Water Balance

Question 1

What is interstitial fluid ?

Answer 1

This is the fluid in the spaces between cells

Question 2

What is osmosis dependent on ? What is osmotic pressure?

Answer 2

The concentration of dissolved particles…. so Osmotic Pressure, which is a measure of the solute concentration

Question 3

Water balance needs to be highly regulated because

Answer 3

water intake needs to equal water output to maintain homeostasis level with same blood volume and blood pressure. Cells need water to function in metabolism, and water is needed to dissolve substances

Question 4

What helps to regulate water balance?

Answer 4

Hypothalamus, ADH

Question 5

What is the percentage of water in adipose, bone, blood and skeletal muscle respectively?

Answer 5

Water is contained in all tissues, with adipose (fat) tissue containing about 10% water, bone about 22% water, blood about 83% water and skeletal muscle about 65% water.

Question 6

What property of water makes it so useful in human body physiology?

Answer 6

The ability of water to dissolve so many types of substances allows our cells to metabolize the carbohydrates and proteins that our bodies use as food, digest our food, transport waste and control body temperature.

Question 7

Where is water located in the body?

Answer 7

Water is located in two main compartments of the body. : inside the cells (the intracellular fluid compartment) and outside of the cells (the extracellular fluid compartment). The intracellular fluid (ICF) accounts for about 60% of the fluid in the body which in a 150 lb. (70 kg) adult male consists of about 25 liters. The extracellular fluid (ECF) accounts for about 40% which in a 150 lb. (70 kg) adult male consists of about 15 liters.

Question 8

What are the two sections of extracellular fluid ?

Answer 8

Extracellular fluid consists of two sections: plasma, the fluid portion of blood which contains about 3 liters (8% of total body water) and interstitial fluid, the fluid in the microscopic spaces between cells which contains about 12 liters (32% of total body water)

Question 9

Do electrolytes or non electrolytes have a greater effect on the movement of water across semi-permeable membranes?

Answer 9

Electrolytes (ionic solutes which become charged in solution) because when dissolved in water they dissociate into two or more ions. This contributes to the osmolarity of a solution (a measure of the solute concentration) to a greater degree than non electrolytes (which do not dissociate in water). Basically, electrolytes influence the concentration levels, which affects the movement of water. Osmosis is dependent on the solute concentration levels.

Question 10

Osmosis is dependent on the ……..

Answer 10

The concentration of dissolved particles …the osmolarity and the osmotic pressure

Question 11

What are the major electrolytes located in the blood plasma and the interstitial fluid?

Answer 11

Na+, HCO₃^- (bicarbonate) and Cl-

Question 12

What are the major electrolytes of the intracellular fluid?

Answer 12

K+, Mg⁺²,and HPO₄^-2 (hydrogen phosphate).

Question 13

Does plasma/interstitial fluid or intracellular fluid have the highest protein content?

Answer 13

Blood plasma

Question 14

Compare the ratio electrolyte and nonelectrolyte content in interstitial fluid, plasma and intracellular fluid.

Answer 14

The nonelectrolyte content (cholesterol, fats, phospholipids and proteins) greatly exceeds the electrolyte content of dissolved materials in all 3 of these compartments constituting 60% in interstitial fluid, 90% in blood plasma and 97% in intracellular fluid.

Question 15

Track the movement of fluids between intracellular, blood plasma and interstitial compartments and what pressures affect this?

Answer 15

The movement of fluid between compartments occurs according to hydrostatic and osmotic pressures. Transfer from blood plasma to interstitial fluid occurs at the capillaries with hydrostatic pressure driving fluid from blood plasma to the interstitial compartment and osmotic pressure driving fluid from the interstitial fluid to blood plasma. Fluid flows freely in both directions between the interstitial and intracellular compartments driven by osmotic pressure. There is also a flow of fluid from the interstitial compartment into the lymph capillaries due to osmotic pressure.

Question 16

What is the ultimate, universal , all encompassing, equation of water balance?

