Muscular System Flashcards

Flashcards about the Muscular System

Muscular System

An organ system consisting of skeletal, smooth, and cardiac muscles.

Characteristics of Muscles

Excitable, contractile, extensible, elastic

Functions of the Muscular System

Produce locomotion, stabilize joints, maintain posture, produce heat

Cardiac Muscle

Found only in the heart; short, branching fibers connected by intercalated disks; striated; involuntary.

Smooth Muscle

Found in digestive tract, blood vessels, bladder, airways, and uterus; nonstriated; involuntary.

Skeletal Muscle

Attached to bone; striated; voluntary.

Skeletal Muscle - Myofibrils

Bundles of tiny myofibrils that run the length of the muscle

Skeletal Muscle - Myofilaments

Even finer fibers that form units called sarcomeres

Motor Neuron

A nerve that stimulates a skeletal muscle to contract.

Neuromuscular Junction

The connection between a motor neuron and a muscle fiber.

Botulism

Form of food poisoning; toxins prevent release of ACh and prevents muscle contraction

Myasthenia gravis

Disease where the body produces antibodies against the receptors of ACh resulting in muscle weakness

Tetanus (lockjaw)

Serious illness caused by Clostridium bacteria; causes painful tightening of muscles.

Curare

Plant extract that binds with ACh receptor sites, stopping nerve transmission and causing paralysis.

Origin

The end of the muscle attached to the more stationary bone

Insertion

The end of the muscle attached to the more mobile bone

Agonist (prime mover)

Muscle that causes the desired action

Synergist

Muscle that assists the agonist

Antagonist

Muscle that opposes the action of the agonist

Strength Training

Muscles enlarge (hypertrophy).

Lack of Use

Muscles shrink (atrophy).

Endurance Exercise

Increase the growth of blood vessels in the muscle

Naming Conventions for Muscles

Size, shape, location, number of origins, direction of muscle fibers, actions

A single muscle cell is called a:

Muscle fiber.

Which muscle or muscle group elevates the ribs during inspiration?

External intercostals

During muscle contraction, the sarcoplasmic reticulum releases which substance?

Calcium

At rest, muscles obtain most of their energy by metabolizing:

Fatty acids.

The end of the muscle that’s attached to the more mobile bone is called the:

Insertion

Which of the following correctly describes skeletal muscle?

It is known as voluntary muscle.

What is the name of the connective tissue that surrounds the muscle as a whole?

Epimysium

What is the chief function of T tubules?

They allow electrical impulses to travel deep into the cell.

Besides ATP, muscle contraction requires

calcium.

When extending the forearm:

the triceps brachii is the prime mover, and the brachialis is the antagonist.