Chapter 41 Excretory System Flashcards
The process of filtration from the capillaries into Bowman’s capsule is driven by _____.
blood pressure
During filtration in the kidney, which of the following is least likely (under normal circumstances) to enter Bowman’s capsule from the bloodstream?
plasma proteins
Nitrogenous waste products such as urea are derived from the metabolic breakdown of _____.
proteins
The hormone erythropoietin is released by the kidney ____.
in response to low levels of oxygen in blood
True or False: Animals must regulate solutes and water in their body fluids.
True
Osmoregulation (Osmotic Regulation)
controls concentration of solutes
Ionic Regulation
controls ions in body fluids
Volume Regulation
regulation of the total amount of water in a body fluid
What is an example of volume regulation in humans?
regulating blood volume
What do the regulation processes in excretory systems rely on?
osmosis
Osmosis
diffusion of water
Is water a solute or solvent?
solvent
Examples of Osmotic Fluids
- plasma
- cytosol
- interstitial fluid
True or False: Water and molecules will NOT diffuse across semipermeable membranes.
false
What are the three main water/solute balance functions of the excretory systems?
- get rid of excess salts
- conserve solutes
- get rid of excess (or conserve) water
Hypotonic Solution
- less solute in the solution and more solute in the cell
- causes the cell to inflate
What is the direction of water movement in a hypotonic solution?
water is flowing into the cell
Isotonic Solution
the solute concentration is the same both inside and outside the cell
What is the direction of water movement in an isotonic solution?
water flows in and out of the cell simultaneously
Hypertonic Solution
- more solute is in the solute than inside the cell
- causes the cell to shrivel
What is the direction of water movement in a hypertonic solution?
water flows out of the cell
True or False: Animals are either osmoregulators or osmoconformers.
true
Can animals be both osmoregulators and osmoconformers?
YES
Osmoregulator
animals that maintain osmolarity that is appropriate for that animal
Osmoconformer
have internal osmolarity that changes with the environment
Salt Glands
bundles of secretory tubules with arterioles and veins
What is the function of salt glands?
remove excess salt from the body and allow conservation of water
Rectal Gland
salt gland in sharks that is connected to the digestive system
Do humans have salt glands?
NO
What are the 2 metabolic wastes in the excretory system?
nitrogenous wastes and CO2 and water
Nitrogenous Wastes
end products of protein and nucleic acid metabolism
CO2 and Water Wastes
end products of carbohydrate and fat metabolism
What is the functional unit of a kidney?
nephron
Kidney
main excretory organ that produces urine
Ureter
carries urine to bladder
Bladder
storage site for urine
Bowman’s Capsule
surrounds the glomerulus and helps store urine
Glomerulus
ball of capillaries in the kidney
Loop of Henle
part of tubule that dips into medulla
What does the collecting duct do in the kidney?
concentrates urine
What are the three processes that nephrons are involved with?
- filtration
- secretion
- reabsorption
Where does filtration occur in the nephron?
Bowman’s capsule
What is filtered out of the nephron?
water and solutes
What stays in the blood during filtration?
proteins and blood cells
What happens to filtration rate if blood pressure increases?
filtration rate will speed up and more urine will be produced
What is filtration similar to?
a coffee maker
Reabsorption in Nephrons
conserves water, ions, and other molecules
What is likely to be reabsorbed in nephrons?
glucose
Secretion in Nephrons
active pumping of molecules into tubule
What is likely to be secreted from the kidney?
urea, extra wastes
What do kidneys do when it comes to pH?
kidneys regulate pH of extracellular fluids
What are the major buffers in the blood with kidneys and pH?
bicarbonate ions
The more CO2 in the blood, the more ____ because reaction moves right.
hydrogen ions (H+)
How do kidneys raise pH?
by removing hydrogen ions and returning bicarbonate
What does low blood pressure cause in the excretory system?
secretion of renin
What does renin cause?
secretion of angiotensin
What does angiotensin cause?
secretion of aldosterone
Angiotensin
stimulates thirst
Aldosterone
increases sodium reabsorption to help conserve water
Renin
raises blood pressure
What does an antidiuretic hormone do?
makes the body conserve water
When is an antidiuretic hormone released?
in response to dehydration
True or False: Osmoregulators have internal solute concentrations that change as environmental solute concentrations change.
False
