E1 Ch 2 Fluid/Electrolyte and Acid/Base Imbalances

Question 1

water content of the body

Answer 1

• 50-60% of adult weight
• varies with body mass, gender, and age (higher for infants, so they are more sensitive to fluid changes; generally higher for men)
• 40% of body weight is intracellular fluid
• 20% of body weight is extracellular fluid like intravascular fluid, interstitial fluid, cerebrospinal fluid, and transcellular fluid (pericardial fluid, pleural fluid, peritoneal fluid, synovial fluid)

Question 2

movement of water

Answer 2

• amount of water entering the body should equal the amount of water leaving the body
• fluid intake: ingestion of solid food or fluids
• fluid loss: urine, feces, perspiration, exhaled air
• assessed by daily weight
• one liter of fluid weighs 1 kg (2.2 lbs)

Question 3

thirst

Answer 3

hypothalamus; detects fluid volume and concentration; triggered by increased osmolality; promotes intake of fluid

Question 4

ADH

Answer 4

antidiuretic hormone; limits the amount of water excreted by the kidneys; produced by the hypothalamus and stored in the posterior pituitary gland; triggered by increased osmolality

Question 5

aldosterone

Answer 5

increases reabsorption of Na and H2O from the kidney tubules; decreases potassium; triggered by low BP; released by adrenal glands on kidney

Question 6

ANP and BNP

Answer 6

increases Na and H2O elimination; released by myocardial cells; regulation of fluid, sodium, and potassium levels; increases urination

Question 7

renin angiotensin aldosterone system

Answer 7

maintains blood and perfusion pressure
- drop in BP indicates loss of fluid
- causes juxtaglomerular complex to release renin
- renin present in blood circulation causes liver to activate angiotensinogen
- turns into angiotensin I
- ACE (angiotensin converting enzyme) turns angiotensin I into angiotensin II
- angiotensin II causes vasoconstriction, aldosterone release, ADH release