The Kidneys

location, structure, macro + microstructure

Location of the kidneys

o   retroperitoneal from T12 – L4

o   Posterior-superior surface: deep to ribs 11 & 12

o   Posterior-inferior surface: related to psoas major muscle and quadratus lumborum muscle

* R kidney lower than left

Why is the artery to the right kidney longer then the left?

the abdominal aorta being slightly left to midline + crosses the vena cava posteriorly

When do the ureters become pelvic rather then abdominal?

Once it passes the bifurcation at the common iliac artery

What is found at the transpyloric plane?

superior pole of R kidney and hilum of L kidney

Describe what surrounds the kidneys from deep to superficial

Renal capsule

Perirenal fat

Renal fascia (Gerota’s)

Pararenal fascia 

What is in the medial portion of the kidney?

Vertical cleft

renal hilum

renal sinus (space within the kidney occupied by renal pelvis, calyces, blood vessels, nerves and fat)

At what level is the superior mesenteric artery

L1

Name the arteries that supply the kidneys

Anterior branch of renal artery:

o   superior (apical) segmental artery

o   anterosuperior segmental artery

o   antero-inferior segmental artery

o   inferior segmental artery

Posterior branch of renal artery:

o   posterior segmental artery

What type of arteries are segmental arteries (arteries in the kidneys)?

end arteries 

What imaginary line shows the segments of the kidney supplied by the anterior and posterior divisions?

Line of Brodel

What are the veins of the kidney called and where are they located?

right renal vein:  anterior to the renal arteries

left renal vein: posterior to superior mesenteric artery

** both drain into the IVC

Which vein is longer and why?

left renal vein

the vena cava lies slightly to the right

What else drains into the left renal vein?

the left suprarenal vein and left gonadal vein

What is the Renal corpuscle made up of?

glomerulus

Bowmans capsule

Name the vascular components of the nephron

o   Afferent arteriole

o   Glomerulus

o   Efferent arteriole

Peritubular capillaries

Name the tubular components of the nephron

o   Bowman’s capsule

o   Proximal tubule

o   Loop of Henle

o   Distal tubule

Collecting duct

What part of the nephron is mixed tubular and vascular?

Juxtaglomerular apparatus

Difference between a Juxtamedullary nephron and a Cortical (superficial) nephron

What type of capillaries are in the renal capsule?

fenestrated

Name the layers of the glomerulus and how they ensure correct molecules are filtered

Fenestrated endothelium → permeable to water and low molecular weight solutes + negative charged

Glomerular Basement membrane → strongly negative charge

Visceral epithelial cells (made of podocytes → with spaces in between called slit diaphragm)

→ highly negatively charged matrix

→ filtration slit diaphragm: size selective filter (large molecules cannot enter)

Describe the arterial supply of the renal parenchyma

Renal segmental artery → interlobar artery (pass between 2 lobes) → arcurate artery (arch on top of the pyramid) → smaller interlobular artery → afferent arterioles

Describe the venous drainage of the kidneys

Peritubular capillaries → interlobular vein → acruate vein → ascending vasa recta

Lymphatic drainage of the kidneys

lateral aortic (or para-aortic) lymph nodes (located at the origin of the renal arteries)

What is the function of the Juxtaglomerular apparatus?

regulate systemic blood pressure and glomerular arteriolar resistance (blood flow) and filtration rate

What are the components of the juxtaglomerular apparatus?

o   macula densa

o   juxtaglomerular granular cells (modified SMC in a/efferent arterioles)

o   extraglomerular mesangial (Lacis) cells

Function of the macula densa

monitor the concentration of salt (NaCl) in the distal tubule

Describe the 2 poles of the renal corpuscle

vascular pole: where blood vessels enter and exit → afferent in and efferent out

tubular pole (also called the urinary pole): where the Bowman's capsule opens into the proximal convoluted tubule → glomerular filtrate exit 

The proximal tubule is split into 2 parts, name them

pars convuluta (bendy bit) 

pars recta (straight bit)