1. Urinary System
Cleaning up the system

2. Parts Kidney - filters the blood
Ureter – transports the waste material to the bladder
Urinary Bladder – stores the waste products
Urethra – releases waste products out of the body

4. Kidney Located next to the vertebral column.
Top about even with the 12th thoracic vertebra and the bottom about even with the 3rd lumbar vertebra
Reddish brown, bean shaped
Adults about 13 cm long, 6 cm wide, and 3cm thick
Located in a fibrous capsule

5. Function
Maintain homeostasis by regulating the blood pH, volume, and composition
Removes metabolic wastes from blood
Are diluted with water and electrolytes to make urine
Secretes erythropoietin – controls rate of red blood cell production
Helps activate vitamin D
Secretes renin, an enzyme that maintains blood volume and pressure

6. Structures
Renal sinus – hollow chamber where blood vessels, nerves, lymphatic vessels and the ureter enter and leave
Renal pelvis – superior end of the ureter expanded into a sac inside the renal sinus
Renal medulla – inner region of the kidney composed of the renal pyramids
Renal cortex – outer shell around medulla that dips into the medulla to create the renal columns
Nephrons – the functional unit of the kidney about 1 million/kidney

9. To clean blood, you need blood
Renal Artery
Branches from the abdominal Aorta
15-30% of total cardiac out put is sent to the kidneys when you are at rest
The renal artery branches into smaller and smaller vessels until it becomes the afferent arterioles that lead to the nephrons
Renal Vein
“Clean” blood travels through ever larger vessels to the renal vein
Empties into the Inferior Vena Cava that leads to the heart

11. Okay, we got blood, now it is the nephron's turn
Blood vessels become tangled into a glomerulus which is located in a glomerular capsule (AKA Bowman's capsule)
Fluid in the blood is filtered into the capsule ( the proximal end of the renal tubule)
Renal tubule becomes highly coiled then dips down into the Loop of Henle
This is interlaced with capillaries
Fluid is returned to the blood and electrolyte balances are fine tuned here
The renal tubule climbs back up and empties into the collecting duct – we now have urine

14. We got urine... now what?
The collecting ducts merge together and empty into a minor renal calyx which in return empties into a major calyx, which them empties into the renal pelvis, which empties into the ureter
The ureter is a tube that leads to the urinary bladder
Uses peristaltic waves to move the urine down its length

16. We made it to the bladder
A hollow, distensible, muscular organ
Stores urine and then forces out the urethra
In the pelvic cavity, behind the symphysis pubis and under the parietal peritoneum
A sphincter at the neck of the bladder hold urine in until the pressure inside is to a certain level Involuntary control
External urethral sphincter – skeletal muscles – voluntary control

19. Micturition AKA urination
How do we know to go? By the amount there
150 ml typically = urge to go
300 ml sensation of fullness, bladder contraction intensify
600 ml typically = pain
Bladder signals spinal cord, which releases involuntary sphincter, you feel like you must go
External urethral sphincter is released when you go to the restroom

20. Kidney Dialysis
As shown in the diagram above, there are two separate circuits along which liquids flow. They are:
1. The blood-flow from the patient, into the dialyser, through the dialyser, then back to the patient, and
2. The flow of dialysate around its own circuit which includes the dialyser plus some other stages.