Homeostasis

Question 1

What are the three types of homeostatic balance?

Answer 1

-Fluid Balance
-Acid Base Balance
-Electrolyte Balance

Question 2

What are the two types of fluid?

Answer 2

-Intracellular fluid
-Extracellular fluid

Question 3

How many liters and what percentage of your body’s weight does intracellular fluid make up?

Answer 3

-25 L
-40%

Question 4

What two types of fluid comprise Extracellular fluid?

Answer 4

-Interstitial fluid
-Plasma

Question 5

How many liters do interstitial fluid and plasma individually comprise and what percentage of your body’s weight do they sum to?

Answer 5

20% of your bodies weight
Interstitial Fluid
-12 L
-80% of ECF
Plasma
-3L
-20% of ECF

Question 6

What is the relationship between fluid in and fluid out?

Answer 6

In take matches losses
-2,500 mL/day In = 2,500 mL/day out

Question 7

What is the breakdown of how fluid enters the body?

Answer 7

-Metabolic water = 200mL
-Food = 700 mL
-Drink = 1,600 mL

Question 8

What is the breakdown of how fluid leaves the body?

Answer 8

-Feces = 200 mL
-Expired Air = 300 mL
-Cutaneous transpiration = 400 mL
-Sweat = 100 mL
-Urine = 1,500 mL

Question 9

What would occur if you were so overhydrated you had no ADH?

Answer 9

-Dec. in osmolality of ECF
Leads to
-Dec. of ADH released from posterior pituitary
Leads to
-Dec. in # of aquaporins in collecting duct
Leads to
-Dec. in H2O reabsorption from collecting duct
Leads to
-Large volume of dilute in urine

Question 10

What would occur if you were so dehydrated we had maximal ADH?

Answer 10

-Inc. in the osmolality of ECF
Leads to
-Inc. in ADH released from posterior pituitary
Leads to
-Inc. in # of aquaporins in collecting duct
Leads to
-Inc. H2O reabsorption from collecting duct
Leads to
-Small volume of concentrated urine.

Question 11

What does alcohol inhibit?

Answer 11

ADH

Question 12

What does caffeine inhibit?

Answer 12

Aldosterone

Question 13

What hormone would be secreted if someone had hypertonic dehydration and why?

Answer 13

Since hypertonic dehydration is caused by a loss of just H2O, just ADH is released.

Question 14

What hormone would be secreted is someone had isotonic dehydration and why?

Answer 14

Since isotonic dehydration is caused by the loss of H2O and solutes, both ADH and aldosterone will be released.

Question 15

What is a potential cause for hypertonic dehydration?

Answer 15

profuse sweating

Question 16

What is a potential cause of isotonic dehydration?

Answer 16

hemorrhage

Question 17

What is dehydration caused by?

Answer 17

Negative water balance

Question 18

Define hypovolemia

Answer 18

volume depletion

Question 19

Is hypotonic hydration common or uncommon and why?

Answer 19

It is uncommon because of the filtration done by the kidneys.

Question 20

What is a potential consequence of hypotonic hydration?

Answer 20

edema

Question 21

What is hypotonic hydration?

Answer 21

Excess water and normal sodium

Question 22

What is the osmolarity for hypovolemia and volume excess?

Answer 22

Both isotonic, so normal

Question 23

What is the osmolarity of hypertonic dehydration?

Answer 23

Hypertonic, so elevated

Question 24

What is the osmolarity of hypotonic dehydration?

Answer 24

hypotonic, so reduced

Question 25

What is the primary regulator of sodium?

Answer 25

Aldosterone

Question 26

What hormones affect Na+ concentrations?

Answer 26

ADH, ANP, Aldosterone, and other hormones

Question 27

Are Na+ imbalances common or not common?

Answer 27

No common because increases or decreases in Na+ are accompanied by proportional changes in H2O

Question 28

What does hypernatremia cause?

Answer 28

-Water retention -Hypertension -Edema

Question 29

How much sodium should be in the perfect diet and how much is in the typical diet?

Answer 29

Perfect diet = .5 g/day Usual = 3-7 g/day

Question 30

What is the relationship between the electrolyte balance of Na+ and K+?

Answer 30

-More Na+ in ECF -More K+ in ICF -Basis for membrane potentiality

Question 31

What is the principal extracellular cation?

Answer 31

Na+

Question 32

What is the principal intracellular cation?

Answer 32

Potassium

Question 33

What is the most important electrolyte for water balance?

Answer 33

Na+

Question 34

What does aldosterone do?

Answer 34

Na+ reabsorption and K+ secretion

Question 35

What does hyperkalemia cause?

Answer 35

Increase in RMP

Question 36

What does hypokalemia cause?

Answer 36

hyperpolarizes cells?

Question 37

What are the functions of Na+?

Answer 37

-RMP -AP -Na+/K+ pump

Question 38

What are the functions of K+?

Answer 38

-RMP -AP -Na+/K+ pump -Most important electrolyte in cell volume -Protein synthesis

Question 39

What is the normal amount of K+ to secrete?

Answer 39

about 10% but DCT and CD can alter secretion based on levels

Question 40

What is the most dangerous electrolyte imbalance?

Answer 40

K+

Question 41

What are the functions of Ca2+?