Answer 16

Water intake = water output The amount of water one takes in each day must equal the amount of water one loses each day to maintain water balance.

Question 17

About how much water do humans need every day to maintain water balance?

Answer 17

Humans ingest or produce about 2500 ml of water each day with a majority of this water, 1500 ml, being ingested in fluid form. The other 1000 ml of water is either ingested by food or a very small amount is produced by metabolic reactions in the body. Humans also lose about 2500 ml of water each day with the majority, 1500 ml, being lost by urine excretion. The other 1000 ml is lost through feces, sweat, and respiration.

Question 18

Water Uptake - where do our fluids come from?

Answer 18

Question 19

What closely regulates water intake and output?

Answer 19

The hypothalamic thirst mechanism and Anti-Diuretic hormone (ADH)

Question 20

How does the thirst center and ADH respond to changes in blood volume and osmolarity?

Answer 20

A decrease in plasma volume or increase in plasma osmolarity (especially that of Na+), activates the thirst center which stimulates the need to drink. At the same time ADH is released, causing the kidneys to conserve water by releasing more concentrated urine. Conversely, an increase in plasma volume or decrease in plasma osmolarity, inhibits the thirst center and ADH release, causing the kidneys to release large volumes of dilute urine

Question 21

What happens to the body during dehydration

Answer 21

The water output has significantly exceeded the water intake in that the loss of water from the plasma and interstitial fluid causes an osmotic flow of water from the intracellular compartment. This can occur through excessive vomiting, prolonged diarrhea, heavy sweating, extreme blod loss, severe burns, diabetes mellitus and diabetes insipidus. Symptoms include decreased urination, disorientation, dry reddened skin, fever, thickened mucus, thirst and weight loss. Electrolytes are also lost in addition to water during dehydration.

Question 22

What happens to the body during water intoxication?

Answer 22

The plasma and interstitial fluid become diluted (an abundance of water over solutes) and this causes an osmotic flow of water into the intracellular compartment, causing cells to swell, which can lead to cerebral swelling, muscle cramping, nausea and vomiting due to metabolic disturbances, which if not quickly corrected can lead to convulsion, coma and death.

Question 23

What does the treatment for water intoxification involve?

Answer 23

Correction of this condition involves intravenous treatment with hypertonic NaCl solution (saline) which pulls the excess water out of the cells.

Question 24

What is edema?

Answer 24

Tissue swelling due to excess accumulation of fluid in the interstitial compartment caused by fluid flow from the bloodstream due to high blood pressure because of vessel blockages, congestive heart failure or high blood volume due to retention of Na+ or from any condition which prevents return of fluid to the bloodstream such as unusually low plasma protein levels because of protein malnutrition, liver disease or kidney disease. Both increased fluid flow from the bloodstream and decreased return to the bloodstream cause excessive fluid buildup in the interstitial compartment resulting in diminished tissue function due to the greater distance that the nutrients and oxygen must travel. The most serious effect, however, is that of the diminished efficiency of the circulatory system caused by the lower blood pressure and blood volume due to the loss of water from the blood serum compartment.

Question 25

Describe the movement nutrients, wastes, CO2, O2 into and out of the lungs, GI tract, cells and kidneys

Answer 25

Question 26

What functions does salt have in the body?

Answer 26

Bone metabolism, respiratory functions, pH balance, neuron signal activation and osmotic fluid movement

Question 27

What is the most abundant cation in the plasma and interstitial fluid?

Answer 27

Na+

present as NaHCO3 (sodium bicarbonate) and NaCl (sodium chloride)

present at ten times the concentrations of the total of the other significant anions, thereby exerting the greatest influence on electrolyte (and fluid) balance.

Remember that when salt is absorbed, water must also be absorbed to maintain osmotic pressure from which comes the familiar statement “water follows salt”.

Question 28

Water follows ____________

Answer 28

salt

This is important because Na+ is the most abundant ion in the body, which means that its presence and concentration influences the movemetn of water.

