Muscle Tissue Histology

Question 1

What is muscle cytoplasm referred to as?

Answer 1

Sarcoplasm

Question 2

What is muscle smooth endoplasmic reticulum referred to as?

Answer 2

Sarcoplasmic reticulum

Question 3

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

Answer 3

Sarcolemma

Question 4

What is a muscle cell referred to as?

Answer 4

Muscle fiber or myofiber

Question 5

What embryonic tissue is muscle derived from?

Answer 5

Mesoderm

Question 6

What are the three types of muscle tissue?

Answer 6

Skeletal, cardiac, and smooth

Question 7

What are the four special characteristics of muscle tissue?

Answer 7

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

Question 8

What are the 4 functions of muscle tissue?

Answer 8

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

Question 9

What are five characteristics of skeletal muscle

Answer 9

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

Question 10

What is the function of skeletal muscle?

Answer 10

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

Question 11

Where is skeletal muscle located?

Answer 11

In skeletal muscles attached to bones and occasionally skin

Question 12

Describe cardiac muscle?

Answer 12

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

Question 13

What is the function of cardiac muscle?

Answer 13

As it contracts it propels blood into circulation, involuntary control

Question 14

What is a fusiform cell?

Answer 14

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

Question 15

Where are smooth muscle nuclei generally located?

Answer 15

In the center of the cell

Question 16

Describe the contraction strength and duration of smooth muscle?

Answer 16

Weak and slow contractions

Question 17

What are the three classifications of skeletal muscle in humans?

Answer 17

Type I
Type IIa
Type IIb

Question 18

What are type I skeletal muscle fibers?

Answer 18

Slow, red oxidative fibers

Question 19

What are type IIa skeletal muscle fibers?

Answer 19

Fast, intermediate oxidative-glycolytic fibers

Question 20

What are type IIb skeletal muscle fibers?

Answer 20

Fast, white glycolytic fibers

Question 21

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

Answer 21

Lots of myoglobin (dark red in color)

Question 22

Where does type I skeletal muscle derive its energy?

Answer 22

Primarily from aerobic oxidative phosphorylation of fatty acids

Question 23

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

Answer 23

Slow, continuous contractions over long periods of time

Question 24

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

Answer 24

Many mitochondria, lots of myoglobin and glycogen (intermediate)

Question 25

How does type IIa skeletal muscle derive its energy?

Answer 25

Utilizes both oxidative metabolism and anaerobic glycolysis to produce energy

Question 26

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

Answer 26

Rapid contractions and short bursts of activity

Question 27

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

Answer 27

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

Question 28

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

Answer 28

Fewer

Question 29

How does type IIb skeletal muscle derive its energy?

Answer 29

Primarily via anaerobic glycolysis

Question 30

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

Answer 30

Rapid contractions, but fatigue quickly

Question 31

What is the diameter of a myofibril?

Answer 31

2 micrometers

Question 32

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

Answer 32

Sarcomere

Question 33

What is the width of a sarcomere?

Answer 33

2.5 micrometers

Question 34

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

Answer 34

1.6 micrometers long and 15 nanometers wide

Question 35

What are the dimensions of thin (actin) filaments?

Answer 35

1 micrometer in length and 8 nanometers wide

Question 36

A sarcomere extends from what to what?

Answer 36

Z disc to Z disc

Question 37

What is the center most line of a sarcomere?

Answer 37

The M line

Question 38

What section of a sarcomere immediately surrounds an M line?

Answer 38

The H zone

Question 39

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

Answer 39

The A band

Question 40

What band in muscle fibers extends between two adjacent sarcomeres?

Answer 40

The I band

Question 41

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

Answer 41

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

Question 42

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

Answer 42

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

Question 43

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

Answer 43

Terminal cisternae

Question 44

What is a neuromuscular junction?

Answer 44

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

Question 45

What is a motor unit?

Answer 45

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

Question 46

What is the function of the troponin complex?

Answer 46

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

Question 47

What is the first step of skeletal muscle contraction?

Answer 47

Myosin cross bridge attaches to the actin myofilament

Question 48

What is the second step of skeletal muscle contraction?

Answer 48

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

Question 49

What is the third step of skeletal muscle contraction?

Answer 49

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

Question 50

What is the fourth step of skeletal muscle contraction?

Answer 50

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

Question 51

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

Answer 51

Endomysium, perimysium, and epimysium

Question 52

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

Answer 52

Endomysium

Question 53

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

Answer 53

Two per sarcomere at A-I junction

Question 54

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

Answer 54

One per sarcomere at Z line

Question 55

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

Answer 55

Diads

Question 56

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

Answer 56

Triads