Glomerular Structure and Function Flashcards
At what vertebral level do the kidneys lie in?
T12 to L3
Which kidney lies lower than the other?
Right kidney, because of the liver
The kidneys are approximately what length?
The length of three vertebrae
From most deep to superficial, what are the four layers of fascia/fat surrounding the kidneys?
- Renal capsule (deep)
- Perirenal fat
- Renal fascia
- Pararenal fat (superficial)
The renal parenchyma can be divided into two main structures, what are they?
Outer cortex
Inner medulla
The medulla of the kidney is divided into triangular shapes called?
Renal pyramids
The apex of the renal pyramid is called?
Renal papilla
What structure collects urine from the renal papilla - and what does it drain into finally?
Minor calyx, draining into major calices
The kidneys are supplied by what arteries? Where do these arteries arise from?
Renal arteries, from abdominal aorta
Describe the pattern of division of the renal arteries as it supplies the renal parenchyma
Renal artery -> Segmental artery -> Interlobar artery -> Arcuate artery -> Interlobular artery (90 degrees from arcuate artery) -> Afferent arterioles -> Glomerulus
The kidneys are drained by what veins? What do they then drain in to?
Renal veins, draining into inferior vena cava
Why is the left renal vein longer than the right renal vein?
Because the inferior vena cava lies to the right hand side
What structures are more anterior (front) - the inferior vena cava or the abdominal aorta - as it enters the kidneys?
Inferior vena cava (anterior)
Lymph from the kidneys drain into…?
Lateral aortic nodes
What are the two types of nephrons in the kidney, and how are they different?
Cortical nephrons - short Loops of Henle
Juxtomedullary nephrons - long Loops of Henle
What are the three cellular layers within the Glomerulus?
Fenestrated endothelium
Basement membrane
Epithelium with podocytes
The Juxtaglomerulus Apparatus is in close contact with the ______ Convoluted Tubule
Distal
The Juxtaglomerulus Appatarus is comprised of three distinct structures - what are they?
Macula Densa
Granular cells
Extraglomerular mesangial cells
What is normal GFR in humans?
125ml / min
Cations less than 68kDa are restricted from passing through the glomerular filtration barrier, true or false?
False, anions are
How much blood is filtered by the kidneys per min?
1.2 litres
To increase GFR, how would the afferent / efferent arterioles need to change?
Afferent = dilate Efferent = constrict
Give 4 examples of substances which can increase GFR
Prostaglandins
Kinins
Dopamine
NO
Give 3 examples of substances which can decrease GFR
High dose Angiotensin II
Noradrenaline
ADH
Angiotensin II has what effect on the afferent and efferent arterioles of the kidney?
In low dose, efferent arteriole constriction
In high dose, afferent arteriole constriction
Angiotensin II blockade has what effect on the efferent arteriole?
Dilatation
What are the two types of mesangial cells?
Extraglomerular
Intraglomerular
Angiotensinogen is released by what?
Liver
In response to angiotensinogen release, what happens?
Renin is released by the kidneys
Angiotensinogen + Renin = ?
Angiotensin I
Where is ACE released from? What does it do?
Kidney and lung endothelia, converts Angiotensin I to Angiotensin II
What is the role of Angiotensin II?
Stimulates aldosterone release from the kidneys, to increase reabsorption of Na+ and increasing BP
Aldosterone also depletes K+ levels
Angiotensin II also causes vasoconstriction in renal arterioles to increase BP further
What are some problems with using Serum creatinine as a measure for GFR?
- It is actively secreted by the tubules (up to 15%)
- Insensitive as a marker for early kidney disease
- It is affected by muscle mass
- Affected by certain drugs
