Muscle Anatomy

Question 1

Describe the structure of skeletal muscle.

Answer 1

Skeletal muscle is striated, multinucleated, and under voluntary control.

Question 2

What are the characteristics of cardiac muscle?

Answer 2

Cardiac muscle is striated, mononucleated, and involuntary.

Question 3

Define smooth muscle.

Answer 3

Smooth muscle is non-striated, mononucleated, composed of spindle-shaped cells, and under involuntary control.

Question 4

What are the three types of vertebrate muscle mentioned in the content?

Answer 4

The three types are striated (skeletal) muscle, smooth (visceral) muscle, and striated (cardiac) muscle.

Question 5

How is skeletal muscle different from cardiac muscle in terms of nucleation?

Answer 5

Skeletal muscle is multinucleated while cardiac muscle is mononucleated.

Question 6

Do skeletal muscles fall under voluntary or involuntary control?

Answer 6

Skeletal muscles fall under voluntary control.

Question 7

Describe the appearance of smooth muscle cells.

Answer 7

Smooth muscle cells are spindle-shaped.

Question 8

What is the suggested reading mentioned in the content?

Answer 8

The suggested reading is Vander’s Human Physiology Chapter 9.

Question 9

Describe the anatomy of skeletal muscle.

Answer 9

Skeletal muscle is composed of muscle fibers, each containing myofibrils that are stacked along the entire length. Myofibrils, in turn, consist of parallel filaments - thick filaments made of myosin and thin filaments made of actin.

Question 10

What is the composition of thick filaments in a myofibril?

Answer 10

Thick filaments in a myofibril are composed of myosin with a diameter of 15nm.

Question 11

What is the composition of thin filaments in a myofibril?

Answer 11

Thin filaments in a myofibril are composed of actin with a diameter of 5nm.

Question 12

Define the striated appearance of skeletal muscle.

Answer 12

Skeletal muscle has a striated appearance due to the specific arrangement of myosin and actin filaments, creating alternating light I bands and dark A bands.

Question 13

What is the structure of each muscle fiber in skeletal muscle?

Answer 13

Each muscle fiber contains an array of myofibrils along its entire length.

Question 14

How are the myofibrils arranged within a muscle fiber?

Answer 14

Myofibrils within a muscle fiber are stacked along the entire length.

Question 15

Describe the content of I bands in skeletal muscle.

Answer 15

I bands in skeletal muscle are light bands that contain thin filaments.

Question 16

Describe the content of A bands in skeletal muscle.

Answer 16

A bands in skeletal muscle are dark bands that contain thick and thin filaments.

Question 17

What gives skeletal muscle its striated appearance?

Answer 17

The specific arrangement of myosin and actin filaments in skeletal muscle gives it a striated appearance.

Question 18

What is the significance of the parallel arrangement of filaments in myofibrils?

Answer 18

The parallel arrangement of filaments in myofibrils allows for the coordinated contraction of muscle fibers.

Question 19

How do thick and thin filaments contribute to muscle contraction?

Answer 19

Thick and thin filaments in myofibrils slide past each other during muscle contraction, leading to muscle shortening.

Question 20

Describe the structure of myosin filaments in skeletal muscle.

Answer 20

Myosin filaments in skeletal muscle are thick filaments with a diameter of 15nm.

Question 21

Describe the structure of actin filaments in skeletal muscle.

Answer 21

Actin filaments in skeletal muscle are thin filaments with a diameter of 5nm.

Question 22

Describe the sliding filament theory in muscle contraction.

Answer 22

The sliding theory states that muscle contraction occurs as actin filaments slide over myosin filaments, causing sarcomeres to shorten.

Question 23

What are the two main types of muscle fibers and their characteristics?

Answer 23

The two main types of muscle fibers are slow twitch (Type I) fibers, which are fatigue-resistant and used for endurance activities, and fast twitch (Type II) fibers, which are used for short, fast bursts of activity.

Question 24

Define Type I muscle fibers and their function.

Answer 24

Type I muscle fibers are oxidative, fatigue-resistant, have slow contraction times, and are used for aerobic activities requiring long endurance.

Question 25

How do Type IIa muscle fibers differ from Type IIb fibers?