Answer 41

-Bones -Muscle Contraction Second Messenger Systems -Blood Clotting

Question 42

What keeps calcium in homeostasis?

Answer 42

Parathyroid hormone and calcitonin

Question 43

What does hypercalcemia cause?

Answer 43

It inhibits depolarization so it causes muscle weakness, depressed reflexes, and cardiac arrhythmia.

Question 44

What does hypocalcemia cause?

Answer 44

Overly excitable nervous and muscle tissue; can lead to tetany - laryngospasm.

Question 45

What are the functions of phosphates?

Answer 45

-Concentrated in the ICF -ATP -Nucleic Acids -Phospholipids

Question 46

What happens when you have low levels of phosphates?

Answer 46

Low levels cause kidneys to reabsorb all of the phosphates

Question 47

What happens when you have to many phosphates?

Answer 47

Parathyroid hormone indirectly cause excretion of excess phosphates.

Question 48

What are the functions of Cl-?

Answer 48

-HCl -Abundant ECF anion -Chloride Shift

Question 49

What causes hyperchloremia?

Answer 49

Excess dietary intake or IV saline

Question 50

What is Cl- homeostasis linked to?

Answer 50

Cation homeostasis (Na+, K+, Ca2+

Question 51

What causes hypochloremia?

Answer 51

usually linked to hyponatremia

Question 52

What is the Ph of a solution determined by?

Answer 52

Determined solely by its hydrogen ions (H+)

Question 53

What is an acid (for the purposes of this class)?

Answer 53

Any chemical that releases H+ in solution

Question 54

What is a base (for the purposes of this class)?

Answer 54

Any chemical that accepts H+

Question 55

What is one of the most important aspects of homeostasis?

Answer 55

Enzymes are sensitive to pH so any slight deviation from the normal pH can shut down entire metabolic pathways and alter the structure & therefore function of macromolecules.

Question 56

What are the three chemical buffer systems to resist pH change?

Answer 56

-Bicarbonate -Phosphate -Protein

Question 57

What are the two physiological buffer systems to resist pH change?

Answer 57

-Renal -Respiratory

Question 58

How is the bicarbonate buffer system used to lower pH?

Answer 58

Lungs conserve CO2 and kidneys secrete HCO3

Question 59

How is the bicarbonate buffer system used to raise pH?

Answer 59

Kidneys excrete H+ and lungs secrete CO2

Question 60

What is the equation for the bicarbonate buffer system?

Answer 60

CO2 + H2O <> H2CO3 <> HCO3- + H+

Question 61

What does hyporventilating cause in the respiratory control of pH?

Answer 61

Lowers pH by releasing H+

Question 62

What does hyperventilating cause in the respiratory control of pH?

Answer 62

Raises pH by binding H+

Question 63

Does respiratory control of pH or do the chemical buffers neutralize more acid?

Answer 63

The respiratory control of pH neutralizes two or three times as much acid as chemical buffers.

Question 64

What is the chemical formula for the phosphate buffer system?

Answer 64

HPO4 <>HPO4 + H+

Question 65

What is an important buffer for the ICF and renal tubules?

Answer 65

The phosphate buffer system because phosphates are more concentrates and function closer to their optimum pH of 6.8.

Question 66

What is the main buffer in the ICF?

Answer 66

The protein buffer system is responsible for 75% of all chemical buffering.

Question 67

What are the two protein groups that give proteins there robust buffering abilities and why?

Answer 67

Carboxyl -COOH -Side groups release H+ when pH rises Amino -NH2 -Bind H+ when pH gets too low

Question 68

What is the relationship between bi carb and the kidneys?

Answer 68

The kidneys secrete, reabsorb, and generate new HCO3.

Question 69

What system can neutralize more acid or base than either the respiratory system or chemical buffers?

Answer 69

The Renal control of pH because the renal tubules secrete H+ in the tubular fluid and bound and free H+ are excreted in the urine giving the renal control of pH the only way for H+ ions to be expelled form the body.

Question 70

What causes respiratory acidosis?

Answer 70

-Hypoventilation, apnea, or respiratory arrest -Asthma -Emphysema -Cystic Fibrosis -Chronic Bronchitis -Narcotic overdose

Question 71

What causes metabolic acidosis?

Answer 71

-Excess production of organic acids as in diabetes mellitus and starvation -Long-term anaerobic fermentation -Hyperkalemia -Chronic Diarrhea -Excessive alcohol consumption -drugs such as aspirin and laxatives

Question 72

What causes respiratory alkalosis?

Answer 72

-Hyperventilation due to pain or emotions such as anxiety -Oxygen deficiency (as at high elevation)

Question 73

What causes metabolic alkalosis?

Answer 73

-Rare but can result from chronic vomiting -Overuse of bicarbonate (antacids) -Aldosterone hypersecretion?

Question 74

What happens if your blood pH falls below 6.8?

Answer 74

Your CNS is depressed which leads to coma and death

Question 75

What happens if your blood pH rises above 7.8?

Answer 75

CNS is overexcited which leads to tetany and death

Question 76

Why do we need more bicarb that carbonic acid?

Answer 76

Since most metabolic functions produce acid as a by-product, in order to maintain homeostatic conditions we require a surplus of bases and a very small amount of acids.