Bio 67A Ch 7

Why does the body require calcium? Phosphate?

Calcium essential for § Muscle contraction § Blood clotting § Nerve impulse transmission Phosphate § ATP utilization § Plasma membrane

What are the functions of the skeletal system?

Support Storage of minerals Blood cell production (hemopoeisis, red bone marrow) Triglyceride storage(yellow bone marrow) Protection Movement § Levers

Conjecture: why is bone such a vascular tissue (think importance of calcium homeostasis

because of all the blood vessels that run in it

Where would one find compact bone and why? Where would one find spongy bone and why?

compact in diaphysis spongy in epiphysis and metaphysis

What does the statement, "No projection or groove is ever found on a bone unless there is an attachment or structure to cause it," mean in terms of bone shapes?

it means that if stress is applied to those bones by muscles then we will loose bone mass if we don't use it

Compare/contrast the structure and function of compact and spongy bone

Compact bone § Dense or cortical bone § Osteon § Haversian canal § Blood supply § Innervation 80% bone mass Spongy bone § Cancellous or trabecular bone § Located internal to compact bone 20% bone mass

What are the three types of cells found in bone and what is their function

Osteocytes § Matrix § Lacunae § Lamellae § Canaliculi ¡ Osteoblasts § Inner or outer surface § Osteogenesis ▪ Synthesize osteoid and collagen ¡ Osteoclasts § Bone remodeling ▪ HCl

What is the function of red bone marrow? Yellow bone marrow

Red bone marrow • Myeloid tissue • Hemopoietic (blood cell forming) • Reticular CT, immature blood cells, and fat • In children • Located in spongy bone and medullary cavity of long bones • In adults • Located only in selected areas of axial skeleton ˗ Skull, vertebrae, ribs, sternum, ossa coxae, proximal epiphyses of humerus and femur Yellow bone marrow § Product of red bone marrow degeneration as children mature § Fatty substance § May convert back to red bone marrow • During severe anemia ˗ Condition with reduced erythrocytes (red blood cells) • Facilitates production of additional erythrocytes

How does the skeletal system alter direction and magnitude of muscle force? Why do bone shapes matter?

System of levers § Muscle contraction exerting a pull on the skeleton ¡ Alter direction and magnitude of forces generated by muscles Protects organs in different areas

Know the function of the anatomical terms: osteon, concentric lamellae, interstitial lamellae, circumferential lamellae, perforating canals, trabeculae, etc.

osteon:(uncalcified bone matrix) produced by osteoblasts, contains ▪ Collagen protein Semisolid ground substance of proteoglycans and glycoproteins ▪ Gives bone tensile strength by resisting stretching ▪ Contributes to bone flexibility concentric: thin plate between layers interstitial: same circumferential: same perforating canals: veins pointing toward trabeuclae trabeculae: spongy bone is made of this

What is periosteum? Endosteum? What structures/cells can be found in them?

¡ Periosteum § Dense, fibrous CT (outer layer) and cellular layer (inner) § Protect, isolate § Blood supply and innervation § Bone growth, repair (osteoprogenitor cells) § Continuous with CT of joints and tendons ¡ Endosteum § Lines marrow cavity § Osteoprogenitor cells and osteoblasts § Incomplete simple epithelium