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Flashcards in Intro to Renal Physio Deck (78):
1

Kidney's endocrine function

EPO (peritubular capillary cells), Vitamin D/Calcitriol (tubule cells, PTH and 1-alpha hydrogenase)

2

Kidney and CV systems are

interdependent

3

Functional unit of kidney

nephron

4

two parts of a nephron

Bowman's capsule/gomerulus and tubule

5

Cortical nephron

glomeruli in cortex, Loop of Henle dips into outer medulla (electrolyte excretion)

6

Juxtamedullary nephron

glomeruli in cortex, Loop of Henle dips DEEP into inner medulla (urine concentration)

7

Path of blood from renal a to renal v

renal a -> afferent arteriole -> glomerular capillaries -> efferent arteriole -> pertitubular capillaries (cortical loops and medullary loops (vasa recta)) -> renal v

8

Bowman's space

space between glomerular capillary and tubule, collects filtrate

9

JGA

thick ascending limb passes through angle of afferent and efferent arterioles

10

Macula Densa

specialized cells in the thick ascending limb
sense NaCl flow through tubule and send feedback to afferent arteriole's juxtaglomerular cells

11

Tubuloglomerular Feedback

communication about NaCl flow from the macula densa to the glomerular arteriole

12

Renin producing cells are located _______

in the afferent arteriole adjacent to the macula densa

13

Extraglomerular mesangial cells

participate in transmitting infor from macula densa to afferent and efferent arterioles

14

What is the site of renin release

JGA

15

3 causes for renin release

renal SNS, decreased stretch or flow through afferent arteriole (renal baroreceptor), and stimulation from the macula densa ([NaCl])

16

Function of Renin

catalyzes Angiotensinogen --> Angiotensin I/II (ACE) which leads to the production of aldosterone by the adrenal cortex

17

Renin promotes the activation of what 2 hormones

Aldosterone (adrenal cortex) and ADH

18

Function of Aldosterone

(adrenal cortex) --> increases the activity of Na/K-ATPase -> increase Na+ followed by H2O reabsorption

19

Function of ADH

translocation of aquaporins to the surface of the collecting duct -> increase H2O reabsorption

20

SNS on renal function

Vasoconstriction of afferent and efferent arterioles

21

SNS impact on JGA

increases release of renin from afferent and efferent arteriole granular cells

22

SNS impact on tubules

reabsorption of Na

23

SNS's NT and receptor

NE and alpha-adrenergic

24

Function of Mesangium

structural support of glomerular capillaries, secretion of prostaglandins (dilation of afferents), secretion of cytokines, and are phagocytic

25

What happens when immune complexes (infection or autoimmune) clog mesangium area?

Inflammatory response -> scarring -> loss of glomerular function -> renal failure

26

Proteinuria is a marker of

systemic endothelial cell dysfunction

27

Proteinuria may be a result of kidney damage but may also ___________

cause tubular and interstitial inflammation, ishemia, and fibrosis

28

Hypoalbuminemia via proteinuria

excessive loss of plasma protein, formation of peripheral edema, alters acid-base balance, and circulating hormones

29

4 types of proteinuria

Glomerular, tubular, exercise, and orthostatic

30

3 Layers to the glomerular filtration barrier

endothelium w/ fenestra, basement membrane, podocytes

31

Endothelium of the glomerular filtration barrier

large fenstra with negatively charged glycoproteins (not a size barrier - 70um)

32

Basement Membrane of the glomerular filtration barrier

composed of ECM, negatively charged

33

Podocytes of the glomerular filtration barrier

Negatively-charged podocytes create filtration slits which is covered by a slit diaphragm

34

Slit Diaphragm of the glomerular filtration barrier

thin, negatively-charged, selectively porous membrane

35

What protein largely makes up the slit diaphragm and

nephrin

36

What passes through the slit diaphragm?

H2O and electrolytes (unless damage has occurred)

37

glomerular filtration barrier size barrier

20-42A; easily passes molecules 42A

38

glomerular filtration barrier between the range of 20-42A

Dependent on charge and size, a cationic molecule will pass more easily

39

Albumin does not pass the glomerular filtration barrier because

IT is highly NEGATIVELY-charged, size is irrelevant because it is 36A

40

Size of albumin

36A

41

Glomerular proteinuria may be due to

physiologic or pathological, transient or permanent, and can cause huge loss of protein

42

Would it be more worrisome to have positive or negative proteins in the urine?

Negative; because the negatively charged glomerular filtration barrier should prevent the passage of negative molecules

43

Loss of glomerular charge selectivity is > or < important than loss of size selectivity on Albuminuria

Charge is more important because size is already within range of 20-42A

44

How would one detect the loss of glomerular size selectivity

you would see medium-sized proteins (like albumin) and larger proteins (like IgGs) in the urine

45

What level of proteins are normally found in urine?

