NUSCTX 10S MIDTERM 1 EXAM
QUESTIONS WITH COMPLETE
SOLUTIONS
Dehydration - Answer-At risk: excessive sweating, elderly, babies
•Measured as % body weight
-1-2% strong thirst
-3-5% dry mouth, reduced urine output
-6-8% muscle weakness, dizziness, exhaustion, increased body temperature
-9-11% ↓blood volume & pressure, delirium
-20% coma and death
water needs - Answer-Depends on age, body size, health status, physical activity,
environment, diet
Men: 3.7 liters/day
Women: 2.7 liters/day
Hydrophilic - Answer-attracted to water (polar) Water is a polar molecule
hydrophobic - Answer-Water fearing
Osmosis - Answer-the movement of solvent (water) across the membrane from a
region of relatively low concentration to a region of high concentration (solute).
function of electrolytes - Answer-regulate fluid balance
-Cell permeable to water, not electrolytes
-Osmosis: water moves from a low to a high
nerve and muscle response
-Impulses created by a change in the electrical charge across the nerve cell
membrane due to change in electrolyte concentrations
-Muscle, similar change in electrolyte concentrations but with the addition of calcium
Ions Functions - Answer-- Because they are largely confined to particular fluid
compartments and are more numerous than nonelectrolytes, certain ions control the
osmosis of water between fluid compartments.
- Certain ions help maintain the acid-base balance required for normal cellular
activities.
- Ions carry electrical current, which allows production of action potentials.
- Several ions serve as cofactors needed for optimal activity of enzymes.
Acids - Answer-- chemical agents that release hydrogen ions when added to water
- classified as weak or strong depending on the amount of hydrogen ions that
dissociate when placed in water
Diet, Acid-Base Balance, and Osteoporosis - Answer-- if the level of calcium in the
blood gets too low, this important electrolyte is drawn from the bones
, - excess dietary sodium = calcium loss
- over time, this can lead to low bone density
Regulation of Electrolytes - Answer-• Blood levels of electrolytes tightly controlled
• Largely regulated by the kidneys
-Reabsorb or filter depending on blood levels
-Reabsorb sodium as a means to reabsorb water (fluid balance)
-Salt-sensitive people do not filter as well, retain more water and have increased BV
and BP.
Sodium (Na+) - Answer-• Principle extracellular cation
• Functions: fluid balance, nerve transmission, muscle contractions
• Kidneys regulate levels well
-filter excess
-reabsorbed if low BV
• When ↑ Na+intake, thirst signals to dilute with water
• Toxicity: high blood pressure, bloating
• Deficiency: rare, hyponatremia in athletes that replace fluids w/o electrolytes
(headache, dizzy, nausea, muscle cramps, coma, death)
Sodium Sources & Needs - Answer-•Estimated requirement: 200-500 mg/d
•AI: 1,500 mg/d (19-50 y.o.)
•UL: 2,300 mg/d (1 tsp salt)
•Average US intake: 3,300 mg daily
•Sources: salt, processed foods
Potassium (K+) - Answer-•Principle intracellular cation
•Functions: fluid balance, nerve transmission, muscle contraction (heartbeat
regulation)
•Deficiency: rare
•Toxicity: not unless kidney disease,
•could lead to possible heart attack
•Sources: Abundant in fresh foods &•fruits & vegetables
•Lost in processing
Chloride (CI-) - Answer-•Major extracellular anion
•Food source: salt, NaCl is 60% Cl-
•Functions: fluid balance, nerve impulse, part of HCl•Deficiency: rare, can occur with
vomiting
•Toxicity: None
Primary Systems to that regulate water balance - Answer-- Retain Water and
increase blood pressure -Anti diuretic hormone (ADH)
- Retain levels of sodium, potassium and hydrogen in blood and blood pressure-
Renin-angiotensin-aldosteronepathway (system)
thirst mechanism - Answer-a cluster of nerve cells in the hypothalamus that stimulate
our conscious desire to drink fluids in response to an increase in the concentration of
salt in our blood or a decrease in blood pressure and blood volume
QUESTIONS WITH COMPLETE
SOLUTIONS
Dehydration - Answer-At risk: excessive sweating, elderly, babies
•Measured as % body weight
-1-2% strong thirst
-3-5% dry mouth, reduced urine output
-6-8% muscle weakness, dizziness, exhaustion, increased body temperature
-9-11% ↓blood volume & pressure, delirium
-20% coma and death
water needs - Answer-Depends on age, body size, health status, physical activity,
environment, diet
Men: 3.7 liters/day
Women: 2.7 liters/day
Hydrophilic - Answer-attracted to water (polar) Water is a polar molecule
hydrophobic - Answer-Water fearing
Osmosis - Answer-the movement of solvent (water) across the membrane from a
region of relatively low concentration to a region of high concentration (solute).
