- Approximately what percentage of an average person's body is water? -
ANSWER The average person's body is about 50-60%water
Cellular function requires a fluid medium with a homeostatic balance (3) -
ANSWER 1. *Water*, in which daily water intake and loss are equal
2. *Electrolyte* in which the amount of electrolytes absorbed by the small
intestine balances the amount lost from the body, mainly through the urine
3. *Acid-base* in which the body rids itself of acid (H+ ions) at a rate that
balances its metabolic production, maintaining a stable pH
How is water compartmentalized in the body? - ANSWER Compartments in
which water is found include
1. 65% in intracellular fluid (ICF) within cells
2. 35% in the extracellular fluid (ECF) which includes
a. 25% Intestinal fluid around cells
b. 8% blood plasma and lymph
c. 2% Transcellular fluid, such as cerebrospinal, synovial, serous, vitreous &
aqueous senses of humor, bile, and fluids in the GI, urinary, and respiratory
tracts
- How is water balance maintained in the body?
A person is in a state of *water balance* when daily water intake/losses are
equal - ANSWER 1. Water gains come mainly from ingested water, in
addition to a small amount of water from cellular respiration
2. Water is lost mainly in urine, as well as from feces, expired breath, and sweat
through the skin
, 3. ADH(vasopressin) can cause a significant water loss
4. Intravenous (IV)Fluids may be needed to replace water loss
- To what signals of dehydration does the thirst center in the hypothalamus
respond? How is thirst satiated?
Fluid intake is regulated by the *thirst center* in hypothalamus - ANSWER
The hypothalamus responds to signs of *Dehydration* such as
a. *Angiostein II*, produced in response to falling blood pressure
b. *Decreased atrial stretch*, due to low blood volume
c. Signals from *Osmoreceptor neurons in the hypothalamus* that monitor
blood osmolarity
d. *ADH (vassopressin)*, is synthesized and released in response to rising
blood osmolarity
e. ADH stimulates water reabsorption from kidney tubules
Thirst is stimulated and satiated by
a. Sympathetic signals
b. Short term satiation
c. Long-term satiation - ANSWER a. The thirst center sends sympathetic
signals to the salivary glands to inhibit Salivation
b. Short-term satiation of thirst is accomplished by cooling and moistering the
mouth and inflating the stomach
c. Long-term satiation of thirst depends on absorbing water from the small
intestine and lowering blood osmolarity
- What factors (hormones) control urine output, and under what conditions is
each hormone released? What effects does each hormone produce? - ANSWER
1. ADH
2. Aldosterone
3. Arial Naturetic peptide
ADH - ANSWER ADH is secreted by the *posterior pituitary gland* in
response to dehydration which *causes the kidneys to reabsorb water*
ANSWER The average person's body is about 50-60%water
Cellular function requires a fluid medium with a homeostatic balance (3) -
ANSWER 1. *Water*, in which daily water intake and loss are equal
2. *Electrolyte* in which the amount of electrolytes absorbed by the small
intestine balances the amount lost from the body, mainly through the urine
3. *Acid-base* in which the body rids itself of acid (H+ ions) at a rate that
balances its metabolic production, maintaining a stable pH
How is water compartmentalized in the body? - ANSWER Compartments in
which water is found include
1. 65% in intracellular fluid (ICF) within cells
2. 35% in the extracellular fluid (ECF) which includes
a. 25% Intestinal fluid around cells
b. 8% blood plasma and lymph
c. 2% Transcellular fluid, such as cerebrospinal, synovial, serous, vitreous &
aqueous senses of humor, bile, and fluids in the GI, urinary, and respiratory
tracts
- How is water balance maintained in the body?
A person is in a state of *water balance* when daily water intake/losses are
equal - ANSWER 1. Water gains come mainly from ingested water, in
addition to a small amount of water from cellular respiration
2. Water is lost mainly in urine, as well as from feces, expired breath, and sweat
through the skin
, 3. ADH(vasopressin) can cause a significant water loss
4. Intravenous (IV)Fluids may be needed to replace water loss
- To what signals of dehydration does the thirst center in the hypothalamus
respond? How is thirst satiated?
Fluid intake is regulated by the *thirst center* in hypothalamus - ANSWER
The hypothalamus responds to signs of *Dehydration* such as
a. *Angiostein II*, produced in response to falling blood pressure
b. *Decreased atrial stretch*, due to low blood volume
c. Signals from *Osmoreceptor neurons in the hypothalamus* that monitor
blood osmolarity
d. *ADH (vassopressin)*, is synthesized and released in response to rising
blood osmolarity
e. ADH stimulates water reabsorption from kidney tubules
Thirst is stimulated and satiated by
a. Sympathetic signals
b. Short term satiation
c. Long-term satiation - ANSWER a. The thirst center sends sympathetic
signals to the salivary glands to inhibit Salivation
b. Short-term satiation of thirst is accomplished by cooling and moistering the
mouth and inflating the stomach
c. Long-term satiation of thirst depends on absorbing water from the small
intestine and lowering blood osmolarity
- What factors (hormones) control urine output, and under what conditions is
each hormone released? What effects does each hormone produce? - ANSWER
1. ADH
2. Aldosterone
3. Arial Naturetic peptide
ADH - ANSWER ADH is secreted by the *posterior pituitary gland* in
response to dehydration which *causes the kidneys to reabsorb water*
