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Flashcards in Lesson 1-2 Deck (31)
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1

Water determines the structure and biological properties of:

Proteins, Nucleid acids, Lipids, biological membrane

2

Water has a tendency to inoize into?

Ionize into hydrogen and hydroxyde ions. This ionization is crucial to waters role in cellular function. The amount of hydrogen and hydroxide ion in a solution is: (H+) x (OH-) = 10^-14 mol/l

3

pH in water?

- In pure water, there is one hydrogen ion for every hydroxide ions, so they are both equal 10^-7 mol/l. - as pH = -log (H+), in pure water pH =7

4

Claude Bernard stated:

Life is an expression of the physical reality and the maintenance of life is guaranteed by the constancy of the fluid matrix or "milieu interieur"

5

Walter Bradford Cannon stated:

Stability of internal environment = Homeostasis

6

Fluid compartments in the Body:

Total Body Fluid:

- Intracellular fluid (ICF)

-Extracellular Fluid (ECF):

    - Interstitial fluid (ISF), Intravasal fluid (IVF), Trancellular fluid (TCF)

7

Intracellular fluid

Comprises 2/3 of the bodys water. It is primarly a solution of potassium and organic anions, proteins etc. The cell membranes and cellular metabolism control the constituents of this ICF.

8

Extracellular fluid (ECF)

Is 1/3 of the bodys water. ECf is primarly NaCl and NaHCO3 solution. It is further subdivided into: - Interstitial fluid (surrounds the cells, but does not circulate. 3/4 of ECF) - Intravasal fluid IVS (blood plasma, circulates as the extracellular components of blood. 1/4 of ECF) - Transcellular fluid TCF (set of fluid that are outside of the normal compartments, 1-2%. Cerebrospinal fluid in the CNS, aqueous humor and vitreous humor, synovial fluid in the joints, glandular secretion, serous fluid etc)

9

Components of homeostasis

Isovolemia, isosmosis, isoinoia, isohydria

10

Isovolemia =

The constancy of the volume of ECF

11

dehydration =

decreased volume of ECT, less than 20%

12

overhydration =

Increased volume of ECF, more than 20%

13

hypovoloemia=

decreasedvolume of blood plasma

14

hypervolemia=

increased volume of blood plasma

15

oedema=

increased volume of ISF

16

Isosmosis =

The constancy of the osmotic pressure of ECF

17

Osmotic pressure depends on?

the number of solute particles per unit volume = osmotic concentration (osmolarity)

18

Difference between Isosmotic and Isotonic?

For an isosmotic solution to be isotonic, the membrane must be equally impermeable to all solutes. - All isotonic solution are isosmotic! - But not all isosmotic solutions are isotonic!

19

Isohydria =

The constancy of the pH of ECF

20

pH of ECF=

7.4

21

pH in blood =

-log 2.5 x 10^-7 = 7.4 (7.35-7.45)

22

pH is acidosis when?

it is between 7.35-7.0

23

pH is alkalosis when?

it is between 7.45 and 7.8

24

Acid-base balance is regulated by:

Acid-base buffer systems, respiratory centers in the brain ste and the kidneys

25

Buffer systems or buffer pairs tend to....?

reisits change in pH, when H+ or OH- is added

26

What is buffer capacity?

it is a measure of the efficiency of a buffer in resting changes in pH. Conventionally, the buffer capcaity is expressed as the amount (mol) of strong acid or base, that must be added to 1 liter of the solution to change its pH by one unit.

27

Bicarbonate buffer system: 

mainly in ECF

28

Phosphate buffer system: 

Mainly in ICF

29

Protein buffer system: 

in plasma and ICF

30

Hemoglobin buffer system: