Muscle Tissue Overview

A type of tissue responsible for movement, posture maintenance, joint stabilization, and heat generation.

Cells are elongated and contain myofibrils, giving the sarcoplasm a fibular appearance. They stain acidophilic, indicating the presence of proteins.

A type of connective tissue that surrounds muscle fibers, blood vessels, and nerves. It helps to hold muscle fibers together.

The ability of muscle tissue to shorten or contract.

The ability of muscle tissue to return to its original length after contraction.

The ability of muscle tissue to respond to stimuli.

The ability of muscle tissue to transmit impulses.

A type of muscle tissue that is found in the walls of hollow organs and is responsible for involuntary movements.

Muscle fibers are spindle-shaped or fusiform, meaning they are tapered at both ends. They lack striations and have a single, centrally located nucleus.

Smooth muscle contracts slowly and uniformly, allowing for sustained, involuntary contractions.

Smooth muscle is found in the walls of various internal organs, such as the digestive system, bladder, and blood vessels.

A type of muscle tissue that is found only in the heart. It is responsible for the rhythmic contractions of the heart.

Cardiac muscle is striated, meaning it has a striped appearance under a microscope. It is also involuntary, meaning it contracts automatically without conscious control.

The cardiac conduction system is responsible for generating and conducting electrical impulses in the heart, which triggers muscle contractions and blood pumping. It comprises the sinoatrial node, atrioventricular node, Bundle of His, Purkinje fibers, and left/right branches.

Located at the junction of the superior vena cava and right atrium, the sinoatrial node regulates heart rate based on the body's requirements.

Located on the lower part of the interatrial septum, this node delays cardiac impulses to allow efficient atrial contraction and blood flow before ventricular contraction.

This bundle within the septum of the heart carries cardiac impulses to the ventricles through Purkinje fibers.

These branches carry nerve impulses that cause contraction of the right and left ventricles, respectively.

Located beneath the endocardium, these fibers relay cardiac impulses to the ventricular cells, causing their contraction.

A type of muscle tissue that is attached to the skeleton and allows for voluntary movements. It is striated, meaning it has a striped appearance under a microscope.

Skeletal muscle is responsible for producing skeletal movement, maintaining posture, supporting soft tissues, regulating body temperature, and storing nutrients.

Skeletal muscle is found throughout the body, attached to bones, and responsible for all voluntary movements.

Embryonic cells that fuse to form muscle fibers.

Unfused myoblasts that remain in adult skeletal muscle, helping with muscle regeneration and repair.

The plasma membrane that surrounds the sarcoplasm of a muscle fiber. It contains mitochondria, myofibrils, and other organelles.

A network of tubules that surrounds myofibrils, storing calcium ions that are crucial for muscle contraction.

Cylindrical bundles of myofilaments, composed of thin actin filaments and thick myosin filaments.

Protein filaments within myofibrils, comprised of actin and myosin, responsible for muscle contraction. Thin filaments contain primarily actin, while thick filaments contain primarily myosin.

Repeating functional units of myofilaments responsible for muscle contraction. They are arranged end to end within a myofibril and contain both thick and thin filaments.

Dark bands within a sarcomere, containing thick myosin filaments. They are also referred to as A bands.

Light bands within a sarcomere, containing thin actin filaments. They are also referred to as I bands.

Skeletal muscle fibers that contain abundant myoglobin, mitochondria (sarcosomes), and have a rich blood supply. They are slow contracting, fatigue resistant, and use oxidative phosphorylation for energy.

Skeletal muscle fibers that have less myoglobin, fewer mitochondria (sarcosomes), and a poorer blood supply. They contract quickly, fatigue rapidly, and use anaerobic glycolysis for energy.

Skeletal muscle fibers with characteristics of both red and white fibers, capable of fast contraction and can be converted to fast fibers with training.