Urinary System Flashcards
What does the urinary system consist of? (4)
Major organs etc
- 2 Kidneys: urine formation
- 2 Ureters: conduit to bladder
- Bladder: for storage of urine
- Urethra: elimination of urine from the body
What are the 5 major functions of the kidney?
- Excretion of metabolic wastes(urea, creatine, bilirubin, drugs, etc)
- Regulation of water, BV, electrolyte balance
- BP regulation: renin-angiotensin-aldosterone system
- Regulation of acid-base balance
- Production of hormones:Erthyropoietin/Vit D (Ca2+ absorption in small intestine
Where are the kidneys located? Shape?
- Paired bean shaped organs located-retro-peritoneally on the posterior abdominal wall
- Paravertebral gutters-either side of the aorta and inferior vena cava
- Left kidney T12-L3
- Right kidney lower d/t liver being large
What is the relations of the R Kidney?
Superiorly, Anteriorly, Posteriorly
- *Superior: *suprarenal glands
- Anteriorly: Liver, duodenum, ascending colon, hepatic flexure, jejunum
- Posteriorly: 12th rib, diaphragm, psoas major, quadratus lumborum, transversus abdominus muscle, iliohypogastric and ilioinguinal nerves
L also is located near rib 11
What are the relations to the L Kidney anteriorly?
Superior/Posterior same for both kidneys
- Spleen
- Splenic flexure
- Stomach
- Pancreas
- Descending colon
- Jejunum
What are the 3 layers and functions of the coverings of the kidneys?
-
Renal Capsule
* Directly covers the renal cortex
* Protects kidney from trauma and damage-penetrates kidney parenchyma to form trabeculae that lobulate the kidney - Perirenal fat
-
Renal fascia (Gerota’s fascia)
* Encapsulates kidneys/suprarenal glands
* Anchors kidney into surrounding structures
* Divides the fat around kidney into perirenal fat/pararenal fat
Acts like a ligament
Parenchyma of the Kidney: 2 layers-distinct features
-
Renal Cortex
* Lies immediately beneath renal capsule
* Extends inwards as the renal column between renal pyramids of the medulla and contains nephrons -
Renal Medulla
* Darker in colour with a striated appearance
* Composed of 8-15 renal pyramids
* Apex of pyramids directed into the sinus of the renal papilla
* Structure of the papilla is perfored by the ducts of Bellini
What is the nephron?
Functional unit of the kidney
What are the two main structures in the nephron?
What are their subdivisions
-
Renal Corpuscle: filters blood
* Glomerulus: capillary network
* Glomerular capsule-double-walled cup surrounded glomerulus -
Renal Tubule: filtered fluid passes into
* Proximal convoluted tubule
* Loop of Henle:divided into thin/thick for ascending/descending
* Distal convoluted tubule
What are the 3 basic functions of the nephron?
- Glomerular Filtration: water and solutes in are filtered and moved into the glomerular capsule
- Tubular Reapsorption:filtered fluid then moves through renal tubules and reabsorbed (99%)
- Tubular Secretion: secretion of other materials such as wastes, drugs, and excess
What are the two layers of the glomerular capsule and what are the cells associated with them?
- Visceral layer:modified simple squamous epithelial cells (podocytes “toe like projections”)-forms the inner wall of the capsule
- Parietal layer: simple squamous epithelium-forms the outer wall of the capsule
Glomerular Filtration: 3 barriers to cross
- Glomerular endothelial cells: fenestrations
- Basal lamina: between endothelium and podocytes (fused together)
-
Pedicels of podocytes create filtration slits
* Permits filtration of water/small solutes
* Prevents filtration of most plasma proteins/blood cells/platelets
How is the volume of fluid filtered so large? (3)
- Large surface area
- Thin and porous membrane
- High glomerular capillary BP
What are the 2 types of nephrons?
- Cortical
-
Juxtamedullary
* flow of fluid is the same except juxtamedullary has thin/thick ascending limb of the loop of henle
Minor Calyx features (5)
- Associated with a single renal pyramid
- Cup-shaped and surrounds a renal papilla
- Receives from renal papilla for passage into ureter
- Delivers urine to the major calyx
- Each kidney has 8-18 of them
Renal Pelvis features (3)
- Expanded upper end of ureters
- Lies within the renal sinus
- Connects 3-4 major calyces together to the ureter
Circulation of blood in the Kidney
- Abdominal Aorta
- Segmental arteries
- Interlobar arteries
- Arcuate arteries
- Cortical radiate arteries (interlobular)
- Afferent arterioles
- Glomerular capillaries
- Efferent arterioles
- Peritubular capillaries “vasa recta”
- Cortical radiate veins
- Arcuate veins
- Interlobar veins
- Renal veins
- Inferior Vena Cava
Bolded is where exchange happens
What renal vein is longer? Why?
Left-IVC is on the right side of the body-has to cross anteriorly to the abdominal aorta
* receives the left suprarenal vein and left gonadal veins
What is the difference between Renal Hilum and Renal Sinus?
Renal Hilum: concavity located on medial border-where structures enter and leave. Contains renal vein, artery and pelvis of the ureter
Renal Sinus: cavity within kidney occupied by renal pelvis, calyces, blood vessels and fat
Polycycstic Kidney Disease features and 2 types
- Inherited kidney disorder
- Tubules have >100 cysts which results in failure
1. Autosomal dominant: renal failure late in life
2. Autosomall recessive: renal failure in early life
TX: kidney transplant
Renal Transplant things to know (2)
- Placed in the pelvis of the recipient-renal artery and vein are attached to a nearby artery and vein
- Transplant ureter attached to the bladder
- Diseased kidneys are left in place
Ureter features
- Musucular tube from renal pelvis to posterior surface of bladder
- Approx 10 inches long
- Retroperitoneal descends on the anterior surface of the psoas major muscle
- Passes anterior to the bifurcation of the common iliac artery before descending into pelvis
What are the 3 constriction points of the ureters?
- Ureteropelvic Junction
- Where is crosses the pelvic brim
- Pierces bladder wall
Histology of the Ureter
3 layers
- Mucuosa: transitional epithelium-stratified epithelium which can stretch, lamina propria
- Muscularis 3 layers: Inner longitudinal, middle circular, outer longitudinal
- Adventitia
First 2/3 of muscularis is: Inner longitudinal, outer circular
What ligament attaches to the bladder?
Median Umbilical ligament (Urachus)
Histology of the bladder
3 layers
-
Mucuosa: transitional epithelium-stratified epithelium which can stretch
* dense lamina propria - Muscularis 3 layers: Inner longitudinal, middle circular, outer longitudinal
- Adventitia: adipose tissue