Concentration Mechanisms & Urine Formation - Quiz 3 Flashcards Preview

Summer 2020 - Physiology 2 - Renal > Concentration Mechanisms & Urine Formation - Quiz 3 > Flashcards

Flashcards in Concentration Mechanisms & Urine Formation - Quiz 3 Deck (38)
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1

Where in the Kidney is Renin made?

Juxtaglomerular Apparatus

2

What are the 4 components of the Juxtaglomerular Apparatus?

Afferent Smooth Muscle Cells

Efferent Smooth Muscle Cells

Extraglomerular Mesangial Cells

Macula Densa Cells

3

What is the most potent vasoconstrictor known?

Angiotensin II

4

What is the Renin Angiotensin Pathway?

  1. Renin cleaves Angiotensinogen that came from the Liver to Angiotensin I
  2. ACE from the Lungs converts Angiotensin I to Angiotensin II

5

What does Angiotensin II do?

Vasoconstriction

↑Aldosterone Synthesis & Release

↑ADH Release

↑Thirst

Feedback Renin Inhibition

Releases Prostaglandins

6

Along w/ Vasoconstriction, What is the purpose for Angiotensin II to release Prostaglandins?

To maintain GFR even w/ Vasoconstriction

7

How does Angiotensin II affect the Adrenal Gland?

Stimulates it to Release Aldosterone causing Salt & Water Reabsorption

8

What is Aldosterone?

Steroid made in the Zona Glomerulosa of the Adrenal Cortex that acts on the Distal Tubule & Collecting Ducts to Secrete Potassium & Hydrogen Ions, while Reabsorbing Sodium

9

What stimulates the release of Aldosterone?

Angiotensin II

Increased ECF Potassium

Decreased Sodium

10

What is the Atrial Naturetic Peptide?

Hormone made in the Atria that does the opposite of the Angiotensin Pathway by

↓Na Reabsorption

↑GFR

Inhibit Renin, Aldosterone, & ADH

11

What is Conn's Syndrome?

Aldosterone Secreting Tumor that causes

HTN

Hypernatremia

Hypokalemia

12

What are the Concentrating & Diluting Mechanisms of the Kidney?

ADH

ANP

Countercurrent Multiplier

Urea

13

What dictates the Obligatory Urine Volume?

The max concentrating ability of the kidney - normally 0.5L/day

14

What is ADH?

An Octapeptide made in the Hypothalamus, then Stored & Release by the Posterior Pituitary to Conserve Water by Concentrating Urine

15

How does an increase in ECF Osmolarity affect the Osmoreceptor cells in the Anterior Hypothalamus?

Causes them to Shrink --> sends signal to Posterior Pituitary --> ADH Release 

16

Which part of the Kidney does ADH work to Increase Water Permeability?

Late Distal Tubules

Coritcal & Medullary Collecting Ducts

 

17

What stimulates ADH release?

Osmoreceptors

Mechanoreceptors/Baroreceptors

Angiotensin II

Sympathetic Stimulation

Anesthesia

Nicotine

18

What Inhibits ADH Release?

Alcohol

Clonidine

Haldol

19

What kind of condition must the Interstitium be in for ADH to work?

Hypertonic

20

What is needed to form Concentrated Urine?

High ADH

Hypertonic Renal Medullary Interstitium

Water

21

What are the Key Features of the Kidneys that help it Concentrate Urine?

Henle's U-Shape - Opposite Flows

Permeability of Certain Nephron Segments

ATP Energy

22

What's the max amount of urine concentration can the kidney produce?

1200 - 1400 mOsm/L

23

What Increases the Osmolality of the Renal Interstitium?

Active Na & Cl Transport in the TAL

24

What is the Osmotic composition of the Fluid that enters the Descending Limb?

Enters as Iso-Osmotic, but a lot gets absorbed making it more concentrated

25

What are the Major Factors that contribute to the Hyperosmolarity of the Medullary Interstitium?

  • Active Transport of Sodium & Co-Transport of Potassium & Chloride out the TAL
  • Active Transport of ions out the Collecting Ducts
  • Facilitated Diffusion of Urea out the Medullary Collecting Ducts
  • Diffusion of a bit of water out the Medullary Tubules

26

How is the High Medullary Interstium Osmolarity preserved in the presence of ADH?

The Large amount of water is reabsorbed into the Renal Cortex rather than the Renal Medulla

27

Why is the Osmotic Gradient the most within the Inner Medulla even though the TAL is located in the Outer Medulla?

Urea

28

What is Urea?

Byproduct of amino acid metabolism produced by the liver at 25-30 g/day

29

What is the role of Urea?

Accounts for 40-50% of Renal Interstitium Osmolarity

30

How does Urea get into the Renal Interstitium?

Permeable in the Inner Medulla only w/ ADH and diffuses to the Interstitium and gets trapped there. 

31

Where in the Kidney is some Urea Permeable w/o ADH?

Thin Ascending Loop

32

What is the Role of the Vasa Recta?

Preserve Medullary Hyperosmolarity by

Removing reabsorbed fluid from Interstitium

&

Minimizing Solute Uptake from Medulla

33

What is the Solute & Fluid movement in the Descending Vasa Recta?

Rapid Flow = More Fluid Leaving than Solute Entering

 

34

What is the Solute & Fluid movement in the Ascending Vasa Recta?

Decreased Hydrostatic Pressure & Increased Blood Osmolality

More Solute Entering than Fluid Leaving

35

What conditions might affect the ability to Concentrate Urine?

Too much or Too Little ADH

Impaired Countercurrent Mechanism

Inability of Distal Tubule, Collecting Tubule, & Collecting duct to Respond to ADH

36

What is Central Diabetes Insipidus?

Failure to Produce ADH

37

What is the treatment for Central Diabetes Insipidus?

Desmopressin - DDAVP

Acts on V2 Receptors to increase Water permeability in the Late Distal & Collecting Tubules

38

What is Nephrogenic Diabetes Insipidus?

Inability of Renal Tubular Segments to respond to ADH