Lecture 11: Urogenital System Flashcards
what does the urinary system do?
eliminates nitrogenous waste and maintains water balance
what can you find in kidneys?
uriniferous tubules
- bowmans capsule: collects fluids from capillaries
- nephric tubule: modifies composition of fluid
- collecting tubule: conveys fluid
what is renal corpuscle?
glomerulus and bowmans capsule
what is a nephron?
nephric tubule and bowmans capsule
what is the process of a uriniferous tubule structure?
- blood components enters bowmans capsule - becomes urine
- further secretion and resorption in blood occurs
- renal portal system provide capillaries that act as a filtrate
how are kidneys developed?
- mesomeric mesoderm forms nephric ridge
- ridge divides into nephrotomes
- nephrotome is the precursor of uriniferous tubule
- ends of nephrotome merge into common excretory collecting duct
what are the 4 things that a nephrotome can do?
- form bowmans capsule
- form narrow tips and be near glomeruli
- form narrow tips be near glomi that each serve multiple nephrotomes
- remain open to coelem
what are holonephros
hypothetical primitive kidney that develops from nephric ridge
- not present in vertebrates
what is the tripartite kidney organization?
- anterior: pronephros
- middle: mesonephros
- posterior: metanephros
- mesonephros + metanephros = opisthonephros
what is an archinephric duct?
collecting duct that forms during early kidney development
- pronephric duct
- mesonephric duct
- opisthonephric duct
what is an accessory urinary duct?
duct that forms later in development and takes over archinephric ducts urine transporting role
describe the hagfish kidney
- pronephros in embryo
- mesonephros forms adult kidney
- 30-35 pairs of mesonephric
describe the lamprey kidney
- pronephros in early ammocoete
- mesonephros added in late stage ammocoete
- metanephric uriniferous tubules added in adult to form opisthonephric kidney
describe the kidney of jawed fish and lissamphibians
- pronephros and mesonephros in embryos
- opisthonephros in adults
- pronephric tubules taken over by testis in males
- archinephric duct transports sperm adn urine in males
describe the amniote kidney
- mesonephros in embryos
- metanephros forms in adults
- mesonephric become vas deferens
describe the reptilian kidney
- metanepheric divided into lobes
- multiple collecting ducts converge to form ureter on each side of the body
describe the mammalian kidney
- renal pelvis: chamber at the entrance to ureter
- kidney tissue surrounding pelvis divided into cortex and medulla
- middle part of tubule forms loop of henle
define ammonotelism
direct excretion of ammonia
define ureotelism
excretion of ammonia as urea
define uricotelism
excretion of ammonia as uric acid
what is the principle of facultative excretion?
ammonia and urea can be excreted in water, but only the latter can be stored
how does osmoregulation occur in salt water fish
- body is hyposmotic to environment; salt leaks into body and water leaks out
what are aglomerular kidneys?
- lack glomeruli, bowmans capsule, distal parts of nephric tubules
- less filtrate enters uriniferous tubules
how does osmoregulation occur in fresh water fish
- body hyperosmotic to environment; water seeps into tissues and salts leak out
how does osmoregulation occur in land species
- lissamphibians: storage of urea and excretion in water
- reptiles: uric acid excretion with minimal water loss
- mammals: excretion of urea in concentrated urine using loop of henle
