Urinary DrillUrinary Drill

Name the functions of the excretory system.Name the functions of the excretory system.

What is the functioning unit of the kidney?What is the functioning unit of the kidney?

How many are there per kidney?How many are there per kidney?

Urinary DrillUrinary Drill

1.1. List & describe the steps for urine List & describe the steps for urine formation.formation.

2.2. What is the renal corpuscle made of?What is the renal corpuscle made of?

3.3. What are the parts of the convoluted What are the parts of the convoluted tubule?tubule?

4.4. What are the name of the cells that open What are the name of the cells that open and close in the glomerulus?and close in the glomerulus?

5.5. What controls the podocytes?What controls the podocytes?

Urinary DrillUrinary Drill1.1. What is the driving force of filtration and What is the driving force of filtration and

secretion?secretion?

2.2. How big is your kidney? Why is the right kidney How big is your kidney? Why is the right kidney lower that the left kidney?lower that the left kidney?

3.3. Where does urea and uric acid come from?Where does urea and uric acid come from?

4.4. How does Aldosterone and How does Aldosterone and Atrial Natriuretic Factor effect urine formation?effect urine formation?

1.1. What is the function of the kidneys?What is the function of the kidneys?

2.2. What is the function of the ureters?What is the function of the ureters?

3.3. What is the function of the urinary What is the function of the urinary bladder?bladder?

4.4. Why are the uretherea, bladder, and Why are the uretherea, bladder, and ureter coated with mucus?ureter coated with mucus?

Urinary SystemUrinary System

FunctionFunction

1. Excretion1. Excretion

2. Regulation of blood volume and pressure.2. Regulation of blood volume and pressure.

3. regulation of the concentration of solutes in 3. regulation of the concentration of solutes in the blood.the blood.

4. Regulation of extracellular fluid pH.4. Regulation of extracellular fluid pH.

5. Vitamin D synthesis.5. Vitamin D synthesis.

I. Kidney StructureI. Kidney Structure

A. ExternalA. External1. Size of your fist.1. Size of your fist.2. Kidney bean shaped.2. Kidney bean shaped.3. Right kidney is 3. Right kidney is

slightly lower slightly lower than than the left, due to the left, due to

liver.liver.4. Renal Fascia - 4. Renal Fascia -

anchors anchors kidney & kidney & adrenal gland to adrenal gland to surrounding tissues.surrounding tissues.

5. Adipose Capsule - 5. Adipose Capsule - Cushion Cushion layer.layer.

6. Renal Capsule - thin, 6. Renal Capsule - thin, transparent layer of transparent layer of

fibrous fibrous tissue.tissue.

B. InternalB. Internal1. Renal medulla - inner most.1. Renal medulla - inner most.

a. Hilum - Concave portion where the renal a. Hilum - Concave portion where the renal artery & artery & vein unit with the kidney.vein unit with the kidney.

b. Renal sinus - space.b. Renal sinus - space.c. Renal pelvis - membrane line basin.c. Renal pelvis - membrane line basin.d. Calyces - funnel shaped channels from the d. Calyces - funnel shaped channels from the

pelvis & pelvis & collects newly formed urine.collects newly formed urine.

2. Renal Cortex - Outermost layer2. Renal Cortex - Outermost layer

3. Renal Pyramids3. Renal Pyramids

4. Renal Columns - Parts of the cortex extends into 4. Renal Columns - Parts of the cortex extends into the medulla.the medulla.

5. Nephrons - functional subunit of the kidney.5. Nephrons - functional subunit of the kidney.

Kidney StructureKidney Structure

C. Blood Supply - 1200ml/min @ rest.C. Blood Supply - 1200ml/min @ rest.

To the nephronTo the nephron From the From the nephronnephron

1. Renal artery1. Renal artery 7. Efferent 7. Efferent ArteriolesArterioles

2. Lobar Arteries - 5 in the renal sinuses2. Lobar Arteries - 5 in the renal sinuses 8. Interlobular 8. Interlobular VeinsVeins

3. Interlobar Arteries - renal pyramids3. Interlobar Arteries - renal pyramids 9. Arcuate Veins9. Arcuate Veins

4. Arcuate Arteries - Between Cortex & medulla4. Arcuate Arteries - Between Cortex & medulla10. Interlobar 10. Interlobar

VeinsVeins

5. Interlobular Arteries - Cortex5. Interlobular Arteries - Cortex 11. Lobar Veins11. Lobar Veins

6. Afferent Arterioles - to nephron6. Afferent Arterioles - to nephron 12. Renal Veins12. Renal Veins

Blood Supply to KidneyBlood Supply to Kidney

D. Nephron Structure - 1 million/kidneyD. Nephron Structure - 1 million/kidney

A portion is in both the medulla & cortexA portion is in both the medulla & cortex

Two partsTwo partsa. Renal Corpusclea. Renal Corpuscle

1. Bowman Capsule1. Bowman Capsule2. Glomerulus2. Glomerulus

a. Fenestrae - pore in endothelial walls of a. Fenestrae - pore in endothelial walls of glomerulus.glomerulus.

