Cne Pathophys Test I

Front 1

How is water balance controlled?

Back 1

by the ADH/thirst system:

- water balance is monitored by circumventricular organs in the brain (SFO & OVLT) --> they monitor osmolarity of plasma
- water depletion = increase in plasma osmolarity --> when this happens, SFO & OVLT stimulate thirst and stimulate the hypothalamus to release ADH
- ADH acts on distal tubules & collecting ducts --> insertion of aquaporins for more water reabsorption

Front 2

How is osmolyte balance controlled?

Back 2

2 ways: systemically & intracellularly

1. systemic control = renin-angiotensin system
2. intracellular control = Na/K ATPase

Front 3

Explain the renin-angiotensin system

Back 3

- low plasma volume = low BP, which is sensed by the JGA granular cells in kidney --> they release renin

- renin converts angiotensinogen (produced by liver) into Ang I

- ACE converts Ang I to Ang II

- Ang II stimulates aldosterone production --> aldosterone acts on distal tubules and collecting ducts to increase Na+ (and therefore H2O) reabsorption and increase K+ secretion

Front 4

Where is the majority of TBW (total body water) located?

Back 4

intracellularly (ICF)

Front 5

What is lymphatic drainage & what is its purpose?

Back 5

Lymphatic Drainage = tiny lymphatic vessels are located at every interface b/w capillaries & tissues. Bulk flow results in more ultrafiltration (out) than is necessary so lymphatic system is designed to drain excess fluid (and to monitor composition of extracellular fluid).

Front 6

What are the possible causes of edema?

Back 6

1. decreased plasma oncotic pressure (pulling pressure) --> from loss/diminished albumin production (malnutrition)

2. increased interstitial oncotic pressure (pushing pressure) --> vascular injury/inflammation lets albumin escape into interstitial space

3. increased capillary blood pressure (pushing pressure) --> HTN, venous obstruction or overload

4. lymphedema (lymphatic blockage)

Front 7

What is "third spacing"?

Back 7

third space = transcellular compartment in between serous membranes (i.e., pericardial sac, peritoneal cavity, pleural cavity

third spacing is when edema collects in these areas

ex: ascites --> when fluid collects in the peritoneal cavity, caused by starvation/liver failure b/c of low albumin

Front 8

3 categories of ECF alterations

Back 8

1. isotonic alterations = some sort of volue change w/o osmolarity being changed

2. hypertonic alterations = osmolarity is elevated

3. hypotonic alterations = osmolarity is decreased

Front 9

types of isotonic ECF alterations

Back 9

- isotonic volume depletion --> hemorrhage

- isotonic volume excess --> excess IV fluids

Front 10

types of hypertonic ECF alterations

Back 10

- hypernatremia --> inadequate water intake, inappropriate administration of hypertonic saline

- water deficit --> inadequate water intake, impaired renal conservation of water

- hyperchloremia --> w/ excess of sodium or deficit of bicarbonate

Front 11

types of hypotonic ECF alterations

Back 11

- hyponatremia --> diuretics, vomiting, diarrhea, burns, water excess (has dilutional effect)

- water excess --> decreased urine formation, SIADH (syndrome where the body produces too much ADH that leads to too much water reabsorption)

- hypochloremia --> w/ deficit of sodium or excess of bicarbonate

Front 12

things that effect potassium balance

Back 12

- aldosterone
- pH of ECF & ICF (with acidosis, K+ moves out of cell. With alkalosis, K+ moves into cell)
- insulin (makes K+ move into cell)
- catecholamines (not a very significant effect)

Front 13

What organs are the primary regulators of acid-base balance in the body?

Back 13

lungs & kidneys

Front 14

major buffer systems

Back 14

1. bicarbonate buffer system (THIS IS THE MOST IMPORTANT ONE)
2. hemoglobin buffer system
3. proteins (intracellular & extracellular)
4. phosphate buffer system

Front 15

bicarbonate buffer system

Back 15

CO2 + H2O <--(carbonic anhydrase)--> H2CO3 <--> HCO3- + H+

2 regulators: lungs & kidneys

1. lungs regulate by rate & depth of breathing (because this influences PCO2) --> RAPID/MINUTES-HOURS

2. kidneys regulate by controlling plasma level of HCO3- & H+ (HCO3- reabsorption or H+ excretion) --> SLOW EFFECT/HOURS-DAYS

Front 16

respiratory alkalosis vs respiratory acidosis

Back 16

respiratory alkalosis = hyperventilation

respiratory acidosis = hypoventilation

Front 17

possible causes of metabolic acidosis

Back 17

- increase in non-carbonic acids (i.e., ketoacids from diabetes)
- uremia (urine in blood)
- ingestion of acidic substances
- bicarbonate loss (diarrhea, renal failure)

**renal failure is the most common cause**

Front 18

possible causes of metabolic alkalosis

Back 18

- loss of non-carbonic acids (i.e., prolonged vomiting, GI suctioning, diuretic therapy)
- excess bicarbonate intake

Front 19

2 types of hypoxic injury

Back 19

1. ischemia