Chapter 6: The Skeletal System - Bone Tissue

Flashcards about the skeletal system and bone tissue.

List the functions of the skeletal system.

Provides support, protects internal organs, assists body movements, mineral homeostasis, participates in blood cell production, stores triglycerides.

What are the classes of bones based on shape?

Long, short, flat, irregular, and sesamoid.

Describe the structure of a long bone.

Diaphysis, 2 epiphyses, 2 metaphyses, articular cartilage, periosteum, medullary cavity, endosteum.

What are perforating fibers?

Collagen fibers from surrounding tendons, ligaments, and joint capsules cemented into circumferential lamellae.

What is the chemical composition of bone tissue?

70% mineral (Ca2+ and PO4 - as hydroxyapatite), 22% protein (95% Type I collagen + 5% proteoglycans and other materials), 8% water

What are the four types of bone cells?

Osteoblasts, osteocytes, osteoclasts, and bone lining cells.

What are osteoblasts?

Bone-building cells that secrete matrix and initiate calcification (Hardening of the bone).

What are osteocytes?

Mature bone cells. Maintain and monitor

What are osteoclasts?

Cells that remodel bones and cause them to release calcium; bone resorption.

What is the function of irregular bones?

Protect internal organs

What is the function of sesamoid bones?

Protect tendons from compressive forces

What is the function of compact bone?

Strongest and good at providing protection and support

What is the function of spongy bone?

Lightweight and provides tissue support.

What are the two types of ossification?

Intramembranous and endochondral.

What is intramembranous ossification?

Bone develops from a fibrous membrane; forms most of the flat bones of the skull and the clavicles.

What is endochondral ossification?

Bone forms by replacing hyaline cartilage; uses hyaline cartilage “bones” as models for bone construction.

What structure is responsible for longitudinal bone growth?

Epiphyseal plate.

What is appositional bone growth?

Increases diameter of existing bones and does not form original bones.

What is bone modeling?

Process in which matrix is resorbed on one surface of a bone and deposited on another. (Bone modeling reshapes bones by removing bone in one place and adding it in another — mostly during growth.)

What happens in the growth zone during longitudinal bone growth?

Cartilage cells undergo mitosis, pushing the epiphysis away from the diaphysis.

What happens in the transformation zone during longitudinal bone growth?

Older cells enlarge, the matrix becomes calcified, cartilage cells die, and the matrix begins to deteriorate.

What happens in the osteogenic zone during longitudinal bone growth?

New bone formation occurs.

How do parathyroid hormone and calcitonin regulate bone cells?

Parathyroid hormone (PTH) removes calcium from bone, and calcitonin adds calcium to bone.

What is involved in the repair of a bone fracture?

Hematoma and callus formation.

List minerals that affect bone growth and remodeling.

Calcium, phosphorus, magnesium, fluoride, and manganese.

List vitamins that affect bone growth and remodeling.

Vitamins A, C, D, K, and B12

List hormones that affect bone growth and remodeling.

IGFs, T3 and T4, sex hormones (estrogen in females, testosterone in males).

How does exercise affect bone growth and remodeling?

Stimulates osteoblasts and, consequently, helps build thicker, stronger bones and retards loss of bone mass that occurs as people age.

What is osteoporosis?

Bone resorption outpaces formation; 80% of those affected are women.

What are rickets and osteomalacia?

Inadequate calcification of extracellular bone matrix; rickets affects children, and osteomalacia affects adults.