1. Anatomy Flashcards
What are the functions of the kidney?
Excretion
Regulation - fluid, ions, homeostasis, acid-base balance
Endocrine - synthesis of renin, erythropoietin and prostaglandins
Metabolism - vit D metabolised, catabolism of insulin, parathyroid hormone, calcitonin
Where are the kidneys located?
Retroperitoneum on posterior abdominal wall, either side of vertebral column Located between T12 and L3 Partially protected by ribs 11 and 12 Hilum at L1 Left kidney slightly higher
How large are kidneys?
11cmx6cm
140g
What is the kidney surrounded by?
Renal capsule
Perirenal fat
Renal fascia
Pararenal fat
What is the cortex?
Outer layer of the kidney
What is the innermost region of the kidney?
Medulla
Within a renal lobe, what is the medulla called?
Renal pyramid
What do the collecting ducts feed into?
Minor calyces which feed into major calyces, then feeds into renal pelvis then ureter
What is the difference between cortical nephrons and juxtamedullary nephrons?
Juxtamedullary loop of Henle descends much further down into the cortex and medulla
What are podocytes?
Large cells that sit on top of the capillaries in the glomerulus
Protrusions called foot processes, wrap around capillaries and create little slits between them
What do the blood vessels for the nephrons come off?
Arcuate arteries
What goes between the arcuate arteries and the efferent arteriole in the nephron?
Interlobular artery
What are the peritubular capillaries?
Capillaries that wrap around the proximal convoluted tubule
What is the vesa recta?
Extension of peritubular capillaries on the juxtamedullary nephrons
Where lots of the water is reabsorbed if needed
Why is the proximal convoluted tubule so close to the glomerulus?
Macula densa cells in the proximal tubule sense what’s happening to the composition of fluid in the tubule, sense how salty the filtrate is to determine how much flow there should be in the glomerulus
What can the macula densa cells cause?
Constriction of either the efferent arteriole or the afferent arteriole, which alters the blood flow in the glomerulus
What do the extraglomerular mesangial cells do?
Provide a skeleton to hold the capillary network
Can pass messages from macula densa cells
Can secrete substances
What are the ureters?
Smooth muscle fibres that propel urine to the urinary bladder
Retroperitoneal
What can the ureters be divided into?
Proximal (abdominal)
Middle (pelvic)
Distal (intramural)
How big are the ureters?
25-30cm long
~1.5mm diameter
Which bony landmarks could you use on an X-ray to approximate the course of the ureter?
L1 ~ hilum
Ureter runs along close to tip of lumbar transverse processes
Crosses sacrum at S1 joint
Ischial spine shows approximate point at which ureter kink towards bladder
Ureters run around pelvis and enter bladder posteriorly
How/where do the ureters enter the bladder?
Vesicoureteral junction
At an oblique angle
What is the trigone?
Triangle formed by the ureteric openings and the internal urethral meatus
What muscle is the bladder made of?
Detrusor muscle
What are the folds in the bladder wall?
Rugae- contract and expand
What is the bladder lined with?
Transitional epithelium - urothelium
What does the bladder rest on when empty?
Symphysis pubis
In women - in front of vagina, uterus and rectum
In men - in front of rectum
How much can the bladder hold?
~750ml
What is the lumen of the ureter lined by?
Urothelium
What are the different parts of the urethra in men?
Prostatic urethra Membranous urethra Bulbous urethra Penile/spongy urethra Navicular fossa External urethral meatus