Question 29

What are the salts with the greatest physiological importance?

Answer 29

Na⁺, K⁺, Ca⁺² and Mg^+2.

Most body salts are obtained from ingested foods and fluids and are lost by way of defecation, sweating and urination.

Question 30

What are the 3 ways through which sodium (and consequently water) balance is maintained?

Answer 30

Aldosterone, Cardiovascular barocepters, and ADH

Question 31

How does aldosterone regulate the concentration of Na+

Answer 31

Aldosterone, secreted by the adrenal cortex in response to a trigger by the renin-angiotensin system of the juxtaglomerular apparatus of the renal tubules, is the major regulator of Na+ (and Cl- which is co-transported) balance. 90% of the Na+ in the renal filtrate is reabsorbed by the proximal tubules and Loops of Henle with the remainder being reabsorbed by the distal convoluted and collecting tubules. When aldosterone release is inhibited, no reabsorption occurs at the distal convoluted and collecting tubules. Aldosterone release can occur directly (without stimulation by renin-angiotensin) in response to high K+ levels or low Na+ ion levels in the extracellular compartment. However, normal triggers for the renin-angiotensin system are supplied by the central nervous system, decreased renal filtrate osmotic pressure or decreased blood pressure. This aldosterone control system is slow-acting, requiring hours to days to take effect.

Question 32

How do the Cardiovascular baroreceptors work?

Answer 32

The cardiovascular baroceptors are located in the aorta and the carotid arteries- they function in regulating the blood volume (which is influenced by the Na+ ion concentration) to maintain blood pressure. If blood volume (and consequently blood pressure) rises, the baroceptors inhibit sympathetic nervous system signals to the kidney, dilating the afferent arterioles which carry blood to the glomerulus. This causes a dramatic increase in the filtration rate, increasing the output of water and Na+ which reduces blood volume to quickly normalize the pressure.

Question 33

Describe the action of ADH in maintaining Na+ levels

Answer 33

Antidiuretic hormone (ADH) is released by the posterior pituitary in response to triggers by the hypothalamus osmoreceptors which have sensed higher Na+ concentration (likely due to a lower water volume) in the extracellular fluid compartment. This water volume decrease could be due to factors such as major blood loss, severe burns, diarrhea, prolonged fever, excessive sweating and vomiting. ADH binds to receptors cells of the collecting ducts of the kidney and promotes reabsorption of water into the blood system. In the absence of ADH (likely due to higher water volume in the extracellular compartment, low Na+ concentration), the collecting ducts allow all water to be freely excreted as very dilute urine.

Question 34

What is hypernatremia and hyponatremia?

Answer 34

Hypernatremia is a higher Na+ concentration and hyponatremia is a lower Na+ concentration.

Hypernatremia, usually caused by dehydration, is common only in infants or mentally confused individuals and can lead to lethargy, convulsion and coma. Hyponatremia, caused by solute loss and/or water retention, can be due to renal disease, diarrhea, skin burns, excessive sweating, vomiting or Addison’s disease (aldosterone deficiency). Symptoms of hyponatremia include (due to low Na+) neurological dysfunction due to brain swelling, (due to water retention) coma, mental confusion, edema and congestive heart failure.

Question 35

What are the functions of K+?

Answer 35

K+, the predominate cation of the intracellular compartment, is required for protein synthesis, acid-base balance and proper functioning of muscles and neurons. As part of the cellular buffer system, which maintains proper acid-base balance, as H+ ions are transported, K+ ions are transported in the opposite direction to maintain cation balance. So in cases of acidosis (H+ entering the cells), there will be a simultaneous K+ loss, causing extracellular K+ increase and a corresponding extracellular K+ decrease accompanying alkalosis.

Question 36

What are the 2 main ways in which potassium balance is maintained?

Answer 36

(1) the role of the cortical collecting ducts of the renal medulla and (2) the effect of the hormone aldosterone.

Question 37

How do the cortical collecting ducts regulate the K+ levels?

