APHY 201 EXAM 1 QUESTIONS WITH VERIFIED
ANSWERS
External body surfaces are... - Answers - continuous with the external environment
What are the 6 external body surfaces? - Answers - 1) Nasal and oral passages
2) Respiratory tract
3) GI tract
4) Urinary tract
5) Reproductive tract
6) Ducts of exocrine glands
Internal body surfaces can only be accessed... - Answers - from an internal body fluid
or
by transport across an external membrane
What are the 3 internal body surfaces? - Answers - 1) Cell membranes of cells within
the body
2) Cardiovascular and lymphatic membranes
3) Serous and connective tissue membranes
Membranes divide the body into compartments that... - Answers - maintain separate
chemical environments
What is the external face of the membrane? - Answers - the surface facing the
environment outside of the body
What is the apical (or huminal) face of the membrane? - Answers - the surface facing
the lumen of a hallow structure
What is the basolateral face of the membrane? - Answers - the surface facing the
intestinal environment
What are the 7 fluid compartments of the body? - Answers - 1) Blood plasma and lymph
2) Interstitial fluid
3) Intracellular fluid
4) Fluid in membranous organelles
5) Cerebrospinal fluid
6) Synovial cavities
7) Chambers in eyeballs and ears
Intracellular fluid contains how much of the body's water? - Answers - 2/3 (28L)
, Extracellular fluid contains how much of the body's water? - Answers - 1/3 (14L)
(3L blood plasma, 11L interstitial fluid)
Filtration - Answers - Pressure driven (blood pressure and fluid hydrostatic pressure)
Diffusion - Answers - Driven by concentration gradients
Osmosis - Answers - Driven by concentration gradients of solutes (only water)
Routes of water loss - Answers - 1) Evaporation from skin and moist membranes, sweat
(+/- 900mL)
2) Feces (+/- 100mL)
3) Urine (+/- 1.5L)
Routes of water gains - Answers - 1) Food, beverages (+/- 2.25L)
2) Metabolism (+/- 250mL)
Primary receptors of the thirst mechanism - Answers - Hypothalamic receptor neurons
signal the thirst center when blood plasma osmolarity > 280 mOsm
Secondary receptors of the thirst mechanism - Answers - Osmoreceptors in the mouth
detect low volume and increase concentration of saliva
Integrating center - Answers - Hypothalamic thirst center
Stimulation of the thirst center causes... - Answers - 1) Stimulation of water-seeking
behaviors through the cerebral cortex
2) Increased water conservation by the kidneys, through ADH from the posterior
pituitary
Temporary cessation of thirst - Answers - Moistening of oral osmoreceptors (inhibits
hypothalamic thirst center only as long as the mouth remains moist)
Long term cessation of thirst - Answers - Return to normal plasma osmolarity (strongly
inhibits thirst center; as long as plasma osmolarity remains normal, thirst is fully
inhibited)
Renal response - Answers - Cannot fix dehydration; only reduces water loss
(reduces filtrate formation and increases water absorption from the urine)
Hypothalamic compensations for overhydration - Answers - Plasma osmolarity < 280
mOsm strongly inhibits thirst by quieting receptor neurons
Renal Response compensations for overhydration - Answers - Increase water loss in
urine by increasing filtrate formation and inhibiting water absorption from the urine
ANSWERS
External body surfaces are... - Answers - continuous with the external environment
What are the 6 external body surfaces? - Answers - 1) Nasal and oral passages
2) Respiratory tract
3) GI tract
4) Urinary tract
5) Reproductive tract
6) Ducts of exocrine glands
Internal body surfaces can only be accessed... - Answers - from an internal body fluid
or
by transport across an external membrane
What are the 3 internal body surfaces? - Answers - 1) Cell membranes of cells within
the body
2) Cardiovascular and lymphatic membranes
3) Serous and connective tissue membranes
Membranes divide the body into compartments that... - Answers - maintain separate
chemical environments
What is the external face of the membrane? - Answers - the surface facing the
environment outside of the body
What is the apical (or huminal) face of the membrane? - Answers - the surface facing
the lumen of a hallow structure
What is the basolateral face of the membrane? - Answers - the surface facing the
intestinal environment
What are the 7 fluid compartments of the body? - Answers - 1) Blood plasma and lymph
2) Interstitial fluid
3) Intracellular fluid
4) Fluid in membranous organelles
5) Cerebrospinal fluid
6) Synovial cavities
7) Chambers in eyeballs and ears
Intracellular fluid contains how much of the body's water? - Answers - 2/3 (28L)
, Extracellular fluid contains how much of the body's water? - Answers - 1/3 (14L)
(3L blood plasma, 11L interstitial fluid)
Filtration - Answers - Pressure driven (blood pressure and fluid hydrostatic pressure)
Diffusion - Answers - Driven by concentration gradients
Osmosis - Answers - Driven by concentration gradients of solutes (only water)
Routes of water loss - Answers - 1) Evaporation from skin and moist membranes, sweat
(+/- 900mL)
2) Feces (+/- 100mL)
3) Urine (+/- 1.5L)
Routes of water gains - Answers - 1) Food, beverages (+/- 2.25L)
2) Metabolism (+/- 250mL)
Primary receptors of the thirst mechanism - Answers - Hypothalamic receptor neurons
signal the thirst center when blood plasma osmolarity > 280 mOsm
Secondary receptors of the thirst mechanism - Answers - Osmoreceptors in the mouth
detect low volume and increase concentration of saliva
Integrating center - Answers - Hypothalamic thirst center
Stimulation of the thirst center causes... - Answers - 1) Stimulation of water-seeking
behaviors through the cerebral cortex
2) Increased water conservation by the kidneys, through ADH from the posterior
pituitary
Temporary cessation of thirst - Answers - Moistening of oral osmoreceptors (inhibits
hypothalamic thirst center only as long as the mouth remains moist)
Long term cessation of thirst - Answers - Return to normal plasma osmolarity (strongly
inhibits thirst center; as long as plasma osmolarity remains normal, thirst is fully
inhibited)
Renal response - Answers - Cannot fix dehydration; only reduces water loss
(reduces filtrate formation and increases water absorption from the urine)
Hypothalamic compensations for overhydration - Answers - Plasma osmolarity < 280
mOsm strongly inhibits thirst by quieting receptor neurons
Renal Response compensations for overhydration - Answers - Increase water loss in
urine by increasing filtrate formation and inhibiting water absorption from the urine