Answer 25

Type IIa muscle fibers are oxidative/glycolytic, fatigue-resistant, with fast contraction times, while Type IIb fibers are glycolytic, fatigue-sensitive, and have very fast contraction times.

Question 26

Describe the characteristics of Type IIb muscle fibers.

Answer 26

Type IIb muscle fibers are glycolytic, fatigue-sensitive, have very fast contractions, are fast, large, white, and produce very high force. They are used for short-term anaerobic activities.

Question 27

Explain the importance of the myotendinous junction in muscle function.

Answer 27

The myotendinous junction is crucial for transmitting force from muscle to tendon, allowing for efficient movement and force generation.

Question 28

What is the role of the neuromuscular junction in muscle contraction?

Answer 28

The neuromuscular junction is where the motor neuron meets the muscle fiber, allowing for the transmission of signals (action potentials) to initiate muscle contraction.

Question 29

Describe the function of the muscle cell plasma membrane, also known as the sarcolemma.

Answer 29

The muscle cell plasma membrane, or sarcolemma, surrounds the muscle fiber and is essential for maintaining the cell’s integrity, regulating the passage of substances, and transmitting signals for muscle contraction.

Question 30

What components make up the basement membrane of a muscle fiber?

Answer 30

The basement membrane of a muscle fiber consists of nidogen, laminin, collagen IV, and perlecan.

Question 31

How are satellite cells positioned in relation to the sarcolemma and basement membrane in muscle fibers?

Answer 31

Satellite cells (muscle stem cells) lie in their own niche between the sarcolemma and the basement membrane.

Question 32

Define the role of satellite cells in muscle fibers.

Answer 32

Satellite cells are muscle stem cells that play a role in muscle regeneration and repair.

Question 33

What structures are found in a muscle besides muscle fibers?

Answer 33

In addition to muscle fibers, a muscle contains myofibrils, muscle cell nuclei, nerves, blood vessels, endomysium, and perimysium.

Question 34

Describe the location of a Satellite Cell in relation to a muscle fiber.

Answer 34

Located outside of the sarcolemma (plasma membrane) of the muscle fiber but below the basement membrane surrounding the muscle fiber.

Question 35

What is the function of a Satellite Cell in muscle cell regeneration?

Answer 35

Regulated by Satellite Cells, muscle cell regeneration is controlled by undifferentiated stem cells.

Question 36

Describe the role of capillary beds surrounding muscle fibers in the context of muscle function.

Answer 36

Capillary beds surrounding muscle fibers deliver necessary oxygen and nutrients, carry away metabolic waste, and provide an extensive vascular network for muscles that require large amounts of energy.

Question 37

What is the function of capillaries in skeletal muscle regarding nutrient and waste transport?

Answer 37

Capillaries in skeletal muscle wrap around muscle fibers to carry nutrients, oxygen, fluids, carbon dioxide, and waste materials to veins and the lymph system.

Question 38

Define quiescent satellite cell in the context of muscle biology.

Answer 38

A quiescent satellite cell is a dormant muscle stem cell located on top of sarcomeres.

Question 39

How are activated satellite cells positioned in relation to muscle fibers?

Answer 39

Activated satellite cells are located on an isolated muscle fiber.

Question 40

Describe the significance of capillaries in skeletal muscle as a source of stem cells.

Answer 40

Capillaries in skeletal muscle are important as they serve as a source of stem cells.

Question 41

What is the role of nerve and blood vessel supply in muscle function?

Answer 41

Nerve and blood vessel supply in muscles provide necessary oxygen, nutrients, and remove metabolic waste produced by muscle fibers.

Question 42

Explain the importance of an extensive vascular network in muscle tissue.

Answer 42

An extensive vascular network in muscle tissue is crucial for delivering oxygen and nutrients while removing metabolic waste.

Question 43

How do capillaries contribute to muscle function beyond nutrient transport?

Answer 43

Capillaries in muscle tissue also serve as a source of stem cells.

Question 44

Describe the location of quiescent satellite cells within muscle tissue.

Answer 44

Quiescent satellite cells are located on top of sarcomeres.

Question 45

What are the functions of capillary beds surrounding muscle fibers?

Answer 45

Capillary beds surrounding muscle fibers deliver oxygen and nutrients, remove metabolic waste, and provide an extensive vascular network for energy-demanding muscles.