Muscle Tissue Properties Quiz

Questions and Answers

Which property of muscular tissue allows it to respond to stimuli from a motor neuron?

Elasticity

Excitability (correct)

Extensibility

Contractility

What is the main function of skeletal muscle?

Regulation of blood flow

Hormone secretion

Involuntary movement

Voluntary movement (correct)

Which layer of connective tissue surrounds individual muscle fibers in skeletal muscle?

Epimysium

Perimysium

Endomysium (correct)

Fascia

What is the role of the epimysium in skeletal muscle structure?

Encases the entire muscle Signup and view all the answers

Which type of muscle is primarily subject to stretching?

Smooth muscle Signup and view all the answers

What are somatic motor neurons primarily responsible for?

Stimulating skeletal muscle contraction Signup and view all the answers

What type of connective tissue extends beyond muscle fibers to form tendons?

Aponeurosis Signup and view all the answers

What distinguishes cardiac muscle from skeletal muscle?

It has striations and intercalated discs Signup and view all the answers

What is the basic functional unit of a myofibril called?

Sarcomere Signup and view all the answers

Which band of the sarcomere contains only thick filaments?

H band Signup and view all the answers

Which proteins help to regulate the contraction process?

Troponin and Tropomyosin Signup and view all the answers

What do the myosin heads contain that is crucial for muscle contraction?

Actin binding and ATP binding sites Signup and view all the answers

What lies in the center of the H band and provides support to thick filaments?

M line Signup and view all the answers

Which of the following is NOT a structural protein that maintains myofibril alignment?

Troponin Signup and view all the answers

Which component is critical for the sliding filament mechanism during contraction?

Cross-bridges Signup and view all the answers

What muscle type is characterized by alternating light and dark bands?

Striated muscle Signup and view all the answers

What does the term 'Deltoid' refer to in muscle nomenclature?

Triangular shape Signup and view all the answers

What does the action described by 'Extensor' indicate about the muscle?

Increases the angle of the joint Signup and view all the answers

Which of the following muscles is classified as a sphincter?

External anal sphincter Signup and view all the answers

What does the muscle action 'Abductor' signify?

Moves the body part away from the midline Signup and view all the answers

The term 'Gracilis' refers to which characteristic of this muscle?

Slender Signup and view all the answers

Which muscle is described by the term 'Piriformis'?

Pear-shaped Signup and view all the answers

What is the action of a muscle classified as 'Tensor'?

Makes body part rigid Signup and view all the answers

Which of these muscles is involved in turning the palm anteriorly?

Supinator Signup and view all the answers

What initiates the sliding process in muscle contraction?

Increase in Ca2+ concentration Signup and view all the answers

Which component of the neuromuscular junction releases acetylcholine?

Synaptic vesicles Signup and view all the answers

What occurs after ATP binds to the myosin head?

Myosin head detaches from actin Signup and view all the answers

What is the function of the synaptic cleft in the neuromuscular junction?

To facilitate communication between nerve and muscle cells Signup and view all the answers

What triggers the release of acetylcholine from synaptic vesicles?

Inflow of calcium ions Signup and view all the answers

Which part of the neuromuscular junction is responsible for receiving the chemical signal?

Motor end plate Signup and view all the answers

How does the neuromuscular junction transform the action potential from the nervous system?

It transforms the electrical signal into a chemical signal. Signup and view all the answers

What role does calcium (Ca2+) play in muscle contraction?

It facilitates the attachment of myosin to actin. Signup and view all the answers

What is the meaning of the term 'Biceps' in muscle nomenclature?

Two heads of origin Signup and view all the answers

Which muscle originates on the sternum and clavicle and inserts on the mastoid process?

Sternocleidomastoid Signup and view all the answers

In the context of muscles of the upper limb, what do the anterior compartment muscles primarily do?

Flex the arm Signup and view all the answers

What autoimmune disease causes progressive damage of the neuromuscular junction?

