Renal Flashcards by Kirilee Wagner

What is the function of the kidneys?

Excrete metabolic waste, foreign chemicals
Secrete and metabolise hormones
Regulate pH
Control blood pressure
Gluconeogenesis
Regulate water and electrolyte excretion

How well did you know this?

Not at all

Perfectly

What waste products are excreted by the kidneys?

Urea
Creatinine
Bilirubin
Hydrogen

How well did you know this?

Not at all

Perfectly

What hormones are secreted by the kidney?

Erythropoetin

Renin

How well did you know this?

Not at all

Perfectly

Why is erythropoetin secreted by the kidneys?

In response to low blood O2 in the kidneys, to increase erythrocyte production

How well did you know this?

Not at all

Perfectly

What ions do the kidneys regulate?

Sodium
Chloride
Potassium
Hydrogen
Calcium
Phosphate
Magnesium

How well did you know this?

Not at all

Perfectly

What are the nephrons function?

Filtration
Reabsorption
Secretion
Excretion

How well did you know this?

Not at all

Perfectly

What determines capacity for filtration?

The size and charge of the barrier

How well did you know this?

Not at all

Perfectly

Name 4 reasons why proteinuria is clinically significant

Hypertension
Diabetes
Pre-eclampsia
As an annual check-up

How well did you know this?

Not at all

Perfectly

What can cause microalbuminuria?

Early diabetes
Hypertension
Glomerular hyperfiltration

How well did you know this?

Not at all

Perfectly

What is microalbuminuria?

Urine excretion of 30-150mg albumin per day

How well did you know this?

Not at all

Perfectly

What 3 factors determine glomerular filtration rate?

+ Glomerular hydrostatic pressure

Glomerular colloid osmotic pressure
Bowman’s capsule pressure

How well did you know this?

Not at all

Perfectly

What is hydronephrosis?

Dilation of the renal pelvis caused by urinary retention due to the obstruction of the free flow of urine

How well did you know this?

Not at all

Perfectly

What factors affect the glomerular capillary hydrostatic pressure?

Constriction of afferent and efferent arterioles

How well did you know this?

Not at all

Perfectly

How much of the cardiac output is directed to the kidneys?

22%

How well did you know this?

Not at all

Perfectly

Why is so much oxygen and nutrients directed to the kidneys?

It is used for renal tubular sodium reabsorption

How well did you know this?

Not at all

Perfectly

What are the key regulators of GFR?

Sympathetic nervous system
Hormones
Autocoids

How well did you know this?

Not at all

Perfectly

How does the sympathetic nervous system control GFR?

Innervation of vasculature

Noradrenaline

What is EDNO and what does it do?

Endothelial-Derived Nitric Oxide

Protects against excessive vasoconstriction

What is the role of prostaglandins in the kidneys?

Increased glomerular filtration rate

What is the myogenic mechanism?

Autoregulation of GFR and renal blood flow
The response to increased arterial pressure
> stretch of blood vessels
> increased Ca++ entry and intracellular Ca++
> increased vascular resistance
» increased blood flow and GFR

What is the macula densa?

A collection of cells in the wall of the distal convoluted tubule.
Sensitive to sodium chloride concentration, increasing renin release and decreasing the blood flow in the afferent arteriole to decrease the GFR etc.

What are the 2 reabsorption (transport) pathways?

Paracellular

Transcellular

Outline the primary active transport of Na+ in the proximal tubule

Active transport via the Na+/K+ pump across the basolateral surface
Establish concentration and electrochemical gradient for Na+
Na+ transport into the epithelial cell from the lumenal surface

Outline the 2 secondary active transport mechanisms

Co-transport of glucose and amino acids with Na+ ions driven by electrochemical gradient
Counter-transport driving a movement of a 2nd substrate in the opposite direction

Why can creatinine be used as diagnostic tools for assessing kidney function?

All creatinine should be excreted

What is transported in the proximal tubule?

Out: Na+, Cl+, HCO3-, K+, H2O, glucose, amino acids In: H+, organic acids, bases

What are the transport characteristics of the thin and thick loops of Henle?

Both ascending limbs impermeable to water | Thin descending limb permeable to water.

How is tubular reabsorption regulated?

``` Hormones - aldosterone, angiotensin, ADH Sympathetic nervous system Arterial pressure Glomerulotubular balance Peritubular physical forces Osmotic factors ```

How does aldosterone regulate tubular absorption?

Acts in the collecting tubule and duct: | Increase NaCl and H2O reabsorption, and K and H secretion

How does angiotensin II regulate tubular reabsorption?

Acts in the proximal and distal tubules, collecting tubule | Increase NaCl reabsorption, and H secretion

How does ADH regulate tubular reabsorption?

Acts in the distal tubule onwards | Increases H2O reabsorption

What is hydronephrosis?

When there is a blockage in the kidneys/ureters, so urine builds up, changing the pressure in the glomeruli.

What is polyuria?

When too much urine is being passed

What is glucosuria?

When glucose is found in the urine

What is the macula densa sensitive to?

Concentrations of NaCl in the distal convoluted tubule

Where is the macula densa?

In the wall of the thick ascending arm of the loop of Henle, at the transition to the distal convoluted tubule

Where is renin secreted?

By the kidneys

Name the systems/organs responsible for fluid output

``` Kidneys Lungs Feces Sweat Skin ```

Outline the response to low oxygen levels received by the kidneys

Stimulated to release erythropoietin Increased erythrocyte production Increased oxygen delivered to kidneys

Outline the blood supply to the kidneys

Aorta > renal arteries > segmental arteries > interlobar arteries > arcuate arteries > interlobular arteries > glomerulus > intertubular capillaries

What (approximate) percentage of the cardiac output is taken by the kidneys?

22%

What is the role of juxtaglomerular cells?

Secrete renin in response to a drop in blood pressure; stimulated by the macula densa cells