Answer 37

When K+ is high in blood plasma because of high K+ in the diet, the renal cortical collecting ducts reabsorb 90% of the ion, allowing the remainder to be excreted in the urine. When K+ is low in blood plasma because of low K+ in the diet, the intercalated cells of the renal cortical collecting ducts reabsorb greater than 90% of the ion, allowing a smaller amount to be excreted in the urine.

Question 38

How does aldosterone regulate Potassium levels?

Answer 38

The adrenal cortex cells which secrete aldosterone are triggered by higher K+ levels to increase the excretion of K+ and simultaneously decrease the excretion of Na+ since these two ions are tied in a one-for-one exchange to maintain electrolyte balance.

Question 39

What is hyperkalemia and hypokalemia?

Answer 39

Both are imbalances in potassium ion conditions. Hyperkalemia is a higher K+ concentration and Hypokalemia is a low K+ concentration.

Hyperkalemia, can be due to renal or adrenal gland disease or potassium leaking out of cells into the blood circulation due to severe tissue damage and can lead to muscle weakness, slow or irregular heartbeat or cardiac arrest. Hypokalemia can be due to diarrhea, vomiting or hyperaldosteronism (over-secretion of aldosterone). Symptoms of hypokalemia include alkalosis, muscle weakness, irregular heartbeat or cardiac arrest.

Question 40

What are the functions of calcium in the body ?

Answer 40

Ca+2 is found as the structural material in bones and teeth as hydroxyapatite, a salt of calcium phosphate. It also has special roles in controlling nerve impulse transmission, muscle action, blood clotting and cell membrane permeability.

Question 41

What maintains calcuim balance?

Answer 41

Calcium balance is maintained by the action of calcitonin and parathyroid hormones which cause the reabsorption of 98% of calcium by the kidney, small intestines and bones. If plasma calcium levels decrease, the parathyroid glands secrete parathyroid hormone (PTH) which causes a subsequent increase in calcium levels by: (1) activating bone-digesting osteoclasts which release Ca+2 and PO4-3 (phosphate) from the bones into the blood, (2) stimulating the small intestine to absorb Ca+2 and (3) increasing the reabsorption of Ca+2 by the renal tubules. In response to increasing plasma calcium levels, calcitonin is released by the thyroid, inhibiting the bone reabsorption action of osteoclasts.

Question 42

What is calcium excess and defiency called.

Answer 42

Hypercalcemia is an excess of calcium and hypocalcemia is a deficiency of calcium.

Hypercalcemia, can be due to hyperparathyroidism or renal disease and can result in bone fractures, kidney stones, irregular heartbeat and cardiac arrest. Hypocalcemia can be due to diarrhea, burns, Vitamin D deficiency and alkalosis. Symptoms of hypocalcemia include tremors, convulsions and the involuntary contraction of muscles.

Question 43

What is the second most abundant intracellular cation next to potassium?

Answer 43

Magnesium, Mg⁺²

40% of all body magnesium is located inside the cells and the remainder in the skeleton. It is required by over 300 enzymes for catalysis of their metabolic reactions and is required for proper myocardial and neuromuscular function. Normally, over 95% of Mg+2 is reabsorbed by the kidneys.

Question 44

What is magnesium excess and magnesium deficiency called?

Answer 44

Magnesium ion imbalance conditions are referred to as hypermagnesemia (higher Mg+2 concentration) and hypomagnesemia (low Mg+2 concentration). Hypermagnesemia, can be due to aldosterone deficiency or overuse of antacids and can result in central nervous system malfunction and coma. Hypomagnesemia can be due to malnutrition, diarrhea or misuse of diuretics. Symptoms of hypomagnesemia include tremors and convulsions.

Question 45

Why is acid base balance important?

Answer 45

Because the operation of all proteins, especially enzymes whicc control the rate of metabolic reactions, is dependant on the pH of the medium in which they function

Question 46

What is the normal pH of the the interstitial fluid, the intracellular fluid, the arterial blood and the venous blood?