b. Podocytes - specialized cells.b. Podocytes - specialized cells.c. Filteration slitsc. Filteration slits

b. Renal Tubule - Series of single layer tubulesb. Renal Tubule - Series of single layer tubules1. Proximal Convoluted tubule1. Proximal Convoluted tubule2. Loop of Henle2. Loop of Henle3. Distal Convoluted tubule3. Distal Convoluted tubule

E. Blood Flow Through E. Blood Flow Through NephronNephron

Blood Afferent - Large -> Blood Afferent - Large ->

Glomerulus - Narrow & Glomerulus - Narrow & creates high back pressurecreates high back pressure

EfferentEfferent

Blood <- Peritubular Tubulars Blood <- Peritubular Tubulars - porus & low pressure - porus & low pressure

NephroNephronn

F. Juxtaglomerular F. Juxtaglomerular ApparatusApparatus

1. Distal convoluted 1. Distal convoluted tubular contacts tubular contacts the afferent the afferent arteriole.arteriole.

2. Regulates the rate 2. Regulates the rate of urine formation.of urine formation.

II. Kidney Function

Removal of unwanted substances (through excretion - urea & uric acid) from the blood stream & maintain a fluid balance electrolyte concentration, & pH.

A. Urine formation

180 L (145 gallons)/day - 35 time your total blood volume.

99% of the fluid is returned to the blood stream.

1% 1-2 L is excreted as urine.

3 step process

1. Filtration - movement of blood plasma across the filtration membrane at the renal corpuscle.

a. Filtrate - fluid & dissolved substances that penetrate the membrane.

b. High hydrostatic pressure at the glomerulus (glomerular capillary pressure) pushes plasma through the filtration membrane.

c. Net Filtration pressure (NFP) 10mm of mercury.

d. Rate of filtration is determined by filtration that is present.

High filtration pressure= high volume of filtrate

ReabsorbtionReabsorbtion

2. Reabsorptiona. 99% of water, majority of nutrients, essential ions

are removed & transported to nearby peritubular capillaries. K+, Ca+, HCO3-, Cl-

b. Reclaiming of material is returned to the blood stream resulting in a concentration of wastes that remain in the tubule.

c. Filtrate vs urine

Filtrate - Same as blood plasma except the lack of proteins.

Urine - more concentration of ions, urea, & uric acid

d. Reabsorption procedureProximal Convoluted Tubule 65% of

reabsorption.

Main site of water & solute reabsorbtion.

Reabsorption in the Proximal Tubule

Urine SubstancesUrine Substances

3. Loop of Henle 15% of reabsorption.

Descending - continues water reabsorption

Solute concentration increases

Ascending - Reabsorption of solutes (Chloride, sodium)

More dilute because of the removal of solutes.

Ascending - Reabsorption of solutes (Chloride, sodium)

More dilute because of the removal of solutes.

Reasorption in Distal tubule

collecting dcut

4. Secretion - Net movement of unwanted substance from the peritubular capillaries into the proximal convoluted.

How does this movement occur?

Active transport - H ions (controls the body’s pH), Potassium ions, Penicillin)

Diffusion – urea

Facilitated diffusion

III. Urea & Uric Acid FormationNitrogen containing wastes products from cellular

metabolismA. Urea

Liver’s metabolism of AA creates ammonia (toxic), so it is quickly converted to urea by the liver & released in to the bloodstream.50% is excreted in urine/50% is reabsorbed by the body.

B. Uric AcidMetabolism of certain nucleic acids.10% is removed by urine

IV. Regulation of Urine Concentration & Volume

Fluctuates in response to our changing condition of our body to maintain a constant blood composition & volume.

Large salty meal -Increases slat in urine & increase urine volume.

After exercise - Urine volume is less with less salt.

Juxtaglomerular regulates urine formation & is triggered when NFP decreases.

A. Renin & Angiotensin – Increases water re-absorption.

Renin converts a plasma protein to Angiotensin.

Angiotensin is then converted in the blood into Angiotensin II.

Angiotensin II effects the adrenal Cortex to release Aldosterone which increases re-absorption of Sodium, Chloride, water (increases blood pressure).

Increases in blood pressure, increases NFP, increased in filtrate production.

B. Aldosterone-Increases water re-absorption.

Released by the Adrenal Gland

Regulates rate of active transport in the distal convoluted tubule & collecting duct.

Increases the re-absorption of sodium by transporting it out.

Water follows because of the concentration gradient.

Volume of urine decreases, increase in blood pressure.

C. Antidiuretic Hormone (ADH) - Posterior Pituitary Gland. Increases water re-absorption.

Increases in blood volume - Pituitary releases ADH.Increases the permeability of distal tubules & collecting ducts to water.Water absorption increases, therefore blood volume increases.Increase in urine concentration.

D. Atrial Natriuretic Factor- decreases water re-absorptionReleased by the cells in the right atrium of the heart when blood pressure changes within the heart.

Reduces the ability of the kidneys to reabsorb water & solutes, resulting in a large volume of urine, therefore blood pressure decreases.

