Lecture 1 Flashcards
Organs of the Urinary System
Our urinary system is made up of the
- Kidneys
- Ureter
- Urinary bladder
- Urethra
What is the role of the kidneys?
- filter our blood
- convert the filtrate to urine
- regulate our BP
Urinary tract is made up of our… which do what?
ureter, bladder and urethra because they store and transport the urine that kidneys made, out of the body.
The kidneys are located ________, at the ___-____level.
Above both of the kidneys is the _______________.
The ___ sits lower than the ___.
The kidneys are located retroperitoneal, at the T12- L3 level.
Above both of the kidneys is the suprarenal (adrenal) gland.
The R sits lower than the L.
What is the renal hilum?
entrance to the renal sinus (the area of the kidney where the BV, nerves and renal pelvis are located).
L Kidney
Transpyloric plane runs through the _____.
Posteriorly, the________ protect the superior aspect of the kidney
L Kidney
Transpyloric plane runs through the hilum.
Posteriorly, the 11th and 12 rib protect the superior aspect of the kidney
R Kidney
Transpyloric plane runs through the what?
Posteriorly, the ________ rib protect the superior aspects of the kidney.
Where is the inferior part of the R kidney located?
R Kidney
Transpyloric plane runs through the superior pole of the R kidney
Posteriorly, the 11th and 12th rib protect the superior aspects of the kidney.
The inferior part of the R kidney is located 1 index finger away from the iliac crest.
The kidney is surrounded by fat. There are 3 layers:
1. Perinephric fat
2. Renal fascia
3. Paranephric fat
Describe the perinephric fat of the kidney
fat that is located next to the capsule of the kidney
and goes into the renal hilum and renal pelvis
Describe the renal fascia of the kidney
Renal fascia covers the [perinephric fat and the suprarenal gland.]
- blends & sheaths renal vessels
- continous with the diaphragmatic fascia.
Describe the paranephric fat of the kidney
Paranephric fat is located above the renal fascia
What is the renal capsule?
Dense irregular CT located on the surface of kidney with an inner layer of myofibroblasts
What is the renal CTX?
Outer portion of the kidney that contains the renal corpuscles
What is the renal medulla?
Medulla= renal pyramids + renal columns
Renal pyramids- cone-shaped masses located in the medulla that project into the calyx
Renal columns- the tissue between the pyramids that go from the cortex –> calyx
What are the renal lobes?
1 pyramid + the surrounding adjacent CTX
What is the renal pelvis?
What are the projections called?
The renal pelvis is where urine is collected. The renal pelvis has projections called renal calyxes (major and minor).
What are the renal and ureter arteries?
Renal arteries branches into segmental arteries
Ureter arteries include:
- renal branches
- gonadal branches
- abdominal aorta branches
- iliac branches
- superior vesicular branches
- pelvic branches (such as rectal, uterine, vaginal and inferior vesicular)
What is the renal- blood supply pathway?
Aorta> renal artery enters the hilum and branches into> segmental artery, goes to a certain segment branches into > interlobar arteries > arcuate artery, which goes overtop the renal pyramid > cortical radiate artery > afferent arteriole> [glomerular capillaries] > efferent arteriole > peritubular capillaries and vasa recta > cortical radiate vein > arcuate vein > interlobar vein > renal vein > IVC.
The kidney receives autonomic NS innervation.
Where does it get its sympathetic and parasympathetic innervation from?
Sympathetic innervation:
- Lesser splanchnic N (T10-T11)
- Least splanchnic N (T12)
- Both synapse on the aorticorenal ganglia
3. Lumbar splanchnic N (L1-L2)
Parasympathetic innveration
- Vagus N.
Urine carrying unit is made up of what?
- Nephron (urine forming unit)- made up of renal corpuscles (bowman’s capsule + glomerulus) and renal tubules
- Cortical and medullary collecting ducts, where the final concentration of urine occurs.
What are the 2 general categories of the nephrons?
- Cortical nephron- most of the nephron is located in the cortex and only a small portion lies in the medulla (loop of henle)
- Juxtamedullary nephron- the loops of henle descend deep into the renal medulla
What are the parts of the nephron? (9, in order)
- Bowman’s capsule
- Proximal convulted tubule
- Proximal straight tubule, which enters the medulla
- Thin loop of henle (descending and ascending loop of henle)
- Thick ascending loop of henle- located in the outer medulla but enters the cortex
- Distal convuluted tubule
- Macula densa is in close proximity to the renal corpyscle
- Collecting tubule
- Collecting duct (located in the cortex and medulla)
- Papillary duct, which collects urine and takes it into the calyx, then ureter.
What part of the nephron does the CTX of the kidney contain?