Answer 46

The normal pH of intracellular fluid is 7.0, that of venous blood and interstitial fluid is 7.35 and the pH of arterial blood is 7.4.

Question 47

What is alkalosis?

Answer 47

When the pH of the arterial blood exceeds 7.45, becoming more alkaline (basic) than normal

Question 48

This is the name of the condition when the the arterial blood pH drops to become more acidic….

Answer 48

Acidosis -

If arterial blood pH drops below 7.35, this pH is more acidic than normal

Question 49

What is the blood acidity controlled by ?

Answer 49

The blood acidity (pH) is controlled by

(1) three fast-acting chemical buffer systems,
(2) the slower-acting brain stem respiratory center
(3) the very slow-acting renal system.

Question 50

What is the pH of any system directly dependent on ?

Answer 50

the concentration of free H+ present, likely due to the ionization of strong acids (which produces H+, raising the H+ concentration and decreasing the pH since the solution becomes more acidic) or bases (which produces OH-, using up H+, lowering the H+ concentration and increasing the pH since the solution becomes more basic).

Question 51

How fast is the effect produced by the chemical buffer systems?

Answer 51

Immediate

Question 52

What do the chemical acid-base buffers do ? How do they work?

Answer 52

They prevent changes in the pH by binding H+ or OH- to prevent increases or decreases in the pH.

Buffers are composed of combinations of a weak acid and its anion or a weak base and its cation. . These pairs act to minimize pH changes since the one substance of the pair (weak acid anion or weak base) reacts with free H+ (acid) to bind it, therefore preventing it from lowering the pH and the other substance (weak acid or weak base cation) reacts with OH- to bind it, therefore preventing it from raising the pH.

Question 53

What are the 3 chemical buffer systems of the body ?

Answer 53

The bicarbonate system

The phosphate system

The protein system

Question 54

What do each of the 3 chemical buffer systems act upon?

Answer 54

The bicarbonate system acts as the main buffer of the interstitial and plasma fluids.

The phosphate system acts as one of the buffers in the urine and intracellular fluid

The protein system acts as the main intracelluar fluid buffer

Question 55

What substances is the bicarbonate buffer system of the interstial and plasma fluid formed of ?

Answer 55

Bicarbonate and Carbonic Acid

The interstitial and plasma bicarbonate buffer system is composed of the weak carbonic acid (H2CO3) and bicarbonate ion (HCO3-). If free H+ is released into the extracellular compartment (interstitial fluid or plasma), bicarbonate reacts with it to bind it as carbonic acid by the following reaction.

H⁺ + HCO₃^- → H₂CO₃

If, on the other hand, free OH- is released into the extracellular compartment (interstitial fluid or plasma), carbonic acid reacts with it to convert it to bicarbonate by the following reaction.

OH^- + H₂CO₃ → HCO₃^-

The buffering capacity of this system is substantial due to the significant concentrations of carbonic acid (formed from CO2, a product of cellular respiration) and bicarbonate (reabsorbed by the kidneys).

Question 56

What substances compose the phosphate system that acts upon the urine and intracellular fluid and how does it minimize any changes to the pH.

Answer 56

Composed of the Weak acid H₂PO₄^- and monohydrogen phosphate ion HPO₄^{- 2}

These act upon inflows of free H+ and OH- by binding them to prevent increases of decreases in the pH.

If free H+ is released into the intracellular compartment, monohydrogen phosphate ion reacts with it to bind it as H₂PO₄^--

If free OH- is released into the intracellular compartment then dihydrogen phosphate reacts with it to convert it to monohydrogen phosphate.

The buffering capacity of this system is large due to the significant concentrations of phosphate concentration in the intracellular compartment.

Question 57

What substances compose the protein buffer system?

Answer 57

• NH₂ or (-NH₃⁺) and -COOH (or -COO^-) groups present on the amino acid sections within the intracellular proteins.
• NH₂ and -COO^- will bind the hydrogen released into the intracellular compartment

Released OH^- will be binded to by -NH₃⁺ or -COOH groups.

