Excretory System Flashcards
(12 cards)
What is the nephron?
The kidney’s functional unit that is responsible for filtering blood and producing urine. It selectively reabsorbs essential substances back into the blood while excreting waste products.
What is osmolarity, and what does it have to do with kidneys?
Number of solute particles per liter of solution (concentration). Osmolarity is constantly modified through filtration of filtrate in the Bowman’s capsule, water/solute reabsorption in the kidneys, medulla is influenced by the osmotic gradient, etc.
What connects the kidneys to the bladder?
The ureter
What is the urethra?
Where urine exits the bladder
Renal Artery versus renal vein
The renal artery brings blood into the kidneys, and the renal vein is where the liquid with waste filtered out and glucose and salt filtered back in exit the kidney, leaving just waste.
What is urea?
A nitrogenous waste is filtered out of the filtrate by the kidneys.
What solutes stay the same in blood both in and outside of the kidney, regardless of the water intake of the person exercising?
Salts and glucose remain the same because they are returned to the blood before it leaves the kidney through reabsorption.
What solute changes in the blood from inside and outside the kidney when the water intake changes? why?
Urea changes the most. When you drink less water, the kidney conserves water, leading to a higher concentration of urea. Drinking more water dilutes the urea concentration.
What are the four steps to kidney filtration?
- Filtration: blood enters the nephrons, and small stuff gets squeezed out into the nephron’s tube.
- Reabsorption: The body takes back what it needs (water, sugar, salt) as the stuff flows through the nephron’s tube
- The blood vessels around the nephron can also push extra waste and stuff the body doesn’t want into the nephron’s tube.
- Excretion (out of the nephron): The leftover fluid and waste in the nephron’s tube become urine and leave the kidney.
State the changes in urine as the person drinks more water during exercise
As the person drinks more water during exercise, the lower osmolarity of the filtrate results.
Hypotonic, Hypertonic, Isotonic
Hypotonic: low solute
Hypertonic: high solute
isotonic: just right solute vs solvent
Why can’t a saltwater fish survive in a freshwater environment?
A saltwater aquarium is very hypertonic compared to the inside of a fish’s body. Freshwater fish don’t have the structures that manually balance salt levels, so water from the fish will leave its cells, leading to them becoming hypertonic and dehydrate
