Introduction, Body Fluids, And Composition Flashcards
Passive transport
With gradient
Can be diffusion or facilitated diffusion
Active transport
Against gradient
Requires enzyme
-primary action
-secondary action
Movement of solutes from area of higher to lower concentration
Diffusion
What kind of movement is diffusion
Random
Speed of diffusion
Faster with temperature and concentration gradient
What can diffusion utilize?
Channel if non-permeant
Carrier proteins bind to and move non specific non-permeable solutes across membrane
Facilitated diffusion
What is the rate of diffusion equation
J=PA(Ca-Cb)
P=permeability (cm/sec)
A=surface area for diffusion
Ca-Cb=difference in concentration of two solutes (mmol/L)
Solution A and B are separated by 4cm^2 of membrane that is permeabel only to calcium. It’s permeability was measured at 2.76X10-5 cm/sec. the partition coefficient of calcium is 10^-8, as measured in an oil water mixture. The urea concentration of solution A is 10 mg/ml while solution B is 1 mg/ml. What is the initial diffusion rate of urea and in what direction will it move?
No movement will occur because it is only permeable to calcium
This type of transport requires energy (ATP), always moves a solute AGAINST its gradient, and name usually include ATPase, -porter, or exchanger
Active transport
What direction does active transport move things?
Can move one or more molecules in varying direction
Types of directional active transport
- symport (cotransport)
- antiport/exchanger (countertransport)
Active transport that moves in the same direction
Symport (cotransport)
SGLT1 (Na+-glucose transporter 1)-moves Na+ and glucose into the cell in small intestine and kidney. This is an example of what kind of active transport
Symport (cotransport)
NCX (Na+-Ca+ exchanger)-moves Ca2+ out and Na+ into cell. Usually in excitable cells (retina). What kind of active transport is this?
Antiport/exchange (countertransport)
Primary active transport
ATP is used to directly move solutes
-pumps and ATPases usually
Secondary active transport
The gradient set up by primary transport is used to move solutes
Tertiary active transport
Uses cargo brough in by secondary to bring in another solute
How does Digitalis (Na+/K+ ATPase inhibitor) increase the strength of cardiac contractions?
Lowers the Na+ concentration gradient, which lowers energy, which means calcium stays inside the cell
What is maximum transport
If a form of transport utilizes a carrier protein that binds to the substrate it can become saturated.
When does saturation occur?
When the concentration of a solute is greater than the number of available transporters can handle
Maximal rate of transporter movement is called the what
Transporter maximum
What is an example of transport maximum
Glucosuria in diabetes
What kind of specificity do transport proteins have?
Stereospecificity
What is an example of sterospecificity?
D-glucose is bound and transported, L-glucose is not bound or transported
How do drugs uses the transporters stereospecificity to perform its action
Transporters also recognize closely related molecules. These compete for binding sites and can affect Tm.
-Farxiga blocks SGLT1 by occupying the binding site, reaches lower Tm at lower actual concentration
Predict how the movement rate of sodium through a channel would change if the concentration gradient of sodium was increased by 100%
Rate would be doubled
Predict how the movement rate of glucose would change if the concentration gradient of glucose was increased 100%
Insufficient data. Depends on initial concentration gradient
Which of the following could exhibit a transport maximum?
A. Movement of sodium though Nav(voltage gated Na+ channel)
B. Movement of O2 into blood
C. Movement of potassium via Na-K ATPase
D. Movement of CO2 out of tissues
C. Movement of potassium view Na-K ATPase
What is the movement of water
Osmosis
How can water pass freely through most cell membranes?
- channels called aquaporins
- difference in concentration of solutes that cannot pass generates a pressure difference
- this pushes water from area of low solute concentration to area of high solute concentration
- positive correlation with temperature
What is the pressure that stops movement in osmosis?
Osmotic pressure
What is osmosis basically?
Diffusion of water
What is the number of particles per molecule in a concentration?
Osmolarity (gC)
What is the amount of dissolved stuff in body?
Osmolality
Comparison of two fluids separated by a semi-permeable membrane, with respect to the bathing solution
Tonicity
If the Inside of cell has more dissolved solutes, what ill water do and what is it called?
Water rushes in, cell bursts
-hypotonic (hyposmotic)
Dissolved solutes are equal with no net water movement is called what
Isotonic (isosmotic)
When there is less solute inside the cell than outside the cell, what does water do and what is it called?
Water rushes out, cell shrivels
-hypertonic (hyperosmotic)
What does someone lose in their sweat?
Some water and NaCl
How does sweating affect the Osm of ECF and ICF?
ICF Osm went up, ECF Osm went up
Why would you give someone who had a heat stroke an IV with cold saline instead of cold water?
Cold water will make RBCs lyse
Used to visualize how osmolality and volume changes
Darrow-Yannett diagrams
Darrow-yannett diagram
- used to visualize how osmolality and volume changes
- osmolality (cxn) on Y
- volume on X
- splits ECF and ICF
- all fluid changes originate in ECF and may or may not affect ICF
