Muscular System Overview

These flashcards cover key vocabulary and concepts from the lecture on the muscular system.

Skeletal muscle

Muscle that is attached to bones, voluntary and consciously controlled.

Cardiac muscle

Muscle that makes up the heart wall, involuntary and responsible for heart pumping.

Smooth muscle

Muscle found in internal organs, involuntary and regulates various functions.

Fascia

Thin covering of connective tissue around a muscle.

Tendon

Cord-like mass of connective tissue that connects muscle to a bone.

Aponeurosis

Sheet-like mass of connective tissue that connects muscle to bone, skin, or another muscle.

Epimysium

Connective tissue that surrounds the entire muscle, lying beneath the fascia.

Perimysium

Connective tissue that surrounds fascicles within a muscle.

Endomysium

Connective tissue that surrounds muscle fibers (cells) within a fascicle.

Skeletal muscle fiber

Multinucleated cell, the basic unit of skeletal muscles.

Sarcolemma

Cell membrane of muscle fibers.

Sarcoplasm

Cytoplasm of muscle fibers.

Myofibrils

Long, parallel structures in muscle fibers consisting of thin and thick filaments.

Sarcomere

Basic unit of muscle contraction, composed of actin and myosin.

Neuromuscular Junction (NMJ)

Synapse where motor neuron stimulates a skeletal muscle fiber.

Acetylcholine (ACh)

Neurotransmitter used for communication between motor neurons and muscle fibers.

Calcium ions (Ca2+)

Essential for muscle contraction, released from the sarcoplasmic reticulum.

Myoglobin

Oxygen-storing protein in muscles, enhancing aerobic respiration.

Oxygen Debt

The amount of oxygen required to restore muscle to resting state after exertion.

Muscle Fatigue

Inability to contract muscle due to prolonged activity or other factors.

Agonist

Muscle that causes an action.

Antagonist

Muscle whose contraction opposes the action of the agonist.

Hypertrophy

Increase in muscle size due to exercise.

Atrophy

Decrease in muscle size due to disuse.

Skeletal muscle

Muscle that is attached to bones, voluntary and consciously controlled.

Cardiac muscle

Muscle that makes up the heart wall, involuntary and responsible for heart pumping.

Smooth muscle

Muscle found in internal organs, involuntary and regulates various functions.

Fascia

Thin covering of connective tissue around a muscle.

Tendon

Cord-like mass of connective tissue that connects muscle to a bone.

Aponeurosis

Sheet-like mass of connective tissue that connects muscle to bone, skin, or another muscle.

Epimysium

Connective tissue that surrounds the entire muscle, lying beneath the fascia.

Perimysium

Connective tissue that surrounds fascicles within a muscle.

Endomysium

Connective tissue that surrounds muscle fibers (cells) within a fascicle.

Skeletal muscle fiber

Multinucleated cell, the basic unit of skeletal muscles.

Sarcolemma

Cell membrane of muscle fibers.

Sarcoplasm

Cytoplasm of muscle fibers.

Myofibrils

Long, parallel structures in muscle fibers consisting of thin and thick filaments.

Sarcomere

Basic unit of muscle contraction, composed of actin and myosin.

A-band

Dark area of the sarcomere containing the entire length of the thick (myosin) filaments.

I-band

Light area of the sarcomere containing only thin (actin) filaments, bisected by the Z-disc.

T-tubules (Transverse tubules)

Invaginations of the sarcolemma that extend deep into the muscle fiber, conducting electrical impulses to the sarcoplasmic reticulum.

Sliding filament model

The theory describing muscle contraction where thin (actin) filaments slide past thick (myosin) filaments, shortening the sarcomere.

Motor Unit

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

Neuromuscular Junction (NMJ)

Synapse where motor neuron stimulates a skeletal muscle fiber.

Acetylcholine (ACh)

Neurotransmitter used for communication between motor neurons and muscle fibers.

Calcium ions (Ca2+)

Essential for muscle contraction, released from the sarcoplasmic reticulum.

Myoglobin

Oxygen-storing protein in muscles, enhancing aerobic respiration.

Oxygen Debt

The amount of oxygen required to restore muscle to resting state after exertion.

Muscle Fatigue

Inability to contract muscle due to prolonged activity or other factors.

Agonist

Muscle that causes an action.

Antagonist

Muscle whose contraction opposes the action of the agonist.

Hypertrophy

Increase in muscle size due to exercise.

Atrophy

Decrease in muscle size due to disuse.