Chapter 15- Urinary system Flashcards
what are the principle organs of excretion in the body
lungs, liver, skin, and kidneys
what are the three regions of the kidney
outer cortex, inner medulla, and renal pelvis
what parts of the nephron are located in the cortex
convoluted tubules and Bowman’s capsule
what parts of the nephron are located in the medulla
loop of henle and the collecting duct
what are the three processes that lead to urine formation
filtration, secretion, and reabsorption
how does the filtrate concentration compare to blood
it is isotonic
what is filtration driven by
hydrostatic pressure
where does filtration occur
the glomerulus
is filtration active or passive
passive
what happens in secretion
the nephron secretes waste substances such as acid, ions, and other metabolites from the interstitial fluid into the filtrate
is secretion active or passive
it can be either
what happens in reabsorption
essential substances and water are reabsorbed from the filtrate and returned to the blood
where does reabsorption occur
in the PCT
is reabsorption active or passive
active
what gets reasborbed
glucose, salts, and amino acids
what cannot be filtered in the glomerulus
larger components of blood such as cells or proteins
what is reabsorbed at the PCT
amino acids, glucose, water-soluble vitamins and salts are reabsorbed with water
how do reabsorbed solutes reenter circulation
through the peritubular capillaries which are part of the vasa recta
what is secreted at the PCT
hydrogen ions, potassium ions, ammonia, and urea
what is the descending loop of henle permeable to
water
what is the ascending loop of henle permeable to
salts
why does the ascending loop of henle thicken
because of the increased amount of mitochondria
why does the thick ascending loop of henle need more mitochondria
they procude additional ATP needed to power active transporters that pump out Na+ and Cl- from the filtrate
describe the concentration of the filtrate in the descending loop of henle vs the ascending loop
in the descending loop the filtrate is more concentrated, in the ascending loop the filtrate becomes diluted
what happens in the DCT
reabsorption and secretion
what hormone does the DCT respond to and what effect does it have
aldosterone, which promotes sodium and water reabsorption
what hormones does the collecting duct respond to
aldosterone and ADH
what is the countercurrent multiplier system
energy is used to create a concentration gradient
what are the maximum osmolarities at the cortex and deep cortex
cortex- 300
deep cortex-1200
what type of hormone is aldosterone
steroid hormone
what does aldosterone do
up-regulates the active transport of sodium and potassium ions along the DCT and collecting duct, resulting in decreased excretion of sodium ions and increased excretion of potassium ions
what does ADH do
directly affects water reabsorption in the DCT and collecting duct by opening additional aquaporins
what do ADH and aldosterone BOTH do
decrease urine output and increase blood pressure
what is the main difference between ADH and aldosteron
aldosterone does not affect the osmolarity of the blood, but ADH does
