study exam 2

Chapter 6: The Skeletal System

1. Functions of the Skeletal System:

   • Support: Provides a framework for the body.

   • Protection: Protects vital organs (brain, heart, lungs).

   • Movement: Serves as levers for muscle attachment.

   • Mineral Storage: Stores minerals like calcium and phosphorus.

   • Blood Cell Production: Red bone marrow produces blood cells.

   • Energy Storage: Yellow bone marrow stores lipids.

2. Bone Structure:

   • Diaphysis: Shaft of the bone.

   • Epiphysis: Ends of the bone.

   • Metaphysis: Region between the diaphysis and epiphysis (contains the growth plate).

   • Medullary Cavity: Hollow center of the diaphysis, containing yellow marrow.

   • Periosteum: Outer layer covering bones.

   • Endosteum: Inner layer lining the medullary cavity.

3. Types of Bones:

   • Long: Longer than wide (e.g., femur).

   • Short: Cube-shaped (e.g., carpals).

   • Flat: Thin, flat shape (e.g., skull).

   • Irregular: Complex shapes (e.g., vertebrae).

   • Sesamoid: Develop within tendons (e.g., patella).

4. Bone Tissue:

   • Compact Bone: Dense, forms the outer layer, provides strength.

   • Spongy Bone: Less dense, inside of bone, contains red marrow.

   • Osteocytes, Osteoblasts, Osteoclasts: Different bone cells responsible for maintenance, formation, and resorption.

5. Bone Growth & Ossification:

   • Intramembranous Ossification: Bone develops from fibrous membrane (e.g., skull bones).

   • Endochondral Ossification: Bone replaces hyaline cartilage (e.g., long bones).

   • Bone Growth: Involves longitudinal growth (increasing length) and appositional growth (thickening).

6. Bone Remodeling: Continuous process of bone resorption and formation, influenced by mechanical stress and hormones.

7. Hormonal Regulation:

   • Growth Hormone (GH): Stimulates bone growth.

   • Sex Hormones: Estrogen and testosterone promote bone growth during adolescence.

   • Calcitonin: Lowers blood calcium levels by promoting bone formation.

   • Parathyroid Hormone (PTH): Increases blood calcium levels by stimulating bone resorption.

   • Calcitriol: Enhances calcium absorption in the gut.

8. Bone Fracture and Repair:

   • Steps: Hematoma formation → Fibrocartilaginous callus → Bony callus → Bone remodeling.

9. Bone Disorders:

   • Osteoporosis: Decreased bone density, leading to fractures.

   • Rickets/Osteomalacia: Vitamin D deficiency leading to softening of bones.

Chapter 8: Joints and Movement

1. Joints Classification:

   • Structural: Fibrous, Cartilaginous, Synovial.

   • Functional: Synarthroses (immovable), Amphiarthroses (slightly movable), Diarthroses (freely movable).

2. Fibrous Joints:

   • Sutures (skull), Syndesmoses (interosseous membranes), Gomphoses (teeth).

3. Cartilaginous Joints:

   • Synchondroses (hyaline cartilage), Symphyses (fibrocartilage).

4. Synovial Joints:

   • Features: Joint capsule, synovial fluid, hyaline cartilage.

   • Six Types: Plane, hinge, pivot, condyloid, saddle, ball-and-socket.

5. Movement Types:

   • Gliding Movements: Sliding (e.g., intercarpal joints).

   • Angular Movements: Flexion, extension, abduction, adduction, circumduction.

   • Rotation: Turning around an axis.

   • Special Movements: Elevation, depression, pronation, supination, inversion, eversion.

6. Aging and Joints: Cartilage wears down, leading to stiffness and pain.

7. Arthritis:

   • Osteoarthritis: Degenerative joint disease due to wear and tear.

   • Rheumatoid Arthritis: Autoimmune disease affecting joints.

Chapter 10: The Muscular System

1. Muscle Types:

   • Skeletal Muscle: Voluntary, striated, attached to bones.

   • Cardiac Muscle: Involuntary, striated, found in the heart.

   • Smooth Muscle: Involuntary, non-striated, found in organs.

2. Muscle Properties:

   • Contractility: Ability to shorten.

   • Excitability: Responds to stimuli.

   • Conductivity: Transmits electrical signals.

   • Elasticity: Returns to original length.

   • Extensibility: Can be stretched.

3. Skeletal Muscle Structure:

   • Myofibrils: Muscle fibers' internal structure, containing sarcomeres.

   • Sarcomere: Functional unit of muscle contraction.

   • Filaments: Thin (actin) and thick (myosin) filaments.

   • Troponin & Tropomyosin: Regulate muscle contraction by blocking/allowing actin-myosin interaction.

   • Dystrophin: Protein that stabilizes the muscle membrane.

4. Muscle Contraction:

   • Cross Bridge Cycle: Myosin binds to actin, pulls, and releases (power stroke).

   • Calcium and ATP: Essential for contraction and relaxation.

5. Neuromuscular Junction:

   • Acetylcholine: Neurotransmitter that stimulates muscle contraction.

   • Synaptic Cleft: Gap between nerve and muscle.

6. ATP Production:

7. • Creatine Phosphate: Quick ATP source.

   • Anaerobic Respiration: ATP without oxygen (lactic acid).

   • Aerobic Respiration: ATP with oxygen (efficient).

8. Muscle Fibers:

   • Slow Oxidative: Endurance.

   • Fast Glycolytic: Quick, explosive movements.

   • Fast Oxidative-Glycolytic: Combination of both.

9. Muscle Contractions:

   • Isotonic: Muscle changes length (concentric, eccentric).

   • Isometric: Muscle does not change length.

10. Training:

    • Endurance Training: Increases aerobic capacity.

    • Resistance Training: Increases muscle mass and strength.

    • Hypertrophy: Increase in muscle size.

    • Atrophy: Decrease in muscle size.