Excretory System Flashcards
What is osmosis?
the process by which water moves from regions of high water concentration → low water concentration
What is osmolarity?
the total solute concentration within a specific volume of solvent
What is the concentration of a hypertonic solution?
high solute
low water
cells become dehydrated and shrivel up
What nitrogenous waste is produced by aquatic organisms?
ammonia
What is the concentration of a hypotonic solution?
low solute
high water
cells swell and burst
What nitrogenous waste is produced by mammals, amphibians, sharks, and some fish?
urea
What is the concentration of an isotonic solution?
equal solutes
equal water
What nitrogenous waste is produced by birds, insects, and reptiles?
uric acid
What kind of directional system is the loop of Henle characterized by?
countercurrent flow
In what order does the excretory system work?
kidney → ureter → bladder → urethra
What are the two functions of the excretory system?
- maintain osmotic balance
- remove metabolic waste
In what order does filtrate pass thru the nephron?
renal artery
↓
glomerulus
↓
Bowman’s capsule
↓
proximal tubule
↓
loop of Henle
↓
distal tubule
↓
collecting ducts
What does secretion mean?
solutes are excreted from the blood into the nephron
What does reabsorption mean?
solutes are excreted from the nephron back into the blood
What happens during glomerular filtration?
- blood enters kidney thru renal artery
- fluid from blood in glomerulus enters into the Bowman’s capsule
- fluid is processed as filtrate
What happens in the proximal tubule during tubule reabsorption/secretion?
- NaCl, H2O, and other solutes are reabsorbed into the interstitial fluid
- H+ and ammonium are secreted into filtrate
What happens in the descending loop of Henle during tubule reabsorption/secretion?
water is reabsorbed into the interstitial fluid
What happens in the ascending loop of Henle during tubule reabsorption/secretion?
NaCl is reabsorbed into the interstitial fluid
What happens in the distal tubule during tubule reabsorption/secretion?
- H+, ammonium, and potassium are secreted into filtrate
- NaCl, H2O, and bicarbonate are reabsorbed into interstitial fluid
What hormone plays a role in water conservation during urine production?
ADH
If a person is ____, ADH will not be released.
hydrated
If a person is ____, ADH will be released.
dehydrated
What happens when ADH is released?
Water is reabsorbed into the interstitial fluid and water is retained in the body
What happens when ADH is not released?
Water is retained within the filtrate and withheld from the body
When the blood has high osmolarity:
____ solutes ____ water
↑ ____ secretion
↑ ____ reabsorption
↑ solutes ↓ water
↑ salt secretion
↑ water reabsorption
When the blood has low osmolarity:
____ solutes ____ water
↑ ____ secretion
↑ ____ reabsorption
↓ solutes ↑ water
↑ water secretion
↑ salt reabsorption
What is the purpose of the loop of Henle?
to create a concentration gradient for water and solute balance
How is sodium homeostasis maintained when blood pressure is high?
the blood loses excess ions and water
↓ blood volume
↓ blood pressure
How is sodium homeostasis maintained when blood pressure is low?
the blood retains ions and water
↑ blood volume
↑ blood pressure
ANP ____ sodium reabsorption in collecting ducts
decreases
Aldosterone ____ sodium reabsorption in collecting ducts
increases
When blood pressure is high, ____ levels increase
ANP
When blood pressure is low, ____ levels decrease
aldosterone
