HUBS 191 Lecture 7 Flashcards
what do excitable cells use chemical and electrical gradients for
rapid signalling events
what is osmosis
the movement of water across a semi permeable membrane to equalise solute concentration
for hubs what’re the components of a cell
intercellular space, extracellular space and a semi-permeable membrane
why is water concentration dynamic on both sides of the membrane
because we lose and gain water constantly through sweating, respiration etc
what does osmosis work to do in the cell
balance tonicity between the intercellular and extracellular spaces
what is isotonic
when the concentration of solute is the same in the ECF and the ICF - there is no concentration gradient
what is hypertonic
when the concentration of solute molecules is greater in the ECF because water has been lost
what happens when a cell is hypertonic
water molecules will move from the ICF to the ECF to dilute the solute and even out the concentration
what is hypotonic
when the ECF takes in water so the solute is more dilute in the ECF
what happens when a cell is hypotonic
water molecules will move from the ECF into the ICF to bring the concentrations back to equal
where are most of the negatively charge ions in a cell
on the inside - because most proteins are negatively charged
what does a bigger chemical or electrical gradient mean
a faster and stronger signal
what is the sodium potassium exchange pump
an active pump that maintains the chemical and electrical gradients across the cell membrane. it moves three sodium out of the cell and two potassium in for every ATP used
how do chemical and electrical gradients provide rapid signalling
as soon as the channel for a solute opens up on the plasma membrane the solute will rush down it’s concentration gradient and send a signal to the cell.
