Anatomy and Physiology

Chapter 7 focuses on the physiology of the skeletal system, particularly bone tissue.
Importance is emphasized as this chapter is often challenging for students during exams.
Understanding the factors affecting bone health is crucial (e.g., changes in height in the elderly).

Osteology: The study of bones.
Osteocytes: Bone cells responsible for maintaining bone tissue.
Skeletal System Components:
- Primarily consists of bones, which are living organs rich in cells, blood vessels, and nerves.
- Bones are sometimes mistaken as non-living structures but are vital to physiological processes.

Types of Tissues within Bones:
- Blood and bone marrow fill the internal spaces.
- Connective Tissue: Bones consist of a matrix (ground substance and fibers).
Mineralization: Bones are distinctive as the hardest form of connective tissue due to calcium-based salts that crystallize.

Cartilage: Forms part of the skeletal framework, providing flexibility and support.
Ligaments: Connect bones together (e.g., ACL and MCL in the knee).
Tendons: Connect muscles to bones, facilitating movement.

Support: Provides structural support for the body.
Movement: Bones function as levers for muscle action.
Electrolyte Balance:
- Bones store electrolytes (sodium, potassium, chloride, calcium, phosphate) crucial for physiological functions.
- As nutritional intake changes with age, calcium depletion from bones can lead to osteoporosis.
Blood Cell Production:
- Found within bone marrow, red and white blood cells are produced in the skeletal system.

Bone Types:
- Long Bones: Such as femur and humerus; elongated structure.
- Flat Bones: Such as cranial bones; thin and flat structure.
- Parts of Long Bones:
  - Diaphysis: The long shaft of the bone.
  - Epiphysis: The swollen ends of long bones; contains articular cartilage at joint surfaces.
  - Medullary Cavity: The interior space filled with bone marrow.
  - Articular Cartilage: Cushions joints at the epiphysis.
Growth Plate: Growth occurs at the epiphyseal plate, which transforms into an epiphyseal line in adults.

Definition: A dense connective tissue that surrounds the outer surface of bones.
- Outer Layer: Dense irregular connective tissue, providing structural support and attachment for muscles and ligaments.
- Inner Layer: Contains osteogenic cells that play a role in bone growth and repair.
Function: The periosteum helps anchor blood vessels and nerves to the bone, facilitating growth and healing.

Osteons: The functional and structural unit of compact bone, consisting of concentric layers of bone tissue.
- Haversian System: Contains a central canal with blood vessels and nerves, surrounded by lamellae (layers of bone).
Examination of a transverse section of long bones reveals osteons and the medullary cavity essential for nutrient distribution and structural support.

Chapter 7 discusses the vital roles and complex structures of bone tissue. Students should focus on both the physiological functions of the skeletal system and the anatomy to understand how bone health is maintained and impacted over a lifespan.