. The protein system provides 3 times the buffering capacity of all the other systems combined due to the substantial concentration of proteins in the cells.

Question 58

Carbon dioxide is carried in the blood plasma in the form of ……..

Answer 58

bicarbonate

Question 59

How does the respiratory center regulate the blood pH?

Answer 59

The key reaction to understand is the reversible reaction containing the reactants of Carbon dioxide and water that forms the Carbonic acid which dissacociates into hydrogen and bicarbonate.

CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3-

If blood pH begins to fall (becoming more acidic) then the respiratory center is excited and causes more Carbon dioxide to be removed which pushes the reaction to the left and uses up H+- this increases the pH to restore the correct pH.

If blood pH begins to rise and become more basic, there is an accumulation of CO2 which pushes the reaction to the left to form more H+ that will decrease and restore the correct pH.

Question 60

Respiratory acidosis and respiratory alkalosis - what can cause them ?

Answer 60

Respiratory center malfunctions that lead to pH imbalances due to CO2 retention or removal

Question 61

What is unique about the kidneys in their acid-base balance role?

Answer 61

Only the kidneys have the ability to actually remove (rather than just bind) acids and bases from the body and even though this mechanism is much slower-acting than the chemical buffers or the respiratory center, it is the major system used to manage acid-base imbalance caused by metabolic processes or disease.

Question 62

The major renal acid-base regulating process is by way of excreting or reabsorbing ______________

Answer 62

bicarbonate ion.

An excretion of bicarbonate ion results in the retention of H+ and the reabsorption of bicarbonate results in the excretion of H+.

Question 63

What does acid-base balance by the renal mechanism depend on ?

Answer 63

Acid-base balance by the renal mechanism depends on H+ secretion by way of the renal filtrate in response to the pH of the extracellular fluid.

Question 64

How does the renal mechanism react when the pH of the peritubular capillaries is low ?

Answer 64

When the pH of the perilubular capillaries is low (due to H+ formed by the dissociation of H2CO3 formed from high CO2 levels), (1) the CO2 diffuses into the tubule cell where it (2) forms carbonic acid (catalyzed by the enzyme carbonic anhydrase) which (3) dissociates to form bicarbonate ion and H+. The bicarbonate (4) passes back into the peritubular capillary blood and (5) the H+ passes into the renal filtrate, thereby raising and normalizing the blood pH.

Question 65

How does the renal mechanism react when the blood pH is too high?

Answer 65

H+ in the filtrate (6) combines with bicarbonate to form H2CO3 which (7) decomposes to CO2 and (8) diffusion of this into the tubule cell and then the peritubular blood lowers and normalizes the pH. This pH-regulation is depicted in the figure below.

Question 66

How does the renal regulating mechanism act regarding the conservation of bicarbonate ?

Answer 66

Another important renal pH-regulating mechanism is the conservation of bicarbonate, the most important anion responsible for chemical buffering of the extracellular compartment. Bicarbonate can be replenished in the plasma by reclaiming it from the renal filtrate. H+ in the tubule cell is (1) secreted into the filtrate where it (2) combines with filtered bicarbonate to form H2CO3 which (3) diffuses into the tubule cell (as CO2) to be (4) converted back to bicarbonate and (5) transported into the plasma to regenerate needed buffering capacity (called the alkaline reserve). This pH-regulation is depicted in the figure below.

Question 67

What happens if the concentration of bicarbonate in the filtrate is diminished (used up to buffer the blood) in response to developing blood acidosis?