function of electrolytes - Answer-regulate fluid balance
-Cell permeable to water, not electrolytes
-Osmosis: water moves from a low to a high
nerve and muscle response
-Impulses created by a change in the electrical charge across the nerve cell
membrane due to change in electrolyte concentrations
-Muscle, similar change in electrolyte concentrations but with the addition of calcium
Ions Functions - Answer-- Because they are largely confined to particular fluid
compartments and are more numerous than nonelectrolytes, certain ions control the
osmosis of water between fluid compartments.
- Certain ions help maintain the acid-base balance required for normal cellular
activities.
- Ions carry electrical current, which allows production of action potentials.
- Several ions serve as cofactors needed for optimal activity of enzymes.
Acids - Answer-- chemical agents that release hydrogen ions when added to water
- classified as weak or strong depending on the amount of hydrogen ions that
dissociate when placed in water
Diet, Acid-Base Balance, and Osteoporosis - Answer-- if the level of calcium in the
blood gets too low, this important electrolyte is drawn from the bones
, - excess dietary sodium = calcium loss
- over time, this can lead to low bone density
Regulation of Electrolytes - Answer-• Blood levels of electrolytes tightly controlled
• Largely regulated by the kidneys
-Reabsorb or filter depending on blood levels
-Reabsorb sodium as a means to reabsorb water (fluid balance)
-Salt-sensitive people do not filter as well, retain more water and have increased BV
and BP.
Sodium (Na+) - Answer-• Principle extracellular cation
• Functions: fluid balance, nerve transmission, muscle contractions
• Kidneys regulate levels well
-filter excess
-reabsorbed if low BV
• When ↑ Na+intake, thirst signals to dilute with water
• Toxicity: high blood pressure, bloating
• Deficiency: rare, hyponatremia in athletes that replace fluids w/o electrolytes
(headache, dizzy, nausea, muscle cramps, coma, death)
Sodium Sources & Needs - Answer-•Estimated requirement: 200-500 mg/d
•AI: 1,500 mg/d (19-50 y.o.)
•UL: 2,300 mg/d (1 tsp salt)
•Average US intake: 3,300 mg daily
•Sources: salt, processed foods
Potassium (K+) - Answer-•Principle intracellular cation
•Functions: fluid balance, nerve transmission, muscle contraction (heartbeat
regulation)
•Deficiency: rare
•Toxicity: not unless kidney disease,
•could lead to possible heart attack
•Sources: Abundant in fresh foods &•fruits & vegetables
•Lost in processing
Chloride (CI-) - Answer-•Major extracellular anion
•Food source: salt, NaCl is 60% Cl-
•Functions: fluid balance, nerve impulse, part of HCl•Deficiency: rare, can occur with
vomiting
•Toxicity: None
Primary Systems to that regulate water balance - Answer-- Retain Water and
increase blood pressure -Anti diuretic hormone (ADH)
- Retain levels of sodium, potassium and hydrogen in blood and blood pressure-
Renin-angiotensin-aldosteronepathway (system)
thirst mechanism - Answer-a cluster of nerve cells in the hypothalamus that stimulate
our conscious desire to drink fluids in response to an increase in the concentration of
salt in our blood or a decrease in blood pressure and blood volume
