Mech Exam 2

Front 1

4 main functions of kidney/nephron

Back 1

1. Reabsorb
2. Secretion
3. Eliminate/conserve H20 from body
4. Adjust pH of plasma

Front 2

Reabsorb

Back 2

what you digest from glucose/sm prot/AA get filtered into tubular fluid

Front 3

Where does secretion occur

Back 3

-in the renal tubular cells

Front 4

Tubular cells have what mechanism that "sucks" drugs/toxins out of peritubular cap and interstitium and secrete them into tubular fluid

Back 4

-active secretory/transport mechanism

Front 5

why are many drugs and toxins not readily filtered into tubular fluid by glomeruli

Back 5

-they are bound to plasma proteins (usually albumin)

Front 6

Eliminating/conserving H20 from body does what...

Back 6

-it adjusts the urine osmolality

Front 7

when body is water deprived, it will create what...

Back 7

-body will create a very concentrated urine (1200 milliosmoles/liter)

Front 8

when have too much water....

Back 8

body gets rid of dilute urine (low osmolality)

Front 9

how does body adjust the pH of the plasma

Back 9

-by secreting H+ ions and making and conserving bicarbonate ions

Front 10

Aldosterone increases ___ reabsorption int he renal tubules and increases ____ & ______ secretion into tubular fluid.

Back 10

-Na
-K & H

Front 11

if there's too much aldosterone, what increases and what does that cause?

Back 11

-Plasma Na
-causes water retention

Front 12

At the same time that Na increases, you have what being secreted?

Back 12

-K+ and H+ are being secreted and dumped, so hypokalemia and increased plasma pH occur

Front 13

Kidney takes 25 OH Vit D and converts it to 1.25 (OH)2 Vit D (active form), it increases what?

Back 13

-increases Ca++ absorption from GI tract into blood for distribution to bone and other tissues

Front 14

ADH gets released from wher in response to what?

Back 14

-released from posterior pituitary
-in response to dehydration

Front 15

diuresis means what

Back 15

-increased Na and water excretion by the kidneys

Front 16

PTH released in response to what?

Back 16

-in response to the plasma not having enough Ca++

Front 17

what does PTH do?

Back 17

-causes bone osteoclast activity, removes Ca++ from bone and releases it into the plasma

Front 18

blood flowing into kidney is what % plasma and what % cells

Back 18

-55% plasma
-45% cells

Front 19

what is the flow of blood through the kidney

Back 19

-in through the afferent arteriole, to flomerular capillaries, to bowman's capsule, proximal tubule, collecting duct, renal pelvis, ureters

Front 20

What is the first step of urine production?

Back 20

-filtration

Front 21

what occurs during filtration?

Back 21

-fluid and substances filtered into proximal tubule are quickly reabsorbed by proximal tubule cells and carried back into circulation by peritubular cap.

Front 22

the capillaries are composed of a single layer of endothelial cells that permit what?

Back 22

-they permit leakage of fluid out of the blood into Bowman's capsule and then the proximal tubule

Front 23

what are fenestrae?

Back 23

holes that allow greater fluid movement

Front 24

Mesangial cells

Back 24

contractile, phagocytic, and respond to inflammatory complement cascade by secreting chemical junk

Front 25

what is the filtration barrier?

Back 25

-a triple layer of negatively charged membranes:
-flomerular capillary endothelial cells
-basement membrane
-visceral epithelial cells (podocytes)

Front 26

when does the filtration barrier charge disappear?

Back 26

-disappears due to glomerulitis
-(filtration barrier becomes excessively leaky to RBC and plasma prot)

Front 27

Minimal Change Disease

Back 27

-typically a childhood disease in which the negative charge of the filtration barrier goes away

Front 28

massive proteinuria

Back 28

lose protein/albumin into the urine and bad things happen

Front 29

GFR

Back 29

-how much plasma is filtered out of the capillaries into Bowman's capsule and therefore into the proximal tubule

Front 30

Equation for amt plasma filtered

Back 30

amt excreted (urinated) = amt filtered + amt secreted - amt reabsorbed

Front 31

ERPF

Back 31

-Effective Renal Plasma Flow - the total amt of plasma going through all the glomeruli per minute

Front 32

PAH

Back 32

-Para-aminohippuric acid - freely filtered into the tubular fluid and none of it is reabsorbed

Front 33

GFR equation

Back 33

GFR = [U] i.n. x V/Pi.n.

Front 34

ERPF equation

Back 34

[U]pah x V/[P]pah

Front 35

what is the value of ERPF?

Back 35

585 ml/min

Front 36

What is Total Renal Plasma Flow?

