Block 2 Renal Function

Front 1

What are the 4 functions of the kidney

Back 1

1. filters
2. reabsorbs/eliminates electrolytes & bicarb
3. eliminates metabolic wastes
4. Regulates H20

Front 2

What are the 3 endocrine functions of the kidney

Back 2

1. BP control (RAA --> vasoconstriction / aldosterone --> Na reabsorption)

2. Vit D activation

3. RBC production via EPO

Front 3

How much urine do the kidneys filter per hr? per day?

Back 3

1cc/kg/hr (approx 1700L/day)

1.5 L urine/day

Front 4

What vertebral level are the kidneys located

Back 4

T12-L3

Front 5

Which kidney is lower?

Back 5

Right

Front 6

What is the hilus?

Back 6

Site of BVs and nerve enter/exit and site of ureter exit

Front 7

How many lobes does the kidney have?

Back 7

approx 18 lobes

Front 8

What is contained in the outer cortex?

Back 8

glomeruli, convoluted BVs, and nephron tubules

Front 9

What is contained in the inner medulla?

Back 9

cone shaped masses called pyramids

Front 10

What is the inner medulla divided into?

Back 10

Columns

Front 11

What are the apices topped with?

Back 11

Papillae - perforated by openings of collecting ducts

Front 12

Calices

Back 12

join to form renal pelvis (wide, funnel like structure at the end of the ureter)

Front 13

Describe the blood supply of the kidney

Back 13

1 renal artery -> 5 segmental a -> divide/branch inside kidney

Front 14

What is the smallest branch?

Back 14

intralobar a

Front 15

Describe the distribution of blood flow

Back 15

90% to cortex, 10% to medulla, <1% to papillae

Front 16

What effect does the SNS have on the kidneys?

Back 16

When decr perfusion, BF is shifted to medulla, GFR is decreased, but
*urine concentrating ability remains*

Front 17

What is the functional unit of the kidney and what two components is it made up of?

Back 17

nephron - made up of the glomerulus and tubular structures

Front 18

What encases the capillaries in the glomerulus?

Back 18

bowman's capsule

Front 19

Describe the flood flow through the glomerulus.

Back 19

IN via afferent arteriole, OUT via efferent arteriole into peritubular capillaries

Front 20

The three parts of the capillary membrane layer

Back 20

1. capillary endothelial layer
2. glomerular basement membrane
3. capsular epithelial layer

Front 21

What is the structure and function of the capillary endothelial layer?

Back 21

larger fenestrations that restrict movement of RBCs and Large molecules ONLY (albumin)

Contains aquaporin-1 channels -> fast movement of water

Front 22

What is the structure and function of the glomerular basement membrane?

Back 22

"the URINATOR"/ boss of "operation golden flow"

Made of collagen + glycoproteins + mucopolysaccharides

Front 23

What is the structure and function of the capsular epithelial layer?

Back 23

foot processes (podocytes) --> slit pores that pass ultrafiltrate in bowmans space

Front 24

Which layer determines permeability of the glomerular capillary membrane? What pathology can result?

Back 24

glomerular basement membrane

Where pathologic blood cell and protein leakage occurs

Front 25

What is the mesangium?

Back 25

the area around the capillary NOT surrounded by endothelium and basement membrane

Front 26

Where do mesangial cells lie and what do the do?

Back 26

they lie between capillary tufts
- support the glomeruli
- produce substance that coats endothelial cells not covered by basement membrane
- regulates glomerular BF via contraction
- can become phagocytes
*are involved in glomerular diseases*

Front 27

What does urine start as?

Back 27

ultrafiltrate of plasma = protein free plasma

Front 28

What capillary filtration factors affect GFR?

Back 28

1. filtration pressure
2. colloid osm pressure
3. capillary permeability

Front 29

What is the glomerular filtration rate (ml/min)?

Back 29

125 ml/min

Front 30

What is the rate of urine output

Back 30

1ml/min or 60ml/hr

Front 31

3 components of urine formation

Back 31

1. filtration of glomerulus
2. reabsorption
3. secretion

Front 32

Where does 2/3 of all resabsorption/secretion occur?

Back 32

proximal tubule

Front 33

What is reabsorbed in the proximal tubule?

Back 33

100% of glucose and AAs
>90% of uric acid
60% of inorganic salts via ACTIVE TRANSPORT
Phos reabs regulated by parathyroid hormone & FGF-23
HIGHLY PERMEABLE TO WATER

Front 34

What does the loop of henle play a role in? How?

Back 34

concentrating urine
reabsorbs more Na than H20

Front 35

What is the function of the descending loop of Henle?

Back 35

H2O leaves by osmosis due to salty interstitial fluid

Front 36

What is the function of the ascending loop?

Back 36

NA actively transported out via ion pumps
passive reabs of Ca2+

Front 37

General functino of the distal tubule? is it permeable to water?

Back 37

more NA leaves by active transport followed by H2O

relatively impermeable to H2O - further dilutes

Front 38

Which hormones/drugs act on the distal tubule?

Back 38

aldosterone/thiazide diuretics

Front 39

Function of the late distal tubule/collecting duct

Back 39

final refinement of Na and water

Front 40

Which hormones act on the late distal tubule/collecting duct?

Back 40

*ADH*, Aldosterone

Front 41

The late distal tubule/collecting duct is the major site for regulation of ___?

Back 41

K+

Front 42

2 types of cells in the late distal tubule/collecting duct? what the secr/resorb? hormonal action?

Back 42

1. intercalated: reabs: K+ and *HCO3* / secr: H+

2. Principal: reabs: Na+ / secr: K+
*ADH, aldosterone*

Front 43

How does the RAA system work?

Back 43

turns on Na/K+ATPase in distal tubule
Reabs Na & H2O - increases blood vol *DOES NOT change osmolarity*

Secretes K+ --> decr serum K+

Front 44

What does aldosterone do? Where does it act?

Back 44

regulates BP and H+
- the last 3% Na reabs determine final concentration
- acts in distal tubule & collecting ducts

Front 45

What does ADH do?

Back 45

makes collecting duct more permeable to water

more H2O reabs - Decr blood osmolarity

Front 46

3 things that regulate renal BF?

Back 46

1. neural & humoral (vasoconstriction/dilation)
2. autoregulatory
3. juxtaglomerular complex

Front 47

Name some vasoconstrictors/dilators?

Back 47

Constrictors: angiotensin II
Dilators: dopa, NO, PGs

Front 48

How does the juxtaglomerular complex work?

Back 48

modified smooth muscle cells in efferent arteriole --> renin --> angiotensin II --> constricts --> INCR GFR

Na reab via aldosterone

Direct reab in proximal tubule

Front 49

3 elimination functions of kidney?

Back 49

1. renal clearance (*glucose = 0)
2. regulation of pH (via HCO3/H+)
3. BUN elimination (end product of protein metabolism)