Muscle Tissue Overview and Structure

The largest group of tissues in the body, responsible for movement, comprised of skeletal, cardiac, and smooth muscle.

Connective tissue that covers the entire skeletal muscle, giving it its shape and structure.

Bundles of muscle fibers grouped together and covered in perimysium.

Connective tissue that surrounds each fascicle, providing structural support and helping to organize muscle fibers.

Individual muscle cells, surrounded by endomysium.

Connective tissue that wraps individual muscle fibers.

Specialized nerve cells that transmit signals from the brain and spinal cord to skeletal muscles, triggering muscle contractions.

The plasma membrane of a muscle fiber, responsible for transmitting electrical signals and ensuring proper muscle function.

T tubules are thin, tube-like structures that extend from the surface of a muscle fiber to its interior. They act as pathways for action potentials to quickly travel into the muscle fiber, triggering muscle contraction.

The sarcolemma acts as the outer membrane of a muscle fiber. It's responsible for conducting action potentials, which are electrical signals that initiate muscle contraction.

Myofibrils are long, cylindrical contractile units found within muscle fibers. They contain the proteins that enable muscle contraction.

The sarcoplasmic reticulum is a network of membrane-bound sacs that surround each myofibril. It stores and releases calcium ions (Ca2+), which are essential for muscle contraction.

A sarcomere is the basic functional unit of muscle contraction. It's a repeating unit within a myofibril that contains thick and thin filaments.

Thick filaments are primarily composed of the protein myosin, which plays a vital role in muscle contraction by binding to actin.

Thin filaments are made up of three proteins: actin, troponin, and tropomyosin. They interact with thick filaments during muscle contraction.

The A band is the region within a sarcomere that contains both thick and thin filaments, while the I band is the region that only contains thin filaments.

A protein that converts ATP energy into mechanical energy, leading to muscle force production.

Each myosin molecule has two heads, each with an Actin Binding site and an ATP Binding site.

Thin filaments consist of the protein Actin, which forms a helix. They are also composed of two regulatory proteins, Tropomyosin and Troponin.

During muscle relaxation, Tropomyosin covers the Actin Binding site on Actin, preventing Myosin from attaching.

When Calcium binds to Troponin, it activates it, causing it to move Tropomyosin away from the Actin Binding site, allowing for Myosin to bind.

Titin is a large, elastic protein that spans half a sarcomere, from Z disc to M line. It helps anchor thick filaments and keeps the sarcomere from overstretching.

Myomesin molecules form the M line, which helps to align the thick filaments within the sarcomere.

The Sliding Filament Mechanism describes how muscle shortens during contraction. This occurs as thick and thin filaments slide over each other, driven by the movement of Myosin heads along the Actin.

The process by which bone marrow produces red blood cells, white blood cells, and platelets.

Calcium and phosphorus

The functional unit of a muscle fiber, responsible for muscle contraction by the sliding filament theory.

Refers to the process by which the sarcomere shortens during muscle contraction. This occurs as thin filaments (actin) slide past thick filaments (myosin), pulling the Z discs closer to the M line.

A type of muscle fiber that generates ATP primarily through aerobic metabolism, characterized by its high endurance and slow contraction speed.

Muscle fibers that are involved in short bursts of high-intensity activities such as sprinting, are characterized by their fast contraction speed and moderate fatigue resistance.

Types of muscle fibers characterized by their rapid contraction speeds and low endurance, they rely on anaerobic metabolism for ATP production.

A type of muscle fiber that contracts slowly and is fatigue-resistant.