- Renal corpuscles (bowman’s capsule and glomerulus)
- Proximal and distal convoluted tubule
- Proximal straight tubule of the nephron (NTRS medulla)
- Parts of the collecting ducts.
What does the medulla of the kidney contain?
- renal columns
- renal pyramids
Cortical (medullary) rays are what?
[Collecting ducts & straight tubules]
that run in between the
[renal corpuscles & convoluted tubules]
within the CTX.
The kidneys make EPO based on the amount of O2 in our blood.
What part of the kidney is responsible for this?
Fibroblasts in the renal interstitium
Renal corpuscle= [_________] + [________].
It is located in the cortex of the kidney.
Renal corpuscle= [Bowmans capsule] + [glomerulus].
Describe what the glomerulus is and the layers of the Bowman’s capsule.
The glomerulus is fenestrated capillaries that branch from the afferent and efferent arterioles.
Bowmans capsule (glomerular capsule) is made up of three layers:
- Parietal layer is made up of simple squamous epithelium
- Visceral layer is made up of podocytes that surround the capillaries and create fenestrated slits
- Glomerular space- contains filtrate
Renal corpuscle has two poles: what are they?
Renal corpuscle has two poles: a vascular pole, made up of our afferent and efferent arteriole and the urinary pole, where the PCT starts.
Filtration barrier lies in between the blood and the capsular space of BC.
What are the 3 layers?
- Glomerular capillary endothelium is made up of a thick luminal glycocalyx
- Capillaries have truly open fenestrations, but a few have pores with diaphragms.
- Endothelium also has aquaporins
- Endothelium can also generate NO and PGE2, which regulates filtration.
- Basement membrane that acts a physical & chemical barrier that restricts the movement of things >70kD
- Made up of type 4 and 13 collagen, laminin, entactin, proteoglycans
- Restricts the movement of strong anti-anionic characteristics
- Restricts the movement of albumin
-
Visceral layer of Bowman’s capsule contains podocytes, specialized cells that surround the capillaries and form filtration slits between its feet.
* The slits have diaphragm that regulate the size, patency and selectivity of filtration.
SO, in order for fluid to make its way out of the capillary for filtration, it has to go through…
Fenestration of the capillary > basement membrane > between the slits of the podocytes > Bowman space.
Filtration barrier restricts ….;
but allows….
Filtration barrier restricts the passage of BCs, immunoglobins and large proteins;
but allows the passage of water, ions, glucose, AA and urea.
Where are mesangial cells located and what are their functions?
Located: visceral layer of the BC (podocytes) and have direct contact with the glomerular endothelial cells.
Functions:
- Provide support to the glomerular loops and ECM of the podocytes
- Phagocytize
- Control filtration rate
- Prevent glomerular distension d/t high glomerular BP
- Secrete growth factors and cytokines d/t injury
- Proliferate in certain kidney diseases
Proximal Convoluted Tubule
-most abundant tubule-
Located:
Roles:
Cell type:
Located: Renal cortex
Roles: Resorption and secretion (so alot of mT)
Cell type: [simple cuboidal –> simple columnar with microvilli], creating a apical brush border. Cells contain a bunch of mT.
Describe the basal and lateral cell membrane of the proximal convoluted tubule.
Basal and lateral cell membrane are highly folded, increasing the SA.
Located on these cell membranes are
- Na+/K+-ATPase pumps
- Aquaporins
- Glucose transporters (sGLT2)
- AA transporters
How does the proximal straight tubule differ from the proximal convoluted tubule?
1. Not as tall as the PCT
2. Has a less-developed brush border.
3. Contains sGLT1 (glucose co-transporters)
Loop of Henle
Located:
Roles:
Cell type: (differs for thick and thin LoH)
Located: Loops into the medulla and then back up to the CTX, ending near the vascular pole.
Roles: creates a hyperosmotic gradient that allows the reabsorption of water
Cell type:
- [Thin limb of the LoH]- thin permeable simple squamous epithelium that does not have brush border. Nuclei bulge into the lumen
- [Thick limb of the LoH]- simple cuboidal epithelium with many microvillus, but not a visible brush border.
Distal Convoluted Tubule
Located:
Roles:
Cell type:
Located: CTX. Begins a variable distance from the macula densa of the thick ascending LoH.
Roles: Reabsorbs Na+ via angiotensin II
Cell type: Simple cubiodal epithelium with sparse microvillus, creating a smoother lumen than the thick ascending LoH. However, the cells are taller.
Collecting Ducts
Located:
Roles:
Cell type:
Located: CTX–> deep into the medulla. Receive urine from several nephrons and then combine with several other CD to form papillary ducts, which then drain into the renal minor calyx.
Roles: Reabsorb water.
