Musculoskeletal System - Bones

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Musculoskeletal System - Bones

• Homeostasis
• Bone Function
• Bone Structure
• Bone Growth

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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

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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

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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

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Bone Function

• 5 major functions
• Movement
• Support
• Protection
• Mineral Storage
• Blood cell formation

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Bone Structure

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

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Bone Structure

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

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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.

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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

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Bone Growth

• The skeletal system helps maintain Calcium level
  homeostasis.
• http//bcs.whfreeman.com/thelifewire/content/chp42
  /4202003.html

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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

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Axial Skeleton

• Down the center of the skeleton
• Skull
• Vertebrae
• Ribs
• Sternum

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Appendicular Skeleton

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

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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 -
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