histology Flashcards
what is the role of the urinary tract?
- maintains water and electrolyte homeostasis, body fluid osmolarity and acid base balance
- excrete toxic metabolic waste products (mainly urea and creatinine)
- acts as an endocrine gland, producing renin and erythropoietin
what is the kidney covered in?
-thin but strong collagenous capsule
what is contained in the hilum of the kidney?
-ureter, renal artery and renal vein
what is considered a lobe of the kidney?
-each medullary pyramid and its associated cortisol tissue is considered a lobe of the kidney
what is this?
renal cortex
what is this?
renal papillae
what is this?
Calices
-top arrow is the minor calyx and bottom arrow is the major calyx
what is this?
renal pelvis
what is this?
Medulla containing renal pyramids
what is at each tip of the medulla in the kidney?
at the tip of each medulla is a minor calyx
where are medullary rays found?
-in the cortex
what is the kidney capsule continuous with?
-the capsule is continuous with the connective tissue that lines the renal sinus
histological slide of cortex and medulla
what is a nephron?
-basic functional unit of the kidney
what are nephrons composed of?
-renal corpuscle nd renal tubules
what is the renal corpuscle responsible for
-produce and collect glomerular filtrate
what is the renal corpuscle made of?
-made of knotted ball of capillaries called the glomerulus and then there is a gap and it is surrounded by simple squamous epithelium (Bowman’s capsule)
what supplies the capillaries in the renal corpuscle?
-an afferent arteriole and drained by an efferent arteriole
what two cell layers separate the blood from the glomerular filtrate?
-the capillary endothelium and specialised epithelium which lie on top of the glomerular capillaries (these epithelial cells are called podocytes)
what is the role of mesangial cells?
- produce a connective tissue core called the mesangium
- support and removal of debris
where do the afferent and efferent arterioles enter and leave Bowman’s capsule?
- opposite the beginning of the renal tubule
- thus there is a vascular and urinary pole
summary slide
what are the 3 components of glomerular filter?
- fenestrated endothelium of capillary wall
- the thick basement membrane (shared by endothelium and podocyte)
- the filtration slits between the pedicels (small arrows)
what is the role of the proximal convoluted tubule?
- reabsorption of water, proteins, amino acids, carbohydrates and glucose
- 70% of sodium (active transport) and water (diffusion) is reabsorbed
- almost all glucose and amino acids reabsorbed (by co-transporters)
what is the role of the renal corpuscle?
-production and collection of glomerular filtrate
electron micrograph of proximal convoluted tubule
what is the role of the loop of Henle?
-the creation of a hyperosmotic environment in the medulla
what is the role of the distal convoluted tubule?
acid-base and water balance (absorption of water, Na and bicarbonate, excretion of K and H ions)
where is the loop of Henle located?
in nephrons in the medulla
what is the loop of henle made up of?
- a thick descending limb
- a thing descending limb which makes a hairpin turn and begins the journey back out of the medulla as the thin ascending limb which then transitions to a thick ascending limb
what are the thick limbs of the loop of Henle lined with?
-simple cuboidal epithelium
what are the thin limbs of the loop of Henle lined with?
simple squamous epithelium
what are vasa recta?
-loops of thin-walled blood vessels that dip down into the medulla and then climb back up to the cortex
distal convoluted tubule cell
what controls the reabsorption of sodium in the distal convoluted tubules?
-aldosterone which is secreted from the adrenal corte
is the collecting duct part of the nephron?
no
what are in the medullary rays?
-collecting ducts, along with the straight segments of the proximal and distal tubules are gathered together in parallel bundles to the surface of the kidney and called medullary rays
what effect does ADH have on the collecting duct?
-increases the permeability of the collecting duct allowing more water to pass in
what are almost all conducting parts of the urinary tract lined with?
-special epithelium called transitional epithelium or urothelium
what are umbrella cells?
-domed, thick, and inflexible cells at the luminal surface
what is the ureter lined with?
transitional epithelium
bladder histology slide
what type of epithelium is the penile urethra lined with?
-stratified columnar epithelium which then becomes stratified squamous near the tip of the penis
what is the membranous urethra lined with?
-transitional epithelium changed to stratified columnar epithelium
what is the prostatic urethra lined with?
transitional epithelium
what is the female urethra lined with?
initially lined by transitional epithelium which transitions to stratified squamous near its termination
