Muscle Tissue Histology Flashcards

1
Q

What is muscle cytoplasm referred to as?

A

Sarcoplasm

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2
Q

What is muscle smooth endoplasmic reticulum referred to as?

A

Sarcoplasmic reticulum

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3
Q

What is the plasma membrane or plasmalemma referred to as in a muscle cell?

A

Sarcolemma

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4
Q

What is a muscle cell referred to as?

A

Muscle fiber or myofiber

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5
Q

What embryonic tissue is muscle derived from?

A

Mesoderm

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6
Q

What are the three types of muscle tissue?

A

Skeletal, cardiac, and smooth

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7
Q

What are the four special characteristics of muscle tissue?

A
  1. excitability (or irritability)
  2. contractility
  3. extensibility
  4. elasticity
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8
Q

What are the 4 functions of muscle tissue?

A
  1. producing movement
  2. maintaining posture
  3. stabilizing joints
  4. generating heat
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9
Q

What are five characteristics of skeletal muscle

A

Voluntary control, strong quick contractions, striated, large elongated cylindrical syncytial (multinucleated) cells, and peripheral oval nuclei

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10
Q

What is the function of skeletal muscle?

A

Voluntary movement, locomotion, manipulation of the environment, facial expression, and voluntary control

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11
Q

Where is skeletal muscle located?

A

In skeletal muscles attached to bones and occasionally skin

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12
Q

Describe cardiac muscle?

A

Branching, striated, generally uninucleated cells that interdigitate at specialized junctions (intercalated discs)

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13
Q

What is the function of cardiac muscle?

A

As it contracts it propels blood into circulation, involuntary control

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14
Q

What is a fusiform cell?

A

These are cells that are wide in the middle but taper towards the ends

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15
Q

Where are smooth muscle nuclei generally located?

A

In the center of the cell

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16
Q

Describe the contraction strength and duration of smooth muscle?

A

Weak and slow contractions

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17
Q

What are the three classifications of skeletal muscle in humans?

A

Type I
Type IIa
Type IIb

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18
Q

What are type I skeletal muscle fibers?

A

Slow, red oxidative fibers

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19
Q

What are type IIa skeletal muscle fibers?

A

Fast, intermediate oxidative-glycolytic fibers

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20
Q

What are type IIb skeletal muscle fibers?

A

Fast, white glycolytic fibers

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21
Q

What do type I skeletal muscle fibers have that creates the dark red color?

A

Lots of myoglobin (dark red in color)

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22
Q

Where does type I skeletal muscle derive its energy?

A

Primarily from aerobic oxidative phosphorylation of fatty acids

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23
Q

Describe the contraction duration and speed of type I skeletal muscle?

A

Slow, continuous contractions over long periods of time

24
Q

What would one find in abundance in type IIa skeletal muscle? (3)

A

Many mitochondria, lots of myoglobin and glycogen (intermediate)

25
Q

How does type IIa skeletal muscle derive its energy?

A

Utilizes both oxidative metabolism and anaerobic glycolysis to produce energy

26
Q

Describe the contraction duration and speed of type IIa skeletal muscle?

A

Rapid contractions and short bursts of activity

27
Q

What would we find lots of in type IIb skeletal muscle?

A

Glycogen, this is what gives this type of muscle the pale color

28
Q

In respect to the other two kinds of skeletal muscle how many mitochondria do type IIb have?

A

Fewer

29
Q

How does type IIb skeletal muscle derive its energy?

A

Primarily via anaerobic glycolysis

30
Q

Describe the contraction duration and speed of type IIb skeletal muscle?

A

Rapid contractions, but fatigue quickly

31
Q

What is the diameter of a myofibril?

A

2 micrometers

32
Q

What is the functional unit of the muscle, smallest unit of contraction ?

A

Sarcomere

33
Q

What is the width of a sarcomere?

A

2.5 micrometers

34
Q

What are the dimensions of a thick (myosin) filament?

A

1.6 micrometers long and 15 nanometers wide

35
Q

What are the dimensions of thin (actin) filaments?

A

1 micrometer in length and 8 nanometers wide

36
Q

A sarcomere extends from what to what?

A

Z disc to Z disc

37
Q

What is the center most line of a sarcomere?

A

The M line

38
Q

What section of a sarcomere immediately surrounds an M line?

A

The H zone

39
Q

What section of a sarcomere surrounds the H zone of a sarcomere?

A

The A band

40
Q

What band in muscle fibers extends between two adjacent sarcomeres?

A

The I band

41
Q

As a muscle partially contracts what happens to the different of the sarcomere?

A

Thick and thin filaments slide past one another. The sarcomere, I band, and H zone are narrower and shorter, Z discs get closer together

42
Q

When a muscle fully contracts what happens to the different parts of the sarcomere?

A

The H zone and I band dissapear, and the sarcomere is at its shortest length. The thick and the thin filaments do not change lenght. Z discs again get closer together

43
Q

The sarcoplasmic reticulum that butts up against the T tubule is called what?

A

Terminal cisternae

44
Q

What is a neuromuscular junction?

A

(Motor end plate) this is a chemical synapse between a motor (efferent) neuron and a skeletal muscle fiber (cell)

45
Q

What is a motor unit?

A

Defined as the motor (efferent) neuron and all the muscle fibers (cells) it innervates

46
Q

What is the function of the troponin complex?

A

To block the myosin head from interacting with the actin filament, thus preventing contraction

47
Q

What is the first step of skeletal muscle contraction?

A

Myosin cross bridge attaches to the actin myofilament

48
Q

What is the second step of skeletal muscle contraction?

A

Working stroke- the myosin head pivots and bends as it pulls on the actin filament, sliding it toward the M line

49
Q

What is the third step of skeletal muscle contraction?

A

As new ATP attaches to the myosin head, the cross bridge detaches

50
Q

What is the fourth step of skeletal muscle contraction?

A

As ATP is split into ADP and P(inorganic), cocking of the myosin head occurs

51
Q

What are the three connective tissue sheaths associated with skeletal muscle?

A

Endomysium, perimysium, and epimysium

52
Q

What layer of connective tissue immediately surrounds the muscle fiber (cell)?

A

Endomysium

53
Q

How many T tubules do skeletal muscle sarcomeres have and where?

A

Two per sarcomere at A-I junction

54
Q

How many T tubules do cardiac muscle sarcomeres have and where?

A

One per sarcomere at Z line

55
Q

Do cardiac muscle fibers have diads or triads associated with the T tubule?

A

Diads

56
Q

Do skeletal muscle fibers have diads or triads associated with the T tubule?

A

Triads