Lecture 2: Anatomy of the urinary system Flashcards
What are the functions of the kidney and urinary tract?
- Excretion of waste products and drugs: filter plasma
- Regulation: Controls body fluid volume and ionic compounds. Major role in homeostasis. Involved in the acid-base balance
- Endocrine: site of synthesis of renin (BP and sodium balance), site of EPO production (erythrocyte production), site of prostaglandins (regulation of renal function)
- Metabolism: where vit D is metabolised into its active form. Site of catabolism for low-molecular-weight proteins (insulin/PTH/calcitonin)
Where is the anatomical location of the kidneys?
Retroperitoneal on the posterior abdominal wall, either side of the vertebral column
-located between T12 and L3 vertebrae
-partially protected by ribs 11 and 12
(look at size difference b/w to two kidneys in one person)
What is the size of the kidneys?
11cm long
6cm wide
140g
Which kidney is higher up?
Left
As the liver sits on top of the right kidney, pushing it down slightly
What is the hilum of the kidney?
Part of the kidney that makes it bean shaped, where all the tubes enter the kidney.
-located at L1
What structure comes out of the kidneys?
Ureter, which travels down the lumbar spinal processes into the pelvis
When do the ureters move inwards towards the bladder?
At the level of the ischial spine
How is the kidney held in place?
-pararenal fat (in line with kidney)
-renal fascia
-perirenal fat (near to kidney)
-renal capsule
Then withing the capsule is the kidney
(however the kidneys aren’t in a fixed position)
What is the blood supply to the kidney?
-abdominal aorta (left/right renal artery comes directly off the aorta to supply the left/right kidneys)
In front of this is the inferior vena cava (IVC)
-the IVC has branches coming directly off called the right/left renal vein
What is the structure of the inner kidney?
- cortex
- medulla (renal pyramids found here)
What is encompassed in the renal lobe?
The renal pyramid as well as the cortex above it. There are many renal lobes
What is found between the renal lobes?
Renal columns
Where are the nephrons found?
Within the renal lobes, collecting ducts run into the minor calyces, which in turn feed into the major calyces, which then feeds into the renal pelvis, and then the ureter
How does the osmolality change in the medulla?
Gets more salty the further in you go
What are the two different types of nephron?
- cortical, short LoH (85% of nephrons in body)
- juxtamedullary, long LoH (15% of nephrons in body): good at concentrating urine ad have lots of space for water reabsorption
What feeds the blood supply into the nephron?
Afferent arteriole, which then forms a network of capillaries known as the glomerulus which is encased by Bowman’s capsule
How does the blood leave the glomerulus?
Efferent arteriole (leaving through an arteriole and NOT A VEIN!)
What cells sit on top of the capillaries in Bowman’s capsule?
Podocytes (large cells)
- protrusions (foot processes), which wrap around the capillaries forming slits: one part of the filtration system
- stop really large solutes passing through
Whats the first part of the nephron after the glomerulus?
Proximal convoluted tubule
- reabsorb a high proportion of solutes
- all AA’s and glucose absorbed here
What are the different part of the LoH?
LoH is found after the proximal convoluted tubule
- descending limb (thin)
- ascending limb (thick and thin)
What is found after the LoH in the nephron?
Distal convoluted tubule
-nestles near the glomerulus forming the juxtaglomerular apparatus