[3] Overview of Renal Physiology and Glomerular Filtration Flashcards Preview

[OS 206] 3rd Lecture Exam > [3] Overview of Renal Physiology and Glomerular Filtration > Flashcards

Flashcards in [3] Overview of Renal Physiology and Glomerular Filtration Deck (55)
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1
Q

3 Options of ERSD

A

Transplant
Dialysis
Death

2
Q

A man contains about what % of body weight in water?

A

60%

3
Q

Specifically what part of the kidney produces renin?

A

Granular cells in the Juxtaglomerular Apparatus

4
Q

Function: Renin

A

Converts Angiotensinogen -> Angiotensin I

5
Q

What is the rate limiting step of the Renin-Angiotensin-Aldosterone System?

A

Renin conversion of Antiotensinogen to Angiotensin I

6
Q

What converts Angiotensin I to Angiotensin II?

A

Angiotensin Converting Enzyme

7
Q

What produces Angiotensin Converting Enzyme?

A

Mostly by the lungs and some by the kidneys

8
Q

Function: Angiotensin II

A
  1. Stimulation of sympathetic activity
  2. Formation of aldosterone
  3. Arteriolar vasoconstriction causing increase in BP
  4. Stimulation of ADH secretion from posterior lobe of pituitary gland causing water absorption
  5. Cardiac and vascular hypertrophy
9
Q

What stimulates thirst?

A

Angiotensin II

10
Q

Angiotensin is stimulated by?

A

Low BP
Decreased sodium delivery to the macula densa
Sympathetic Stimulation

11
Q

Where is Erythropoietin produced?

A

Peritubular Capillary and Endothelial Cells in the Kidney

12
Q

Main stimulus of erythropoietin

A

Hypoxia

13
Q

Stages of Erythropoiesis

A
  1. Stem and Progenitor Stage

2. Precursor Stage

14
Q

Steps of Erythropoiesis

A

Pluripotential Stem Cell -> Unipotential Stem Cell -> Burst Forming Colonies -> Colony Forming Units -> Precursor Cells

15
Q

What do precursor cells need to mature?

A

Folic Acid
Iron
Vitamin B

16
Q

If a patient has a kidney problem what do you need to do before administering erythropoietin?

A

Give iron and vitamin B to ensure maturation of RBCs

17
Q

What happens to stem cells without erythropoietin?

A

Apoptosis

18
Q

What is Calcitriol

A

Active metabolite of Vitamin D

19
Q

What is Vitamin D important in the absorption of?

A

Calcium

20
Q

What happens to Vitamin D in the presence of sunlight?

A

Activates 7-dehydrocholesterol -> cholecalciferol (Vitamin D3)

21
Q

Composition: Renal Corpuscle

A

Glomerulus

Bowman’s Capsule

22
Q

What epithelial cells cover the Glomerulus?

A

Podocytes

23
Q

Composition: Renal Tubule

A

Proximal Tubule
Loop of Henle
Juxtaglomerular Apparatus
Distal Convoluted Tubule

24
Q

Types of Nephrons

A

Cortical

Juxtamedullary

25
Q

Characteristics of the Cortical Nephron

A

Short Loop of Henle

Almost Absent Thing Ascending Limb

26
Q

Network of Peritubular Capillaries and Series of Vascular Loops

A

Vasa Recta

27
Q

Where do you find the vasa recta?

A

Juxtaglomerular Nephron

28
Q

Vasa Recta receives how much of the renal blood flow?

