Handout for Discussion Sessions of Monday, September 1 and Wednesday, September 3
Objectives for first lectures
To appreciate the basic role of diffusion in the movement of
molecules in solution and across cell membranes.
To understand in general terms how
molecules move across cell membranes.
To understand the problems created for a cell by
To understand how movements of ions can generate membrane potentials.
understand the structure of a typical nerve cell.
To be able to outline the components of and flow
of information in a simple reflex.
To be able to define in general terms local potentials and
action potentials and how this reflex circuit uses these potentials.
To understand the resting
membrane potential and how it is generated.
To understand the consequences of a membrane
permeable to more than one ion.
1. Define (from lecture and/or your readings in the book and notes): homeostasis, osmolarity,
osmosis, isotonic, hypertonic, hypotonic, diffusion, active transport, facilitated diffusion,
neuron, neuroglia, axon, ganglion, nucleus, soma or cell body, dendrites, axon hillock, nerve
impulse, axon terminal, synapse, microtubules, Nissl bodies, efferent, afferent, central nervous
system, peripheral nervous system, golgi complex, motor neuron, axoplasmic transport,
interneuron, reflex, muscle spindle, chemical transmitter substance, threshold, synaptic
A hypothetical cell contains a solution of protein and is bathed in an iso-osmolar solution of
sucrose (iso-osmolar signifies the solution has the same concentration of dissolved solute
molecules as that present on the inside of the cell).
Tell why this cell is at equilibrium if the membrane is impermeable to sucrose and the