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Foundations Exam 1 > Physio > Flashcards

Flashcards in Physio Deck (31):
1

Why can't albumin fit through the plasma membrane?

1. (-) charge
2. size

2

What are cells that lack direct communication with external environment? And what do they do?

1. heart and blood vessels: deliver O and nutrients
2. liver and kidneys: remove wastes and toxins
3. N.S.: monitor and regulate the organ system

**semi permeable membranes are what keep these systems separate

3

what is the equation for total body weight?

TBW= ECF (33%) + ICF (67%)

ECF: is made up of blood plasma and interstitial fluid which bathes cells

ICF: intracellular fluid

4

what is the volume of distribution?

the total volume that substance distributes after injection
-this is totally dependent upon the property of the substance

5

what are the different body compartments and what separates them?

blood plasma---BLOOD CAPILLARY WALLS--->interstitial fluid---CELL MEMBRANES---> Intracellular fluid

6

dilution principle and tracers

this principle can be used to determine the SIZE of a fluid in a compartment
-one uses the tracer because it distributes uniformly into the compartment of interest

7

what does tritium oxide measure?

total body weight

8

what does mannitol measure?

ECF

9

what does evans blue dye measure?

plasma

10

age/organs and water content

-water content decreases with age
-and different organs have different water contents kidney and heart have a lot

11

what is whole blood volume?

cells + plasma (ECF)

12

what is hematocrit?

% of blood vol. made up by cells
~40-50%

13

how does one derive total blood volume?

TBV= plasma volume x100/ (100-hematocrit)

14

what is simple diffusion?

when MEMBRANE PERMEABLE solutes move from high concentration to low [ ]

-only small and uncharged
ex: O2, CO2, NO, water

15

what is facilitated diffusion?

-only transport solutes DOWN an gradient
-no energy
-use transporters

ex. RBC--glucose transporters: only if [ ] outside is greater than inside **ONLY IN RBCs**
**aquaporins--move water more rapidly through membrane

16

what is primary active transport?

-transport AGAINST gradient
-energy is required (ATP)

ex. Ca-ATPase

17

what is the Na-K-ATPase Transporter? What does this have to do with osmolarity?

-it is present in all cells
-3 Na out of cell
-2 K into the cell... making the cell slightly negative
-because there is more negative charge inside the cell, there may be more osmotically active particles in the cell than out
-This transporter is very important for reducing osmotic particles inside the cell --> so that they don't burst!

18

What is secondary active transport?

-energy isn't DIRECTLY linked to ATP
-uses one gradient to power another

19

What is co transport?

aka symport
-it is a type of secondary transport
-both molecule are moving in the same direction

ex. Na--amino acid transporter
Na--glucose transporter: this pump works no matter what the glucose [ ] is outside of the cell

20

What is counter transport?

-antiport
-type of secondary
-moving in opposite directions

ex. Ca-Na exchanger

21

Osmosis

-bilayer membranes are permeable to water
-flow of water from low to high [solutes]
-movement is due to differences in osmotic pressure between the 2 compartments

22

What is osmotic pressure? How is it calculated?

=the pressure that would be needed to externally prevent migration of water across the membrane
-it is a colligative property

=gCσRT
g=# particles
C= concentration
σRT=a constant

23

What is Osmolarity? What is it determined by? What is the normal for body fluids?

-determined by the # of dissolved solute particles
= the [ ] of all particles
-Na is a major player in determining this of ECF
-ALL body fluids have the same ~290 mOsm/L

24

what is a reflection coefficient?

σ
-it is dependent upon what the membrane deflects back
-water can move through so for water its 0
-albumin cannot move through so for that its 1
-it is dependent on size AND charge

25

What is tonicity?

=describes the tendency of an external solution to resist expansion of an intracellular volume

26

isotonic, hypertonic, hypotonic

-this is in relation to the the solutes in solution

isotonic= same [ ] of solutes outside and inside

hypertonic= more solutes outside, water exits and cell will shrink

hypotonic= more water outside than inside the cell, water enters the cell --> burst!

27

What are some IV solutions used for tx of things?

1. 154 mM NaCl-isosmotic, used in surgeries to replace plasma volume

2. 300 mM D glucose aka dextrose, isosmotic, used to tx hypernatremia

28

What is HYPERnatremia?

-high [ ] of Na outside of the cells
-severe dehydration
-most often due to lack of free water
tx: Dextrose 5%
enters body cells by facilitated diffusion --> CO2 and water

29

What is HYPOnatremia?

-excess water will result in this
-decreased Na in ECF
-swelling, arrhythmia, other things assoc. with imbalanced Na

30

What should one drink after 60 min. of vigorous exercise?

-gatorade OR fruit juice which will replenish carbs
*always drink in moderation though... bc can lead to hyponatremia

31

what is hemostasis?

=ability of organ to maintain tight control over the [ ] of various solutes in body fluids under different conditions

-use hormones to regulate different things