Lecture 17 - Urinary System Flashcards
What are some of the complications of kidney failure? (7)
- Anemia
- Fluid Retention
- Hypertension
- Hyperkalemia
- Hypocalcemia
- Azotemia (high blood nitrogen and creatinine)
- Proteinuria
What is the functional unit of the kidney?
Nephron
What is the glomerulus?
Tuft of capillaries
What type of cells make up the parietal layer of the renal corpuscle?
Simple Squamous Epithelium
Where does glomerular filtrate enter?
Capsular Space
What happens in the glomerulus?
Filtration
To go from the plasma of the glomerulus to bowman’s space, which structure does water and solutes cross?
- Endothelial layer of the glomerular capillaries (btwn the cells or through the cells)
- Glomeruluar basement membrane
- Visceral layer of bowman’s capsule (between the cells)
What makes up the glomerular basement membrane?
Lamina Lucida - Densa - Lucida
How does filtration membrane prevent proteins and cells from being filtered?
Size Selective and Charge Selective Barrier
size selective has predominant role
How will a mutation in type IV collagen effect filtrate in bowmans capsule?
Filtrate will have a higher percentage of protein
What are mesangial cells?
- They are contractile and phagocytic cells
- Remove trapped residues from the glomerular basement membrane and filtration slit diaphragm
- Structural support for glomerular capillaries or podocytes
- Help regulate blood flow in the glomerular ccapillaries
Where does blood go when it leaves the glomerulus?
Out the efferent
What is the name of the capillaries that surround the loops of henle in the medulla?
Vasa Recta
Proximal Convoluted Tubule functions
- All glucose and amino acids are resorbed
- 2/3rds salt and water resorbed
- Organic acids and bases are secreted into the tubule (peritubular capillary)
Distal Convoluted tubule
- About 5% salt is reabsorbed
2. Parathyroid hormone increases Ca2+ reabsorption
How can you differentiate the PCT and the DCT?
PCT has larger cells, many microvilli, more eosinophilic
DCT has smaller cells, sparse microvilli, less eosinophilic
What are the three limbs of the Loop of Henle?
- thin descending
- thin ascending
- thick ascending
What are the difference betwen the thin and thick limbs of the loop of henle?
- location in the nephron
- what they reabsorb
What does the thin descending limb reabsorb?
- Water which diffuses through aquaporin channels
What does the thin ascending limb reabsorb?
- Passive diffusion of Na and Cl
- Impermeable to water
What does the thick ascending limb reabsorb?
- Active transport of Na, Cl, K (20-25%)
- Impermeable to water
What kind of cells are found in the thin limbs of the loop of henle?
simple squamous
What kind of cells are found in the thick limb of the loop of henle?
simple cuboidal
How can you tell the difference between the thick ascending limb and the collecting duct?
The cells of the collecting duck are more columnar and stain lighter.
What is the function of the collecting duct?
- Aldosterone and Antidiuretic Hormone highly regulate Na (in), K (out), and Water
- reabsorb little salt but controls everything
Why is the loop of Henle structured the way it is and why is it located in the medulla with the collecting duct?
Enables you to produce concentrated or dilute urine depending on ADH
What occurs with a lot of ADH?
- Reabsorb water
- concentrate urine
What occurs with no ADH?
- no water reabsorption
- dilute urine
What do juxtaglomerular cells do?
secrete renin, alter blood pressure
What kind of muscle is in the afferetn arteriole?
Smooth Muscle
What are the extraglomerular mesangial cells called?
Lacis cells
What does the macula densa do?
senses the amount of NaCl in the distal tubule
What is the process of urine production?
- Glomerular filtrate
- starts in capsular space
- modified in the tubule
- ends in the collecting duct
- urine
What type of epithelium is the urothelium?
Transitional
What is the purpose of the muscularis layer of the ureter?
When it contracts it transports urine to the bladder
How many layers of smooth muscle are in the muscularis layer?
3
What will cause urination?
- contraction of the detrusor
- relaxation of the trigone
What are uroplakins?
rigid appearing membrane plaques on the luminal surface of the bladder epithelium
What is the advantage of the urothelial plaques?
designed to provide protection from toxic and hypotonic urine
What tissue types make up the urethra?
- urothelium
- stratified and pseudostratified columnar
- stratified squamous
