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Flashcards in Renal physiology Deck (70):
1

What is the major function of the Kidney?

To maintain homeostasis for a large number of solutes and water

2

How is homeostasis maintained?

Through the kidney by changing its rate of excretion

3

What is the key solute in renal physiology?

Sodium (Na+)

4

In what fluid compartment is Na restricted to?

Sodium is restricted to the extracellular space.

5

What electrolyte determines the (ECFV) extracellular fluid volume

Total body sodium

6

What does ECFV determine?

Blood Pressure and Blood Volume

7

Since Na+ determines osmolality what does that influence?

Total body water

8

What is Vasopressin?

Peptide hormone that stimulates water reabsorption in principal cells of collecting ducts and constriction of arterioles

9

How does Vasopressin work?





Vasopressin regulates the body's retention of water by acting to increase water absorption in the collecting ducts of the kidney nephron. Vasopressin increases water permeability of the kidney's collecting duct and distal convoluted tubule by inducing translocation of aquaporin-CD water channels in the kidney nephron collecting duct plasma membrane.

10

Which is the major intracellular cation?

Potassium K+

11

What is the major extracellular anion?

Cl-

12

Which organ regulates the total body content of Cl-

Kidney

13

What is the other major extracellular anion?

Bicarbonate HCO3−

14

What is the percentage of Body water in humans?

Males:60% Females:50%

15

What is the major ECFV buffer?

Bicarbonate

16

What is the key factor in Acid-Base balance?

Bicarbonate

17

What is the normal body pH?

7.40

18

What are some of the waste materials that the kidney excretes?

1.Urea (by-product of protein metabolism)
2.Creatinine
3.Uric acid

19

What glycoprotein produced by the kidney is responsible for rbc production?

Erythropoietin

20

In terms of anemia what what kind of anemia would reduced kidney function be associated with?

1.Low reticulocyte count
2.Normocytic normochromic anemia




21

What is the major source of 1-alpha hydroxylase

Kidney

22

What are the minor sources of 1-alpha hydroxylase?

Skin (kerationocytes) Bone (osteoblasts) and immune cells

23

What is the function of 1-alpha hydroxylase?




1-alpha hydroxylase is located in the proximal tubule of the kidney and a variety of other tissues, including skin, immune cells, and bone. The enzyme catalyzes the hydroxylation of calcidiol to calcitriol which is the bioactive form of Vitamin D

24

Would reduced kidney function result in reduced 1-alpha hydroxylase as well as reduced Vitamin D?

Yes.

25

What is the Chief source of Renin in the body?

Kidney

26

What is Renin?


proteolytic enzyme produced by granular cells in the kidney that catalyzes the formation of angiotensin I from angiotensinogen

27

Where is renin produced?

Juxtaglomerular apparatus by specialized cells
(granular cells)

28

What is Bradykinin?


nonapeptide hormone that causes a slowly developing contraction of intestinal smooth muscle, vasodilation, and increased renal sodium excretion

29

Which of the Prostaglandins are perticularly important in maintaining homeostasis and are vasodilatory?

PGI2 & PGE2

30

Which is the critical organ that maintains BP?

Kidney

31

What is angiotensin II?



peptide hormone formed from the proteolysis of angiotensin I by converting enzyme in the lungs; potent vasoconstrictor, enhances the effectiveness of sympathetic nerve stimulation to blood vessels, and promotes salt and water retention in the body primarily by stimulating the release of aldosterone from
the adrenal cortex.

32

What are some of the secondary functions of the kidney?

1.Catabolism of small peptides i.e Insulin (decreased nephron mass = slower degradation of insulin)
2.Produce small amounts of glucose via gluconeogenesis during fasting
3.Elimination of many medications

33

What is meant by positive balance?

State in which intake plus endogenous production > renal excretion rate
2.Leads to increased total body content of the substance

34

What is meant by negative balance?

Intake plus endogenous production < renal excretion rate

35

How does one examine whether the kidney is functioning correctly?

