Lesson 1-2

Question 1

Water determines the structure and biological properties of:

Answer 1

Proteins, Nucleid acids, Lipids, biological membrane

Question 2

Water has a tendency to inoize into?

Answer 2

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

Question 3

pH in water?

Answer 3

• 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

Question 4

Claude Bernard stated:

Answer 4

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”

Question 5

Walter Bradford Cannon stated:

Answer 5

Stability of internal environment = Homeostasis

Question 6

Fluid compartments in the Body:

Answer 6

Total Body Fluid:

• Intracellular fluid (ICF)
• Extracellular Fluid (ECF):
• Interstitial fluid (ISF), Intravasal fluid (IVF), Trancellular fluid (TCF)

Question 7

Intracellular fluid

Answer 7

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.

Question 8

Extracellular fluid (ECF)

Answer 8

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)

Question 9

Components of homeostasis

Answer 9

Isovolemia, isosmosis, isoinoia, isohydria

Question 10

Isovolemia =

Answer 10

The constancy of the volume of ECF

Question 11

dehydration =

Answer 11

decreased volume of ECT, less than 20%

Question 12

overhydration =

Answer 12

Increased volume of ECF, more than 20%

Question 13

hypovoloemia=

Answer 13

decreasedvolume of blood plasma

Question 14

hypervolemia=

Answer 14

increased volume of blood plasma

Question 15

oedema=

Answer 15

increased volume of ISF

Question 16

Isosmosis =

Answer 16

The constancy of the osmotic pressure of ECF

Question 17

Osmotic pressure depends on?

Answer 17

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

Question 18

Difference between Isosmotic and Isotonic?

Answer 18

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!

Question 19

Isohydria =

Answer 19

The constancy of the pH of ECF

Question 20

pH of ECF=

Answer 20

7.4

Question 21

pH in blood =

Answer 21

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

Question 22

pH is acidosis when?

Answer 22

it is between 7.35-7.0

Question 23

pH is alkalosis when?

Answer 23

it is between 7.45 and 7.8

Question 24

Acid-base balance is regulated by:

Answer 24

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

Question 25

Buffer systems or buffer pairs tend to….?

Answer 25

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

Question 26

What is buffer capacity?

Answer 26

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.

Question 27

Bicarbonate buffer system:

mainly in ECF

Answer 27

Question 28

Phosphate buffer system:

Mainly in ICF

Answer 28

Question 29

Protein buffer system:

in plasma and ICF

Answer 29

Question 30

Hemoglobin buffer system:

Answer 30

Question 31

Henderson-Hasselbalch equation

Answer 31