Monthly Archives: December 2012

11.2a Muscles & Joints

Bones, Ligaments, Tendons, Nerves

The bones provide rigid framework against which muscles attach and against which leverage can be produced, changing the size or direction of forces generated by muscles.Ligaments connect bone to bone, restricting movement at joints and helping to prevent dislocation.Muscles attach to bones via tendons, and when muscles contract, they create the forces that move bones; using leverage, small muscle contractions can produce large bone movements. Tendons attach muscles to bone. Lastly, nerves provide a communication network along which messages can be sent signaling muscles to contract at a precise time and extent, so that movement is coordinated.

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6.5a Neurons

resting potential = an electrical potential across a cell membrane when not propagating an impulse

action potential Рthe localized reversal (depolarization) and then restoration (repolarization) of electrical potential between the inside and outside of a neuron as the impulse passes along it

11.3b: The Kidney

  • proteins:
    • large molecules
    • do not pass from glomerulus into nephron during ultrafiltration
  • glucose:
    • small moleucles
    • pass from glomerulus into nephron during ultrafiltration
    • reabsorped from filtrate back to blood plasma at proximal convoluted tubule
    • by co-transport with sodium ions
    • active transport of sodium ions
    • drives glucose reabsorption by facilitated diffusion
  • urea:
    • small moleucles
    • pass from glomerulus into nephron during ultrafiltration
    • concentrated in medulla
      • as water is reabsorbed
      • but urea is not reabsorbed