Histology Of Muscles

Question 1

What is the architecture of skeletal muscle?

Answer 1

1. Muscle
2. Fascicles/ bundles
3. Muscle cell/ fibre
4. Myofibrils
5. Protein filaments/ Myofilaments (actin & myosin)

Question 2

What is a sarcomere?

Answer 2

The functional unit of muscle, located between two Z-lines.

Question 3

What are the three types of muscle tissue?

Answer 3

• Skeletal muscles
• Cardiac muscles
• Smooth muscles

Question 4

What is the primary role of dystrophin?

Answer 4

Involved in Duchenne’s muscular dystrophy; its absence causes progressive muscle weakness

Question 5

What are the connective tissue coverings of muscle?

Answer 5

• Epimysium: covers entire muscle
• Perimysium: covers fiber bundles (fascicles)
• Endomysium: covers individual fibers

Question 6

What is the role of muscle spindles?

Answer 6

Mechanoreceptor essential for proprioception, sensitive to stretch.

Question 7

Fill in the blank: The cytoplasm of a muscle cell is called _______.

Answer 7

sarcoplasm

Question 8

What is a T-triad?

Answer 8

Made up of a T-tubule and two terminal cisternae.

Question 9

What is the structure of a muscle cell/fibre?

Answer 9

• Long cylindrical structure
• Unbranched
• Multinucleated cell
• Cytoplasm filled with actin & myosin
• Oval nuclei in the periphery

Question 10

True or False: Actin and myosin are organized into sarcomeres in smooth muscle.

Answer 10

False

Question 11

What happens to the I-band and H-band during muscle contraction?

Answer 11

They shorten, but the A band remains constant.

Question 12

What are the two types of skeletal muscle fibers?

Answer 12

• Type 1: Oxidative, slow twitch, red
• Type 2: Glycolytic, fast twitch, white

Question 13

What is the function of satellite cells in muscle tissue?

Answer 13

Play a role in the repair of damaged muscle fibers.

Question 14

What is the function of the neuromuscular junction?

Answer 14

Axon terminals of motor neurons release neurotransmitters to the sarcolemma of muscle fibers.

Question 15

What is the role of the basal lamina in muscle tissue?

Answer 15

Covers each muscle fiber and is immediately outside the sarcolemma.

Question 16

Fill in the blank: The contractile unit of the myofibril is called a _______.

Answer 16

sarcomere

Question 17

What is the difference between extrafusal and intrafusal fibers?

Answer 17

• Extrafusal fibers: normal muscle fibers
• Intrafusal fibers: located within the muscle spindle

Question 18

What is the significance of the osteotendinous junction?

Answer 18

Show fibrous or fibrocartilaginous insertions, providing compressibility and resistance to varied forces.

Question 19

What are the main muscle proteins involved in contraction?

Answer 19

• Actin
• Myosin
• Titin
• Dystrophin

Question 20

True or False: The I-band is formed by overlapping thick filaments.

Answer 20

False

Question 21

What is the structural feature of a muscle cell that allows for quick signal transmission?

Answer 21

T-tubules

Question 22

What is the role of the perimysium in muscle tissue?

Answer 22

Covers fiber bundles (fascicles) and contains neuromuscular spindles.

Question 23

What occurs at the myotendinous junction?

Answer 23

Interlocking of muscle fibers and tendinous collagen.

Question 24

Fill in the blank: The term ‘sarcoplasm’ refers to the _______ of a muscle cell.

Answer 24

cytoplasm

Question 25

What are terminal cisternae?

Answer 25

Expanded larger sacs of sarcoplasmic reticulum.

Question 26

What type of muscle fibers are fatigue-resistant and suited for sustained activity?

Answer 26

Type 1: Oxidative, slow twitch, red

Question 27

What are the collagen types found in the connective tissue coverings of muscles?

Answer 27

* Type I: Epimysium and Perimysium * Type III: Endomysium * Type IV: Basal lamina

Question 28

True or False: Muscle contraction results in a change in the length of the thin and thick filaments.

Answer 28

False

Question 29

What type of muscle is voluntary and striated?

Answer 29

Skeletal muscle

Question 30

What type of muscle is involuntary and striated?

Answer 30

Cardiac muscle

Question 31

What type of muscle is involuntary and non-striated?

Answer 31

Smooth muscle

Question 32

What is a fascicle in muscle structure?

Answer 32

Bundles of muscle fibers

Question 33

What are the contractile units of muscle fibers called?

Answer 33

Sarcomeres

Question 34

What fills the cytoplasm of muscle cells?

Answer 34

Actin and myosin

Question 35

What is the plasma membrane of a muscle cell called?

Answer 35

Sarcolemma

Question 36

What surrounds the T-tubules in muscle cells?

Answer 36

Terminal cisternae

Question 37

What is the function of the sarcoplasmic reticulum?

Answer 37

Calcium storage and release

Question 38

What defines the limits of the A band in skeletal muscles?

Answer 38

Thick and overlapping thin filaments

Question 39

What is the I band in muscle structure?

Answer 39

Isotropic, non-overlapping thin filaments

Question 40

What does the M line represent?

Answer 40

Myosin filaments connected by protein in center

Question 41

What happens during muscle contraction to the I and H bands?

Answer 41

They shorten

Question 42

What is dystrophin's role in muscle cells?

Answer 42

Connects myofilaments to connective tissue

Question 43

What covers the entire muscle?

Answer 43

Epimysium

Question 44

What covers fiber bundles in muscle?

Answer 44

Perimysium

Question 45

What type of muscle fibers are Type 1?

Answer 45

Oxidative, slow twitch, red

Question 46

What type of muscle fibers are Type 2?

Answer 46

Glycolytic, fast twitch, white

Question 47

What type of connective tissue is tendon made of?

Answer 47

Irregular dense connective tissue

Question 48

What is the myotendinous junction?

Answer 48

Interlocking of muscle fibers and tendinous collagen

Question 49

What is the role of satellite cells in muscle?

Answer 49

Repair muscle fibers after acute injury

Question 50

What are the nuclei in tendons referred to as?

Answer 50

Tenocytes

Question 51

What is the osteotendinous junction?

Answer 51

Tendon fibers into cartilage, leading to bone

Question 52

True or False: The A band of a sarcomere changes length during contraction.

Answer 52

False

Question 53

Fill in the blank: The cytoplasm of muscle cells is also known as _______.

Answer 53

Sarcoplasm