<20), plasma proteins, and renal tubule of urogenital tract proteins

46

What is microalbunimuria?

excretion of 30-300mg of albumin/day; indicative of vascular dysfunction

47

What is non-nephrotic proteinuria?

<3000mg/day excreted protein

48

What is nephrotic range proteinuria?

>3000mg/day excreted protein; may include excessive sloughed off tubular cells, RBCs, lipiduria, peripheral edema if hypoalbuminemia

49

If protein is filtered where would it be reabsorbed? (<20A or plasma protein)

proximal tubule via endocytosis

50

What protein can be measured to determine if the proximal tubule is functioning properly?

Beta-2 microglobulin; this protein is small and freely filtered but generally reabsorbed via endocytosis

51

Proximal tubular damage may be caused by

ischemia, immunological damage, or heavy metal intoxication damage

52

What will happen with albumin during proximal tubular damage?

albumin in urine will increase slightly bc it is still restricted by the glomerulus, but the small amount that enters the filtrate will not be reabsorbed

53

Dip stick lab tests may identify which types of proteinuria

Glomerular proteinuria (large amounts of albumin) BUT NOT tubular proteinuria bc there is still a SMALL amount of albumin that is excreted

54

What is overflow tubular proteinuria?

Small proteins that are filtered as filtrate normally are reabsorbed, but if they are filtered in excessive amounts the amount may exceed the body's ability to reabsorb them (NOT due to tubular damage)

55

2 types of non-pathological proteinuria

Exercise and orthostatic

56

Exercise proteinuria

strenuous exercise leads to transient increase in protein excretion (albumin); can be tubular and glomerular proteinuria

57

Orthostatic proteinuria

Upright position increases the excretion of protein (normal when lying down)

58

Control of Micturition

internal and external urethral sphincter

59

Internal urethral sphincter

involuntary, smooth muscle, tonic contractile tone (until pressure threshold of filling is reached)

60

external urethral sphincter

skeletal muscle, voluntary, innervated by the pudendal n

61

Pudendal n

innervates external urethral sphincter and carries sensory afferents from bladder and urethra

62

Detrusor muscle

smooth muscle that surrounds the epithelial lining of the bladder

63

Sacral n (pelvic n) carries

parasympathetic efferents to the detrusor muscle for voiding bladder (M3 receptor); sensory afferents (info to spine on fullness of bladder)

64

Hypogastric n.

Sensory afferents (info to spine on fullness of bladder), efferents to bladder neck for contraction and storage of urine (alpha receptors) and some efferents to detrusor for relaxation (Beta-3 receptor)

65

3 nerves that supply the bladder and their function

Pudendal n (S2-S4): somatic innervation of external urethral sphincter
Hypogastric n (L1-L3): sympathetic innervation to the bladder neck for contraction and filling and to detrusor for relaxation; sensory afferents
Sacral (Pelvic) n (S2-S4): parasympathetic innervation to detrusor muscle for voiding; sensory afferents

66

Micturition Reflex

spinal reflex that is modified by higher brain centers (pontine micturition center)

67

What happens if the higher brain centers are separated from the spinal control of micturition?

Incontinence

68

First step in micturition reflex

Bladder filling causes stretching of the detrusor muscle causing afferent sensory information to be sent to the spinal cord (150mL mild "fullness" signal and 400mL very strong signal)

69

Second step in micturition reflex

parasympathetic efferent signal sent back to detrusor muscle causing contraction (may cause internal urethral sphincter to open)

70

Once urine begins entering urethra and a second set of sensory afferents, ________

sympathetic signal is sent to the bladder neck and internal urethral sphincter that inhibits its tonic contraction

71

The final step in micturition is

voluntary relaxation of the external urethral sphincter allows voiding

72

Higher brain function can modify the afferent signals and micturition reflex

inhibit the parasympathetic contraction of the detrusor muscle, to avoid voiding. (decreased the sensitivity to the micturition reflex)

73

What would happen to the micturition reflex if the spinal cord was transectioned?

Voluntary control is obliterated, and the micturition reflex will simultaneously contract the detrusor and EUS interfering with voiding

74

What would happen to the micturition reflex if sympathetic nerves were blocked?

Nothing

75

Urge Urinary Incontinence

involuntary leakage accompanied by the feeling of urgency; overactive parasympathetics to detrusor (treated by anti-cholinergic) or interstitial cystitis "painful bladder syndrome"

76

Stress Urinary Incontinence

involuntary leakage accompanied by increased intra-abdominal pressure (coughing, sneezing); due to insufficient urethral sphincter

77

Overflow Urinary Incontinence

Inability to completely empty bladder -> large bladder volume -> dribbling -> due to obstruction (BPH in men)or underactive parasympathetic innervation to the detrusor muscle

78

Urinary Incontinence due to transient conditions

not associated with a lower UT dysfunction; bladder infection, increased urine production, mental status, medications