Muscle Cell Structure and Function
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Questions and Answers

What type of movement is primarily associated with hinge joints?

  • Circumduction
  • Flexion and extension (correct)
  • Gliding
  • Rotation

Which type of joint allows for bi-axial movement but prohibits rotation?

  • Condyloid
  • Ellipsoid (correct)
  • Ball-and-socket
  • Saddle

Which of the following joints is an example of a ball-and-socket joint?

  • Shoulder joint (correct)
  • Metacarpophalangeal joint
  • Proximal radioulnar joint
  • Carpometacarpal joint

What type of joint is characterized by a saddle-shaped articulating surface?

<p>Saddle joint (D)</p> Signup and view all the answers

Which joint allows for monoaxial movement?

<p>Hinge joint (D)</p> Signup and view all the answers

Which joint type is primarily involved in gliding movements?

<p>Planar joint (C)</p> Signup and view all the answers

What describes the articulating surfaces of a condyloid joint?

<p>Elliptical convex surface fits into an elliptical concave (D)</p> Signup and view all the answers

What is a primary characteristic of pivot joints?

<p>Surfaces fit into each other for rotational movement (A)</p> Signup and view all the answers

What is the name of the joint formed between the acromion process of the scapula and the clavicle?

<p>Acromioclavicular Joint (B)</p> Signup and view all the answers

Which joint is formed between the 5th lumbar vertebra and the sacral bone?

<p>Lumbosacral Joint (D)</p> Signup and view all the answers

What joint is referred to as the metacarpophalangeal joint?

<p>Joint between metacarpal and proximal phalanges (A)</p> Signup and view all the answers

Which of the following joints is formed by the articulation of the temporal and mandible bones?

<p>Temporomandibular Joint (A)</p> Signup and view all the answers

What joint is specifically involved in the bending of the elbow?

<p>Elbow Joint (C)</p> Signup and view all the answers

Which joint connects the radius and ulna at the proximal end?

<p>Proximal radioulnar Joint (D)</p> Signup and view all the answers

What is the name of the joint formed at the hip where the coxal bone articulates?

<p>Coxal Joint (C)</p> Signup and view all the answers

Which joint is known for connecting the tarsals and the metatarsals?

<p>Tarsometatarsal Joint (B)</p> Signup and view all the answers

Which component of a synovial joint provides lubrication?

<p>Synovial membrane (B)</p> Signup and view all the answers

What is the primary function of articular (hyaline) cartilage in synovial joints?

<p>Provide a cushion and smooth surface for joint movement (C)</p> Signup and view all the answers

Which of the following structures is NOT typically part of a synovial joint?

<p>Tendon sheath (C)</p> Signup and view all the answers

What role does the bursa play in relation to synovial joints?

<p>Reduces friction between tendons and bones (B)</p> Signup and view all the answers

What does the term 'Rectus' in muscle naming indicate?

<p>Parallel to midline (C)</p> Signup and view all the answers

Which layer of the joint capsule is primarily responsible for protecting the joint and holding it together?

<p>Fibrous capsule (C)</p> Signup and view all the answers

Which prefix indicates a muscle is the smallest in size?

<p>Minimus (D)</p> Signup and view all the answers

What does the term 'Oblique' signify in muscle nomenclature?

<p>Diagonal to midline (C)</p> Signup and view all the answers

Which term is used to describe a muscle that primarily performs action to flex?

<p>Flexor (C)</p> Signup and view all the answers

If a muscle has the prefix 'Biceps', how many origins does it have?

<p>Two (B)</p> Signup and view all the answers

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

<p>Triangular shape (D)</p> Signup and view all the answers

The prefix 'Major' in muscle nomenclature indicates what about the muscle?

<p>It is one of the largest muscles in its group. (C)</p> Signup and view all the answers

What do the terms 'Levator' and 'Depressor' signify in terms of muscle action?

<p>'Levator' raises while 'Depressor' lowers a body part (B)</p> Signup and view all the answers

What defines the basic functional unit within a myofibril?

<p>Sarcomere (B)</p> Signup and view all the answers

What are the two types of contractile proteins found within a sarcomere?

