Lecture on Hyaline Cartilage and Muscular System

Hyaline Cartilage and Joint Types

• Hyaline Cartilage: Found in certain joints.
• Chondro-: Refers to cartilage.
• Immovable Joints in Adults: Held by ligaments, such as teeth (gomphosis).
• Syndesmosis: Slightly movable, held by ligaments.
• Pubic Symphysis:
  • Functional Classification: Amphiarthrosis (slightly movable).
  • Structural Classification: Cartilaginous, specifically a synthesis.

Bone Growth and Epiphyseal Plate

• Epiphyseal Plate: Made of hyaline cartilage, responsible for bone growth.

Importance of Vocabulary

• Vocabulary is critical for understanding.
• Additional practice available online.

Importance of Test 3 Material

• Foundation for other A&P topics: muscles, nervous system, cardiovascular, respiratory, digestive, lymphatic, immune.
• Essential for understanding signal transmission and muscle contractions.

Muscle Types and Functions

• Main Function: Movement.
• Muscle Types:
  • Skeletal Muscle: Striated, multinucleated, voluntary control.
  • Smooth Muscle: Non-striated, involuntary control.
  • Cardiac Muscle: Found in the heart, involuntary control.

Characteristics of Muscles

• Extensibility: Ability to stretch and lengthen.
• Elasticity: Ability to recoil after stretching.
• Contractility: Ability to shorten and produce movement.
• Excitability: Ability to receive and respond to electrical signals.

Skeletal Muscle Structure

• Multinucleated: Due to fusion of myoblasts during development.
• Muscle Growth: Through hypertrophy (cells grow larger, no new cells).
• Satellite Cells: Minor repair function for muscle cells.

Muscle Organization

• Layers:
  • Skeletal Muscle: Made of fascicles.
  • Fascicles: Made of muscle cells (fibers).
  • Muscle Cells: Made of myofibrils.
  • Myofibrils: Made of protein fibers.

Muscle Cell Anatomy

• Sarcolemma: Muscle cell membrane, conducts action potentials.
• T-Tubules: Invaginations that carry action potential deep into the muscle cell.
• Sarcoplasmic Reticulum (SR): Wraps around myofibrils, stores calcium.
  • Terminal Cisterns: Ends of SR, involved in calcium release.
• Sarcoplasm: Liquid within muscle cells containing mitochondria, myoglobin, and glycogen.

Physiology of Muscle Contraction

• Action Potential Pathway:
  1. Travels along sarcolemma.
  2. Enters through T-tubules.
  3. Communicates with SR through terminal cisterns.
  4. Opens calcium voltage gates, releasing calcium into sarcoplasm.

Key Concepts for Understanding

• Integration of anatomy and physiology.
• Importance of electrical signals and ion movement.
• Muscle contraction dependent on structure and signaling.

Additional Notes

• Encourage review of lecture materials.
• Importance of understanding foundational concepts for future courses.

End of Lecture