Shared Flashcard Set

Details

Renal 3 - Glomerular Filtration
Renal 3 - Glomerular Filtration
37
Physiology
Undergraduate 4
11/19/2016

Additional Physiology Flashcards

 


 

Cards

Term
Primary function of the kidney
Definition
maintain homeostasis of electrolytes!
Term
What is ultrafiltration?
Definition
removal of substances from the blood
Term
What is tubular secretion?
Definition
removal of substances from the blood that weren't removed during ultrafiltration
Term
Main 'stages' of kidney filtration
Definition
Ultrafiltration
Reabsorption
Secretion
Excretion to external environment
Term
What does BUN stand for? How is it produced?
Definition
Blood Urea Nitrogen

-product of AA breakdown
Term
Is the kidney an exocrine or endocrine organ?
Definition
both!

Primarily it excretes metabolic byproducts, toxins etc but it also evolved in Vit D metabolism, erythropoietin activity, and renin-angiotensin-aldosterone system
Term
What regulates the rate of BUN, SDMA and creatinine removal from plasma?
Definition
The rate of glomerular filtration / level of kidney function.
Term
What are the vascular components of the nephron?
Definition
Glomerulus
-afferent arteriole, glomerular capillaries, efferent arteriole

Peritubular capillary
Term
What are the tubular components of the nephron?
Definition
Bowman's capsule
Proximal tubule
LoH
Distal Tubule
Collecting Duct
Term
What does the juxtaglomerular apparatus do?
Definition
Involved with regulating blood pressure systemically, and glomerular filtration rate at the level of the nephron
Term
Where is the macula densa found?
Definition
specialized region of the distal tubule epithelium, next to JG cells
Term
What structure releases renin?
Definition
juxtaglomerular apparatus
Term
What is glomerular filtration rate?
Definition
volume of plasma filtered by all glomeruli in a given time period
Term
Are glomeruli more permeable to positively or negatively charged ions?
Definition
positive
Term
What is removed from the plasma during glomerular filtration?
Definition
protein!
Term
What is glomerulonephritis?
Definition
immune-mediated pathology that leads to protein in the urine, edema in the extremities, chronic renal failure
Term
What factors determine glomerular filtration rate?
Definition
1. Renal blood flow & perfusion pressure

2. Difference between outside blood pressure, and inside colloid oncotic pressure within the capillaries

3. Surface area available & ultrafiltration coefficient of the glomerular membrane
Term
What is the filtration coefficient?
Definition
the tension on the glomerular membrane
Term
How can renal blood flow be controlled? (3)
Definition
Myogenic response

Hormones & ANS Factors

Intrinsic response (tubuloglomerular feedback)
Term
What hormones cause vasoconstriction?
Definition
Renin-angiotensin-aldosterone system
Endothelin
Term
What hormones cause vasodilation?
Definition
dopamine
PGE2
PGI2
Term
What do ANS factors do in regards to renal autoregulation?
Definition
Increase vascular resistance or promote renin release
Term
How does the myogenic response work?
Definition
Contraction of smooth muscle in response to adenosine, local hypoxia etc to regulate blood flow rate
Term
What do adrenergic receptors do? in regard to renal autoregulation
Definition
change the resistance in arterioles
Term
How does tubuloglomerular feedback work?
Definition
1. GFR increases = increased tubular flow
2. Macula densa senses increased net flow of NaCl
3. Adenosine produced by macula densa targets mesangial cells, increasing Ca2+ in cytosol
4. Afferent arteriole constricts in response to Ca2+, increasing resistance and inhibiting renin secretion
5. Hydrostatic pressure in glomerulus decreases
6. GFR decreases
Term
Where is renin primarily stored & produced?
Definition
juxtaglomerular cells
Term
A ______ in afferent arteriole pressure causes the release of renin from the JG cells, whereas ______pressure inhibits renin release.
Definition
reduction

increased
Term
How does NaCl influence renin release?
Definition
Macula densa senses [NaCl] in tubular fluid, and if concentration is elevated then renin release will be inhibited. If concentration is low, JG cells will be stimulated to release renin.
Term
How does the renin-angiotensin-aldosterone system work?
Definition
1. Renin released from JG cells

2. Renin acts on angiontensinogen in blood, converting it to Angiotensin I

3. ACE from lungs acts on AI, converting to to active Angiotensin II.

4. AII promotes vascular constriction, aldosterone release to increase Na & fluid reabsorption via aldosterone (adrenal cortex) and ADH (posterior pituitary)
Term
What stimulates JG cells to release renin?
Definition
-decreased afferent arteriole pressure
-decreased [Na] detected by macula densa
-prostaglandins PGE2 & PGI2
Term
What is renal clearance?
Definition
the rate at which a substance is cleared from plasma

Cl(x) = U(x) / P(x) * V
Term
What is key in order for a measure of renal clearance to reflect filtration?
Definition
The substance must be freely filtered, and not re-absorbed or secreted in to the tubule
Term
What substances are often used to measure filtration?
Definition
inulin
creatinine
Term
What is azotemia
Definition
Increased concentration of SDMA, inulin or creatinine in the plasma
Term
What is renal azotemia?
Definition
Increased concentration of SDMA/inulin/creatinine due to an issue with the kidney itself (glomeruli function is reduced, or fewer glomeruli working)
Term
How can you ID whether a glomerulus is 'leaky'?
Definition
look for protein in urine
Term
How can ou ID whether glomeruli are filtering enough blood?
Definition
look for azotemia (check the blood!)
Supporting users have an ad free experience!