Structure And Fxn Of The Renal And Urologic System

Front 1

The glomerular filtration membrane filters blood through which 3 layers?

Back 1

1. inner capillary endothelium
2. middle basement membrane
3. outer layer of the capillary epithelium

Front 2

The macula densa and juxtaglomerular cells form the juxtaglomerula apparatus to...

Back 2

1. renal blood flow
2. glomerular filtration
3. secretion of renin

The juxtaglomerular apparatus consists of the juxtaglomerular cells, macula densa, and mesengial cells which acts as a renal pressure sensor. If blood pressure decreases, the juxtaglomerular apparatus will release renin.

Front 3

What enhances the reabsorptive function of the proximal tubule?

Back 3

microvilli

Front 4

Renal blood flow is regulated by what three processes?

Back 4

1. Autoregulation (prevent large changes in GFR when there are increases or decreases in systemic BP. Solute and water excretion and thus BV are regulated when arterial pressire changes)

2. Neural Regulation (ANS thru sympathetic fibers cause vasoconstriction and decrease blood flow)

3. Hormonal regulation (renin-angiotensin system can increase systemic arterial pressure and change RBF)

Front 5

Autoregulation in relation to RBF is..

Back 5

prevents large changes in GFR when there are increases or decreases in systemic BP. Tubuloglomerular feedback keeps RBF and GFR constant. As GFR in/decreases, macula densa cells sense the change of filtered sodium. When GFR and sodium increase, the macula densa cells stimulate afferent arteriolar vasoconstriction and decrease GFR and vice versa.

Front 6

Neural Regulation of Renal Blood Flow

Back 6

The blood vessels of the kidney are innervated by the ANS by sympathetic fibers that cause vasoconstriction and decrease RBF.

Decreased RBF also diminishes excretion of Na and water, promoting increase in BV and increase in systemic pressure

Exercise, body position and hypoxia influences RBF causing mild vasoconstriction.

Front 7

How does hypoxia affect renal blood flow

Back 7

Severe hypoxia stimulates chemoreceptors of carotid and aortic bodies and decreases RBF by sympathetic stimulation

Front 8

How does the hormonal regulation affect RBF?

Back 8

Renin-angiotensin system increases systemic arterial pressure and change RBF. Decreased BP in afferent arterioles decreases stretch in juxtaglomerular cells, decreased NaCl concentration in distal convoluted tubule, and sympathetic nerve stimulation of beta adrenergic receptors on juxtaglomerular cells.

Front 9

Four functions of nephrons

Back 9

1. filters plasma

2. reabsorbs and secretes different substances along tubular structures

3. forms a filtrate of protein-free fluid (ultrafiltration)

4. regulates the filtrate to maintain body fluid volume, electrolyte compositioin, and pH within normal limits

Front 10

Tubular reabsorption is the...

Back 10

movement of fluids and solutes from the tubular lumen to the peritubular capillary plasma

Front 11

tubular secretion is the...

Back 11

transfer of substances from the plasma of the peritubular capillary to the tubular lumen.

Front 12

What is the normal specific gravity for urine?

Back 12

1.001-1.035

High number: concentrated
Low number: diluted

Front 13

Normal pH for urine?

Back 13

4.0 - 8.0. Average is 6.0, usually slightly acidic.

Front 14

antidiuretic hormone is secreted by

Back 14

posterior pituitary or neurohypophysis

Front 15

ADH increases

Back 15

water permeability and reabsorption in the last segment of the distal tubule. Concentration of final urine is controlled by ADH. Excreted urine can have a high osmotic concentrated up to 1400 mOsm

Front 16

ADH can cause what change in urine volume?

Back 16

It can cause oliguria or diminished excretion of urine that is less than 400 ml/day or 30ml/hr. ADH reabsorbs water back into body by sodium retention in event of low BP

Front 17

What happens when there is an absence of ADH?

Back 17

- dilution of urine
-distal tubules and collecting ducts become impermeable to water.
- ADH has no effect on sodium reabsorption, it continues to be actively transported from the distal tubule

Front 18

Atrial Natriuretic Peptide

Back 18

- inhibits RAAS
- promotes excretion of water
- inhibits Na reabsorption
- decreases BV and BP

Front 19

How does GFR and creatinine reflect kidney function?

Back 19

When GFR decreases, Creatinine in plasma increases. Filtration and excretion of creatinine would be reduced when GFR reduces.

Concentration of creatinine increases during trauma or breakdown of muscular tissue

Front 20

What are the symptoms of Uremia (elevated BUN and creatinine)

Back 20

Fatigue

Anorexia

Nausea

vomiting

pruritis

Front 21

Acute Renal Failure definition

Back 21

sudden deterioration of kidney fxn with accumulation of wastes, oliguria

Front 22

Etiology of Acute Renal Failure

Back 22

surgery

trauma

infection

hemorrhage

nephrotoxic agents

PRERENAL: most common cause of ARF

decreased RBF

GFR from decreased filtration pressures

liver failure

hemorrhage

shock

hypovolemia

infectious shock

Front 23

Acute Renal Failure may be classified as...

Back 23

Prerenal
Intrarenal
Postrenal

Front 24

Prerenal acute failure is caused by

Back 24

impaired renal blood flow.

GFR declines bc of decrease in filtration pressure

Poor perfusion can result from:
vasoconstriction
hypotension
hypovolemia
hemorrhage
inadequate CO

Front 25

Intrarenal acute failure usually results from...

Back 25

acute tubular necrosis (ATN) caused by ischemia (after surgery), sepsis, obstetric complications, severe trauma, burns, nephrotoxins

Front 26

What are the three pathophysiologic explanations for oliguria for ATN (intrarenal acute renal failure)...

Back 26

1. Tubular obstruction theory: necrosis causes sloughing of cells, cast formation, or ischemic edema that results in tubular obstruction, which causes increase pressure and reduces GFR

2. Back leak theory
Glomerular filtration remains normal but tubular reabsorption of filtrate is accelerated as a result of permeability caused by ischemia

3. Alterations in RBF
increased RAAS, stones, tumors, strictures in lower track

Front 27

Postrenal acute renal failure usually occurs with...

Back 27

urinary tract obstruction (affects kidney bilaterally), or neurogenic bladder

Characteristics:
hours of anuria
flank pain
polyruria

Front 28

Stages of chronic renal failure are...

Back 28

Chronic renal insufficiency

Chronic renal failure

End-Stage Renal Failure

Front 29

Chronic renal insufficiency refers to a decline...

Back 29

decline in renal fxn

- increase in creatinine and urea

- no systemic symptoms

Front 30

End-stage renal failure

Back 30

- less than 10% of renal fxn

- dialysis or transplant required to sustain life

Front 31

what causes azotemia?

Back 31

Chronic renal insufficiency or renal failure.

Azotemia is increased sereum urea levels and creatinine