Normal Kidney Function Part I Flashcards Preview

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Flashcards in Normal Kidney Function Part I Deck (34)
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1

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

Changing the Rate of Excretion

2

What determines the extracellular fluid volume (ECFV)?
• why is this so important?

Na+ , this is the KEY solute in renal physiology

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

3

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

ICFV - K+
ECFV - Na+

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

4

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

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

5

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

60% - Males
50% - Females

***Differences in muscle mass accounts for the variation

6

What is the dominant extracellular cation, and anion?
• others that are predominant?

Cl- = anion
Na+ = cation
HCO3- = anion

7

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

1. Works to buffer pH in the extracellular fluid

2. Keeps PLASMA pH at 7.40

8

What major Minerals does the kidney maintain the levels of?

• Calcium
• Phosphorus
• Magnesium

9

What are the waste materials excreted by the kidney?
• what are these materials the by-product of?

• Urea - Byproduct of PROTEIN Metabolism

• Creatinine - byproduct of MUSCLE metabolism

• Uric Acid - byproduct of NUCLEIC ACID breakdown

10

What are the 4 main endocrine functions of the kidney?

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

11

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

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!

12

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?

1-ALPHA-HYDROXYLASE is only found in the kidney

• Produces CALCITRIOL (1-alpha-hydroxylase)

• Nephron dysfunction => less 1-alpha hydroxylase => less Vit. D

13

What paracrine and autocrine functions does the kidney have?
• molecules produced and their jobs

• Bradykinin - vasodilatory and natriuretic

• Prostaglandins - important in GFR maintenance

• Endothelial Factor production - NO (veno-/artero- dilatory), Endothelin (potent vasocontrictor used in endothelial injury)

14

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

• 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

15

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

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

16

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

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

17

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

Neutral - intake = output

Positive - intake greater than output

Negative - output greater than intake

18

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

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

~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?

• Blood is filtered by the glomerulus with the end product being ULTRAFILTRATE

• Starling Forces (osmolarity and hydrostatic pressure drive this)

20

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

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

21

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

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

22

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

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

What is the best measure of Kidney function and why?

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

What 4 main processes occur in the kidney?
• describe what is happening in each of these processes?

• 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

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

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

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

26

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

• Pelvic - Urethral Junction

• Crossover the pelvic brim

• Urinary Trigone

27

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

Prostatic Urethra often obstructed with Benign Prostatic Hypertrophy

• Longer Urethra gives less chance for a UTI

28

Advantages and disadvantages to the short female urethra?

Advantages:
• less obstruction here

Disadvantages:
• More UTIs from gram - organisms

29

Renal Circulation from Aorta to the Vena Cava.

- 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

Compare the following for the two different types of nephron.
• Abundance
• Perfusion
• Size
• Location

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