UNIT 2 - Lecture 5: Acid Base 1

Question 1

How much of total body water is intracellular fluid?

Answer 1

2/3

Question 2

How much of total body water is extracellular fluid?

Answer 2

1/3

Question 3

What are the 2 components of extracellular fluid and what are the proportions?

Answer 3

Interstitial fluid = 3/4

Plasma fluid = 1/4

Question 4

What separates intracellular fluid from extracellular fluid?

Answer 4

plasma membrane

Question 5

What separates interstitial fluid from plasma fluid?

Answer 5

capillary endothelium

Question 6

What are the 3 major influences on total body water volume?

Answer 6

1. Thirst drive
2. Renal output
3. GI output

Question 7

What are the 3 minor influences on total body water volume?

Answer 7

1. Sweat
2. Salivation
3. Panting

Question 8

What is osmolality and what does it govern?

Answer 8

solute particles / Kg fluid

Governs H2O movement between compartments

Question 9

What are the 4 greatest contributors to osmolality?

Answer 9

1. Na⁺
2. K⁺
3. Glucose
4. BUN

Question 10

In this situation, which way would water move?

Answer 10

Question 11

In this situation, which way would water move?

Answer 11

Question 12

What does it mean if a cell is in a hypotonic environment? What eventually happens to the cell?

Answer 12

The osmolality outside the cell is LOWER than inside;

Water wants to move INTO the cell –> cell lyses

EX: animal drinks too much water too quickly

Question 13

What does it mean if a cell is in an isotonic environment?

Answer 13

The osmolality inside the cell and the osmolality outside the cell are in equilibrium.

*we want this!*

Question 14

What does it mean if a cell is in a hypertonic environment? What will eventually happen to the cell?

Answer 14

The osmolality outside the cell is HIGHER than inside the cell.

Water wants to move OUT OF the cell –> cell shrinks –> loss of function

Question 15

What condition is most common:

Hypotonic

Isotonic

Hypertonic

Answer 15

Hypertonic

Question 16

Hypothalamic osmoreceptors are sensitive to a ___% change in osmolality.

Answer 16

1%

Question 17

Hyperosmolality triggers release of _____, which increases H₂O _____ in the renal collecting ducts.

Answer 17

ADH, reabsorption

Question 18

Hypoosmolality _____ release of ADH, causing _____ H₂O reabsorption in the renal collecting ducts.

Answer 18

inhibits, decreased

Question 19

What can be used to directly measure osmolality?

Answer 19

osmometer

Question 20

What is osmolarity?

Answer 20

solute particles / L of fluid

Question 21

T/F: Osmolality ~ Osmolarity

Answer 21

True

Question 22

What is the RI for osmolarity?

Answer 22

280-310 mOsm/L

Question 23

What is the osmolar gap?

Answer 23

Measured osmolaLity - Calculated osmolaRity

Question 24

What should the osmolar gap be?

Answer 24

Difference should be <10 mOsm/L

Question 25

What is implied if the osmolar gap is increased (\>10 mOsm/L) and what are examples?

Answer 25

There is pathologic presence of unmeasured osmole; Ethylene glycol\*\*\*, propylene glycol, mannitol

Question 26

What are some common hyperosmolality disorders?

Answer 26

1. Hypernatremia 2. Diabetes mellitus\*\* 1. DKA 3. Ketosis 4. Azotemia 5. Ethylene glycol toxicosis 6. Exogenous drug over ingestion

Question 27

What are some common hyposmolality disorders?

Answer 27

1. Hyponatremia\*\* (common as far as hyposmolality disorders but rare in the grand scheme) 2. Hypotonic fluids 1. Water toxicosis 2. Hypotonic IV fluids

Question 28

Why should we determine osmolality?

Answer 28

\>350 mOsm/L = associated with severe neurological depression and is a negative prognostic indicator for survival

Question 29

What is normal blood pH?

Answer 29

Slightly alkaline @ 7.35-7.45

Question 30

What are some serious issues that can arise from pathologic alterations in blood pH?

Answer 30

1. Cardiac dysrhythmias 2. Hypotension with flaccid vascular tone 3. Enzyme dysfunction 4. Electrolyte transport dysfunction 5. Insulin resistance

Question 31

What are some general factors that affect pH?

Answer 31

1. Lungs 2. Kidneys 3. Electrolytes 4. Metabolism 5. Organic acids 6. Diet

Question 32

What are the 3 systems controlling pH?

Answer 32

1. Plasma Buffer System 2. Visceral Response 3. Electrolyte Shifting

Question 33

What is the most important component of the plasma buffer system?

Answer 33

HCO₃^-

Question 34

What are the 3 components of the plasma buffer system?

Answer 34

HCO₃^-, proteins (albumin), organic phosphates

Question 35

What are the 2 types of visceral response?

Answer 35

metabolic and respiratory

Question 36

What 2 things can happen in the metabolic visceral response?

Answer 36

1. Kidney can excrete or reabsorb H⁺ or HCO₃^- 2. Liver can generate HCO₃^-

Question 37

What 2 things can happen in the respiratory visceral response?

Answer 37

Lung can retain or release CO₂

Question 38

In electrolyte shifting, there is a transcellular movement of _____ and \_\_\_\_\_.

Answer 38

K⁺ and H⁺

Question 39

When the body is in an acidic state, _____ goes into the cells while _____ leaves.

Answer 39

H⁺, K⁺

Question 40

When the body is in an alkaline state, _____ leaves the cells while _____ enters.

Answer 40

H⁺, K⁺

Question 41

Plasma bicarb buffer and visceral response work through which carbonic acid reaction?

Answer 41

Henderson Hasselbalch equation: CO₂ + H₂O ⇔ H₂CO₃ ⇔ HCO₃^- + H⁺

Question 42

Which way does the Henderson Hasselbalch equation shift when the body fights acidosis and how?

Answer 42

to the left; Thru hyperventilation - decrease plasma CO₂ to drive the equation to the left and lower H⁺

Question 43

Which way does the Henderson Hasselbalch equation shift when the body is fighting alkalosis?

Answer 43

to the right; Through hypoventilation - increases plasma CO₂ to drive to the right and raise H⁺