<p>Thick and thin filaments (D)</p> Signup and view all the answers

Which region of a sarcomere contains no thin filaments?

<p>H-band (B)</p> Signup and view all the answers

What structure separates one sarcomere from another?

<p>Z-disc (C)</p> Signup and view all the answers

What is the role of the sliding filament mechanism in muscle contraction?

<p>It initiates the muscle shortening (D)</p> Signup and view all the answers

In muscle anatomy, what is referred to as the fixed end of a muscle?

<p>Origin (A)</p> Signup and view all the answers

Which statement is true regarding the nature of muscle fibers?

<p>They have multiple peripherally located nuclei (B)</p> Signup and view all the answers

What is the primary function of T tubules in muscle fibers?

<p>To facilitate electrical impulses (D)</p> Signup and view all the answers

Study Notes

Muscle Cell Structure

  • Long cylindrical cells encased in endomysium and sarcolemma.
  • Contains sarcoplasm, myofibrils, multiple peripheral nuclei, mitochondria, T tubules, sarcoplasmic reticulum, and terminal cisterns.
  • Muscle fascicle is a bundle of muscle fibers.

Myofibrils and Sarcomeres

  • Myofibrils are threadlike contractile elements in muscle fibers extending the entire length of the fiber.
  • Sarcomeres, the basic functional units of myofibrils, contain thick filaments (myosin) and thin filaments (actin, tropomyosin, troponin).
  • Sliding of thin filaments past thick filaments leads to muscle shortening.

Sarcomere Regions

  • Z-disc: Dense material separating adjacent sarcomeres.
  • A-band: Dark central part containing thick filaments and overlapping thin filaments.
  • I-band: Lighter area with only thin filaments, bisected by the Z-disc.
  • H-band: Center section of the A-band containing only thick filaments.
  • M-line: Center region of the sarcomere that anchors thick filaments.

Joint Structures

  • Synovial joints are the most complex joint structures.
  • Types of Synovial Joints:
    • Hinge: Allows flexion and extension (e.g., elbow).
    • Saddle: Allows flexion, extension, abduction, adduction (e.g., carpometacarpal joint).
    • Pivot: Allows rotation (e.g., proximal radioulnar joint).
    • Condyloid: Permits bi-axial movement (e.g., radiocarpal joint).
    • Ball-and-socket: Allows multi-directional movement (e.g., shoulder and hip joints).
    • Plane: Non-axial gliding movements (e.g., intercarpal joints).
    • Ellipsoid: Bi-axial movement, no rotation (e.g., radiocarpal joint).

Naming Joints

  • Joints are named based on the bones they connect or their Greek/Latin terminology.
  • Examples include:
    • Acromioclavicular joint (Acromion and Clavicle)
    • Lumbosacral joint (Lumbar Vertebrae and Sacral Bone)
    • Metacarpophalangeal joint (Metacarpal Bone and Proximal Phalanges)

Functions of the Muscular System

  • Key functions include movement, posture maintenance, and heat production.

Naming Muscles Characteristics

  • Orientation relative to midline:
    • Rectus: Parallel (e.g., Rectus abdominis)
    • Transverse: Perpendicular (e.g., Transversus abdominis)
    • Oblique: Diagonal (e.g., External abdominal oblique)
  • Size descriptors:
    • Maximus: Largest
    • Minimus: Smallest
    • Longus: Long
    • Brevis: Short
  • Shape: e.g., Deltoid, Trapezius, Serratus.
  • Action descriptors: e.g., Flexor, Extensor, Abductor, Adductor.
  • Number of origins: e.g., Biceps, Triceps, Quadriceps.
  • Location-based naming: e.g., Temporalis (near temporal bone).
  • Origin and insertion: e.g., sternocleidomastoid (originates on sternum/clavicle, inserts on mastoid process).

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Description

Explore the intricate structure and function of muscle cells in this quiz. Learn about myofibrils, sarcomeres, and the role of various components such as Z-discs and A-bands in muscle contraction. Test your knowledge on the fundamentals of muscle anatomy and physiology.

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