q

How many nuclei do cardiac cells have?

A

Uninucleate or binucleate

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5
Q

What is the name of the structure that joins cardiac cells?

A

Intercalated discs

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6
Q

What does it mean that cardiac cells are auto-rhythmic?

A

They can contract without input from the nervous system

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7
Q

Where is smooth muscle found?

A

Walls of visceral organs and walls of arteries

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8
Q

What is the shape of smooth muscle cells?

A

Fusiform

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9
Q

How many nuclei do smooth muscle cells have?

A

Uninucleate

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10
Q

Which muscle cells are striated/not striated?

A

Cardiac and skeletal are striated, smooth is not

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11
Q

What muscle type is fatigue resistant?

A

Smooth

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12
Q

What is the shape of skeletal muscle cells?

A

Large cylindrical shape

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13
Q

How many nuclei do skeletal muscle cells have?

A

Multinucleated

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14
Q

Skeletal muscle cells are formed from the fusion of what cells?

A

Myoblasts

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15
Q

What are the 6 functions of skeletal muscle?

A

Movement,
Maintenance of posture,
Temperature regulation,
Storage and movement of materials,
Support and protection abdominal organs,
Joint stabilization

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16
Q

What bodily functions are performed with skeletal muscle?

A

Swallowing, urination, and defecation

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17
Q

What type of muscle is vascular?

A

Skeletal

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18
Q

What is mysia and the three layers of it?

A

Layers of connective tissue is skeletal muscle
1. Epimysium
2. Perimysium
3. Endomysium

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19
Q

What is the structure of epimysium?

A

Dense, irregular connective tissue

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20
Q

What layer of the mysia is most superficial and covers a muscle?

A

Epimysium

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21
Q

What is a bundle of skeletal muscle fibers called?

A

Fascicle

22
Q

What layer of the mysia forms the fascicles?

A

Perimysium

23
Q

What is the structure of the endomysium?

A

Collagen and reticular fibers

24
Q

What layer of the mysia wraps the myofibers?

A

Endomysium

25
Q

What layer of the mysia contains extracellular fluid and nutrients to support the muscle fiber?

A

Endomysium

26
Q

What structure wraps muscle groups?

A

Deep fascia

27
Q

What does the collagen of a tendon intertwine with to attach to a muscle?

A

The collagen of the three layers of the mysia

28
Q

What is a broad, tendon-like sheet that mysia may fuse to called?

A

Aponeurosis

29
Q

What are myofibrils composed of?

A

Chains of sarcomeres

30
Q

What does the fusion of myoblasts allow for?

A

Multiple codes of genes in a cell, permitting the production of large amounts of proteins and enzymes

31
Q

What is the plasma membrane of muscle fibers called?

A

Sarcolemma

32
Q

What is the cytoplasm of muscle fibers called?

A

Sarcoplasm

33
Q

What are the functional units of skeletal muscles called?

A

Sarcomeres

34
Q

What is the name of the specialized smooth endoplasmic reticulum of skeletal muscle cells? What does it store/release/retrieve?

A

Sarcoplasmic reticulum

Ca++ ions

35
Q

What are linked together to form a myofibril?

A

Sarcomeres

36
Q

What is a z-line/z-disc?

A

Structure that sits between the sarcomeres of a myofibril

37
Q

What is the thick filament of a sarcomere composed of?

A

Myosin

38
Q

What are the thin filaments of a sarcomere composed of?

A

Actin

39
Q

Which filament (thick or thin) is anchored directly to the z-disc?

A

Thin filament

40
Q

What winds around the chains of the actin filament and covers the myosin-binding sites to prevent actin from binding to myosin?

A

Tropomyosin

41
Q

What extension of the nervous system controls the muscles?

A

Motor neurons

42
Q

What is the name of the site where a motor neuron meets a muscle cell?

A

Neuromuscular junction

43
Q

How many skeletal muscle fibers are innervated?

A

All of them

44
Q

When an action potential is received from a motor neuron, across what structure does it propagate?

A

Sarcolemma

45
Q

What do t-tubules stand for and do?

A

Transverse tubules

These ensure that the electrical impulse is carried into the muscle cell, to the sarcoplasmic reticulum

46
Q

What is the part of the sarcoplasmic reticulum that is near the t-tubules?

A

Terminal cisternae

47
Q

What is the name of the portion of the t-tubule with terminal cisternae on either side?

A

Triad

48
Q

What are skeletal muscle cells commonly referred to?

A

Muscle fibers or Myofibers

49
Q

What are the steps of sarcomere contraction?

A
  1. Signal from motor neuron
  2. Local membrane initiates action potential that spreads across sarcolemma and t-tubules
  3. Ca++ ions release from the terminal cisternae which diffuses across the sarcoplasmic reticulum
  4. Ca++ binds to troponin, causing tropomyosin to slide away from the binding sites on actin strands
  5. Myosin heads bind to actin
  6. Thin filaments are pulled my myosin heads to the center of sarcomere
50
Q

What are the steps of muscle relaxation?

A
  1. Signaling from the motor neuron ends
  2. Electrical impulses on the sarcolemma and t-tubules dissipate
  3. Ca++ ions pumped back into the sarcoplasmic reticulum
  4. Tropomyosin reshields the binding sites on the actin strand and the thin filaments return to their original position
51
Q

How can a muscle stop contracting even when an electrical impulse is present?

A

It runs out of ATP