Histology and Embryology Flashcards
which germ layer is the kidney and bladder derived from
mesoderm
what are the 3 nephric stages of kidney development and which stages are functional
pronephros
mesonephros - function between weeks 6-10 then regress
metanephros - becomes the permanent kidney
what forms the metanephrons
ureteric bud
metanephric blastema
what becomes the collecting system
the ureteric bud
what does the collecting system consist of
Ureter Renal Pelvis Major calyces Minor calyces 1-3 million Collecting Ducts
what does the metanephric blastema become
the nephron
what is the nephron and its function
Functional unit of the Kidney
Filtration of blood and production of urine
where do the kidneys develop before they ascend to there final position
pelvic region
what is pelvic kidney
when one kidney fails to ascend
what is horseshoe kidney
Inferior poles of Metanephroi meet and fuse before ascent
– kidney trapped beneath IMA
what is the bladder formed from
the cloaca (hindgut endoderm)
what is Bladder Exstrophy
skin over the lower abdominal wall does not form properly.
The bladder is open and exposed on the outside of the abdomen
what is the kidney covered by
thin but strong capsule of dense collagen fibres
where is the site of entry of renal artery and exit of renal vein and ureter
the hilum
going from kidney to ureter
1 - renal pelvis
2 - major calyces
3 - minor calyces
position of the medulla
divided into medially pyramids, with apices pointing towards the hilum (called the papillae) ending on the minor calcyces
what is the nephron composed of
the renal corpuscle and renal tubules
what is the renal corpuscle formed from
group of capillaries called the glomerulus and the Bowman’s capsule
what is bowman’s capsule
cup of simple squamous epithelium at the blind end of the nephron which the capillaries invaginate
what separates the blood from the glomerular filtrate
2 cell layers
- capillary endothelium
- podocytes
what are podocytes
specialised epithelium which lies on top of the glomerular capillaries
has pores
what is between the two cell layers
thicker than usual basal lamina
what is the role of mesangial cells
produce a connective tissue core called the mesangium
help removal of debris
histology of loop of henle
simple squamous lining in which the nuclei typically protrude into the lumen
transition to the thick ascending limb, which is lined by a simple cuboidal epithelial cells with abundant mitochondria
what is the named given to the blood vessels that dip down into the medulla from above and then climb back up to the cortex
vasa recta
where are the distal convoluted tubule found and what are they lined by
found in the cortex
lined by simple cuboidal epithelium
what is the difference between proximal and distal conducted tubules
DCT lack a brush border of extensive microvilli
what are medullary rays
collecting ducts + proximal and distal tubules together in parallel bundles running perpendicular to the surface of the kidney
what is the lining of collecting ducts
simple columnar epithelium
what is the Juxtaglomerular Apparatus
- specialized structure formed by the distal convoluted tubule and the glomerular afferent arteriole.
- its main function is to regulate blood pressure and the filtration rate of the glomerulus
what is the Juxtaglomerular Apparatus composed of
The macula densa.
The juxtaglomerular cells.
The extraglomerular mesangial cells (or lacis cells)
what cells secrete renin and where are they found
Juxtaglomerular cells
found in the afferent arteriole
where is urine produced at the renal papilla collected
minor calyx, flows into the major calyx, renal pelvis, ureter and then into the bladder.
what are almost all of the conducting parts of the urinary tract lined with
transitional epithelium or urothelium
what domed cells are at the luminal surface of transitional epithelium
umbrella cells
what is below the epithelium
lamina propria
what is the female urethra composed of
transitional epithelium which transition to stratified squamous near its termination
what is the each part of the male urethra composed of
prostatic urethra - transitional epithelium
membranous urethra - transitional epithelium changes to stratified columnar.
penile urethra - stratified columnar epithelium which near the tip of the penis becomes stratified squamous.
