histology Flashcards
what is the nephron composed of?
renal corpuscle and renal tubules
what forms the renal corpuscle?
a tuft of capillaries called the glomerulus and the cup of simple squamous epithelium at the blind end of the nephron which the capillaries invaginate into (Bowman’s capsule)
what is the role of the renal corpuscle?
production and collection of glomerular filtrate
what is the urinary space?
(aka bowman’s space) space between the visceral and parietal layers, into which the filtrate enters after passing through the filtration slits.
what are podocytes and what is their function?
specialised cells of the glomerulus that wrap around the capillaries and neighbour the cells of bowman’s capsule
what are mesengial cells?
form stalk like core of glomerulus, control glomerular filtration
what are the 3 components of the glomerular filter?
fenestrated epithelium of capillary wall
thick basement membrane
filtration slits between pedicles
what is the main function of the proximal convoluted tubule?
reabsorption of water, proteins, amino acids, carbohydrates and glucose
what is larger- proximal or distal convoluted tubules?
proximal
what is the function of the loop of henle?
creation of hyperosmotic environment in medulla by reabsorbing water and NaCl from the filtrate
what is the blood supply to the medulla of the nephron?
vasa recta- loops of thin walled vesels
what is the function of the distal convoluted tubule?
acid-base and water balance (absorption of water, Na and bicarbonate, excretion of K and H ions)
what is reabsorption of na+ in the distal convoluted tubule (DCT) controlled by?
aldosterone (secreted from adrenal cortex)
is the collecting duct part of the nephron?
no
what are medullary rays?
bundles of proximal and distal tubules running perpendicular to the kidney surface pointing towards the medulla
what type of epithelium lines almost all of the conducting parts of the urinary tract?
transitional epithelium/urothelium (same thing different names)
what are cells at the luminal surface called?
umbrella cells - because they are domed
how many layers of smooth muscle are there near the bladder?
3 - drops down to 2 as you get further away
what is the different in length between the male and female urethra?
female - 3-5cm
male - approx. 20cm (prostatic urethra 3-4cm, membranous urethra approx. 1 cm, penile urethra approx. 15cm)
describe the epithelium of the female urethra
initially lined by transitional epithelium which transitions to stratified squamous near its termination
describe the epithelium of the male urethra
Prostatic urethra: Lined by transitional epithelium.
Membranous urethra: Here transitional epithelium changes to stratified columnar.
Penile urethra: lined by stratified columnar epithelium which near the tip of the penis becomes stratified squamous.
