Human Physiology (Biol 236)
Exam Outline
It is to be understood that you will have read the corresponding sections of the textbook for lecture topics that we have covered!


Chapter 2, part 2 Outline (updated 9/92022)
Transport Across Cell Membranes
• What is the difference between permeable and selectively permeable membrane?

Know the 4 types of passive transport:
1. Simple diffusion (gases like O2 and CO2 can do this)
2. Facilitated diffusion
- facilitated diffusion with ion channels (such as ion channels for Na+, Ca+2, K+, or Cl-)
- facilitated diffusion with protein carriers (they are like a revolving door on cell membrane)
3. Osmosis (know how water moves across cell membranes when a cell is in a hypertonic, hypotonic, and isotonic solution)
4. Filtration (or dialysis) - this is how arterial blood gets filtered by kidney nephrons.

Know the two categories of active transport:
Primary active transport (Ca+2, H+, and Na+/K+ pumps - and where you would find these types of pumps)
Secondary active transport (co-transport and counter transport)
Regarding co-transport of Na+ and glucose, what is its significance with respect to oral rehydration therapy? Why does this co-transport help hydrate patients having diarrhea? See online reading: Oral Rehdyration Therapy and counter-transport
• For bulk transport:
- What is endocytosis? (phagocytosis, pinocytosis, and receptor-mediated endocytosis)
- What is exocytosis?

Cell Membrane Potential and Depolarization of Cell Membranes (action potentials)
• What is the normal resting cell membrane potential? (-70mv)
What are the steps for formation of an action potential (depolarization) and return to resting state (repolarization) in a cell?
1. stimulus occurs above the membrane threshhold
2. Opening of Na+ channels and inward movement of Na+ ions, which causes membrane potential to go to +30mv & causes depolarization (an action potential that stimulates a cell)
3. Opening of K+ channels and outward movement of K+ ions = repolarization or rest of a cell (but often causes membrane potential to go too low (-80mv), called hyperpolarization.

4. Na+/K+ pumps pump 3 Na+ out of cell for every 2 K+ pumped into cell. This brings membrane potential back to -70mv.
Why can hyperkalemia result in cardiac arrest or death? See clinical app on hyperkalemia


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