Urinary System- Lecture 10/21/21 Flashcards
Major functions of kidney (6)
- Removal of metabolic waste products from blood
- Regulation of ion concentration
- Regulation of blood acid-base balance
- Rgulation of blood pressure
- Regulation of erythrocyte production (EPO)
- Vitamin D activation
medulla
Striated segment containing collecting ducts and loops of henle
Arcuate artery
Curved artery surrounding the medulla
Interlobular artery
Radial projections from the arcuate artery, defines the borders of a lobule
Calyx
Collect concentrated urine for the ureter
Parts of the nephron
Renal corpuscle + tubule and loop of henle
Renal corpuscle
Glomerulus and bowman’s capsule
Afferent arteriole
Brings blood into the glomerulus, bigger than efferent
Efferent arteriole
Brings blood out of the glomerulus, smaller than afferent
Urineferous tubule
Nephron+ collecting duct
Cells of the Bowman’s capsule =
- Endothelial cells
- Mesangial cells
- Podocytes
Mesangial cells
- Support glomerulus
- Phagocytose
- Contractile (blood pressure)
- b.p monitoring
Podocytes
octopus like cells that form the filtration slits between fenestrated capillary and Bowman’s space
PCT characteristics
- Brush border (fuzzy lumen)
- Abundant mitochondria
- 80% of ultrafiltrate
DCT characteristics
(Resorbs mostly water and NA+)
- No brush border
- fewer mitochondria (less eosinophilic)
2 steps of resorption
- Pump nutrients into ECM (active)
Uptake into capillaries (pinocytosis)
Renal medulla
- Generation of salt gradient
- Resorption of water
- Acid-base balance
Alpha intercalated cells of collecting duct
Secrete H+
B intercalated cells of collecting duct
Secrete HCO3-
Light cells of collecting duct
Respond to antidiuretic hormone, increases H2O uptake
ADH
Secreted by posterior pituitary, increase H2O uptake by collecting duct
Diabetes insipidus
inability to make or respond to ADH, diluted urine
Diabetes mellitus
Insulin deficiency leads to osmotic diuretics, glucose is osmotically active
Renal calculi
precipitates of calcium oxalate uric acid precipitates
Blockage may cause hydronephrosis
Blood pressure monitoring (2 ways)
- Arterial pressure in afferent arteriole (baroreceptor)
- Ion concentration in DCT (chemoreceptors)
Juxtaglomerular apparatus make up (3)
1? JG cells
2- macula densa
3- Lacis cells
Macula densa
Thickening of DCT next to afferent arteriole, responds to low salt concentration (low bp)
JG cells
Respond to arterial pressure (baroreceptors) and macula densa, secrete renin
Renin mechanism action
Cleaves angiotensinogen to Angiotensin I
ACE
In the lungs, cleaves angiotensin I to angiotensin II
Angiotensin II
Stimulates adrenal cortex to secrete aldosterone (increase bp via water resorption) And Vasocontriction
Aldosterone mechanism of action
Acts on DCT to increase sodium absorption
Transitional epithelium (urothelium)
Pseudostratified with domed (umbrella) cells
Ureter
Transitional epithelium with no muscularis mucosae, three layers of muscularis externa in distal 1/3