Back 36

the amount of plasma delivered to the whole kidney

Front 37

What's the value of Total RPF?

Back 37

650 ml/min

Front 38

What is hemocrit?

Back 38

-the fraction of whole blood volume comjposed of RBC's

Front 39

what is the value of hemocrit?

Back 39

45%

Front 40

What is the fraction of whole blood?

Back 40

1-45% = 55%

Front 41

Calculation for Total renal blood flow

Back 41

TRBF = TRPF/(1-Hct) = 650 ml/min/0.55 = 1200ml BLOOD/min

Front 42

How much of the total blood volume is filtered each time around?

Back 42

20%

Front 43

macula densa

Back 43

-part of the thick ascending limb of the tubule that passes between the branches of the afferent/efferent arterioles

Front 44

the ________ cells in the afferent artiole detect changes in BP in the afferent arteriole

Back 44

-granular

Front 45

If BP decreased, granular cells secrete what?

Back 45

-they secrete more renin

Front 46

If BP is increased, granular cells secrete what?

Back 46

-they secrete less renin

Front 47

Renal flow through the kidney

Back 47

-afferent arteriole - to glomerular capillaries - which release fluid called glomerular filtrate - enters Bowman's capsule - into proximal tubule - to descending loop - to Loop of Henle - to ascending loop - to distal convoluted tubule - to collecting duct

Front 48

H20 is passively reabsorbed from the fluid of the ____________

Back 48

- from the thin descending Loop of Henle

Front 49

Na+ is passively reabsorbed from the fluid of the ____________

Back 49

-from the thin ascending limb

Front 50

Counter-current multiplier

Back 50

-cyclic mechanism that creates a very high interstitial osmolality (1200mOsm) at the bottom of Henle's loop.

Front 51

In dehydration, what horomone is released and from where

Back 51

-ADH from the posterior pituitary

Front 52

What does ADH do in dehydration?

Back 52

-it creates new pores in the collecting duct through which water can move by osmosis. The osmotic "suction" that pulls water out of collecting duct is created by high osmolality of the interstitium above.

Front 53

Even though water is being drawn into the interstitium, high osmolality is not diluted b/c.....

Back 53

-the peritubular capillaries take it away, AND
-b/c the counter-current multiplier mechanism works to maintain the high osmolality.

Front 54

Renal clearance

Back 54

-used to determine how fast your kidneys excrete a substance/drug

Front 55

definition of clearance

Back 55

-the "virtual" volume of plasma from which the substance of interest has been entirely removed
(how many individual ml of blood are cleared of solute they are carrying)

Front 56

equation for Clearance

Back 56

Cx = Ux x V/Px
-expressed in ml/min

Front 57

What is the breakdown product of P-Cr?

Back 57

-Creatinine

Front 58

T/F
low creatinine clearance means that the person has a renal problem (azotemia)

Back 58

-T

Front 59

Creatinine is ideal b/c...

Back 59

-it's freely filtered and not reabsorbed

Front 60

T/F
a patient's creatinine clearance is approximately = that patient's GFR

Back 60

-T

Front 61

T/F
pt's plasma concentration of creatinine should be constant if their clearance of creatinine is constant and in the correct range

Back 61

-T

Front 62

Renal Artery Stenosis

Back 62

-Blood flow to kdiney is inadequate
-kidney tries to overcome pressure problems by producing renin, angiotensin, angiotensin 2, aldosterone, ADH

Front 63

Causes of renal artery stenosis

Back 63

1. atherosclerosis in renal artery vessels
2. fibromuscular dysplasia

Front 64

4 things to look for in Renal artery stenosis

Back 64

1. refractory HTN as Sx and HTN medication doesn't work
2. new onset of HTN in older pt with h/o norm BP
3. ARF upon starting ACE inhibitor
4. bruit

Front 65

ARF upon starting ACE inhibitor has 3 effects:

Back 65

-low renal blood flow causes low glomerular filtration press (GFP)
-efferent arteriole constricts to try to raise GFP, which causes HTN
-given ACE inhibitor, efferent arterioles are forced to dilate, which lowers GFP, resulting in RF

Front 66

Fibromuscular Dysphagia

Back 66

-primarily in young women 25-45
-unexplained HTN
-idiopathic
-fibromuscular structure crowds lumen of arteriole leading to HTN
-"Beads on a string" appearance
Rx: angioplasty

Front 67

Primary hydronephrosis

Back 67

-urine backs up into kidney and press causes damage to glomeruli, nephron, etc
-blockage occurs at uretero-pelvic jct

