Chapter 10 - Muscular System: Types and Properties of Muscle Tissue

Which type of muscle tissue has the ability to contract and shorten?

Skeletal muscle

Which type of muscle tissue is found in the heart?

Cardiac muscle

Which property of muscle tissue allows it to return to its original shape after being stretched?

Elasticity

Which skeletal muscle function is responsible for maintaining body posture?

Support and maintenance of posture Signup and view all the answers

What is the basic structural unit of skeletal muscle?

Muscle fiber Signup and view all the answers

Which type of muscle tissue is found in the walls of blood vessels and the digestive tract?

Smooth muscle Signup and view all the answers

What is the primary function of the epimysium?

To encase the muscle belly and anchor it to the tendon Signup and view all the answers

Which of the following is NOT a unique structure found in muscle fibers?

Golgi apparatus Signup and view all the answers

What is the function of myoglobin in muscle fibers?

To replace hemoglobin and increase affinity for oxygen at higher temperatures Signup and view all the answers

Which connective tissue layer separates individual muscles?

Deep fascia Signup and view all the answers

What is the primary function of the thick filaments (myosin) in skeletal muscle?

To generate the force for muscle contraction by interacting with the thin filaments Signup and view all the answers

What is the function of the sarcoplasmic reticulum in muscle fibers?

To store and release calcium ions for muscle contraction Signup and view all the answers

Which of the following structures makes up the contractile unit of a myofibril?

Sarcomere Signup and view all the answers

What is the role of the regulatory proteins (troponin and tropomyosin) in the thin filaments?

They control the binding sites for myosin on the actin molecules Signup and view all the answers

What is the purpose of the $M$-line in the organization of the thick and thin filaments?

To anchor the myosin tails in the middle of the sarcomere Signup and view all the answers

What is the significance of the $H$-zone in the sarcomere?

It is the area where only the thick filaments are present, with no overlap with the thin filaments Signup and view all the answers

What is the relationship between the motor neuron and the muscle fibers it innervates?

Each motor neuron innervates a group of muscle fibers, forming a motor unit Signup and view all the answers

What is the significance of the all-or-none response of a motor unit?

It means that all the muscle fibers in a motor unit contract simultaneously Signup and view all the answers

What is the primary reason for increased muscle strength after eccentric contractions?

Increased myosin binding to actin leads to muscle repair and strength gains Signup and view all the answers

In isometric contractions, what is the relationship between the force of contraction and the force of the load?

The force of contraction is equal to the force of the load Signup and view all the answers

Which factor is primarily responsible for determining the amount of muscle tension produced during exercise?

The rate of motor unit recruitment (coding frequency) Signup and view all the answers

Which of the following statements about cardiac muscle is incorrect?

Cardiac muscle fibers are surrounded by all three connective tissue layers (endomysium, perimysium, and epimysium) Signup and view all the answers

Which type of smooth muscle is characterized by individual fibers, each with its own motor neuron terminal?

Multi-unit smooth muscle Signup and view all the answers

What is the approximate muscle mass loss between the ages of 30 and 80?

10% between ages 30-50, and an additional 40% by age 80 Signup and view all the answers

Which of the following correctly describes the order in which energy sources are used during muscle contraction?

Creatine phosphate, glycogen (stored in muscle), fat, glycogen (recruited from liver) Signup and view all the answers

Which of the following statements about slow-twitch (Type I) muscle fibers is NOT true?

They have a high force production. Signup and view all the answers

Which of the following is true about the "wash theory" in relation to muscle fiber types?

It states that fast-twitch (Type IIb) fibers can convert to fast-oxidative (Type IIa) fibers, but not to slow-twitch (Type I) fibers. Signup and view all the answers

What is the primary energy system used by fast-twitch (Type IIb) muscle fibers?

Anaerobic fermentation Signup and view all the answers

Which of the following statements about the distribution of muscle fiber types is true?

A single motor unit can contain different types of muscle fibers. Signup and view all the answers

What is the difference between concentric and eccentric muscle contractions?

Concentric contractions involve muscle shortening, while eccentric contractions involve muscle lengthening. Signup and view all the answers