Muscle Physiology Flashcards

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Questions and Answers

Define the term: Muscle tissue is excitable.

The muscle cell membrane can depolarize and repolarize creating action potential (AP).

Define the term: Muscle tissue is extensible.

It can be stretched.

Define the term: Muscle tissue is elastic.

It will return to resting length after being stretched.

Define the term: Muscle tissue is contractile.

Can shorten and pull on attachments. Signup and view all the answers

What is the location, function, and composition of the epimysium?

Location: Tough wrapping around the entire muscle; Composition: Dense irregular connective tissue; Function: Maintaining muscle shape through contraction. Signup and view all the answers

What is the location, function, and composition of the perimysium?

Location: Wrapping around the fascicles of muscle cells; Composition: Dense irregular connective tissue. Signup and view all the answers

What is the location, function, and composition of the endomysium?

Location: Wrapping individual muscle cells; Composition: Areolar connective tissue. Signup and view all the answers

What is a fascicle?

A bundle of 8-15 muscle fibers. Signup and view all the answers

What is the composition and function of a tendon?

Composition: Dense regular connective tissue; Function: Connect muscle to bone. Signup and view all the answers

What is an aponeurosis?

A strong sheet of tissue that acts as a tendon to attach muscles to bone. Signup and view all the answers

Describe the relationship between a tendon and the -mysiums of that muscle.

The tendon arises from the epimysium and the perimysium that keeps extending and become the tendon. Signup and view all the answers

Describe the relationship between an aponeurosis and the -mysiums of the muscle.

Aponeurosis flattens out and connects broad muscles to their attachment points. Signup and view all the answers

What is the sarcolemma and its function?

Sarcolemma is the cell membrane of a muscle cell; Function: Barrier. Signup and view all the answers

What is sarcoplasm?

Cytoplasm of a muscle cell. Signup and view all the answers

What are T-tubules?

Infoldings of sarcolemma that conduct impulses from the surface of the cell to the interior. Signup and view all the answers

What is the function of the sarcoplasmic reticulum?

Holds and hides calcium from the rest of the cell. Signup and view all the answers

What are the terminal cisternae of the sarcoplasmic reticulum?

Structures within skeletal muscle cells that serve as reservoirs of calcium ions. Signup and view all the answers

What is a triad in the muscle?

1 T-tubule and 2 terminal cisternae. Signup and view all the answers

What are myofibrils?

Protein structures that make up muscle fibers; function: where shortening happens. Signup and view all the answers

What is the role of mitochondria in muscle cells?

Produce ATP so the myofibrils can shorten. Signup and view all the answers

What is myoglobin?

Proteins that hold oxygen for mitochondria to utilize. Signup and view all the answers

What is glycogen in muscle cells?

Is a form of stored glucose for mitochondria to utilize. Signup and view all the answers

What are myofilaments?

The contractile proteins, actin and myosin, of muscle cells. Signup and view all the answers

Explain the relationship between the sarcolemma and T-tubules.

The T-tubules are an extension of the sarcolemma that infold onto itself. Signup and view all the answers

What is the function of tropomyosin?

Covers actin's active sites to make them unavailable. Signup and view all the answers

What is the location and function of troponin?

Location: Handle on tropomyosin; Function: Moves tropomyosin off active sites when calcium attaches. Signup and view all the answers

What is G-actin?

Assembles into a polymer of two twisting chains - F-actin. Signup and view all the answers

What is F-actin?

Is two twisted rows of globular G-actin; The active sites on G-actin strands bind to myosin. Signup and view all the answers

Study Notes

Muscle Tissue Characteristics

Muscle tissue is excitability, meaning its cell membrane can undergo depolarization and repolarization to generate action potentials.
Muscle tissue is extensibility, allowing it to be stretched without damage.
Muscle tissue is elastic, enabling it to return to its resting length after being stretched.
Muscle tissue is contractile, which allows it to shorten and exert force on attachments.

Muscle Connective Tissue

Epimysium: Tough, dense irregular connective tissue surrounding an entire muscle; maintains shape during contraction.
Perimysium: Dense irregular connective tissue wrapping around fascicles (bundles) of muscle cells.
Endomysium: Areolar connective tissue enclosing individual muscle cells.

Muscle Structure

Fascicle: A bundle of 8-15 muscle fibers organized together.
Tendon: Composed of dense regular connective tissue; it connects muscles to bones.
Aponeurosis: A strong sheet of connective tissue serving as a tendon to attach flat muscles to bones.

Tendon and Aponeurosis Relationship to Mysiums

Tendons derive from epimysium and perimysium; they transition from dense irregular to dense regular connective tissue for strong attachment to bone.
Aponeurosis flattens out to anchor flat muscles; instead of a tubular shape, it appears like a sheet.

Key Muscle Cell Components

Sarcolemma: The muscle cell membrane, composed of a phospholipid bilayer, acting as a barrier.
Sarcoplasm: The cytoplasm found within muscle cells.
T-tubules: Infoldings of the sarcolemma that conduct impulses into the cell, specifically to the sarcoplasmic reticulum.
Sarcoplasmic reticulum: An organelle forming a web around myofibrils; it stores calcium ions vital for muscle contraction.
Terminal cisternae: Calcium ion reservoirs located within skeletal muscle cells.

Muscle Cell Functional Units

Triad: Consists of one T-tubule and two terminal cisternae, forming a functional unit for muscle contraction.
Myofibrils: Organelles comprising muscle fibers; responsible for the muscle's shortening actions.
Mitochondria: Generate ATP required for myofibril contraction; essential for muscle energy.
Myoglobin: Oxygen-binding proteins that supply oxygen for mitochondrial processes.
Glycogen: Stored glucose in muscle cells, providing energy during contraction.

Muscle Filaments

Myofilaments: Composed of contractile proteins, actin (thin filament) and myosin (thick filament).
Tropomyosin: Protein that wraps around actin, blocking its active sites, thereby preventing contraction when muscle is relaxed.
Troponin: Located on tropomyosin; when calcium binds to it, it moves tropomyosin away from actin's active sites, allowing contraction.
G-actin: Globular actin proteins that polymerize to form filamentous actin (F-actin).
F-actin: Two intertwined chains of G-actin; has active sites for myosin binding during muscle contraction.

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Description

Test your knowledge on muscle physiology with these flashcards. Each card defines key terms related to muscle tissue, such as excitability, extensibility, and elasticity. Ideal for students of biology and related health sciences.