Muscle Tissues Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a primary function of smooth muscle tissue?

Stabilizing joints

Generating heat

Skeletal movement

Regulating the size of the lumen of hollow viscera (correct)

Which of the following statements about skeletal muscle is true?

Skeletal muscle cells are smaller than smooth muscle cells.

Skeletal muscle fibers are uninucleated.

Skeletal muscle contractions are involuntary.

Skeletal muscle fibers show cross-striations. (correct)

Which feature distinguishes cardiac muscle from skeletal and smooth muscle?

Only located in the gastrointestinal tract

Multinucleated fibers

Involuntary contraction (correct)

Presence of striations

What type of muscle tissue is responsible for maintaining a state of partial contraction in blood vessels?

Smooth muscle Signup and view all the answers

What is the basic unit of contraction in skeletal muscle fibers?

Sarcomere Signup and view all the answers

What characteristic is NOT typical of smooth muscle cells?

Contain multiple nuclei Signup and view all the answers

Which of the following best describes the diameter of smooth muscle fibers?

Between 3 to 8 μm Signup and view all the answers

Which connective tissue surrounds individual muscle fibers?

Endomysium Signup and view all the answers

What is the appearance of myofibrils in a longitudinal section of skeletal muscle fibers?

Striated with alternating light and dark bands Signup and view all the answers

What is the primary source of all muscle tissues in humans?

Mesoderm Signup and view all the answers

Which of these is NOT a function of skeletal muscle?

Regulating airflow in respiratory passages Signup and view all the answers

What is the name of the connective tissue that surrounds each bundle of muscle fibers?

Perimysium Signup and view all the answers

Which band is found at the center of each A-band in myofibrils?

M-line Signup and view all the answers

What is a unique characteristic of cardiac muscle fibers compared to skeletal muscle fibers?

They are involuntary and branched Signup and view all the answers

What type of filaments are responsible for the striated appearance in myofibrils?

Thin (actin) and thick (myosin) filaments Signup and view all the answers

What role does the sarcolemma play in skeletal muscle fibers?

It serves as the plasma membrane of the muscle fiber Signup and view all the answers

Study Notes

Muscular Tissues

Muscles function in movement, posture maintenance, joint stabilization, and heat generation.
Three types of muscle tissue exist: smooth, striated (skeletal), and cardiac.
All three types originate from the mesoderm.

Smooth Muscle

Found in hollow viscera, blood vessels, respiratory passages, and glands.
Spindle-shaped cells with a single, centrally located nucleus.
Cytoplasm contains actin, myosin, and intermediate filaments.
Contractions are involuntary, slow, sustained, and resistant to fatigue.
Muscle fibers are smaller than skeletal muscle fibers.
Fibers are densely packed, often with the narrower portion of one fiber next to the wider portion of a neighboring fiber.
Size: Length (18-200 μm), Diameter (3-8 μm).
Cells are rounded or polygonal in shape and may or may not contain nuclei.

Smooth Muscle Functions

Regulates lumen size of hollow viscera.
Produces peristaltic movements in the digestive tract.
Maintains muscle tonus in blood vessels.
Synthesizes collagen and elastin.

Skeletal Muscle

Composed of long, cylindrical, multinucleated cells with striations.
Makes up 40% of body weight.
Contractions are voluntary, fast, and forceful.
Cells contain myofibrils which consist of overlapping actin and myosin filaments
The sarcomere is the basic unit of contraction within a myofibril.
The plasma membrane is called sarcolemma.
Size: Length (1-40 mm), Diameter (10-100 μm).
Surrounded by connective tissues; epimysium (enclosing the entire muscle), perimysium (enclosing bundles of muscle fibers), and endomysium (enclosing individual muscle fibers).

Cardiac Muscle

Found only in the heart.
Cells are branched, striated, and have a single, centrally located nucleus.
Cells connect via intercalated disks at branching points.
This creates a network, which facilitates rapid and coordinated contraction.
Contractions are involuntary, rhythmic, and sustained.
Cardiac muscle cells are self-excitable, beating without external nervous stimulation.
Fibers have diameters from 9 to 22 μm. .

Skeletal Muscle Structure

LM (light microscopy): Fibers are cylindrical, nuclei are peripheral, sarcoplasm (cytoplasm) contains myofibrils, and cross-striations are present.
EM (electron microscopy): Sarcoplasm contains sarcoplasmic reticulum (SER), mitochondria, glycogen, lipid droplets, and myofibrils.

Myofibrils

Myofibrils show alternating light (I-bands) and dark (A-bands) striations.
A band contains an H-zone (pale area) bisected by an M-line.
Each I-band is bisected by a Z-line.
Sarcomeres lie between the successive Z-lines.

Sarcomere

A sarcomere is the contractile unit of skeletal muscle.
It extends from one Z-line to the next.
Contains thin (actin) and thick (myosin) myofilaments.

Cardiac Muscle Cells

Branch and interconnect to form a network (syncytium).
Intercalated discs connect adjacent cells, ensuring rapid conduction of impulses.
Cells are striated and have one central nucleus.
Cells are self-excitable.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on muscular tissues, focusing primarily on smooth muscle. This quiz covers the functions, structure, and characteristics of smooth muscle, as well as its role in the body. Perfect for biology students learning about human anatomy.