A

0.7%

29
Q

[Cortical Nephron vs. Juxtamedullary Nephron]

Location

A

CN: Near Cortex
JN: Reaches Medulla

30
Q

[Cortical Nephron vs. Juxtamedullary Nephron]

Source of Afferent Arterioles

A

CN: Interlobular Artery
JN: Interlobular Artery/Arcuate Artery

31
Q

[Cortical Nephron vs. Juxtamedullary Nephron]

2nd Set of Capillaries

A

CN: Peritubular Capillary
JN: Vasa Recta

32
Q

Pathway of Vitamin D Metabolism

A

Sunlight -> 7-dehydrocholesterol -> Cholecalciferol (Vitamin D3) -> 25-hydroxyvitamin D3 -> 1,25-dihydroxyvitamin D3

33
Q

3 Basic Renal Processes

A
  1. Glomerular Filtration
  2. Tubular Reabsorption
  3. Tubular Secretion
34
Q

Define: Glomerular Filtration

A

Filtration of the plasma in the glomerulus

Ultrafiltrate collects in the urinary space of Bowman’s capsule and flows to the tubular lumen

35
Q

Differentiate Tubular Secretion vs. Tubular Excretion

A

Excretion: Elimination through urine
Secretion: Peritubular capillary into the lumen

36
Q

Components of GFR

A

Blood
Filtration Membrane
Ultrafiltrate Formation

37
Q

Comparison of Blood Flow to Different Organs

  1. Kidney
  2. Heart
  3. Brain
  4. Liver
  5. Resting Muscles
A
  1. Kidney: 4.0 mL/g/min.
  2. Heart: 0.9
  3. Brain: 0.6
  4. Liver: 0.2
  5. Resting Muscles: 0.1
38
Q

Most blood flow to the kidney goes to?

A

Renal Cortex

70% of the Kidney’s Weight but 92% of Blood Flow

39
Q

Parts of a Renal Corpuscle

A
  1. Endothelial Fenestration
  2. Basement Membrane
  3. SM Membrane between Pedicels
40
Q

Parts of the Basement Membrane

A
  1. Lamina Dense: Central Layer

2. Lamina Rara Interna and Externa

41
Q

Most important factor for filterability

A

Size

42
Q

What passes easier, positively or negatively charged molecules?

A

Negative

43
Q

Normal GFR

A

125ml/minute

44
Q

Starling Hypothesis Equation

A

Jv = Kf [(Pcap – PIF) – σ(πcap – πIF)] = Kf (∆P - ∆π)

45
Q

Define: Mesangial Cell

A

Supports the glomerular capillary and secretes the extracellular matrix
Secretes prostaglandins and cytokines
Has contractile properties (most important for GFR)

46
Q

Sample problem:

What is the net filtration pressure if the glomerular capillary hydrostatic pressure (Pcap) is 55mmHg, plasma oncotic pressure (πcap) is 30 mmHg and hydrostatic pressure at Bowmann’s capsule (Pif) is 15 mmHg? (Oncotic pressure in the Bowman’s capsule (πif)) = 0)

A

NFP = [(Pcap – Pif) – (πcap– πif)]
= (ΔP) – (Δπ)
= (55-15)-(30)
= 10 mmHg

47
Q

[Skeletal Muscle Capillary]

Where is hydrostatic pressure high?
Where is it low?

A

High: Arterial End
Low: Venous End

48
Q

[Renal Capillary]

Where is hydrostatic pressure high?
Where is it low?

A

Generally higher than extracapillary and does not decline significantly with distance

49
Q

[Renal Capillary]

Where is oncotic pressure high?
Where is it low?

A

Oncotic pressure increases due to filtration of protein-free fluid

50
Q

Effect of Angiotensin on GFR

A

Angiotensin vasoconstricts the efferent arteriole

Increases GFR

51
Q

Tubuloglomerular Feedback Mechanism is a function of?

A

Juxtaglomerular Apparatus

52
Q

Explain: Myogenic Reflex Theory

A

If vascular wall tension is to maintain the constancy of blood flow, the radius is forced to increase when pressure drops or the radius is forced to decrease as pressure increases

53
Q

Formula for Vascular Wall Tension

A

T = P x R

P: Pressure Gradient
R: Radius of the Vessel

54
Q

What is the autoregulatory range?

A

100 mmHg - 200 mmHg

55
Q

What does the autoregulation mechanism autoregulate?

A

Constancy of RBF and GFR