BIOS 256: week 5 Questions and Answers 100% Solved
fluid compartments Correct Ans-- fluid continually exchange between compartments
> intracellular and extracellular osmolarity are equal
- osmosis from one fluid compartment to another is determined by the relative
concentrations of solutes in each compartment
> most solute particles are electrolytes
- sodium salts in ECF
- potassium salts in ICF
- electrolytes play the principle role in governing the body's water distribution and total water
content
> electrolytes determine where water goes
> wherever electrolytes go - water will follow
water gain and loss Correct Ans-- fluid balance
> daily gains and losses are equal (about 2,500 mL/day)
, BIOS 256: week 5 Questions and Answers 100% Solved
- gains come from two sources
> preformed water (2,300 mL/day)
- ingested in food (700 mL/day) and drink (1,600 mL/day)
> metabolic water (200 mL/day)
- formed by aerobic metabolism and dehydration synthesis
- C6H12O6 + 6 O2 ---> 6 CO2 + 6 H2O
- sensible water loss is observable
> 1,500 mL/day is in urine
> 200 mL/day is in feces
> 100 mL/day is sweat in resting adult
- insensible water loss is unnoticed
> 300 mL/day in expired breath
> 400 mL/day is cutaneous transpiration
> loss varies greatly with environment and activity
- obligatory water loss
, BIOS 256: week 5 Questions and Answers 100% Solved
> output that is relatively unavoidable
> expired air, cutaneous transpiration, sweat, fecal moisture, and minimum urine output (400
mL/day)
regulation of fluid intake Correct Ans-- dehydration
> reduces blood volume and blood pressure
> increases blood osmolarity
- osmoreceptors in hypothalamus
> respond when BP drops
> respond to rise in osmolarity of ECF (too many solutes and not enough water)
- hypothalamus produces antidiuretic hormone
> promotes water conservation (negative feedback loop)
- cerebral cortex produces conscious sense of thirst
> intense sense of thirst with 2% to 3% increase in plasma osmolarity or 10% to 15% blood
loss
, BIOS 256: week 5 Questions and Answers 100% Solved
> thirst mainly governs fluid intake
- long-term inhibition of thirst
> absorption of water from small intestine reduces osmolarity of blood
- short-term inhibition of thirst
> cooling and moistening of mouth quenches thirst
> distension of stomach and small intestine (stretches with water)
> short-term response designed to prevent overdrinking
regulation of fluid output Correct Ans-- only way to control water output significantly is
through variation in urine volume
> kidneys cannot replace water or electrolytes
> can only slow rate of water and electrolytes loss until water and electrolytes can be
ingested
- control mechanisms of water output
> changes in urine volume linked to adjustments in Na+ reabsorption
fluid compartments Correct Ans-- fluid continually exchange between compartments
> intracellular and extracellular osmolarity are equal
- osmosis from one fluid compartment to another is determined by the relative
concentrations of solutes in each compartment
> most solute particles are electrolytes
- sodium salts in ECF
- potassium salts in ICF
- electrolytes play the principle role in governing the body's water distribution and total water
content
> electrolytes determine where water goes
> wherever electrolytes go - water will follow
water gain and loss Correct Ans-- fluid balance
> daily gains and losses are equal (about 2,500 mL/day)
, BIOS 256: week 5 Questions and Answers 100% Solved
- gains come from two sources
> preformed water (2,300 mL/day)
- ingested in food (700 mL/day) and drink (1,600 mL/day)
> metabolic water (200 mL/day)
- formed by aerobic metabolism and dehydration synthesis
- C6H12O6 + 6 O2 ---> 6 CO2 + 6 H2O
- sensible water loss is observable
> 1,500 mL/day is in urine
> 200 mL/day is in feces
> 100 mL/day is sweat in resting adult
- insensible water loss is unnoticed
> 300 mL/day in expired breath
> 400 mL/day is cutaneous transpiration
> loss varies greatly with environment and activity
- obligatory water loss
, BIOS 256: week 5 Questions and Answers 100% Solved
> output that is relatively unavoidable
> expired air, cutaneous transpiration, sweat, fecal moisture, and minimum urine output (400
mL/day)
regulation of fluid intake Correct Ans-- dehydration
> reduces blood volume and blood pressure
> increases blood osmolarity
- osmoreceptors in hypothalamus
> respond when BP drops
> respond to rise in osmolarity of ECF (too many solutes and not enough water)
- hypothalamus produces antidiuretic hormone
> promotes water conservation (negative feedback loop)
- cerebral cortex produces conscious sense of thirst
> intense sense of thirst with 2% to 3% increase in plasma osmolarity or 10% to 15% blood
loss
, BIOS 256: week 5 Questions and Answers 100% Solved
> thirst mainly governs fluid intake
- long-term inhibition of thirst
> absorption of water from small intestine reduces osmolarity of blood
- short-term inhibition of thirst
> cooling and moistening of mouth quenches thirst
> distension of stomach and small intestine (stretches with water)
> short-term response designed to prevent overdrinking
regulation of fluid output Correct Ans-- only way to control water output significantly is
through variation in urine volume
> kidneys cannot replace water or electrolytes
> can only slow rate of water and electrolytes loss until water and electrolytes can be
ingested
- control mechanisms of water output
> changes in urine volume linked to adjustments in Na+ reabsorption
