Urinary System Anatomy & Physiology Flashcards Preview

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Flashcards in Urinary System Anatomy & Physiology Deck (21)
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1

Kidney plays important role in: (3)

removal of metabolic wastes
regulation of water & electrolytes
maintenance of body's acid-base equilibrium

2

% of initial ultrafiltrate that is reabsorbed

99%
urine output is only 1% of the filtered plasma volume

3

Principle solutes in urine

urea, Cl-, Na+, K+, phosphate, sulfate creatinine & uric acid

4

urine formation consists of what 2 steps?

1. plasma filtration at glomeruli
2. reabsorption & selective secretion by renal tubules

5

anatomy of glomeruli

located in outer cortex of kidney, exclusive site of plasma filtration

6

5 distinct areas of the nephron: (be able to label picture)

1. glomerulus - capillary tuft surrounded by Bowman's capsule where filtration occurs
2. Proximal convoluted tubule
3. loop of henle
4. distal convoluted tubule
5. collecting tubule

7

Afferent arteriole

supplies blood individually to the glomerulus of each nephron

8

force behind glomerular filtration

high hydrostatic pressure of afferent arteriole

9

3 structures of glomerular filtration barrier

1. capillary endothelium
2. trilayer basement membrane - often gets damaged by Ab-Ag complexes
3. filtration diaphrams - located between podocytes of Bowman's space

10

Selectivity of Glomerular filtration

based on molecular size & charge - allows water & small molecules to pass rapidly
endothelium has negative charge that molecules must overcome to pass

11

Podocytes

foot-like structures that surround the glomerulus & share its basement membrane, spaces between them are called 'filtration slit's & they regulate what passes through based on size & charge

12

Renin

large amounts of secretory granules containing renin are present in afferent arteriole of juxtaglomerular apparatus
causes angiotensin formation & aldosterone secretion--> retain Na+ & water

13

3 ways renin can be released

1. decreased arterial blood pressure / volume
2. decreased Na+ or increased K+
3. vascular hemorrhage

14

renal system buffer for blood pH regulation

increases or decreases excretion of H+
increases/ decreases formation of ammonia
increases/decreases reabsorption of HCO3-

15

3 mechanisms that maintain blood pH & relies on tubular secretion of H+

1. H+ secreted into PT lumen preventing loss of HCO3-
2. depends on amount of phophate in the ultrafiltrate
3. depends on ammonia secretion & following change of Na+ for ammonium ions

16

end goal of renal blood pH regulation

H+ secretion results in Na+ or HCO3- reabsorption

17

efferent arterioles

blood leading the way from the glomerulus; these give rise to a second capillary bed ' peritubular cappilaries' that surround the tubules in the corticical region

18

vasa recta

surrounds the loop of henle in the renal medulla

19

Juxtaglomerular Apparatus

controls blood pressure & the rate of filtration
tubular & vascular cells in this area are specialized

20

macula densa

distal tubular cells from the juxtaglomerular apparatus that governs the filtration rate

21

Vasopressin

controls water reabsorption in collecting tubules
causes a change in the tubule epithelium