in what order is the body divided ?
cells - tissues - organ - organ system - human body
what is homeostasis ?
the ability of the body to maintain a relatively constant internal environment
what maintains homestasis ?
negative feedback loop
what are the two forms of negative feedback ?
local control or long-distance control
what are the two body fluid compartments ?
intracellular fluid (ICF) and estacellular fluid (ECF)
how much of the total body water is found in ICF ?
2/3
what do plasma membranes do ?
- provides physical separation
- regulates exchange of substances
- communication with environment
what are the 5 plasma membrane components ?
- glycoprotein
- glycolipid
- cholesterol
- transmembrane protein
- peripheral protein
what does hydrophobic mean ?
water hating
what does hydrophilic mean ?
water loving
what size molecules are easier to move across gates ?
smaller
what is simple diffusion ?
from high concentration to low with zero assistance until meets equilibrium
factors of simple diffusion ?
- hydrophobic (lipid soluble)
- small
what substances participate in simple diffusion ?
oxygen, carbon dioxide and alcohol
Fick’s law of diffusion …
SA x Concentration Gradient / Membrane Thickness
3 passive forms of diffusion :
- simple diffusion
- channel-mediated diffusion
- facilitated diffusion
in what case does diffusion require assistance ?
if it is hydrophilic and/or large
what does it mean to “require assistance” in passive diffusion ?
requires a transmembrane protein to help it across
examples of substances for channel-mediated diffusion :
ions and water
examples of substances for facilitated diffusion :
glucose and amino acids
what is channel mediated diffusion ?
transmembrane protein (open channel)
what is facilitated diffusion ?
transmembrane protein (open and closes channel)
what affects channel mediated diffusion ?
- concentration gradient
- number of channels
- size
- charge
what passive form of diffusion is selective and causes saturation ?
facilitated diffusion
