Muscle Tissue Structure Quiz

Questions and Answers

What is the perimysium?

The sheath of connective tissue surrounding a bundle of muscle fibers.

What does epimysium refer to?

A sheath of fibrous elastic tissue surrounding a muscle.

What is the function of endomysium?

It is a wispy layer of areolar connective tissue that ensheaths each individual myocyte.

What is a tendon?

A flexible but inelastic cord of strong fibrous collagen tissue attaching a muscle to a bone. Signup and view all the answers

Define sarcolemma.

The fine transparent tubular sheath which envelops the fibers of skeletal muscles. Signup and view all the answers

What are transverse tubules?

Extensions of the cell membrane that penetrate into the center of skeletal and cardiac muscle cells. Signup and view all the answers

What is sarcoplasm?

The cytoplasm of striated muscle cells. Signup and view all the answers

What does sarcoplasmic reticulum do?

Organelle of the muscle fiber that stores calcium. Signup and view all the answers

What is a sarcomere?

The contractile unit of muscle. Signup and view all the answers

What are myofibrils?

Tightly packed filament bundles found within skeletal muscle fibers. Signup and view all the answers

Define myofilament.

Actin or myosin-containing structure. Signup and view all the answers

What is a Z disc?

Coin-shaped sheet of proteins that anchors the thin filaments. Signup and view all the answers

What does A band refer to?

Dark area; extends the length of the thick filaments. Signup and view all the answers

What is an I band?

Light band. Signup and view all the answers

What is the H zone?

Thick filaments only. Signup and view all the answers

What does M line signify?

Middle of sarcomere. Signup and view all the answers

What is actin?

A globular protein that links into chains, forming microfilaments in muscle cells. Signup and view all the answers

What is myosin?

A protein present in muscle fibers that aids in contraction. Signup and view all the answers

Define muscle fiber.

A single muscle cell. Signup and view all the answers

What is a neuromuscular junction?

Point of contact between a motor neuron and a skeletal muscle cell. Signup and view all the answers

What does synapse mean?

The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. Signup and view all the answers

What is a motor end plate?

The flattened end of a motor neuron that transmits neural impulses to a muscle. Signup and view all the answers

What is a twitch?

A single stimulus-contraction-relaxation sequence in a muscle fiber. Signup and view all the answers

What is unfused tetanus?

Type of wave summation with partial relaxation observed between twitches. Signup and view all the answers

What is fused tetanus?

When stimulus frequency is so high that no muscle relaxation takes place between stimuli. Signup and view all the answers

Define isotonic contraction.

Muscle shortens because muscle tension exceeds load. Signup and view all the answers

What is isometric contraction?

Muscle contracts but there is no movement, muscle stays the same length. Signup and view all the answers

Study Notes

Muscle Tissue and Associated Structures

Perimysium: Connective tissue sheath surrounding muscle fiber bundles.
Epimysium: Fibrous elastic tissue encasing an entire muscle.
Endomysium: Areolar connective tissue layer surrounding individual muscle fibers, housing capillaries and nerves, overlaying the sarcolemma (muscle cell membrane).
Tendon: Strong, flexible cord of collagen connecting muscle to bone.
Sarcolemma: Transparent tubular sheath enveloping skeletal muscle fibers.
Transverse tubules: Extensions of cell membrane that delve into the center of skeletal and cardiac muscle cells.
Sarcoplasm: Cytoplasm specific to striated muscle cells.
Sarcoplasmic reticulum: Organelle responsible for calcium storage within muscle fibers.

Muscle Fiber Structure

Sarcomere: Functional contractile unit of a muscle.
Myofibril: Dense bundles of filaments situated within skeletal muscle fibers.
Myofilament: Structures containing actin or myosin proteins.
Z disc: Protein sheet anchoring thin filaments and linking myofibrils.
A band: Dark region extending the length of thick filaments.
I band: Lighter band present in the sarcomere.
H zone: Area containing only thick filaments.
M line: Central line of the sarcomere.

Muscle Contraction Proteins

Actin: Globular protein forming chains that create microfilaments necessary for muscle contraction.
Myosin: Major protein in muscle fibers that facilitates contraction.

Muscle Fiber Functions

Muscle fiber: A single muscle cell responsible for contraction.
Neuromuscular junction: Connection point where a motor neuron interacts with a skeletal muscle cell.
Synapse: Junction between the axon of one neuron and the receiving neuron’s dendrite or cell body.
Motor end plate: Flattened end of a motor neuron facilitating neural impulse transmission to muscle.

Muscle Contraction Mechanics

Twitch: Series of events resulting from a single stimulus in a muscle fiber, followed by contraction and relaxation.
Unfused tetanus: Partial relaxation occurring between muscle twitches during wave summation.
Fused tetanus: Sustained contraction with no relaxation due to high stimulus frequency.
Isotonic contraction: Muscle shortens as tension exceeds the load.
Isometric contraction: Muscle tension generates without changing length, resulting in no movement.

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Description

Test your knowledge on the different sheaths of connective tissue surrounding muscle fibers, including perimysium, epimysium, and endomysium. This quiz will help you understand their definitions and functions in muscle anatomy.