DC

Articulations pt 2 and Muscle Tissue pt 1

      • Steroid Injections:

      • Used if symptoms persist, though they have side effects, including potential infection.

    • Fluid Removal:

      • Occasionally required if symptoms worsen.

Arthritis

  • Definition of Arthritis:

    • Inflammation of one or more joints characterized by:

    • Pain

    • Stiffness

    • Decreased range of motion

  • Osteoarthritis:

    • Most common form of arthritis, generally results from:

    • Wear and tear

    • Aging

    • Joint injuries.

  • Rheumatoid Arthritis:

    • Autoimmune disease resulting in joint destruction caused by the patient's own immune system attacking the joints.

  • Gout (Gout Arthritis):

    • Caused by excess uric acid leading to joint damage.

    • Prevalence can be genetic as it tends to run in families.

Management of Osteoarthritis

  • Exercise:

    • Light movement is beneficial to promote synovial fluid circulation, enhancing joint health without excessive strain.

  • Supplements:

    • May provide long-term benefits but require time rather than immediate relief.

  • Skeletal Health:

    • Example of cartilage erosion leading to hip replacement surgery due to osteoarthritis.

Joint Movement and Classification

  • Types of Movements in Joints:

    • Gliding Movements:

    • Can occur in nonaxial joints with sliding between surfaces.

    • Angular Movements:

    • Increase or decrease angle between bones (e.g., flexion, extension, abduction, adduction, rotation).

  • Classifications of Joints by Axes of Motion:

    • Nonaxial:

    • Movement occurs in one plane without an axis.

    • Unaxial:

    • Motion around one axis.

    • Biaxial:

    • Motion around two axes.

    • Multiaxial:

    • Motion around three axes.

Range of Motion

  • Definition:

    • Capacity of a joint to move normally without injury.

    • Nonaxial Joints:

    • Minimum range of motion.

    • Multiaxial Joints (e.g., shoulder):

    • Maximum range of motion, but prone to higher incidence of injury.

Structural Classification of Joints

  • Key Characteristics of Synovial Joints:

    • Have a capsule, lining, and synovial fluid.

    • Some may contain bursa and other structures.

    • Typical types include:

    • Plane Joints:

      • E.g., between wrist bones.

    • Hinge Joints:

      • E.g., elbow.

    • Pivot Joints:

      • E.g., atlas and axis of the spine.

    • Condyloid (Ellipsoid) Joints:

      • E.g., metacarpophalangeal joints.

    • Saddle Joints:

      • E.g., joints of the thumb.

    • Ball and Socket Joints:

      • E.g., shoulder and hip joints.

Common Joint Injuries

  • Knee Injuries:

    • The Unhappy Triad:

    • Occurs in quick directional changes, often injuring ligaments (tibial collateral ligament, lateral meniscus, anterior cruciate ligament).

  • Dislocations:

    • Occur due to excessive twisting or impact, notably in shoulders (glenohumeral dislocation).

Osteoarthritis and Hip Replacement Surgery

  • Hip Replacement Surgery:

    • Involves replacing a damaged joint with a prosthetic device, predominantly performed in elderly patients with severe arthritis, fractures, or trauma.

    • Types include partial or total hip replacement, which replaces affected femur or socket respectively.

Muscle Tissues Overview

  • Muscle Functions:

    • Create movement, maintain posture, stabilize joints, and regulate material flow.

  • Types of Muscle Cells:

    • Skeletal Muscle:

    • Long, striated, multinucleated fibers under voluntary control.

    • Cardiac Muscle:

    • Shorter, branched cells with a single large nucleus, involuntary control with intercalated discs.

    • Smooth Muscle:

    • Long flat cells, involuntary, no striations, found in hollow organs.

Properties of Muscle Cells

  • Contractility:

    • Ability to shorten and generate tension.

  • Excitability or Responsiveness:

    • Ability to respond to stimuli (chemical, mechanical, electrical).

  • Conductivity:

    • Capacity to conduct electrical charges.

  • Elasticity:

    • Ability to return to normal shapes after stretching.

  • ** extensibility:**

    • Can stretch without rupturing (within limits).

Skeletal Muscle Structure

  • Cellular Components:

    • Sarcoplasm:

    • Cytoplasm of muscle cells.

    • Sarcoplasmic Reticulum:

    • Stores calcium, integral in contraction process.

    • Myofibrils:

    • Bundles of protein filaments essential for muscle contraction (50-80% muscle cell volume).

  • Myofilament Types:

    • Thick Filaments (Myosin):

    • Thick contractile protein that forms the structure of muscles.

    • Thin Filaments (Actin, Tropomyosin, Troponin):

    • Actin: Primary contractile protein with binding sites.

    • Tropomyosin: Covers actin binding sites.

    • Troponin: Regulatory protein holding tropomyosin.

    • Elastic Filaments (Titan):

    • Helps the muscle stretch and recoil without damage.

Muscle Contraction Mechanism

  • Process Initiation:

    • Calcium ions released from the sarcoplasmic reticulum are crucial for contraction as they bind to troponin, shifting tropomyosin to expose binding sites on actin to myosin heads.

  • Sliding Filament Theory:

    • Myosin heads attach to actin filaments to produce tension and shorten the muscle fiber.

  • Terminology Clarification:

    • Sarco: Prefix indicates muscle-related terms.

    • Micrometer Size Reference:

    • 1 micrometer is 1/1000 of a millimeter (roughly the diameter of a human red blood cell).