Front 68

Secondary hydronephrosis

Back 68

-blockage anywhere in urinary tract
Rx: remove blockage

Front 69

Polycystic Kidney Disease

Back 69

-it's a cause of adult CRF
-simple cysts: few fluid filled cysts, but no Sx
-polycystic: genetic autosomal dom disorder, chrom 16
-cysts take over renal tissue
-polycystin involved

Front 70

Sx of poylcystic kidney disease (6)

Back 70

1. enlarged kidneys
2. multiple fluid filled cysts
3. pt approx 40 y/o when Sx start appearing
4. hematuria, HTN in 70-75%
5. Increased risk of UTI
6. occasionally cysts in liver are present

Front 71

Rx for Polycystic kidney disease

Back 71

-dialysis until new kidney for transplant

Front 72

CRF

Back 72

-permanent injury to kidney
-scar tissue replaces regular tissue; irreversible
-if ARF isn't controlled, will lead to CRF
-increased BUN and creatinine due to increased GFR

Front 73

Azotemia

Back 73

-increased BUN and Bcre without signs or Sx

Front 74

Uremia

Back 74

-Any RF with signs and Sx
-urea buildup in blood

Front 75

ESRD

Back 75

-stage of RF requiring dialysis/kidney transplant

Front 76

Causes of CRF: (6)

Back 76

1. Diabetes
2. HTN
3. Glomerulonephritis (prim or secondary)
4. interstitial nephritis
5. polycystic kidney disease
6. other (injury to any part of nephron, interstitium, etc)

Front 77

Diabetes (after 10 or more yrs)

Back 77

-diabetes mellitus
-type 1: insulin deficiency
-type 2: insulin resistance in tissue; sx: microalbuminuria - >3.5g prot/day

Front 78

HTN

Back 78

-causes nephrosclerosis, thickening of arterioles, renal blood flow decreases
-low grade proteinuria
-can cause kidney disease but also works other way

Front 79

interstitial nephritis

Back 79

-heavy metals, etc

Front 80

CRF drug of choice

Back 80

-ACE inhibitor (in hope of saving the nephrons that are still alive)

Front 81

Consequences of RF (7)

Back 81

1. Na+ handling
2. water handling
3. K+ handling
4. Acid/base problems
5. Mineral metabolism decreases
6. drug secretion decreases
7. erythropoietin production decreases

Front 82

Na+ handling: decreased ability to secrete or excrete Na+

Back 82

-if increase Na+, Na+ retention, circulating fluid vol increases, leads to HTN and edema
-if decrease Na+, hypotension (?)

Front 83

water handling

Back 83

-if increase water, body fluid will be dilute, leading to hyponatremia
-if decrease water, hypernatremia, leads to confusion, convulsions, coma

Front 84

K+ handling (distal tubule in charge)

Back 84

-become hyperkalemic, display heart dysrhythmias
-pt advised to restrict K+ intake

Front 85

A/B problems: Acidemia created

Back 85

- Increased H+ concentration leads to decrease in enzymatic rxn
-HCO3- not being formed by kidneys, further incrase in H+
-not enough ammonia produced due to high H+ gradient

Front 86

mineral metabolism decreases

Back 86

-vit D deficient b/c not converted to final form
-Ca++ not absorbed as well so get hypocalcemia
-loss of bone mass

Front 87

drug secretion decreases

Back 87

-doses become larger b/c not clearing as fast
-increased action, worse side effects

Front 88

erythropoietin production decreases

Back 88

-anemia develops

Front 89

CRF Sx:
general consequences

Back 89

-N/V
-Fatigue
-Anorexia
-disrupted sleep

Front 90

CRF Sx:
neurological conseq

Back 90

-decreased seizure threshold
-peripheral neuropathy: parasthesias

Front 91

CRF Sx:
hemotolgic conseq

Back 91

-HTN (renin release) - kills heart by overworking LV
-Acute pericarditis due to uremia irritating pericardium - chest pain, chest rub

Front 92

CRF Sx:
skeletal conseq

Back 92

-bone pain
-susceptible to pathologic fx
-soft tissue calcification

Front 93

CRF Sx:
other conseq

Back 93

-GI bleeding

Front 94

CRF Tx

Back 94

-treat sx.

Front 95

Proteinuria

Back 95

-points to glomerulopathy
-glomeruli are leaking

Front 96

Filters in glomeruli: (2)

Back 96

1. size selective filter
2. charge selective filter

Front 97

Size selective filter

Back 97

-glucose, water, urea can filter through
-anything with radius > 4nm won't filter

Front 98

Charge selective filter

Back 98

-albumin neg charge, so blocked by filter

Front 99

Protein in urine

Back 99

-40% albumin
-40% Tamm-Hursfall prot