E. Sympathetic Stimulation- Decreases water reabsorption

Nerve impulses from the sympathetic nervous system stimulate the contraction of smooth muscle in the wall of afferent arterioles.

Vasconstriction results in decreased in blood flow passing through the glomerulus.

Decreased in NFP.

Decreased in filtrate & urine volume.

From heavy exercise or excitement.

Hormonal regulation overview

V. Maintenance of Body Fluids

Uptake of water & electrolytes = removal.Organs involvedSkin, liver, organs of the alimentary canal, & kidney (largest effect).

VI Regulation of pH

7.35 - 7.45 are normal rangesLow pH Acidosis (respiratory or metabolic)

high pH Alkalosis (respiratory or metabolic).

A. Buffers. Resist changes in pH.Three main buffersProteinsPhosphatesBicarbonate - most important because it regulates the respiratory & urinary system.

H20 + CO2 <-> H2CO3 <-> H+ + HCO3In bloodCarbonic anhydrase

B. Respiratory System

(+) CO2, (-) pH, brain increases in deep breathing - more CO2 exhaled pH(+).(-) CO2, (+) pH, brain decreases breathing, less CO2 leaves, CO2 builds up in tissues, (+)H ,(-) pH .

C. Kidney(-) pH, increases the rate of secretion of H @ the same time rate of reabsorbtion of bicarbonate ions.Excess H are removed & restoring the pH.

(+) pH reduces rate of H secretion & bicarbonate reabsorbtionLower pH.

Regulation of pH

Regulation of Potassium

Regulation of Calcium

VII Ureters

A. Carries newly formed urine from the kidneys to the urinary bladder.

B. Pair tubular organ designed for transport.

C. Arise from the renal pelvis.

D. Extend downward along the vertebral column.

E. Behind the peritoneum (retroperitoneal).

E. Wall of each ureter as three layers.

1. Inner - mucus membrane, protects underlying cells from the

passage of urine.

2. Middle -Smooth muscle & elastic fibers, peristaltic contraction.

3. Outer - fibrous connective tissue that protects the underlying tissue.

F. Flap at each opening that acts as a one way valve.

IIX Urinary Bladder

A. Is an expandable saclike like organ that receives urine from the ureters & stores it until release into the urethra.

B. Located on the floor of the pelvis behind the symphysis.

C. Top surface is only covered by peritoneum.

D. Walls are extremely elastic.

E. Average capacity of 500 ml, but it can hold twice that.

F. Ureteral openings.

G. Trigone - frequent site of urinary infections.

H. Walls of the bladder is made up of four layers:

1. Innermost – mucous

2. Connective - supportive.

3. Smooth muscle, Detrusor muscle - longitudinal &

circular layers of fibers.

4. Fibrous connective tissue.

IX UrethraIX UrethraA. Transports urine from the A. Transports urine from the urinary bladder to the urinary bladder to the exterior, differs between exterior, differs between males & females.males & females.

B. Internal urethral sphincter B. Internal urethral sphincter - smooth muscle, involuntary - smooth muscle, involuntary keeps urine in the bladder.keeps urine in the bladder.

C. External urethral sphincter C. External urethral sphincter - skeletal muscle – voluntary- skeletal muscle – voluntary

1. Males1. Malesa. 8 inches longa. 8 inches longb. Passes b. Passes through the through the prostate.prostate.c. Carries c. Carries reproductive reproductive

fluids.fluids.

2. Females2. Femalesa. 1.5 inches a. 1.5 inches

longlong

X. Micturition (voluntary control between 2-3)

A. Process of emptying the bladder & is both a voluntary & involuntary response.

B. 200 ml, bladder wall stretches to activate the stretch receptors.

C. Send a signal to the spinal cord.

D. Motor signal are sent to the bladder by a reflex arc.

E. Detrusor muscle to contract & internal urethral sphincter to relax.

F. As detrusor continues to contract, increase urge to void.

G. Maybe stopped by the exterior urethral sphincter if timing is not appropriate.

H. Further contraction of the detrusor

XI Problems with the Urinary System

A. Anuria - absence of urine due to kidney failure or obstruction

B. Claculi - kidney stones due to increased salts in urine.

Uric acid crystals that precipitate out of the blood stream & build up in the lower gut.

Excess of calcium salts.

C. Cystitis - Inflammation of the urinary bladder due to entry of a bacteria through the urethera.

D. Hematuria - Presence of blood in the urine caused by cuts in the urinary tract

E. Renal Failure & Dialysis

1. loss of the kidney’s ability to respond to changes in the body.

2. rapid loss of fluid, electrolytes.

3. build up of wastesAcute - abrupt stoppage, temporary.

4. Pain, Reduce urine output, bleeding.

5. Injury, infection, drugs.

6. Chronic - progressive loss of kidney function because of reduced glomerular function.

7. Build of urea in blood, pH imbalance, electrolytes imbalance.

8. Kidney failure - no formation of urine, result in rapid build. of of toxic wastes, & acidic pH - death in 8 - 10 days.

9.Kidney transplant or dialysis - 3 times a week.

DialysisDialysis

XII Testing for healthy kidneys

A. Urinalysis - analysis of chemical content of a urine sample