Normal Kidney Function Part I Flashcards

1
Q

How does the kinedy work to keep the total body content at a normal stable level?

A

Changing the Rate of Excretion

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2
Q

What determines the extracellular fluid volume (ECFV)?

• why is this so important?

A

Na+ , this is the KEY solute in renal physiology

Important in maintaining BLOOD PRESSURE - no blood pressure than no life

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3
Q

What ions maintain the intracellular and extracellular fluid volumes (ICFV/ECFV)?
• what ion is important in maintaining total body water?

A

ICFV - K+
ECFV - Na+

**Na+ is the important ion in maintaining total body H2O. - it does this by changing osmolality

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4
Q

What happens in the body when Na+ content is increased?

A

Na+ increased => Increased Osmolality => Thirst Stimulation => Increase H2O intake AND Vasopressin secretion => more H2O conservation

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5
Q

Approximately what percentage of the body is made of water in males and females?

A

60% - Males
50% - Females

***Differences in muscle mass accounts for the variation

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6
Q

What is the dominant extracellular cation, and anion?

• others that are predominant?

A
Cl- = anion
Na+ = cation
HCO3- = anion
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7
Q

What is the role of Bicarbonate (HCO3-) in the body?

A
  1. Works to buffer pH in the extracellular fluid

2. Keeps PLASMA pH at 7.40

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8
Q

What major Minerals does the kidney maintain the levels of?

A
  • Calcium
  • Phosphorus
  • Magnesium
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9
Q

What are the waste materials excreted by the kidney?

• what are these materials the by-product of?

A
  • Urea - Byproduct of PROTEIN Metabolism
  • Creatinine - byproduct of MUSCLE metabolism
  • Uric Acid - byproduct of NUCLEIC ACID breakdown
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10
Q

What are the 4 main endocrine functions of the kidney?

A
  • EPO secretion
  • Renin
  • 1,25 (OH)2 D3 (vit. D production)
  • Paracrine/Autocrine Functions
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11
Q

EPO
• What is it?
• Consequences of Kidney dysfunction on EPO?

A

EPO - Glycoprotein needed to stimulated differentiation of hematopoeitic stem cells into RBCs - ONLY SECRETED BY KIDNEY

**Less Functional Kidney Mass = Less EPO, these ppl. are ANEMIC!

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12
Q

What is the relationship of Vit. D and the kidney?

• lack of function in what part of the kidney could result in osteomalacia or ricketts?

A

1-ALPHA-HYDROXYLASE is only found in the kidney

  • Produces CALCITRIOL (1-alpha-hydroxylase)
  • Nephron dysfunction => less 1-alpha hydroxylase => less Vit. D
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13
Q

What paracrine and autocrine functions does the kidney have?

• molecules produced and their jobs

A
  • Bradykinin - vasodilatory and natriuretic
  • Prostaglandins - important in GFR maintenance
  • Endothelial Factor production - NO (veno-/artero- dilatory), Endothelin (potent vasocontrictor used in endothelial injury)
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14
Q

What is the role of the kidney in Blood Pressure Regulation?
• substances responsible and their actions?

A

• Via RAAS it determines the Extracellular Fluid volume of the body

  • Angiotensin II = vasocontrictor
  • Aldosterone = Na+ reabsorption

• ALSO Many VASODILATORY substances are produced in the kidney

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15
Q

What role the the kidney play in diabetes and in regulation of blood sugar in normal people?

A

Diabetes
• Kidney Degrades Insulin
• [Insulin] stays higher for longer in people with compromised kidneys

Blood Sugar
• can do up to 25% of GLUCONEOGENESIS in fasting state

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16
Q

What is the risk of administering medications to people in renal failure?

A

• if the drug is renally excreted, then drug levels can build up to become toxic

17
Q

What is meant by Neutral, Positive, and Negative Balance?

A

Neutral - intake = output

Positive - intake greater than output

Negative - output greater than intake

18
Q

What is the main thing you can analyze to determine if the kidney is functioning properly?

