Muscle Types and Function

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Questions and Answers

Which ligament of the knee is primarily tested using the Valgus Stress Test?

Posterior Cruciate Ligament (PCL)

Medial Collateral Ligament (MCL) (correct)

Anterior Cruciate Ligament (ACL)

Lateral Collateral Ligament (LCL)

Which movement involves the foot moving upwards towards the shin?

Plantar flexion

Flexion

Circumduction

Dorsiflexion (correct)

What is the primary purpose of Kinesiology tape when applied to an ACL injury?

To relieve pain and improve circulation (correct)

To provide rigid support

To immobilize the joint completely

To enhance muscle strength

Which of the following pairs describes opposing movements of a joint?

Flexion and Extension Signup and view all the answers

What condition would prevent the use of tape on an ACL injury?

Deep vein thrombosis (DVT) Signup and view all the answers

What type of joint is characterized by being fixed or immovable and made primarily of collagen?

Fibrous Joint Signup and view all the answers

Which protein interacts with actin to facilitate muscle contraction?

Myosin Signup and view all the answers

What is the process called when a muscle becomes shorter and tighter?

Contraction Signup and view all the answers

Which layer of connective tissue surrounds a bundle of muscle fibers?

Perimysium Signup and view all the answers

What theoretical model explains the mechanism of muscle contraction through proteins sliding past each other?

Sliding Filament Theory Signup and view all the answers

What term describes the muscle attachment that remains immobile during movement?

Origin Signup and view all the answers

Which of the following best describes the role of ATP in muscle contraction?

It supplies energy for biochemical processes in muscle contraction. Signup and view all the answers

Muscle fatigue refers to which of the following phenomena?

A decrease in muscle force or power output Signup and view all the answers

What type of muscle is primarily responsible for voluntary movements?

Skeletal Muscle Signup and view all the answers

Which of the following best describes the primary function of myosin in muscle contraction?

It facilitates the sliding of actin filaments. Signup and view all the answers

What is a defining characteristic of synovial joints?

They contain synovial fluid to reduce friction. Signup and view all the answers

Which of the following statements is true regarding flexors and extensors?

Flexors decrease the angle between ventral surfaces of the body. Signup and view all the answers

What tool is used to measure the angle of a joint during motion?

Goniometer Signup and view all the answers

Which type of muscle is found in the walls of hollow organs?

Smooth Muscle Signup and view all the answers

What type of joint allows for rotational movement around a single axis?

Pivot Joint Signup and view all the answers

During muscle contraction, what happens to the sarcomere?

It shortens. Signup and view all the answers

Study Notes

Muscle Types

Skeletal Muscle: Striated, voluntary muscle attached to the skeletal system.
Smooth Muscle: Nonstriated, involuntary muscle found in the walls of hollow organs.
Cardiac Muscle: Striated, involuntary muscle that makes up the heart walls.

Sliding Filament Theory

Muscle contraction requires a signal from the central nervous system (CNS).
Muscle fibers contain myofibrils, which allow for contraction.
Myosin and actin are the proteins involved in muscle contraction.
Myosin (thick filament) and actin (thin filament) slide past each other, shortening the sarcomere during contraction.

Sarcomere Structure

Contains structures like the Z disk, M line, myosin, actin, and tropomyosin.

Skeletal Muscle Structure

Shows how muscle fibers, fascicles, and connective tissues work together to enable contraction.

Muscle Rules

Muscles typically have at least two attachments and cross one joint.
Muscles always pull to shorten.
The insertion is the moving attachment point, while the origin remains stationary.
Flexors decrease the angle between ventral body surfaces, while extensors increase it.
Muscles typically work in opposing pairs.
Muscle striations point towards the attachments and indicate the direction of pull.

Joint Types

Fibrous Joints: Fixed and immovable joints primarily composed of collagen.
Synovial Joints: Moveable joints containing synovial fluid to reduce friction.
- Saddle joint
- Ball-and-socket joint
- Hinge joint
- Condyloid joint
- Plane joint
- Pivot joint
Cartilaginous Joints: Joints with some motion, containing hyaline cartilage between bones.

Cartilaginous Joint Structure

Includes bone, articular cartilage, synovial membrane, articular capsule, and joint cavity containing synovial fluid.

Range of Motion

Goniometer: Tool used to measure joint angles during motion.
Rotation: Shows how structures like the head, neck, and arms can rotate.
Circumduction: Demonstrates how a leg can perform circumduction.

Depression and Elevation

Shows how the jaw performs depression and elevation.

Abduction and Adduction

Demonstrates how the arm performs abduction and adduction.

Flexion and Extension

Shows how the legs perform flexion and extension.

Plantar Flexion and Dorsiflexion

Demonstrates how the foot performs plantar flexion and dorsiflexion.

Knee Ligaments

Lateral Collateral Ligament (LCL), Medial Collateral Ligament (MCL), Anterior Cruciate Ligament (ACL), and Posterior Cruciate Ligament (PCL) are the major ligaments of the knee.

Clinical Ligament Tests

Anterior Drawer Test: Assesses ACL injury.
Posterior Drawer Test: Assesses PCL injury.
Valgus Stress Test: Assesses MCL injury.
Varus Stress Test: Assesses LCL injury.

Taping an ACL Injury

Kinesio tape can provide support and pain relief without restricting movement.
Tape should not be applied post-operatively, over open wounds, or to patients with DVT, tumors, cancer, or allergies to adhesives.

Causes of Contraction

Muscle: Tissue that contracts to produce movement or maintain position.
Tendons: Connect muscle to bone.
Ligaments: Connect bones at joints.
Contraction: Muscle shortening and tightening.
Adenosine-triphosphate (ATP): Energy source fuel for cellular processes.
Sarcomere: Repeating unit of striated muscle fibrils.
Actin and Myosin: Proteins responsible for muscle contraction.
Sliding Filament Theory: Explains muscle contraction through sliding of actin and myosin.
Troponin and Tropomyosin: Proteins involved in muscle contraction regulation.

Makeup of a Muscle

Endomysium: Connective tissue surrounding each individual muscle fiber.
Epimysium: Connective tissue surrounding the entire muscle.
Perimysium: Connective tissue surrounding fascicles.
Fascicle: Bundle of muscle fibers.
Myofibril: Long contractile fibers containing actin and myosin.

Building Muscle

Origin: Immobile attachment point of a muscle.
Insertion: Moving attachment point of a muscle.

Mind Over Muscle

Occupational Therapy: Therapy that improves activities of daily living.
Muscle Fatigue: Decrease in muscle force or power output.

Joints in Motion

Fibrous Joint: Fixed and immovable joint.

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Description

Explore the different types of muscle tissue including skeletal, smooth, and cardiac muscle. Understand the sliding filament theory and the structural components of a sarcomere. This quiz will test your knowledge on muscle contraction and the associated rules governing muscle function.