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Flashcards in Final Exam Deck (58):
1

What are the functions of the urinary system?

  • Removal of salt, nitrogenous and foreign substances
  • Maintain blood osmolarity (NaCl and water)
  • Maintain electrolyte balance
  • Regulation of blood pH
  • RBC production
  • Helps control BP
  • Helps increase Ca2+

2

What are the types of filtration in the urinary system?

  • Glomerular
  • Tubular reabsorption
  • Tubular secretion

3

Glomerular filtration =

(GBP - COP) - (PPOP + CHP)

(out) - (in)

4

GBP is

glomerular pressure

OUTWARD force

5

COP is

capsular osmotic pressure

OUTWARD FORCE (but usually 0)

6

PPOP is

plasma protein osmotic pressure

INWARD FORCE

7

CHP is

capsular hydrostatic pressure

INWARD force

8

glomerular filtration rate is defined as

the rate at which filtrate enters the tubule

9

What role do the kidneys play in regulating the GFR?

  1. They regulate blood volume
    1. If BP is too high, GFR is increased resulting in fluid loss
    2. If BP is too low, GFR is decreased resulting in fluid retention

10

What happens to the bodies fluid balance if the GFR is increased?

The body has more time to filter and thus loses more fluid causing BP to drop.

11

What happens to the bodies fluid balance if the GFR is decreased?

The body has less time to filter and thus retains fluid causing BP to increase.

12

If BP is too high, what happens to the GFR and by what mechanism does this occur?

  • Afferent arteriole is vasodilated
  • Efferent arteriole is vasoconstricted
  • GBP increases
  • GFR increases
  • Result = fluid loss and BP drop

13

What factors cause vasodilation of the afferent arteriole?

  • ANP - atrial natriuretic protein from the rt atrium
  • Inhibition of the sympathetic NS by cardiovascular baroreceptors 
  • Norepinephrine reduction/ non-release

14

If BP is too low, what happens in the body to correct?

  • Afferent arteriole is vasoconstricted
  • Efferent arteriole is dilated
  • GBP decreases
  • GFR decreases
  • Result = Fluid retention + Inc. BP

15

What factors cause vasoconstriction of AA?

  • sympathetic NS releases NE on alpha-1 receptors

16

How does a JGA respond to a high GFR?

  • High GFR causes increased pressure in the MD cells of the DCT
  • Increased BP in the MD signals the JG cells
  • JG cells cause the afferent arteriole to vasoconstrict
  • Vasoconstriction of AA
    • Result: Decreased GFR, Decreased BP, fluid levels decrease to baseline

17

How does a JGA respond to a low GFR?

  • Low BP or increased solute sensed by MD cells
  • MD cells signal JG cells
  • JG cells cause vasodilation of AA
    • Result: GFR increases, BP increases, fluid levels rise to baseline

18

The juxtaglomerular apparatus 

  • is part of the renal sympathetic nervous system
  • is made up of
    • the distal tubule (MD cells)
    • afferent arteriole (JG cellls)

19

What is reabsorbed in the PCT?

  • 70% of NaCl
  • 70% of H2O
    • obligatory
    • No ADH needed
  • All glucose
  • 99% amino acids
  • 50% Ca2+

20

What is secreted by the PCT?

  • H+ in the form of NH3/NH4 and titratable acid
    • causes regeneration of HCO3- in blood

21

What is absorbed by the descending loop of Henle?

  • 5% of H2O
    • epithelium freely permeable to H2O
  • NaCl is concentrated in a gradient

22

What are the functions of the ascending limb of the loop of Henle?

  • Thin segment
    • NaCl diffuses out into interstitial fluid
    • Tubular fluid is hypotonic
  • Thick segment
    • Cl- is pumped out of the tubule
    • Na+ follows passively
      • filtrate becomes even more dilute
      • NaCl is flowing out due to osmotic gradient set up by DLH
        • ​​countercurrent multiplication

23

What is the action of the DCT?

  • Site of aldosterone and ADH action
  • Reabsorption
    • 9% Na (via Na+/K+ pump)
    • HCO3- (active transport)
    • 50% Ca exchanged for PO43-
    • 25% H2O
  • Secretion
    • K+, H+, PO43-

24

What is the action of the collecting tube?