A

URINE

**If someone looks like they have a high ECFV then look at urine to see if they are properly compensating via Na+ excretion

19
Q

~180 L/day of blood is filtered by the glomerulus meaning plasma is filtered 60x per day. What is the driving force of this process?
• what is the end product?
• Where is this done?

A
  • Blood is filtered by the glomerulus with the end product being ULTRAFILTRATE
  • Starling Forces (osmolarity and hydrostatic pressure drive this)
20
Q

T or F: the kidneys recieve 25% of cardiac output

A

False, they receive 10%, which is still a ton

21
Q

T or F: ultrafiltrate is iso-osmolar to the plasma

A

TRUE, while it lacks proteins and cells, it is still isosmolar to the plasma overall

22
Q

Of the 180 L/day of ultrafiltrate produced everyday, how much is reabsorbed?
• where is ultrafiltrate produced and where does reabsorption occur?

A

178 or 180 L is reabsorbed into the body meaning we only make 1-2 L of urine per day

• Utrafiltrate is produced in the GLOMERULUS while the TUBULES are responsible for SELECTIVE RE-ABSORPTION AND EXCRETION

23
Q

What is the best measure of Kidney function and why?

A

GFR is the best measure because glomerulus and tubules must work IN CONCERT

• Low GFR is also indicative of dysfunction in the other HOMEOSTATIC mechanisms of the Kidney (endocrine function and BP control)

24
Q

What 4 main processes occur in the kidney?

• describe what is happening in each of these processes?

A
  • Glomerular FILTRATION - starling forces push fluid through fenestrations to make Ultrafiltrate
  • Tubular REABSORPTION - H2O and solutes that the body NEEDS BACK are sucked into the PERITUBULAR CAPILLARIES
  • Tubular SECRETION - Solutes (NOT water) are reabsorbed
  • EXCRETION - urine is excreted
25
Q

What percentage of the 10% of cardiac output goes to the Glomerulus?

A

90% goes to the Glomerulus (9% of body total)

10% goes to kidney tissue (1% of total)

26
Q

What are the 3 sites of possible obstruction within the ureter?

A
  • Pelvic - Urethral Junction
  • Crossover the pelvic brim
  • Urinary Trigone
27
Q

What is the most common spot for urethral obstruction in males?
• Cause of the obstruction?
• advantages?

A

Prostatic Urethra often obstructed with Benign Prostatic Hypertrophy

• Longer Urethra gives less chance for a UTI

28
Q

Advantages and disadvantages to the short female urethra?

A

Advantages:
• less obstruction here

Disadvantages:
• More UTIs from gram - organisms

29
Q

Renal Circulation from Aorta to the Vena Cava.

A
  • Aorta
  • Renal Artery
  • Segmental Artery
  • Lobar Artery
  • Interlobar Artery
  • Arcuate Artery
  • Interlobular Artery
  • Afferent Arteriole
  • Glomerulus
  • Efferent Arteriole
  • Peritubular Capillaries and Vasa recta
  • Interlobular veins
  • Arcuate Vein
  • Interlobar Vein
  • Renal Vein
  • IVC
30
Q
Compare the following for the two different types of nephron. 
• Abundance
• Perfusion
• Size
• Location
A

Cortical Nephrons
• 85% of total Nephrons
• LOWER perfusion pressure than JM nephrons
• SMALLER than JM nephrons (short Loop of Henle)
• in CORTEX

Juxtamedullary Nephrons
• 15% of total nephrons
• HIGHER perfusion pressure 
• LARGER with Longer Loops of Henle
• Next to medulla
31
Q

Between cortical and juxtamedullary nephrons, which has a greater filtration rate and why?

A

Juxtamedullary Nephrons have higher GFR because they have a HIGHER PERFUSION pressure

32
Q

When people donate a kidney do they cut their filtration capacity down to 50%?
• why or why not?

A

NO - they actually end up operating at about 75% capacity because the average kidney only works at a capacity of ~50%

33
Q

What happens to GFR after eating a high protein meal?

A

• It goes up about 20%

34
Q

T or F: some Juxamedullary Apparatuses will descend into the papilla.

A

True