Nephron, Renal Clearance, RBF, GFR

Question 1

Structural and Functional unit of Kidneys

Answer 1

Nephron

Question 2

Cortical Nephron

Answer 2

75% of nephrons
located in the RENAL CORTEX
SHORTER loop of Henle
(+) PERITUBULAR CAPILLARIES

Question 3

Juxtamedullary Nephron

Answer 3

25% of nephrons
located in the CORTICOMEDULLARY junction
LONGER loop of Henle
(+) VASA RECTA

Question 4

2 major parts of Nephron

Answer 4

Renal or Malphigian Corpuscle

Renal Tubules

Question 5

Renal or Malphigian Corpuscle

Answer 5

Afferent arterioles
Glomerular capillaries
Efferent arterioles
Podocytes
Mesangial cells
JG cells
Bowman's capsule and space

Question 6

Renal Tubules

Answer 6

PCT
LH
DT
CD

Question 7

From interstitial cells in peritubular capillary bed

Released in response to hypoxia –> (+) RBC proliferation in bone marrow

Answer 7

Erythropoietin (EPO)

Question 8

PCT converts 25-OG vitamin D3 –> 1,25 vitamin D3 (calcitriol, active form?

1a - hydroxylase - mediates conversion (upregulated by PTH)

Answer 8

Calciferol (Vitamin D)

Question 9

From PCT cells
Promotes NATRIURESIS

LOW dose - dilates interlobular arteries, afferent arterioles, efferent arterioles –> INC RBF

HIGH dose - vasoconstrictor

Question 10

3 Charge and Filtration Barriers of the Glomerulus

Answer 10

Capillary Endothelium
Basement Membrane
Podocytes

Question 11

Other cells in Renal Corpuscle

Answer 11

Mesangial cells
Juxtaglomerular cells
Macula densa

Question 12

Modified smooth muscles in the mesangial cells capable of phagocytosis

Answer 12

Intraglomerular

Question 13

Cells in the mesangial cells that may play a role in RENAL autoregulation and RAAS

Answer 13

Extraglomerular( Lacis cells)

Question 14

At the walls of afferent arterioles

Secrete RENIN

Answer 14

Juxtaglomerular (JG) cells

Question 15

In DT

Monitor Na concentration in the lumen of DT

Answer 15

Macula Densa

Question 16

If substance has a HIGH clearance most will be found in

Answer 16

URINE

Question 17

If substance has a LOW clearance most will be found in

Answer 17

Blood

Question 18

Highest clearance

Answer 18

PAH - filtered and secreted not reabsorbed

used to estimate renal plasma flow and renal blood flow

Question 19

Lowest clearance

Answer 19

protein, Na, glucose, AA, HCO3 and Cl

Question 20

Clearance EQUAL to GFR

Answer 20

Inulin, Creatinine - filtered but not secreted not reabsorbed

*marker for kidney function (glomerular marker)

Question 21

Renal Blood Flow

Answer 21

25 % of Cardiac Output

Question 22

Vasodilation of Renal Arterioles - Increases RBF

Answer 22

PGE2
PGI2
Bradykinin
NO
Dopamine

Question 23

Vasoconstriction of Renal Arterioles - Decreases RBF

Answer 23

Sympathetic NS

Angiotensin II

Question 24

Estimated by PAH clearance

Answer 24

Renal Plasma Flow (RBF)

Question 25

Renal Blood Flow (RBF)

Answer 25

RBF = RPF/ 1-Hematocrit

Question 26

Normal value of GFR

Answer 26

125 mL/min or 180 L/day

Question 27

Increase when GFR decreases

Answer 27

BUN and Creatinine

Question 28

GFR and RBF would increase if we vasodilate

Answer 28

AFFERENT and EFFERENT arterioles

Question 29

Vasoconstriction of Afferent Arteriole

Answer 29

decreased GFR decreased RPF no change on FF

Question 30

Vasoconstriction of Efferent Arteriole

Answer 30

increased GFR decreased RPF increased FF

Question 31

Increased Plasma Protein

Answer 31

decreased GFR no change in RPF decreased FD

Question 32

Ureteral Stone

Answer 32

decreased GFR no change RPF decreased FF

Question 33

Myogenic mechanism

Answer 33

Renal afferent arterioles reflexively responds to stretch by contracting in order to maintain constant renal blood flow and subsequently GFR

Question 34

Causes of K Influx --> HYPOKALEMIA

Answer 34

Insulin Beta adrenergic agonists Alkalosis Hypoosmolarity

Question 35

Causes of K efflux --> Hyperkalemia

Answer 35

``` Insulin deficiency Exercise Beta adrenergic antagonists Acidosis Hyperoosmolarity (-) of NaKATPase pump like digitalis Cell lysis ```

Question 36

Causes of Increased Distal K Secretion

Answer 36

``` High K diet Hyperaldosteronism Alkalosis Thiazide Diuretics Loop Diuretics Luminal Anions ```

Question 37

Causes of Decreased Distal K Secretion

Answer 37

Low K diet Hypoaldosteronism Acidosis K Sparing Diuretics

Question 38

Major extracellular buffer

Answer 38

HCO3

Question 39

Major intracellular buffer

Answer 39

Hemoglobin