  • Reaborption
    • remaining H20 to concentrate urine
      • in outer medulla - by NaCl gradient
      • in inner medulla - by urea gradient
    • filtrate passed to renal pelvis and out ureters to become urine

25

To calculate renal clearance of plasma (plasma clearance)

Clearance of x =   Rate of urinary excretion of x (mg/min)

                             plasma concentration of x (mg/mL)

26

define diuresis

an increased urine flow rate

27

Define diuretic

an agent that increases urine output

28

What are the types of diuretics?

  • afferent arteriole dilators
  • osmotic diuretics
  • metabolic inhibitors

29

What effects do arteriole dilators have on the body?

  • They increase hydrostatic blood pressure
  • Increased GFR
  • increase filtration rate
  • increase fluid loss
  • decrease blood volume
  • decrease blood pressure

30

What are osmotic diuretics?

  • It is a substance excreted in urine that interferes with water reabsorption by osmotically holding water in the tubule
  • They also increase salt excretion which decreases water reabsorption

31

Common osmotic diuretics are

  • Mannitol
  • glucose
    • DM - increased glucose is filtered and remains in the tubes causing polyurea
  • urea
    • produced by liver
    • enters interstitial of medulla
    • pulls water out of collecting duct
    • urea in tube increases NaCl excretion holding water.

32

Common metabolic inhibitor diuretics are

  • loop diuretics
    • inhibit Na+ reabsorption
    • Act at the thin ALH
    • Na+ stays in tubule and is lost,, water follows

33

Increased solutes results in ________ osmolarity

increased

direct relationship

34

Increased fluids results in ______ osmolarity

decreases osmolarity

indirect relationship

35

Aldosterone release from the z. glomerulosa causes

  1. Na+ reabsorption in exchange for K+
  2. Na+ absorption can occur on alone 
    1. water will follow ONLY if ADH is present

36

Aldosterone release may be stimulated by

increased angiotensin II through the RAAS system

High K+ levels

37

Atrial Natriuretic Peptide (ANP) causes what effect in the body

  • Inhibits Na+ reabsorption in the DCT
  • Inhibits ADN release blocking reabsorption in the DCT
  • Causes vasodilation of the AA
    • thus increasing GFR

38

Estrogen has a similar effect as

aldosterone

increases Na+ absorption (bloating)

39

Countercurrent exchange occurs in what regions

descending loop of henle 

ascending vasa recta

40

the solute in the renal cortex is

salt

41

the solute in the renal medulla is

urea

42

normal blood osmolarity is

285-300 mosm/L

43

Increased osmolarity causes

shrinking cells and depolarization

44

ADH causes increased water absorption in the 

DCT and collecting duct

45

diabetes insipidus is

lack of ADH, water loss without sugar

excess water loss, patient is always thirsty

46

Maltase digests

the disaccharide maltose into

glucose + glucose

47

Lactase digests

disaccharide lactose into

glucose + galactose

48

Lipase digests

fats/ triglycerides

49

carboxypeptidase digests

proteins

other protein enzymes are trypsin, chymotrypsin (s. int) and pepsin (stomach)

50

The SI absorbes

  • most nutrients and 8500 ml of water
  • Duodenum: some sugars
  • Jejunum: sugars, amino acids, dipeptides, fat components
  • Ileum: vitamin B12 and bile salts

51

The LI absorbs 

  • 400 mL
  • vitamin B and K

52

receptive relaxation occurs in the

stomach in response to each swallow to allow the food bolus to enter and prevent esophageal reflux

53

gastrin is

a peptide hormone that stimulates secretion of gastric acid by the parietal cells of the stomach and aids in gastric motility.

54

pepsinogen is 

a substance excreted by chief cells in the stomach that is converted into the enzyme pepsin by gastric acids (HCl)

55

autocrine control  of endocrine system is

  • hormone binds to same cell that released it

56

peracrine control on the endocrine system is

  • where the hormone binds to receptors on adjacent cells

57

endocrine control of the endocrine system is

where the hormone is transported through a vein or duct before acting on a cell/organ/system etc.

58