Final: Salt and Water Balance and Nitrogen Excretion Slides Flashcards
(49 cards)
Osmolarity of a solution
Moles of osmotically active particles per liter of solvent
What macromolecules do nitrogenous wastes come from?
Proteins and nucleic acids
What are the nitrogenous wastes? (3)
Urea, ammonia, uric acid
What are ureotelic, ammonotelic, and uricotelic animals?
- Ureotelic: mostly produce urea (humans, mammals)
- Ammonotelic: mostly produce ammonia (fish)
- Uricotelic: mostly produce uric acid (reptiles)
Functions of the renal system (6)
- Regulates water concentration
- Regulates ion concentration
- Excretes metabolic wastes: urea, uric acid, creatinine
- Removes foreign molecules
- Gluconeogenesis
- Releases hormones
Composition of blood dictates and reflects composition of _____ ____
interstitial fluid (want to maintain isosmolarity)
Parts of the renal system (4)
Kidneys, ureters, bladder, urethra
Main function of kidneys
Maintain homeostasis in blood by getting rid of waste products or anything in excess
Function of bladder
Storage of urine for later excretion
Function of ureters
Long, muscular tubes connecting kidney and bladder
Structure of kidneys
Tiny microscopic tubes called nephrons, the functional unit of the kidney
Classifications of nephrons
Cortical or juxtamedullary
Parts of nephrons (6)
- Glomerular capsule
- Proximal convoluted tube
- Descending loop of Henle
- Ascending loop of Henle
- Distal convoluted tubule
- Collecting duct
What happens at the collecting duct of nephrons?
Nephrons empty their contents
When does the fluid in nephrons become urine, and what is it before then?
Becomes urine when it reaches collecting duct, called filtrate until then
What are nephrons surrounded by?
Many capillaries, as their job is to maintain homeostasis
Characteristics of glomerular capsule
Highly permeability so lots of substances can move into nephron (beginning of nephron)
What is in the glomerulus?
Capillaries
What is the renal corpuscle?
Initial blood-filtering component of nephron (many openings to increase permeability)
What are the openings in the renal corpuscle called?
Filtration slits in glomerular capsule, fenestration in glomerulus/capillaries
Path of filtrate in renal corpuscle (3)
- When blood is in glomerulus, filtrate passes through pores in between endothelial cells
- Filtrate goes through basement membrane leading to glomerular capsule
- Passes through filtration slits in between podocytes
Interactions between capillaries and nephron (4)
Filtration, reabsorption, secretion, excretion
What is reabsorption in the kidneys?
Substance needs to cross multiple membranes to reach blood: gets “mistakenly” absorbed by nephrons and needs to get back to blood
Steps in reabsorption in the kidneys
- Move from nephron lumen to apical side of nephron epithelial cells
- Move to basal side of nephron epithelial cells
- Cross basement membrane to reach interstitial fluid
- Cross endothelial cells to reach lumen of capillaries