Exam 1 - Lecture 4 8/30 Flashcards
Osmolarity
We will use this.
Quantity of “stuff” mOsm / 1 liter of solution
Solution has a LITTLE bit less water than 1kg.
Osmolality
Quantity of “stuff” mOsm / 1kgH2O
How much mmHg is 1 mOsm?
19.3mmHg
how to calculate total osmotic pressure?
Corrected osmo x 19.3
e.g. 281 x 19.3 = 5423
mOsm and mEq are units of?
Quantity
Weight per quantity of NaCl per the periodic table?
58.4g/1mol (just important to know the units for this measurement)
Osmotic pressure: Water wants to flow ______ its concentration gradient
Down.
Osmotic pressure: H2O will cross semi-permeable membrane and __________
Defy the force of gravity.
If there is salt only on the left side of the membrane, then water will move to the left side of the U-shaped tube.
1 mOsm of stuff on the left side of the tube would increase the water by how many units of distance?
The water would rise by 19.3mm
What is keeping all of the water from moving to the left side of the tube?
The weight of the water + gravity. If you did it in outer space, water would completely move over to the left side.
Rate of facilitated diffusion is impacted by what?
Amount of transport proteins the body has. Once they are all saturated, diffusion speed cant increase and the speed is maxed out (Vmax)
Rate of simple diffusion is?
No Vmax for simple diffusion. The speed increases linearly with concentration of substance.
Diffusion rate can be affected by what factors?
Membrane (lipid) solubility: More lipid soluble the substance, faster to get across.
Size: smaller the faster
of pores/channels
Kinetic movement (heat): higher is faster
Physical pressure: blood pressure, higher is faster.
Electrical charge: if the charge of the cell is opposite of substance, draws it in faster. e.g. (-) cell drawing in Na+
During the Na+/K+ pump, ATP is used and turned into what?
ADP + Pi
What is a result of 3 Na+ leaving with 2 K+ coming in? And what happens if it stops?
Water follows sodium (osmotic pressure), leaving the cell. When this pump stops, cells become swollen with water. This keeps the osmolarity of the cell in check. This type of edema is extremely difficult to deal with, can only be fixed with the cell getting the appropriate ATP.
How does sodium get into the cell?
Through secondary active transport, and Sodium can also leak slowly into the cell.
Resting membrane potential: Vrm
Na+/K+ is a very important component of Vrm.
At rest, excitable cells are electronegative, compared to conditions outside the cell. Dictated by electrolyte gradients (Na+ 10:1, K+ 1:30)
Vrm is denoted as?
-mV. A potential difference between 2 places.
inside of cell is negative in contrast to outside of cell.
When cells are turned on, they flip:
Positive for a very short period of time. e.g. generate heart beat
Proteins often carry what charge?
Net negative charge. Higher concentration of proteins inside than outside.
Proteins are also an important intracellular _________.
Buffer
