topic 11. powerpoint 11.0 Flashcards
osmosis
passive transport of water across a selectively permeable membrane in response to solute concentration
gradients/pressure gradients
solute concentration
measured as osmolarity
osmolarity
Osmolarity refers to the concentration of solute particles in a solution, specifically in terms of milliosmoles per liter of solution
What is osmoregulation?
maintaining
osmolarity of body fluids
What is the difference between hyperosmotic, hypoosmotic, and isoosmotic?
Hyperosmotic refers to a solution that has a higher osmolarity compared to another solution. Hypoosmotic refers to a solution that has a lower osmolarity compared to another solution. Isoosmotic refers to a solution that has the same osmolarity as another solution.
describe passageway of net flow of water
hypotonic solution| selectively permeable membrane |hypertonic solution
What type of solution will burst?
hypotonic solution, there is a higher concentration of water molecules compared to solute molecules.
What is osmotic pressure?
minimum pressure which needs
to be applied to a solution to prevent the inward flow of
water across a semipermeable membrane
What is the purpose of osmoregulation in animals?
retain isoosmotic
Osmoregulation can be separated into what two groups?
1) osmoregulator: keep the osmolarity of body fluids different from the environment
-mammals
2)osmoconformers: allow osmolarity of bodily fluids to match environment
-sharks
Commonality of groups partaking in osmoregulation is …
excretion as a form of maintaining it
-molecules removed from body to retain isoosmotic
Explain mechanism of how excretion is coupled with osmoregulation
Involves excretory tubules
1) filtration: Extracellular fluids non-selectively pass into the tubule
2) reabsorption: some EF return to the body fluids/blood; in the proximal convoluted tubule
3) Secretion: selective ions[waste] pass into the tubule[filtrate] from body fluids/blood; in the distal convoluted tubule
4)Release: urine is released to the environment
What gets reabsorbed?
glucose, amino acids, ions, water, HCO3-
What gets secreted?
H+ and K+
*retain pH balance
What gets excreted?
Substances that are unneeded or in excess
nitrogenous waste
-ammonia
-urea: ammonia +HCO3-
-uric acid
In mammals, urine is ____ to body fluids.
Almost all other vertebrates produce urine that is____ to body fluids.
hyperosmotic, hypoosmotic
*helps humans conserve water, they have specialized features that allow this
Where does osmoregulaiton take place?
excretory tubules aka nephrons that are located in kidneys
What are some characteristics of nephrons?
-permeability differences
*selective reabsorption and secretion of substances in the kidney.
-different concentration gradients
*permeability differences create concentration gradients that help facilitate reabsorption/secretion
-network of capillaries surrounding it
* helps reabsorb
Urine production overview
1) urine leaves nephrons
2)processed in collecting ducts
3) pools in the renal pelvis
4)Flows through the ureter to the urinary bladder
5)Flows through the urethra to the exterior of the animal
Blood flow in kidneys
Blood flows into the kidneys through the renal artery, intermolecular artery, afferent arteriole, filtered in the glomerulus in bowman capsule, spit into capillaries, efferent arteriole, vasa recta[blood vessels near the Loop of Henle], blood exits through renal vein
What allows for filtration mechanism glomerulus in bowman capsule?
solutes in the blood are easily filtered through spaces in these walls due to the
pressure gradient that exists between the blood in the capillaries and the fluid in the
Bowman’s capsule
What are the two parts of nephrons?
Juxtamedullary nephrons: 20%, long loops that extend into the medulla
Cortical nephrons: 80%, short loops mostly
located in the cortex
Vacta recta is important in maintaining?
the ion gradient of the medulla to
facilitate osmosis with the
Loop of Henle