Examine the urine

36

Where is the plasma ultrafiltrate formed?

At the Glomerulus

37

What is the Glomerulus essentially?

A Big BAll of Capillaries

38

What is Ultrafiltration?



filtration through a selectively permeable membrane that allows passage of small molecules but restricts the passage
of large molecules, such as proteins

39

What is Glomerular ultrafiltrate normally free of?

Proteins and cells

40

What does the kidney require in order to make this filtrate?

An enormous amount of blood flow.

41

What percentage of the Cardiac output does the kidney receive?

10%

42

What percentage of the Glomerular filtrate must be reabsorbed?

98-99%

43

What would result from disability to absorb renal filtrate?

Go into shock.

44

Approximately how many litres a day are reabsorbed?

178

45

What is the major site of Oxygen consumption in the kidney?

Renal tubules

46

What is the best index of overall kidney function?

(GFR) Glomerular filtration rate

47

What are the processes involved in renal function?

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

48

What very potent vasosonstrictor is produced by the kidney in response to endothelial injury?

Endothelin

49

What is the primary function of the tubules?

Re-absorption

50

What is involved in secretion?

Addition of some solutes i.e K+ from peritubular capillaries to the tubules

51

What percentage of renal blood flow does the cortex receive?

90%

52

Where do ALL glomeruli reside?

Renal cortex

53

What resides in the renal Medulla?

Tubular structures:
1.Loops of Henle
2.Collecting Ducts
3.Vasa recta

54

What is in the Hilum?

1.Main renal artery
2.Main renal vein
3.renal pelvis
4.Ureter
5.Renal nerves
6.Lymphatics

55

Where does urine exit?







One urine is formed it exits at the renal papillae of the medulla and goes through a number of minor calyces that come together in 3-5 major calyces then coalesce into the renal pelvis.

56

What is the flow of urine out of the body?

1.Renal Pelvis joins the ureter
2.Descends in the retroperitoneum
3.Crosses over the pelvic brim across vascular structures
4.Down into the urinary trigone of the bladder

57

What are the three points of potential obstruction within the ureter?

1.Pelvic uretal juction
2.Crossover of pelvic brim
3.Urinary trigone (bladder)

58

What are the differences between male and female urethra?

1.Male urethra goes through median lobe of the prostate
2.The male urethra is longer and less UTI prone

59

What is common among aging pertinent to the urethra?

Enlargement of the prostate which obstructs the the prostatic urethra

60

What are the principle type of bacteria associated with female urinary tract infections?

Gram-negative

61

What arteriole enters the Glomerulus?

Afferent arteriole

62

What arteriole leaves the Glomerulus?

Efferent arteriole

63

What are the two types of Nephrons?

1.Cortical
2.Juxtamedullary

64

What percentage of the nephrons are Cortical?

85%

65

What are the differences in the cortical nephrons?

1.NEVER OPERATION @ 100% always have some reserve capacity
2.Closest to renal capsule (superficial nephron)
3.Smaller than Juxtamedullary nephron
4.Perfusion pressure is lower than that of Juxtamedullary nephrons
5.Filtration is lower than that of Juxtamedullary nephrons
6.Have short loops of Henle

66

What are some differences in Juxtamedullary Nephrons?

1.Longer loops of Henle
2.Some will descend into the renal papilla
3.Higher perfusion pressure than Cortical nephrons
4.Filtration rate is higher than in cortical nephrons

67

What are the important functions linked to the Juxtamedullary nephrons? (long loop)



1.Maximal water conservation making maximally concentrated urine
2. Medullary thick ascending limb is major site of Na+ transport (produces hypertonic medullary interstitium)
3.Efferent arterioles becomes descending vase recta which is the only arterial blood supply to medulla

68

What brings the blood supply to the medulla?

Vasa recta

69

What is important in maintaining the medulla in hypertonic fashion pertaining to the vasa recta.


Solute transfer between ascending and descending vasa recta

70

What do the efferent arterioles from CORTICAL nephrons become?

Peritubular capillary network in the renal cortex.