Urinary System Histology Flashcards
Which kidney is more superiorly oriented?
The left kidney
Kidneys do what?
3 things
- Filter blood to keep it pure
- Disposal of nitrogenous waste
- Regulate water and electrolyte balance, acids and bases
The outer layer of the kidney capsule is made primarily of what?
Collagen and fibroblasts
The renal cortex is composed of what?
Renal corpuscles and associated tubules
The renal medulla is composed of what?
straight tubules, collecting ducts and vasa recta
A renal lobe consists of what?
Think ice cream cone:
A renal pyramid
Its overlying cortex
One half of each of the adjacent renal columns
Know the flow of blood through the kidney.
See slides 10 and 11 of this histo lecture
During filtration, what happens?
Fluid is squeezed out of the glomerular capillary bed
What happens during resorption?
Most nutrients, water and essential ions are returned to the blood of the peritubular capillaries
What happens during secretion?
Secretion moves additional undesirable molecules into the tubule from the blood of peritubular capillaries
What is the structural and functional unit of the kidney?
The nephron
What are the two parts of the nephron?
The renal corpuscle
The renal tubule
What happens in the renal tubule?
This is where tubular reabsorption and secretion occurs
Each nephron drains into where?
A collecting tubule/duct
The nephron plus its collecting tubule is called what?
The uriniferous tubule
T/F- medullary rays are named for their destination instead of their location.
True
What are the two components of the renal corpuscle?
The glomerulus (capillaries) Bowmans capsule (a double walled cup enclosing the glomerulus)
T/F bowman’s capsule has two layers- the visceral or external layer and the parietal or internal layer?
False- it does have two layers, but the visceral layer is the internal layer and the parietal layer is the external layer
What is the vascular pole of a renal corpuscle?
It is where afferent and efferent arterioles enter and exit
What is the urinary/tubular pole of a renal corpuscle?
It is where filtrate exits bowman’s space and enters the proximal convoluted tube
What are the simple squamous epithelial cells that come in contact with glomerular capillaries?
Podocytes
What are pedicels?
They are extensions of podocytes
What is the space between two pedicels?
A filtration slit
What is the semipermeable membrane that covers the filtration slit?
Slit diaphragm
Can RBCs pass through the slit diaphragm? Why/ why not?
Nope, they’re too big
The parietal layer of bowman’s capsule is made up of what kind of cells?
Simple squamous epithelium
The renal tubule consists of what three things?
- Proximal convoluted tubule
- Loop of Helne
- Distal convoluted tube
(ultimately goes from the DCT to a collecting duct and then to the bladder)
Which part of the renal tubule extends into the renal medulla?
The Loop of Henle
The thin descending limb is highly permeable to what?
Water
The thin ascending limb is highly permeable to what?
Sodium
Chloride
The proximal convoluted tubule is confined to what?
The renal cortex
The PCT has a brush border made of what?
Long microvilli
The thick descending limb of the loop of Henle is made of what kind of cells?
Simple cuboidal epithelial
T thin descending limb of the loop of Henle is made of what kind of cells?
Simple squamous epithelial
The thin ascending limb of the loop of Henle is made of what kind of cells?
Simple squamous epithelial
The thick ascending limb of the loop of Henle is made of what kind of cells?
Simple cuboidal epithelial
Does the DCT have a brush border?
Nope
What is the juxtaglomerular apparatus?
It is the structure where the afferent arteriole makes contact with the ascending limb of the loop of Henle
What is the juxtaglomerular apparatus composed of?
Macula densa and juxtaglomerular cells
The collecting ducts do what?
Collect urine from the DCT
The collecting ducts are lined with what?
Simple cuboidal epithelium
How are collecting duct cells differentiated from loop of Henle cells?
They are very crisp-very distinct borders- very differentiated from one another- larger lumen than everything else
What is the path of urine through the kidneys to the urethra?
Collecting tubules–collecting ducts–papillary ducts (ducts of Bellin)–minor calyx–major calyx–renal pelvis –ureter–urinary bladder–urethra
What are some more characteristics of collecting duct histology?
Clear cytoplasm and defined/distinct cell membranes
What are the four layers of the walls of the calyces, renal pelvis, ureter and urinary bladder?
Mucosa (has transitional epithelium)
Submucosa
Muscularis (has smooth muscle)
Adventitia
How is urine moved through the ureter?
Peristalsis of the smooth muscle
How long is a ureter?
10-12 inches
What is the capacity of the urinary bladder?
about 250 ml
What type of cells make up the prostatic urethra?
urothelium
What type of cells make up the membranous urethra?
stratified columnar epithelium & pseudostratified columnar
epithelium
What type of cells make up the spongy urethra?
stratified columnar & pseudostratified columnar
In females, what type of cells make up the prostatic urethra?
initially urothelium and then stratified squamous epithelium