Myasthenia gravis Signup and view all the answers

Which of the following statements about Muscular Dystrophy is accurate?

It refers to a group of inherited muscle-destroying diseases. Signup and view all the answers

Which muscle group in the lower limb's posterior compartment primarily functions as flexors?

Knee flexors Signup and view all the answers

What initial symptoms are commonly associated with Myasthenia gravis?

Weakness of eye muscles and throat muscles Signup and view all the answers

Which muscle is correctly matched with the number of origins it has?

Quadriceps - Four heads of origin Signup and view all the answers

Study Notes

Thermogenesis and Muscle Tissue

Muscular tissue plays a vital role in thermogenesis through its properties: excitability, contractility, extensibility, and elasticity.
Excitability: Muscles respond to stimuli from motor neurons or hormones.
Contractility: Muscles contract forcefully in response to nerve impulses.
Extensibility: Muscles can stretch without damage; smooth muscle experiences the most stretching.
Elasticity: Muscles return to original length and shape after contraction or extension.

Types of Muscle Tissue

There are three main types of muscle:
- Skeletal Muscle
- Smooth Muscle
- Cardiac Muscle

Skeletal Muscle Structure

Composed of connective tissue, blood vessels, and nerves; surrounded by hypodermis (areolar and adipose tissues).
Fascia: Dense connective tissue supporting and surrounding muscles and organs.
Three connective tissue layers:
- Epimysium (outer layer)
- Perimysium (surrounds fascicles)
- Endomysium (surrounds individual fibers)
These connections can form tendons and aponeuroses to attach muscles to bones or other muscles.

Skeletal Muscle Microstructure

Sarcomeres are the basic units of myofibrils, separated by Z-discs.
Dark A band (thick filaments) and light I band (thin filaments) create striations characteristic of striated muscle.
Structural elements:
- Myofibrils consist of contractile (actin & myosin), regulatory (tropomyosin & troponin), and structural proteins (titin, myomesin, nebulin, dystrophin).

Contraction Cycle

Myosin ATPase activates by hydrolyzing ATP, energizing the myosin head.
Myosin heads form crossbridges with actin.
Generating force occurs as crossbridges rotate during the power stroke.
Binding of ATP causes myosin heads to detach from actin, allowing the cycle to repeat.
Concentration of Ca2+ in the sarcoplasm initiates filament sliding; reduction stops it.

Neuromuscular Junction (NMJ)

NMJ is the synaptic connection between motor nerves and muscle fibers.
Structural components include: Presynaptic part (nerve terminal), postsynaptic part (motor endplate), and synaptic cleft.
Action potentials convert to chemical signals (acetylcholine) at the NMJ, facilitating communication between nerve and muscle cells.
ACh release is triggered by an influx of calcium ions (Ca2+) in response to nerve signals.

Muscle Nomenclature

Size: Example: Biceps (two heads), Triceps (three heads).
Shape: Example: Deltoid (triangular), Serratus (saw-toothed).
Action: Example: Flexor (decreases joint angle), Extensor (increases joint angle).
Location: Example: Temporalis (near temporal bone), Sternocleidomastoid (originating on sternum and clavicle).

Muscle Groups

Muscles categorized by compartment functions:
- Upper Limb: Flexors (anterior compartment), Extensors (posterior compartment).
- Lower Limb: Extensors (anterior compartment), Flexors (posterior compartment).

Myasthenia Gravis

An autoimmune disorder affecting the neuromuscular junction, leading to decreased functional ACh receptors.
Common symptoms include muscle weakness, particularly in the face and neck, resulting in double vision and swallowing difficulties.

Muscular Dystrophy

Group of inherited diseases causing progressive degeneration of skeletal muscle fibers, leading to muscle wasting and weakness.

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Description

Test your knowledge on the properties of muscular tissue, including excitability, contractility, and extensibility. This quiz explores how these properties enable muscles to function effectively and maintain homeostasis in the body.