L31. Urinary system Flashcards
What is the space of Disse
It is the sub-sinusoidal domain (basal) that has an endocrine function
What are Kupffer cells?
are macrophages that patrol sinusoids and space of disse
What is fibrosis?
Increased in connective tissue or eosphonic collagen fiber
-there is a decreased in blood flow in the sinosuids – leads to blockage and causes hypertension
What 2 veins get blocked up when there is fibrosis
eophogeal vein and superior hemorrhoidal veins
Describe the gall bladder
simple columnar epithelium - highly absorptive
Lamina propria- highly vascular, loose connective tissue
mucosa- highly folded without clearly organized vili or crypts
Prominent Muscularis: overlapping smooth muscle fibers, contractions cause persitalsis initiated by CCK
Adventitia: dense connective tissue
How does bile enter the gall bladder
The sphincter of Oddi must be closed in order for bile to be backed up into the gall bladder
Describe the sphincter of Oddi and how it is controlled
- it is embedded in pancreatic tissue
- smooth muscle is present and CCK mediates it’s RELAXATION
Describe the functions of the urinary system
- produce and excrete urine
- regulate blood pressure and plasma volume
- excrete toxic products via a duct system
State the basic layers of a kidney
Capsule: dense connective tissue
Cortex
Medulla
What is the hilum
It is the region where the renal artery enters and renal vein exits the kidney
What is the function of the kidney
- produces filtrate ( plasma without the proteins)
- modifies the glomerular filtrate to make urine
- making and modifiying of the glomerular filtrate happens in the uriniferous tubules of the kidney
What is the renal corpuscle?
It is the filtrate forming protion of the nephron
What are the tubules of the nephron?
They are the filtrate modifying parts of the nephron
Trace the path of the nephron
renal corpuscle -> priximal tubule -> loop of Henle -> distal tubule
What is the function of the renal corpuscle?
- produces glomerular filtrate in the blood releases it into the Bowman’s space
- Has a parietal and visceral layer.
- glomerular capillaries are covered in podocytes: visceral cell layers
What is the vascular pole?
It is when the afferent and efferent arterioles enter and exit the corpuscle
What does the glomerular filtration barrier consists of
- Fenestrated capillary endothelium
- Basement membrane
- Slit Diaphragms between the pedicels of podocytes
What prevents movement of plasma proteins from the capillary to urinary space
glycoproteins and proteoglycans in basement membrane and slit diaphragms prevent the movement of plasma proteins from capillary to urinary space
What is the function of the proximal tubule?
resorbs most of the NaCl and H2O through pumps and channels
Most of teh glucose is resorbed vai vesciular transport
What is present in urine
ions, glucose, urea, water
Describe the proximal tubule ( cellular machinary)
- simple cubodial epithelium
- has microvili for resorption
- actively resorbs through pumps and channels
- has a lot of mitochondria
- resorbs release water, glucose, ions and amino acids back to the peritubular CT (ti capillaries)
- resorbs water salt and glucose
Describe the function of the loop of Henle
has descending and ascending limb
descending limb has a simple squamous epithelium with aquaporins that allow water to flow out
ascending limb is simple squamous and has many tight junctions.becomes increasingly H2O impermeable as more salt diffuses out of the tubule, as it ascends it becomes a cubodial epithelium
What causes the medulla to be salty
It is due to the diffusion of salt out of the ascending limb of the loop of Henle, as that portion is impermeable to water and only salt passes through
Describe the function of the distal tubule
modifies urine through the macula densa which is part of the juxtaglomerular apparatus
produces dilute high volume urine
Describe the structure of the distal tubule
-simple cubodial epithelium
- water impermeable
continues to pump NaCl out of the filtrate
produces dilute high volume urine
What is the macula densa?
It is the thickening of the distal tubile at the vesicular pole of the renal corpuscle
- columnar epithelial
- when there is a high urine volume stimulates the juxtaglomerular apparatus through gap junctions
What is the function of the juxtaglomerular cells?
- modified pericytes of glomerular arterioles
- secrete renin into the bloodstream
