Muscle Types and Histology Quiz

Spindle-shaped cells with tapered ends, lacking striations due to the absence of sarcomeres. Actin and myosin filaments are organized less regularly compared to skeletal muscle. Responsible for slow, sustained contractions triggered by various stimuli.

Dense bodies within smooth muscle cells serve as attachment points for actin filaments. They contribute to the coordinated contraction of the muscle by transmitting force.

Smooth muscle cells have a remarkable ability to regenerate, with pericytes (cells lining blood vessels) dividing and generating new smooth muscle cells. They can also increase in size through hypertrophy.

Skeletal muscle fibers are large, elongated cells with multiple nuclei located at the periphery. Each fiber contains numerous myofibrils, which consist of organized arrangements of thick (myosin) and thin (actin) filaments.

The repeating units within skeletal muscle fibers, responsible for muscle contraction and relaxation. Each sarcomere contains overlapping thick and thin filaments arranged in a precise pattern.

During development, multiple mononucleated cells called myoblasts fuse together to form a single multinucleated skeletal muscle fiber. This fusion process allows for the formation of large, powerful muscle cells.

The banding pattern observed in skeletal muscle fibers is caused by the regular arrangement of sarcomeres within the myofibrils. These bands are crucial for muscle contraction and relaxation.

The ability of a muscle to receive and respond to a stimulus, usually a nerve impulse.

The ability of a muscle to shorten and generate force.

The ability of a muscle to be stretched or elongated.

The ability of a muscle to return to its original shape after being stretched.

The process where thin actin filaments slide past thick myosin filaments, shortening the sarcomere and causing muscle contraction.

A single motor neuron and all the muscle fibers it innervates.

The state of continuous partial contraction of muscle fibers, helping maintain posture and readiness for action.

A sustained and forceful muscle contraction caused by rapid and repeated nerve stimulation.

The period following strenuous exercise when the body replenishes oxygen levels and removes waste products.

Muscle fibers that contract slowly, are fatigue-resistant, and efficient during long, low-intensity activities. They appear red due to a high myoglobin content.

Muscle fibers that contract quickly and powerfully, but fatigue rapidly. They are important for explosive movements.

A type of Type II muscle fiber that is fast-twitch, moderately resistant to fatigue, and uses both oxidative and glycolytic metabolism.

A type of Type II muscle fiber that is fast-twitch, fatigues quickly, and relies heavily on glycolysis for energy.

The ability to produce force over an extended period. It is related to the efficiency of energy production and utilization.

The ability to exert maximal force in a single effort. It is related to the size and number of muscle fibers.

The process by which muscle cells increase in size in response to training. It involves increased protein synthesis within the muscle fibers.

Specialized sensory receptors that detect muscle length and changes in length. They are important for muscle coordination and movement control.

Specialized sensory receptors that detect tension in tendons. They help prevent excessive force and protect muscles from injury.

Sensory receptors located within joints that provide information about joint angle and motion. They are important for proprioception (body awareness).

The breakdown of proteins into smaller peptides or amino acids, often occurring during digestion or within cells for protein synthesis and repair.

A type of protein hydrolysis that specifically breaks down dipeptides (two amino acids joined together) into individual amino acids.

The most abundant proteins involved in muscle contraction. They generate movement by converting chemical energy into mechanical energy.

A protein found in muscle tissue that binds oxygen for energy usage. The amount of myoglobin determines the color of the muscle.

A protein found in muscle cells that binds calcium ions, triggering muscle contraction.

Long, thread-like structures within muscle cells composed of proteins that allow for contraction.

Thick filaments within myofibrils, primarily made of myosin.

Thin filaments within myofibrils, primarily composed of actin, tropomyosin, and troponin.

A protein that forms thick filaments within myofibrils and plays a crucial role in muscle contraction by interacting with actin.

A globular protein that forms thin filaments within myofibrils and acts as a binding site for myosin during muscle contraction.

The core of the actin filament consists of two intertwined chains of fibrillar actin (F-actin).

Two tropomyosin chains are attached to the F-actin filaments by flexible joints, located within the groove formed by the two actin chains.

Troponin is a protein complex attached to tropomyosin, consisting of three subunits: Troponin C (binds to calcium), Troponin I (inhibits muscle contraction), and Troponin T (binds to tropomyosin).

The interaction between myosin heads and actin filaments forms actomyosin, generating force that causes the thick (myosin) and thin (actin) filaments to slide against each other, leading to muscle contraction.

Creatine and phosphocreatine are nitrogenous compounds found in muscle tissue. Phosphocreatine can donate a phosphate group to ADP, regenerating ATP, essential for muscle contraction.