Muscle Classification and Properties

These flashcards cover key concepts related to muscle classification and properties as discussed in the lecture notes.

What are the three types of muscle tissue?

Skeletal, Cardiac, Smooth.

What is the ability of muscular tissue to contract called?

Contractility.

What is the main function of cardiac muscle?

Propels blood into circulation; involuntary control.

Where is smooth muscle primarily located?

In the walls of hollow organs.

What feature distinguishes skeletal muscle from cardiac and smooth muscle?

It is voluntary and striated.

What is the role of titin in muscle structure?

It anchors myosin and contributes to elasticity.

What happens to the I band during skeletal muscle contraction?

The I band shortens.

What protein complex blocks myosin binding sites on actin in the absence of calcium?

Tropomyosin.

How do myosin filaments structurally form and function?

Myosin filaments consist of heavy and light chains that facilitate cross-bridge formation during contraction.

What causes the muscle to contract when calcium binds to troponin?

The troponin-tropomyosin complex moves, exposing actin's binding sites for myosin.

What are the connective tissue layers associated with skeletal muscle?

Epimysium, Perimysium, and Endomysium.

What is the primary energy source for muscle contraction?

ATP.

What occurs in anaerobic glycolysis?

Only 2 ATP are formed per glucose, and lactic acid is produced.

What characterizes the appearance of cardiac muscle cells?

Branching, striated, generally uninucleate cells with intercalated discs.

What is the term for the network of T-tubules and terminal cisternae in skeletal muscle?

Sarcoplasmic reticulum.

What are the three types of muscle tissue?

Skeletal muscle, which is attached to bones and is responsible for voluntary movements; Cardiac muscle, which makes up the heart and is responsible for involuntary pumping of blood; Smooth muscle, which is found in the walls of hollow organs like the intestines and blood vessels, also under involuntary control.

What is the ability of muscular tissue to contract called?

Contractility refers to the ability of muscle fibers to shorten and generate force, allowing for movement and support of the body's structures.

What is the main function of cardiac muscle?

The primary function of cardiac muscle is to propel blood into circulation throughout the body, providing involuntary control over heartbeats to maintain blood flow.

Where is smooth muscle primarily located?

Smooth muscle is primarily located within the walls of hollow organs such as the stomach, intestines, bladder, and blood vessels, aiding in involuntary movements like digestion and blood flow.

What feature distinguishes skeletal muscle from cardiac and smooth muscle?

Skeletal muscle is characterized by its voluntary control and striated appearance, meaning it has alternating light and dark bands, allowing for precise control of movements.

What is the role of titin in muscle structure?

Titin is a large protein that anchors myosin filaments to the Z-line in sarcomeres, providing structural stability, elasticity, and restoring muscle length after stretching.

What happens to the I band during skeletal muscle contraction?

During skeletal muscle contraction, the I band shortens as the actin filaments slide past the myosin filaments, leading to the contraction of the sarcomere.

What protein complex blocks myosin binding sites on actin in the absence of calcium?

Tropomyosin is the protein complex that wraps around actin filaments, blocking the binding sites for myosin in a relaxed muscle state, preventing contraction.

How do myosin filaments structurally form and function?

Myosin filaments are composed of heavy chains that form a long tail and a head, which interacts with actin filaments during contraction, facilitating cross-bridge formation.

What causes the muscle to contract when calcium binds to troponin?

When calcium ions bind to troponin, it causes a conformational change in the troponin-tropomyosin complex, moving tropomyosin away from actin's binding sites, allowing myosin heads to bind and initiate contraction.

What are the connective tissue layers associated with skeletal muscle?

Skeletal muscle is enveloped in three connective tissue layers: Epimysium, which surrounds the entire muscle; Perimysium, which groups muscle fibers into bundles (fascicles); and Endomysium, which surrounds individual muscle fibers.

What is the primary energy source for muscle contraction?

ATP (adenosine triphosphate) is the primary energy source required for muscle contraction, providing the energy needed for the detachment of myosin heads from actin and to reset the contraction process.

What occurs in anaerobic glycolysis?

In anaerobic glycolysis, glucose is broken down without oxygen, producing only 2 ATP molecules per glucose molecule along with lactic acid as a byproduct, contributing to muscle fatigue.

What characterizes the appearance of cardiac muscle cells?

Cardiac muscle cells are uniquely characterized by their branching structure, striations, and typically single nuclei, along with intercalated discs that facilitate electrical and mechanical coupling between cells.

What is the term for the network of T-tubules and terminal cisternae in skeletal muscle?

The sarcoplasmic reticulum is the specialized organelle in skeletal muscle that stores calcium ions and regulates their release during contraction, with T-tubules facilitating the transmission