muscular system

What are the three types of muscle tissue?

Skeletal muscle, cardiac muscle, smooth muscle.

What are the five primary functions of skeletal muscle?

Move the skeleton, maintain posture, support soft tissues, guard entrances and exits, maintain body temperature.

What covers the entire muscle?

Epimysium.

What divides the muscle into fascicles?

Perimysium.

What covers each muscle fiber?

Endomysium.

What is the role of myofibrils in muscle fibers?

They are cylinder-shaped structures that contain thick and thin filaments that create muscle contractions.

What is a sarcomere?

The smallest functional unit of a skeletal muscle fiber.

What is the significance of the sliding filament theory?

It explains how muscle contraction occurs through the sliding of thin filaments past thick filaments.

What characterizes cardiac muscle tissue?

It is striated, branched, and contains intercalated discs for rapid communication.

What are slow-twitch fibers?

Muscle fibers that are aerobic, have endurance, and are resistant to fatigue.

What differentiates fast-twitch fibers?

They are anaerobic, designed for strength, and fatigue easily.

What are the major actions of skeletal muscles?

Flexion, extension, adduction, abduction.

What are the roles of synergists in muscle action?

They help the prime mover work efficiently.

What do you call the muscle that is primarily responsible for a movement?

Prime mover or agonist.

What muscle assists in the flexion of the elbow?

Biceps brachii.

What function do the intercostal muscles serve?

They elevate and depress the ribs during breathing.

What happens to a sarcomere during muscle contraction?

The I bands get smaller, and Z lines move closer together.

What is a tendon?

A bundle of collagen fibers that attaches muscle to bone.

What is the role of the rotator cuff?

It stabilizes the shoulder joint.

What muscle group is primarily involved in hip flexion?

Iliopsoas.

What are the muscle groups that move the thigh?

Gluteal group, adductors, and iliopsoas.

What are the primary movers of the knee?

Quadriceps (extensors) and hamstrings (flexors).

What are the major superficial and deep muscles of the foot?

Gastrocnemius and soleus (superficial), tibialis posterior (deep).

What is the action of tibialis anterior?

Dorsiflexion and inversion of the foot.

What action do the biceps brachii and triceps brachii perform at the elbow joint respectively?

Biceps brachii flexes the elbow; triceps brachii extends the elbow.

What occurs at the Z line of a sarcomere?

It marks the boundary at each end of the sarcomere.

What do you call the muscle that opposes the movement of another muscle?

Antagonist.

Muscle Tissue

One of the four primary tissue types consisting of elongated muscle cells specialized for contraction.

Skeletal Muscle

Type of muscle tissue that is composed of skeletal muscle fibers, connective tissue, nerves, and blood vessels.

Cardiac Muscle

Muscle tissue found only in the heart, characterized by striated and branched cells connected by intercalated discs.

Smooth Muscle

Type of muscle tissue that is spindle-shaped, single-nucleate, and found in the walls of organs.

Epimysium

Connective tissue layer that covers the entire muscle.

Perimysium

Connective tissue that divides muscles into fascicles or bundles of muscle fibers.

Endomysium

Connective tissue that covers each muscle fiber and ties fibers together.

Muscle Fiber

Individual muscle cell; also known as muscle fiber.

Tendon

Bundle of fibers that attaches muscle to bone.

Aponeurosis

Broad sheet of fibers connecting muscles to each other.

Sarcoplasm

Cytoplasm of a muscle fiber, containing organelles and myofibrils.

Myofibrils

Cylinder-shaped structures in muscle fibers made up of thick and thin filaments.

Sarcoplasmic Reticulum

Specialized smooth endoplasmic reticulum that forms a network around each myofibril.

Sarcomeres

Repeating functional units of myofilaments, the smallest functional units of skeletal muscle fiber.

Sliding Filament Theory

Theory explaining muscle contraction through the sliding of thin filaments over thick filaments.

Prime Mover

Muscle that is chiefly responsible for producing a specific movement.

Antagonist

Muscle that opposes the action of another muscle.

Synergist

Muscle that assists the prime mover in performing its action.

Muscle Hypertrophy

Increase in muscle size through exercise and resistance training.

Muscle Atrophy

Decrease in muscle size typically due to lack of use or illness.

Fast-Twitch Fibers

Muscle fibers that are anaerobic, designed for strength, and fatigue easily.

Slow-Twitch Fibers

Muscle fibers that are aerobic, have more endurance, and are resistant to fatigue.