PY 435 Exam 2 Questions With
Accurate Answers
dry mouth theory (cannon) - ANSWER dry mouth causes thirst
evidence for dry mouth theory - ANSWER cocaine study coated people's mouth in
cocaine so they couldn't feel their mouth become dry and their thirst levels decreased
evidence against dry mouth theory - ANSWER 1. people without salivary glands have
normal thirst levels
2. when you take a sip of water (wetting the mouth) and spit it out, your thirst isn't
quenched
3. sham-drinking experiment
what motivates us to drink? - ANSWER depletion of water from your body cells
intracellular - ANSWER inside of the cell
extracellular - ANSWER between the cells (in the blood and csf)
sham-drinking experiment - ANSWER gave water to dogs (wet their mouths) but drained
the water from their stomachs and they kept drinking water (so thirst was not decreased
from a wet mouth)
methods for wetting the mouth - ANSWER putting a pebble in your mouth to activate
salivary glands, cocaine makes the tongue numb to dryness
what causes thirst? - ANSWER evaporation of water from the body through speaking,
sweating, breathing, vomiting, etc.
osmosis - ANSWER movement of molecules from a high concentration to a low
concentration through a barrier
what % of water in the body is intracellular? - ANSWER 60
thirst happens because - ANSWER the concentration of water in the cells drops
two types of thirst - ANSWER osmotic and hypovolemic
what is osmotic thirst? - ANSWER loss of water from inside the cells; happens when
solute concentration outside the cells increases causing water to exit
why do solutes cause water to exit the cell? - ANSWER the semi-permeable membrane
of cells does not allow certain solutes to enter, to maintain homeostasis, water exits the
, cell
why does eating sugar make you less thirsty than eating salt? - ANSWER sugar can
easily pass through the semipermeable cell membrane and water does not need to exit
the cell
why are diabetics thirstier? - ANSWER without insulin, sugar cannot enter the cell
anderson goat study - ANSWER goat farmers thought that increasing thirst would
increase milk production so anderson injected a salty solution into the goat's
hypothalamus but there was only an increase in urination
anderson - ANSWER found "osmoreceptors" on the lateral hypothalamus that regulate
thirst
baroreceptors in the heart - ANSWER located in the heart, detect a drop in bp and signal
the posterior pituitary to release vasopressin
hypovolemic thirst - ANSWER caused by losing blood volume and losing salts through
excessive exercise
fitzimmons - ANSWER put a balloon in the vena cava (the vein that feeds blood into your
heart) of a dog and it immediately started drinking water
kidneys - ANSWER detect a drop in bp and release renin
renin - ANSWER converts angiotensinogen to angiotensin II
angiotensin II functions - ANSWER 1. constricts blood vessels to compensate for loss so
bp is increased
2. activates subfornical organs to increase thirst
3. stimulates posterior pituitary to release vassopresin
4. stimulates adrenals to secrete aldosterone to retain salt and give you a salt craving
why are there so many areas of the body involved in thirst? - ANSWER because drinking
is so important to life and if one area fails, it wouldn't be as detrimental to thirst if only a
few areas were involved (it's a failsafe)
hunger is caused by - ANSWER a drop in blood-glucose levels
glucostatic hypothesis (mayor) - ANSWER as our blood glucose levels decrease, our
hunger increases and vice versa
gastrocontractions theory (walter cannon) - ANSWER stomach contractions are painful
so to avoid displeasure, we eat and satisfy hunger BUT... this is disproven because
people without stomachs have normal hunger levels
orosensory factors theory (psychologists) - ANSWER seeing/ smelling food induces
Accurate Answers
dry mouth theory (cannon) - ANSWER dry mouth causes thirst
evidence for dry mouth theory - ANSWER cocaine study coated people's mouth in
cocaine so they couldn't feel their mouth become dry and their thirst levels decreased
evidence against dry mouth theory - ANSWER 1. people without salivary glands have
normal thirst levels
2. when you take a sip of water (wetting the mouth) and spit it out, your thirst isn't
quenched
3. sham-drinking experiment
what motivates us to drink? - ANSWER depletion of water from your body cells
intracellular - ANSWER inside of the cell
extracellular - ANSWER between the cells (in the blood and csf)
sham-drinking experiment - ANSWER gave water to dogs (wet their mouths) but drained
the water from their stomachs and they kept drinking water (so thirst was not decreased
from a wet mouth)
methods for wetting the mouth - ANSWER putting a pebble in your mouth to activate
salivary glands, cocaine makes the tongue numb to dryness
what causes thirst? - ANSWER evaporation of water from the body through speaking,
sweating, breathing, vomiting, etc.
osmosis - ANSWER movement of molecules from a high concentration to a low
concentration through a barrier
what % of water in the body is intracellular? - ANSWER 60
thirst happens because - ANSWER the concentration of water in the cells drops
two types of thirst - ANSWER osmotic and hypovolemic
what is osmotic thirst? - ANSWER loss of water from inside the cells; happens when
solute concentration outside the cells increases causing water to exit
why do solutes cause water to exit the cell? - ANSWER the semi-permeable membrane
of cells does not allow certain solutes to enter, to maintain homeostasis, water exits the
, cell
why does eating sugar make you less thirsty than eating salt? - ANSWER sugar can
easily pass through the semipermeable cell membrane and water does not need to exit
the cell
why are diabetics thirstier? - ANSWER without insulin, sugar cannot enter the cell
anderson goat study - ANSWER goat farmers thought that increasing thirst would
increase milk production so anderson injected a salty solution into the goat's
hypothalamus but there was only an increase in urination
anderson - ANSWER found "osmoreceptors" on the lateral hypothalamus that regulate
thirst
baroreceptors in the heart - ANSWER located in the heart, detect a drop in bp and signal
the posterior pituitary to release vasopressin
hypovolemic thirst - ANSWER caused by losing blood volume and losing salts through
excessive exercise
fitzimmons - ANSWER put a balloon in the vena cava (the vein that feeds blood into your
heart) of a dog and it immediately started drinking water
kidneys - ANSWER detect a drop in bp and release renin
renin - ANSWER converts angiotensinogen to angiotensin II
angiotensin II functions - ANSWER 1. constricts blood vessels to compensate for loss so
bp is increased
2. activates subfornical organs to increase thirst
3. stimulates posterior pituitary to release vassopresin
4. stimulates adrenals to secrete aldosterone to retain salt and give you a salt craving
why are there so many areas of the body involved in thirst? - ANSWER because drinking
is so important to life and if one area fails, it wouldn't be as detrimental to thirst if only a
few areas were involved (it's a failsafe)
hunger is caused by - ANSWER a drop in blood-glucose levels
glucostatic hypothesis (mayor) - ANSWER as our blood glucose levels decrease, our
hunger increases and vice versa
gastrocontractions theory (walter cannon) - ANSWER stomach contractions are painful
so to avoid displeasure, we eat and satisfy hunger BUT... this is disproven because
people without stomachs have normal hunger levels
orosensory factors theory (psychologists) - ANSWER seeing/ smelling food induces
