Urinary System Flashcards
major functions of the urinary system
- removal of metabolic waste products from the blood: heme to bilirubn to urobilin (yellow)
- regulation of ion concentration (NA, K , etc)
- regulation of blood acid-base balance
- regulation of blood pressure (renin)
- regulation of RBC production (EPO)
- regulation of VitD production
which hormones are synthesized and released by the kidney
-renin and EPO
how does Vit D interat with the kidney
-synthesized in the skin but activated and released in the kidney
role of vit D
- increases ca absorption in small intestine
- increases ca absorption in renal tubules
- increases osteoclast activity to increase ca levels
renal artery branches into
-interlobar artery and then the arcuate artery and then the interlobular artery
renal collumn is found where
in between renal pyramids
renal pyramids dump into
renal pelvis
lobules are seperated by
interlobular arteries
renal corpuscle
-glomerulus and bormans capsule
nephron
renal corpuslce and tubule
uriniferous tubule
nephron and collecting duct
cells found in the glomerulus
- endothelial cells
- mesangial cells
- podocytes
glomerulus is surrounded by
-bowmans space and capsule
how does the glomerulus and bowmans capsule facilitate filtration
-large afferent arterioles and small efferent arterioles
mesangial cells
- support
- phagocytosis
- repair
- contractile
- BP monitoring (extraglomerular mesangial cels, lacis cells)
podocytes
- surround the glomerulus and facilitate filtration by making small slits with long processes
- share a basement membrane with endothelial cells, filtrate passes through the spaces between the conjoining processes
glomerular filtration
-composition of the filtration system
- 68,000MW allowed to pass through
- barrier is made with type 4 collagen network
- lamin network
- proteoglycans
flow of blood that becomes filtrate in the kidney starting with the interlobar artery
- interlobary artery
- arcuate artery
- interlobular artery
- afferent arteriole
- into bowmans capsule
- proximal convoluted tubule
- loop of henle thick then thin
- distal convoluted tubule
- colecting duct
job of the proximal and distal convoluted tubule
-to remove everything that is useful to us and leave veryting that isnt to be excreting
where does the majority of resorbtion happen?
- 80% in the PCT
- PCT 3: 1 DCT
characteristics of PCT
- brush border with enzyme rich glycocalyx
- endocytic vesicles
- basal infoldings
- abundant mitochondria
- Na/K ATPase
characteristics of the DCT
- resorbs mostly water and Na
- no brush border
- fewer mitochondria
- aldosterone sensitive Na/K ATPase
what is actively absorbed in the PCT
- Na (endocytosis)
- amino acids
- sugars
- peptides (endocytosis)
passive absorption in the PCT
- water
- Cl
two steps of resorption
- pump nutrients into the ECM
- uptake of nutrients into caps
renal medulla
- generation of salt gradient
- resorption of water
- acid base balance
what can we see in cross section of the kidney
- thin and thick loop of henle
- vasa recta
- collecting duct
intercalated (dark) cells
- found in the collecting duct
- regulate pH in the collecting duct
- alpha cells release H+
- beta cells release HCO3-
light cells
- found in the collecting duct
- more common than the dark cells
- respond to ADH and control water resorption
- ciliated which serve as mechanosensors
mutation in cilia of light cells in collecting duct
-mutation in polycystin-1,2 genes lead to ciliopathies and polycystic kidney disease
what is the environment of the medulla like?
-salt-rich, allowing water to be resorbed through the collecting duct via osmotic pressure
ADH
- generated by the pituitary (pons nervosa)
- ats on the collecting duct to promote water resorption which concentrates the urine
- this is blocked by booze which is why we pee so much
diabetes
-insipidus and mellitus
- insipidus: inability to make or respond to ADH, you pee a lot
- mellitus: insulin def leads to elevated glucose which leads to osmotic diuresis
kidney stones
- crystals may form from calcium oxalate or uric acid precipitates
- precipitation may be caused by low fluid intake, high protein diets, refined sugars
- passage of stone is very painful
- blockage may lead to hydronephrosis
blood pressure monitoring
- arteial pressure in afferent arteriole are responded to by JG cells via baroreceptors
- ion concentration in the DCT is responded to by macula densa (chemoreceptors)
contents of the juxtaglomerular apparatus
- Jg cells
- macula densa
- lacis cells
how do we increase BP?
- angiotensin is release by the liver and converted to angiotensin 1 via renin that is released from the kidney
- angiotensin 1 is converted to angiotensin 2 via ACE
- angiotensin 2 acts on the adrena cortex to release aldosteron which causes increased Na resorp in the DCt
- angiotensin 2 also causes vasoconstriction and NaCl/H2O reabsorption in the kidney
what type of epithelium is found on the surface of the minor calyx?
transitional aka urothelium
-this has the ability to stretch which causes the balloon cells to get thin on the surface
ureter
- transitional epithelium
- no muscularis mucosae
- three layers in muscularis externa (distal portion only)
