Urinary Flashcards
Renal system
- Homeostasis
- Endocrine
Mammals/birds/marine fish
Concentration of nitrogenous waste = water conservation for osmosis
- salt water fist are hypotonic compared to their environment, so they are losing water
- fresh water fish are hypertonic to environment
How does the urinary system contribute to homeostasis?
- water
- acid/base
- ions: Na, K, Po4, Cl, etc
Urinary + endocrine system
- erythropoietin
- renin (NOT rennin)
- vitamin D
Organs of the urinary system
- kidneys (usually paired)
- ureters
- bladder
- urethra
- cloaca (for some)
Components of the kidney
- capsule
- parenchyma
- ureter
Retroperioneal
Capsule on the outside is not apart of the peritoneum
- restricts its ability to swell
Hilus
Space where everything enters/exits the kidney
- artery in
- vein/ureter out
Parenchyma
- Cortex: outer layer
- Medulla: inner layer
- Pelvis: collecting space for fluids/urine to then enter the ureter –> immediately continuous with the ureter, NOT the urethra!
Corticomedullary junction
Place where the cortex meets the medulla
Nephron
Structural and functional unit Renal corpuscle and tubular system - glomerulus - proximal convoluted tubule - loop of henle - distal convoluted tubule
Loop of Henle
Extends into the medulla, and reenters the cortex as the distal convoluted tubule
Is the collecting duct part of the nephron?
No, because one collecting duct serves multiple nephrons
- will not be able to see with a light microscope
Lobes of the kidney and pyramid
Most embryologic
- some retained in maturity
- cattle have multiple lobes
Medullary rays
Comparable to lobules
- way to separate parenchyma anatomically
Lobule
Collecting duct + nephrons
Renal Cortex structures
- renal corpuscles (glomeruli)
- proximal convoluted tubules
- distal convoluted tubules
- collecting tubules
- interstitium
- vessels
Where are glomuerli found?
Only can be found in the cortex
Salt concentration is ______ in the medulla
Higher, so water in the tubule gets sucked into the medulla to be saved
Glomerulus
- Capillary tuft
- Basement membrane
- Podocytes
- Bowman’s capsule
- Mesangium
Where does blood filtration occur?
Renal corpuscle (glomerulus)
What is the only place in the body where an arteriole breaks into a capillary and reforms as an arteriole?
Renal corpuscle
What is the barrier between the blood and urinary space?
Glomerulus basement membrane
What are the main filtrating cells?
Podocytes
- interdigitate around capillary walls
Bowman’s capsule
Portion of renal system that surrounds capillary tuft
Mesangium
Highly eosinophilic in the capillary tuft
- holds the blood vessels of the capillary
Juxtaglomerular Apparatus
- portion of the distal convoluted tubule
- macula densa
- juxtaglomerular cells
- extraglomerular mesangial cells
Macula densa
Monitors sodium concentration in the fluid in the tubule
* fluid is not urine until it drops into the renal pelvis and is taken into the bladder
Modified smooth muscle
Muscle knows to contract or relax based on sodium concentration
Where is modified smooth muscle found?
Juxtaglomerular cells
Proximal convoluted tubule
- cuboidal, “brush border” lined by microvili
- tight junctions: want a water tight barrier
- very active (mitochondria), basal striations - responsible for modifying fluid in the tubules
- modify ultrafiltrate (proteins, glucose)
- make up a large portion of the cortex
Loop of Henle
- long limb/short limb
- thin/thick segment
- type 1-4
- squamous to cuboidal
- highly permeable
- microvili, organelles
Medullary washout
If an animal drinks too much water, then the sodium concentration is washed out of the kidney and you lose water retention
Long limb
Animals that are in water deprived environments
- kangaroo rats, cats
Short limb
Beavers, animals in water excess environments
Distal convoluted tubule
- Na (save) and K (clear)
- HCO3 (save) and NH4 (clear)
What is in the cortex?
Glomeruli, proximal tubules, distal tubules, and some segments of collecting tubules
Collecting tubules
- light cells/dark cells
- single cilia, variable microvilli
- some cells have a single cilia, others have microvili
Medulla
- Henle/collecting tubules –> high solute concentration in the interstitium
- Vasa Recta –> specialized capillaries that save extracted water
When is fluid considered to be urine?
Only when fluid enters the renal pelvis is it considered urine
- as long as you change the chemical concentration, it is not considered urine
Renal pelvis
Can observe greatly
- renal pelvis outward is covered in transitional epithelium
Blood supply and lymphatics
- renal artery and vein (25% Cardiac Output)
- arcuate vessels
What follows heart failure
Renal failure
Ureters/bladder/urethra
Transitional epithelium
- anatomic and gender differences
Arcuate vessels
Renal artery branches into these vessels –> serve wedge shaped portion of renal cortex
- reason for renal infarcs at the corticomedullary junction
Female cattle
Urethra enters into the ventral floor of the vagina (short)
Male cattle
Longer urethra
- sigmoid flexure: allows for difficulty when passing a catheter
- less prone to UTIs due to longer distance