Answer 67

he H+ secreted into the filtrate must be buffered and excreted to avoid a radical decrease in urine pH since bicarbonate is no longer available to accomplish the buffering action. (Remember that more H+ is being formed by the system described in diagram A to continue to regulate the blood pH). Two mechanisms exist to accomplish this: the renal phosphate buffer and the ammonia buffer system. The renal phosphate buffer employs monohydrogen phosphate (HPO4-2) to bind the H+ as H2PO4- which is excreted in the urine, as the urine pH is normalized. The ammonia buffer system employs ammonia (NH3) formed by the deamination of glutamine to bind the H+ as NH4+ which is excreted in the urine, as the urine pH is normalized. Both of these mechanisms operate in blood acidosis to add bicarbonate (HCO3-) to the blood and add H+ to the filtrate.

Question 68

What is the normal pressure of CO2 in the blood serum?

Answer 68

35-45 mm

Question 69

What is the normal pH of the blood ?

Answer 69

7.35-7.45

Question 70

What is the normal blood serum HC0₃^- concentration?

Answer 70

22-26 mEq/L

Question 71

Respiratory alkalosis is characterized by

Answer 71

blood pH > 7.45

PCO2 levels are < 45 mm

the HCO3- concentration will be < 22 mEq/L (as the renal system attempts to lower the pH by lowering the HCO3- concentration).

Question 72

Respiratory Acidosis is charcterized by

Answer 72

blood pH < 7.35

PCO2 blood levels > 45mm

if renal compensation is occurring, the HCO3- concentration will be > 26 mEq/L (as the renal system attempts to raise the pH by raising the HCO3- concentration).

Question 73

Metabolic Alkalosis is characterized by:

Answer 73

pH > 7.45 (with abnormally high HCO3- concentration > 26 mEq/L) i

if respiratory compensation is occurring, the PCO2 will be > 45 mm (as the respiratory system attempts to lower the pH by raising the PCO2)

Question 74

Metaboic acidosis is characterized

Answer 74

pH < 7.45 with abnomally low concentrations of HCO3

bicarbonate < 22 mEq/L

if respiratory compensation is occuring, then the PC02 levels will be < 35 mm (as the respiratory system attempts to raise the pH by lowering the PCO2).

Question 75

What happens to the body if ph of the blood exceeds 7.8?

Answer 75

If alkalosis causes the blood pH to rise above 7.8, the nervous system is markedly excited causing extreme nervousness, muscle contraction, convulsion and death usually due to cessation of breathing.

Question 76

What happens to the body if alkalosis causes the blood pH to go below 7.0?

Answer 76

Coma and imminent death- the nervous system is depressed.

Question 77

Which system compensates for respiratory acidosis or alkalosis?

Answer 77

The renal system wil compensate by increasing its reabsorption or excretion of HCO3- bicarbonate to increase or decrease H + levels.

Question 78

What causes respiratory acidosis?

Answer 78

Since there is a high PCO2 pressure in the blood, acidosis is caused by poor gas exchange and ventilation.

caused by shallow breathing or limited gas exchange usually due to diseases such as cystic fibrosis, emphysema or pneumonia.

Question 79

What causes respiratory alkalosis?

Answer 79

Almost always hyperventilation- excess breathing.

Respiratory alkalosis is characterized by higher pH because of lower CO2 pressure (PCO2 < 35 mm) almost always caused by hyperventilation (over-breathing) such as in the case of a panic attack

Question 80

What causes metabolic acidosis?

Answer 80

Characterized by blood pH < 7.35 with normal CO2 levels and abnormally low concentration of HCO3- < 22 mEq/L.

caused by buildup of acidic metabolic products such as acetic acid (alcohol overdose), lactic acid (exercise or shock), diabetic ketosis or loss of HCO3- caused by extreme diarrhea.

Question 81

What causes metabolic alkalosis?

Answer 81

Characterized by blood pH > 7.45 with normal CO2 levels and abnormally high concentration of HCO3- >26 mEq/L

caused by vomiting (loss of acidic stomach contents), intake of excess antacids and constipation which causes abnormal reabsorption of HCO3-.

Question 82

What system compensates for metabolic acidosis and alkalosis?

Answer 82

The respiratory system - increases or decreases the PCO2 levels to increase/decrease the pH.

Question 83

Memorize the Acid Base Disorders Chart

Answer 83