Cell type: simple cuboidal epithelium, but simple columnar are at the ends.
________________ determine the final urine osmolality via ___ and ____, increasing Na+ and water reasorption.
Collecting tubules and ducts determine the final urine osmolality via ADH and aldosterone, increasing Na+ and water reasorption.
Collecting tubules and ducts are made up of two types of cells:
what are they?
1. Light cells (principal cells)
2. Dark cells (intercalled cells)
Collecting tubules and ducts are made up of light cells and dark cells.
What do they do?
- Aldosterone acts on light cells, causing the reabsoprtion of Na+ and thus, water.
- Dark cells transports H+ and HCO3-.
What are the 3 types of capillary beds?
- Glomerular capillaries- fed by afferent arterioles at high pressure and drain into efferent arterioles.
-
Peritubular capillaries- fenestrated capillaries that branch from efferent arterioles and surround the convoluted tubules.
* Reabsorb H20 and Na+. -
Vasa recta- thin walled capillaries that also arise from efferent arterioles and run alongside the LoH.
* Help concentrate urine.
Describe the differences in the endothelium of the descending and ascending vasa recta.
- Descending vasa recta* has a continouous endothelium.
- Ascending vasa recta* has a fenestrated endothelium.
The juxtaglomerular apparatus is located at the end of the thick ascending LoH.
What does it consist of?
Juxtaglomerular apparatus= [macula densa + juxtaglomerular cells]
- Macula densa- distal end that acts as a chemoreceptor by monitoring salt levels. When [plasma Na+] is low–> signals the release of renin from juxtaglomerular cells, increasing Na+ retention, BV and BP
- Juxtaglomerular cells- mechanosensors that secrete renin when the BP is low.
Urinary Tract Organs (3; in order)
- Ureter
- Urinary bladder
- Urethra
____________________ are lined by transitional epithelium (urothelium), which has 3 layers:
Urinary tract organs + renal pelvis and calyxes are lined by transitional epithelium (urothelium), which has 3 layers:
- Superficial layer
- Intermediate layer
- Basal layer
Transitional epithelium (urothelium), has 3 layers.
What are they?
- Superficial layer- can stretch and relax
- Intermediate layer- layer that allows the superficial layer to slide
- Basal layer- consists of stem cells
_________ fuse with the plasma membrane when the cell distended. When not distended, it is endocytosed.
Fusiform vesicles fuse with the plasma membrane when the cell distended. When not distended, it is endocytosed.
Transitional epithelium is impermeable.
What causes this?
Uroplakin proteins forms urothelial plaques
What is a ureter?
The ureter carries urine from the [renal pelvis of the kidney–> bladder], entering obliquely to prevent urine from backflowing.
Ureter has three INDISTINCT MUSCLE layers and an adventitia.
What are the layers?
- Inner longitudinal layer
- Outer circular layer
- Outer longitudinal layer
——adventitia—–
What is the bladder and where is it located?
The bladder is a expandable and collapsible muscular sac that stores urine and is located
[posterior to the pubis]
&
[anterior to the uterus and rectum].
Upon expansion, the bladder enters the___________.
While empty, lies _____________.
Upon expansion, it enters the abdominal cavity.
While empty, lies entirely within the pelvis.
The _____ is the interior and posterior wall of the bladder
where the ureter and urethra open.
Trigone
Describe the wall of the bladder
1. Lined with transitional epithelium
2. Has 3 layers of thick SM called the detrusor m.
3. Fibrous adventitia.
What is the urethra?
The urethra connects the [bladder –> exterior].
It differs in M and W.
The epithelium of the urethra changes with location. Describe this.
- [Origin of urethra]- TE
- [Majority of urethra]- pseudostratified columnar epithelium
- [Distal end]- stratified squamous epithelium
THUS: [TE > pseudostratified columanar > stratified squamous epithelium].
Female urethra
the female urethra is small (only 3-5 cm long). The opening of the urethra is the (external urethral orifice)
- membranous urethra passes through the urogenital diaphram-
- internal urethral sphincter- involuntary SM that is part of the bladder wall
- external urethral sphincter- voluntary SKELETAL M. that stops us from urinating.
urination is restricted until the pressure in the bladder is high enough. Release requires voluntary activity of the skeletal muscle of the external urethral sphincter
Male urethra
20 cm long
Fx: transport urine and semen
3 regions:
- Prostatic urethra- goes through prostate gland
- membranous urethra- same as womens
- Spongy penile urethra- goes through penis; longest part surrounded by erectile tissue (corpus spongiosum) –> uxternal urethral orifice
Polycystic kidney dz
Gentics: _____
What happens:
autosomal odminant
cysts crush tissue and stop drainage;
Asx first and see signs at 30-40
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