The Urinary System By: everybody

KidneysStructure Lie in the retroperitoneal space

2 Kidneys Subdivided into branches

Nephron Vessels Renal Vein Inferior Vena Cava Heart Right Atrium Right Ventricle Etc.

Function Regulates fluid of the bodySorts chemicals from the blood

FiltrationTubular ReabsorptionTubular Secretion

Filtration PressureFiltration Membrane

Hilus The Hilus is the notch where the renal artery, renal vein, and ureters connect with the kidney.

It is an indented surface that acts as a point where nerves and vessels enter or leave

The renal artery and nerves enter the hilus and the renal vein and ureter exit.It opens into the renal sinus.

Problems that can occur:If you get hit in the kidney, the hilus can become detached, which would result in internal bleeding.

The bleeding may involve blood that contains toxins and wasteInternal bleeding may lead to blood poisoning.

Kidney DisordersGlomerulonephritis - Inflammation of the filtration membrane within the renal corpuscle, releasing an increase in the filtration membrane’s permeability; plasma proteins and blood cells enter the filtrate which increases urine volume due to increased osmotic concentration of the filtrateAcute Glomerulonephritis - Often occurs1-3 weeks after a severe bacterial infection, such as strep throat; normally subsides after several days

Chronic Glomerulonephritis - Long-term, progressive process whereby the filtration membrane thickens and is eventually replaced by connective tissue; the kidneys become non-functionalPyelonephritis - Often begins as a bacterial, usually E.Coli, infection of the renal pelvis, which spread to the rest of the kidney; the infection can destroy nephrons, corpuscles, and Loops of Henle, dramatically reducing the kidney’s ability to concentrate urine

Renal Failure - Can result from any condition that interferes with the kidney failure

Continued….Acute Renal Failure - Occurs when damage to the kidney is rapid and extensive; leads to accumulation of wastes in the blood; if renal failure is complete, death can occur in 1-2 weeks Chronic Renal Failure - Caused by permanent damage to so many nephrons that the remaining nephrons are inadequate for normal kidney function; can result from chronic glomerulonephritis, trauma to the kidneys, tumors, or kidney stones

Glomerular Filtration Function

The glomerulus fills the Bowman’s capsule and filters fluid into it

This fluid then flows into the proximal convulted tubule and is carried from the Bowman’s capsule

Materials are pushed out of the blood and into Bowman’s capsule of hepron

Disease and regulation Glomerular nephritis = disease Autoregulation – maintaining GFR Glomerular Filtration Rate (GFR)

Amount of plasma that enters the Bowman capsule per minute

Renal plasma flow x the % of plasma entering the renal canal

Tubular Secretion1 of 3 major processes of urine formationOccurs when the nephron cells transport solutes from the blood into the filtrateUrine filters consists of substances filtered directly from the bloodSecreted directly from the blood and the nephronsThese solutes are secreted from the peritubular capillaries across the wall of the nephron into the filtrateConverts to urine expelled from the body

Atomic makeup Major solutes include

WaterOrganic moleculesProteinGlucoseUrineUric acidCreatinine

Ionic makeup Major Ionic compounds include

SodiumPotassiumChlorineBicarbonateHydrogenAmmoniumCreatineUrea

Urine concentration • When a person drinks enough liquids,

the body must eliminate the excess without losing substances essential for maintaining homeostasis.

• When this process is finished, the product of this is called diluted urine.

• When a person doesn’t drink enough fluid, the amount of diluted urine produced would lead to dehydration.• This person produces concentrated urine that

conserves water.

Countercurrent Mechanism- method for concentrating urine based on movement of ions out of the nephron

It consists of parallel tubes and works so that the fluid in both sets of tubes has the same composition. Movement of Urine- Urine moves from the cortex toward the medulla and the interstitial fluid becomes progressively more concentrated until it achieves a maximum concentration of 1200 mOsm/kg at the tip of the renal pyramid.

Countercurrent Mechanism

UretersTubes that urine flows through

From the kidney to the urinary bladderOne from each kidney

StructureOutside: connective tissueMiddle: Layer of smooth muscleInner: more connective tissue

How urine travels: Pushed through the ureters by peristaltic contractions. These contractions will last between 1-2 seconds and 1-2 minutes. The urine travels at 3 cm / second

The pressure from the urinary bladder compresses at the entry way of the urinary bladder to prevent backflow into the ureters

The Urinary Bladder A hollow, muscular container Different locations for males and females

TrigoneTriangular shape flapPrevents backflow of urineLocated in…

Urethra Function is urination/ expelling of urine from the urinary bladderTube extending from the bladder to the outside of the bodyIn both males and females it drains the bladder, but in males it also conveys sex cells

Voluntarily and involuntarily with the aid of external urethral sphincters, and internal urethral sphincters

8 in. long in males and 1.5 in long in females

Urinary Disorders of Everything Else

BladderCancer

Grows rapidly, blood in urine50% of cases caused by cigarette smoking

CystitisInflammation of the bladder

10x more likely in femalesAbdominal painCan hurt to urinate

UrethraPolyuria- increased urine volume

Symptom of DiabetesNocturia-urination at nightIncontence- inability to control bladder

Usually affects the elderlyBlood Urea Nitrogen Increase- increases chance of infection of urethra

UretersStrictures

Abnormally narrow parts of uretersStones- calcium deposits in ureters that can block urine flow to bladder

Kidneys stones must travel through the ureters

DONE