Musculoskeletal System - Bones Homeostasis Bone Function Bone Structure Bone Growth

Homeostasis “steady state” Need to maintain balance between intracellular and extracellular fluid. 3 points: Each cell metabolizes All cells contribute to the body Combined contributions = stable ECF

Homeostasis 3 players Sensory receptor: sense change in environment; ex) neurons Integrator: processes info; ex) brain Effectors: carry out response; ex) muscles and glands 2 types of feedback: Negative and Positive

Homeostasis Negative Feedback Reverses the altered condition Ex) maintaining body temperature Positive Feedback Intensify the change from the original condition Ex) oxytocin in giving birth

Bone Function 5 major functions Movement Support Protection Mineral Storage Blood cell formation

Bone Structure Made of both living and non-living cells Living= osteocytes Non-living = mineralized matrix of collagen, protein, carbs, and lacunae

Bone Structure 2 kinds of bone tissue: 1. Compact bone: Outside of bones Dense & solid Made of collagen = tensile strength Made of osteons which surround canals that carry blood vessels and nerves 2. Spongy Bone: Inside Flattened struts Can contain red marrow which makes blood cells Can contain yellow marrow

Bone Structure Red bone marrow = makes red blood cells, platelets, and most white blood cells Yellow bone marrow = consists mainly of fat cells. Can be converted back to red marrow.

Bone Growth Start with cartilage template Growth continues at epiphyses; triggered by GH Remodeling= the process of growing or breaking down bone tissue Osteoblasts = deposit bone Calcitonin triggers uptake and production Osteoclasts = breakdown PTH triggers enzyme production that breaks down bone

Bone Growth The skeletal system helps maintain Calcium level homeostasis. man.com/thelifew ire/content/chp42 / html man.com/thelifew ire/content/chp42 / html

Skeleton 206 bones Divided into: Axial Skeleton Head to toe vertical axis Appendicular Skeleton Hanging appendages Ligaments Connect bone to bone Tendons Connect muscle to bone

Axial Skeleton Down the center of the skeleton: Skull Vertebrae Ribs Sternum

Appendicular Skeleton The appendages of the body. Pectoral Girdle: Ex) shoulder blade, arm bones, and fingers Pelvic Girdle Ex) pelvis, leg bones, and toes

Joints Areas of contact/near contact between bones. 3 types: Synovial Have a cavity filled with synovial fluid. Most flexible joints Ex) knee Cartilaginous Somewhat flexible Ex) disk b/w vertebrae Fibrous No cavity b/w bones Not flexible Ex) skull bones Fibrous: A & B. Cartilaginous C & D Synovial E - J