Renal Phys 1

Question 1

3 Main Roles of the Kidney

Answer 1

1. Excretory
2. Regulatory (Homeostasis)
3. Synthesis of Hormones

Question 2

Functional Unit of the Kidney?

Answer 2

nephron

Question 3

Excretory Role of the Kidney

Answer 3

plasma clearance of non-volatile products (urea/creatinine)

Question 4

2 Types of Nephrons

Answer 4

1. Superficial/Cortical Nephrons
2. Juxtamedullary Nephrons

Question 5

Blood supply to the kidney?

Answer 5

renal artery

Question 6

Is the kidney innervated by sympathetic or parasympathetic nerves?

Answer 6

sympathetic (with alpha-1 receptors and norepinephrine as main neurotransmitter)

Question 7

Reason Renal Artery is so short?

Answer 7

high pressure and high flow rate allows for adequate filtration

Question 8

2 Capillary Beds of Kidney

Answer 8

1. Glomerular
2. Peritubular

Question 9

Vasa Recta

Answer 9

peritubular capillaries in the juxtamedullary region

Question 10

Afferent and Efferent Arterioles

Answer 10

afferent carries blood into glomerulus and efferent controls flow out to the vasa recta; allows for fine-tuned control of pressure and flow in glomerular capillaries

Question 11

4 Steps of Plasma Clearance

Answer 11

1. Filtration
2. Reabsorption
3. Secretion
4. Excretion

Question 12

Where does reabsorption occur?

Answer 12

vasa recta

Question 13

What part of the nephron has high hydrostatic pressure?

Answer 13

glomerular capillaries

Question 14

What part of the nephron has high oncotic pressure?

Answer 14

vasa recta/peritubular capillaries

Question 15

Do tubles require a lot of ATP?

Answer 15

yes

Question 16

Why is absorption favored in the vasa recta?

Answer 16

high oncotic pressure d/t proteins in the blood plasma that want to PULL fluid towards them (out of the tubule back into the blood supply)

Question 17

Transporters on Blood Side of Proximal Tubule

Answer 17

primary active transporters (sodium potassium pump)

Question 18

Transporters on Lumenal Side of Proximal Tubule Cells

Answer 18

secondary active cotransporters for glucose and AAs

Question 19

Regulatory Role of the Kidney

Answer 19

maintains ECF and osmolality, electrolytes, blood pressure, and acid-base balance, primarily by retaining or excreting water, salt, H+, and bicarbonate

Question 20

How much sodium does the kidne reabsorb?

Answer 20

basically all of it

Question 21

Macula Densa

Answer 21

cells of the distal tubule that communicate with juxtaglomerular cells that surround the capillaries; can sense flow rate and sodium conc. in the tubule

Question 22

Juxtaglomerular Apparatus

Answer 22

macula densa cells can sense flow rate and sodium concentration through the tubule, and signals to the mesangial cells, which signal to the JG cells, which will then signal to smooth muscle in afferent arteriole to either contract or relax

Question 23

What percent of renal plasma flow is filtered?

Answer 23

~20%

Question 24

Renin Angiotensin Aldosterone System (RAAS)

Answer 24

how the kidney regulartes blood pressure

Question 25

Angiotensin II

Answer 25

increases sodium and water retention and signals to adrenal cortex to produce aldosterone and brain to produce antidiuertic hormone --> inc sodium and water retention more therefore increasing blood volume and cardiac output

Question 26

Cortical Nephron

Answer 26

make up 80-85% of the nephrons, only goes into outer medulla, shorter proximal convoluting tubules therefore salt-losing

Question 27

Juxtamedullary Nephron

Answer 27

make up 15-20% of nephrons in the kidney, goes all the way into inner medulla, longer proximal convoluted tubule, favors reabsorption, salt-conserving

Question 28

Which nephron is responsiible for concentrating urine?

Answer 28

juxtamedullary

Question 29

How does kidney maintain blood pressure?

Answer 29

can shunt blood between the different types of neurons ex: low BP, kidney would shunt blood from cortical nephrons to juxtamedullary since they're better at reabsorbing salt, therefore inc BP

Question 30

What cells sensethe oxygen level in the blood?

Answer 30

renal erythropoietin producing (REP) cells, erythropoietin

Question 31

Effect of Erythropoietin when oxygen levels are low?

Answer 31

1. proliferate blood stem cells so there are more of them (increase mitosis) 2. speeds up differentiation into red blood cells --> inc. # means inc. oxygen in blood

Question 32

Mass Balance Equation

Answer 32

Question 33

2 Outputs from the Kidney

Answer 33

1. Renal Vein 2. Ureter

Question 34

Filtered Load Equation

Answer 34

Fx = GFR * Px

Question 35

Excreted Load Equation

Answer 35

Ex = Ux * V

Question 36

Premise of Renal Mass Balance?

Answer 36

any difference bewteen input and output of the kidney indicates secretion or absorption is occurring

Question 37

If filtered load is higher than excreted load, is there net reabsorption or secretion?

Answer 37

net reabsorption

Question 38

If filtered load is higher than excreted load, is there net reabsorption or secretion?

Answer 38

net secretion

Question 39

Filtered Fraction

Answer 39

GFR divided by RPF (renal plasma flow) should equal about 20%

Question 40

Tubular Transport Rate (reabsorption)

Answer 40

filtered load minus excretion load

Question 41

Concentration of Solute is free or bound?

Answer 41

free, not bound by proteins!