Muscle Tissue Overview and Structure

Skeletal Muscle is attached to the skeleton and is responsible for voluntary movement of the body.

Cardiac muscle forms the heart wall and is responsible for pumping blood throughout the body. It is involuntary, meaning you don't consciously control its contractions.

Smooth muscle is found in the walls of hollow structures like blood vessels, airways, and organs. It is responsible for involuntary movements like digestion and blood vessel constriction.

Skeletal muscle is composed of bundles of muscle fibers held together by connective tissue coverings.

Epimysium is the dense connective tissue covering that surrounds the entire skeletal muscle.

Fascicles are bundles of muscle fibers within a skeletal muscle, covered by perimysium.

Perimysium is the connective tissue that surrounds each fascicle within a skeletal muscle.

Endomysium is the delicate connective tissue that wraps around individual muscle fibers.

The plasma membrane surrounding a muscle fiber, it conducts action potentials to trigger muscle contraction.

A network of interconnected sacs that store and release calcium ions (Ca2+) within a muscle fiber, essential for muscle contraction.

The basic unit of muscle contraction, extending from one Z-disc to the next within a myofibril.

Fine protein fibers that run the length of a muscle fiber, composed of either 'thick' or 'thin' filaments.

A type of myofilament composed primarily of the protein actin, also includes troponin and tropomyosin.

A type of myofilament composed primarily of the protein myosin, responsible for generating the force of muscle contraction.

Proteins that directly participate in the process of generating force during muscle contraction.

Proteins that regulate the interaction between contractile proteins, switching the process of contraction on and off.

The twisted tail of the myosin molecule forms the shaft of the thick filament and points towards the M-line.

Myosin heads, shaped like golf clubs, bind to actin and ATP. Each head has two binding sites, one for actin and one for ATP.

Tropomyosin is a rope-like protein that covers the actin binding sites during relaxation, preventing myosin from binding to actin.

Troponin, a protein with three binding sites, binds to calcium during contraction.

When calcium binds to troponin, it activates troponin, which pulls tropomyosin away from actin, exposing the actin binding sites for myosin.

The sliding filament mechanism describes how thick and thin filaments slide past each other during muscle contraction, shortening the sarcomere.

Titin is a giant, elastic protein that anchors the thick filament to the Z disc and M line, helping sarcomeres return to their resting length after contraction.

Myomesin molecules form the M line, which holds the thick filaments in alignment, ensuring proper sarcomere structure.

The process by which red blood cells (RBCs), white blood cells (WBCs), and platelets are formed in the bone marrow.

The region in a long bone that lies between the diaphysis (shaft) and the epiphysis (end).

The tough outer covering of bone tissue made of dense connective tissue. It helps protect the bone and provides attachment for tendons and ligaments.

Specialized cells that build and maintain bone tissue. Osteoblasts are immature cells that actively produce bone matrix, while mature bone cells are called osteocytes.

Concentric rings of bone tissue that surround the central canal in compact bone. They form the basic functional unit of compact bone, also called an osteon.

The functional unit of contraction in a muscle fiber, responsible for muscle shortening during contraction. It contains thick (myosin) and thin (actin) filaments arranged in a specific structure.

A bundle of muscle fibers within a skeletal muscle, covered by perimysium.

The specialized plasma membrane of a muscle fiber, responsible for carrying electrical signals that trigger muscle contraction.

This protein forms thick filaments within the sarcomere and interacts with actin to generate muscle contraction. It has heads that bind to actin and swivel to pull the thin filaments toward the center of the sarcomere.

This protein forms thin filaments within the sarcomere, interacts with myosin to generate muscle contraction. It is also associated with tropomyosin and troponin.

A type of skeletal muscle fiber that is well-suited for prolonged, low-intensity activity. They contain lots of mitochondria and blood capillaries for aerobic metabolism.