URINARY SYSTEMURINARY SYSTEM

FUNCTIONSFUNCTIONS

HOMEOSTASISHOMEOSTASIS

1.1. Filters bloodstreamFilters bloodstream2.2. Rids the body of nitrogenous waste (urine)Rids the body of nitrogenous waste (urine)3.3. Maintains proper balance of water and salts, Maintains proper balance of water and salts, acids and bases.acids and bases.4.4. Regulate blood volume (and pressure)Regulate blood volume (and pressure)5.5. Stimulate red blood cell productionStimulate red blood cell production6.6. Converts vitamin D to its active formConverts vitamin D to its active form

Organs in the urinary systemOrgans in the urinary system

KIDNEYS- 2 -located against dorsal body wall KIDNEYS- 2 -located against dorsal body wall up near the rib cageup near the rib cage

URINARY BLADDER- muscular sac that stores URINARY BLADDER- muscular sac that stores urine- Located just posterior to pubic urine- Located just posterior to pubic symphisissymphisis

URETER- 2 – tubes running from each kidney to URETER- 2 – tubes running from each kidney to the urinary bladderthe urinary bladder

URETHRA- single tube running from urinary URETHRA- single tube running from urinary bladder to outside the bodybladder to outside the body

KIDNEYS- 3 REGIONSKIDNEYS- 3 REGIONS

1.1. RENAL CORTEX- outermost- light RENAL CORTEX- outermost- light reddish/pinkish color- most absorption will occur reddish/pinkish color- most absorption will occur herehere

2.2. RENAL MEDULLA- will appear a dark red- RENAL MEDULLA- will appear a dark red- contains Medullary (Renal) Pyramidscontains Medullary (Renal) Pyramids

3.3. RENAL PELVIS- white- collects urine from the RENAL PELVIS- white- collects urine from the Medullary Pyramids via the CALYX (Calyces pl.)Medullary Pyramids via the CALYX (Calyces pl.)

URETERSURETERS

25-30 cm long and 6 mm in diameter25-30 cm long and 6 mm in diameter Propel urine via peristalsis to the urinary Propel urine via peristalsis to the urinary

bladderbladder

URINARY BLADDERURINARY BLADDER

Smooth collapsible muscular sacSmooth collapsible muscular sac

Empty- 5- 7.5 cm longEmpty- 5- 7.5 cm long Moderately full- 12.5 cm long ( 500ml or 1 pint)Moderately full- 12.5 cm long ( 500ml or 1 pint)

Maximum- can hold more than twice that amountMaximum- can hold more than twice that amount

Contains 3 layers of smooth muscle with a mucosa Contains 3 layers of smooth muscle with a mucosa (outer lining) of transitional epithelium (various (outer lining) of transitional epithelium (various shapes)shapes)

URETHRAURETHRA

Thin-walled tube that carries urine out of the body Thin-walled tube that carries urine out of the body from the urinary bladder by PERISTALSISfrom the urinary bladder by PERISTALSIS

FEMALES- 3-4 cm – opens anterior to vaginal FEMALES- 3-4 cm – opens anterior to vaginal openingopening

MALES- 20 cm- connects to reproductive system MALES- 20 cm- connects to reproductive system and exits the penile tipand exits the penile tip

Ends at two sphincters at the base of the pelvisEnds at two sphincters at the base of the pelvisINTERNAL URETHRAL SPHINCTER- (INVOLUNTARY)INTERNAL URETHRAL SPHINCTER- (INVOLUNTARY)

EXTERNAL URETHRAL SPHINCTER- (VOLUNTARY)EXTERNAL URETHRAL SPHINCTER- (VOLUNTARY)

NEPHRONS-(page 485)NEPHRONS-(page 485)

Nephron do the actual Nephron do the actual filteringfiltering

Glomerulus – a bed Glomerulus – a bed of of capillaries whose capillaries whose pressure filters liquid pressure filters liquid fraction of bloodfraction of blood

Renal Tubules-Renal Tubules-exchange water and exchange water and ions back to bloodions back to blood

Parts of a NephronParts of a Nephron

1.1. Bowman’s Capsule (Glomerular)-Bowman’s Capsule (Glomerular)- filters out all of the filters out all of the blood- water, salts, urea, bicarbonate ions, hydrogen ions, blood- water, salts, urea, bicarbonate ions, hydrogen ions, glucose, amino acids, drugsglucose, amino acids, drugs

2.2. Proximal Convoluted Tubule-(pct)- Proximal Convoluted Tubule-(pct)- items leaving the tubule items leaving the tubule and reentering the blood- water, sodium chloride, and reentering the blood- water, sodium chloride, bicarbonate ions, glucose, amino acidsbicarbonate ions, glucose, amino acids

3.3. Loop of Henle-Loop of Henle- items leaving the tubule and reentering the items leaving the tubule and reentering the blood- water and sodium chloride onlyblood- water and sodium chloride only

4.4. Distal Convoluted TubuleDistal Convoluted Tubule – (DCT)- same as proximal – (DCT)- same as proximal

Volumes of fluidsVolumes of fluids

Kidneys filter approximately 125 ml/min or Kidneys filter approximately 125 ml/min or 180000ml/day (180 liters) 180000ml/day (180 liters) BUTBUT blood only has 5 blood only has 5 liters of which ~3 liters is plasmaliters of which ~3 liters is plasma

So you filter the entire plasma 60x/daySo you filter the entire plasma 60x/day Results in ~1 ml concentrated urine produced per Results in ~1 ml concentrated urine produced per

min.min. You excrete between 0.6 and 2.5 liters/day You excrete between 0.6 and 2.5 liters/day

(depending on your level of hydration)(depending on your level of hydration) SO, you SO, you mustmust reabsorb roughly 178 liters/day reabsorb roughly 178 liters/day

MECHANISMS FOR MECHANISMS FOR REABSORBTIONREABSORBTION

Tubular reabsorptionTubular reabsorption Purpose: Returns vital substances Purpose: Returns vital substances to circulationto circulation Mechanisms:Mechanisms:

Diffusion: chemicals move down concentration gradient Diffusion: chemicals move down concentration gradient from inside lumen of renal tubule into epithelia and from inside lumen of renal tubule into epithelia and from from epithelia to capillariesepithelia to capillaries

Active transport: move substances out of lumen against Active transport: move substances out of lumen against concentration gradient through concentration gradient through direct use of energy direct use of energy (ATP)(ATP)

MECHANISMS FOR MECHANISMS FOR REABSORBTIONREABSORBTION

Occurs in PCT, DCT and ascending Occurs in PCT, DCT and ascending loop of Henleloop of Henle Pumps can be Pumps can be saturatedsaturated (only so many transporter (only so many transporter

proteins and if they can’t keep up with chemical, proteins and if they can’t keep up with chemical, chemical will appear in urine) – example chemical will appear in urine) – example diabetes diabetes mellitusmellitus

MECHANISMS FOR MECHANISMS FOR REABSORBTIONREABSORBTION

Distal collecting tubule and collecting duct also save Distal collecting tubule and collecting duct also save water but only under hormonal control of water but only under hormonal control of hypothalamus (hypothalamus (antidiuretic hormone)antidiuretic hormone)

MECHANISMS FOR MECHANISMS FOR REABSORBTIONREABSORBTION

ADH triggers collecting duct and DCT to ADH triggers collecting duct and DCT to reabsorb reabsorb waterwater: so ADH prevents water from reaching renal : so ADH prevents water from reaching renal papillae papillae and being wastedand being wasted

If you are hydrated, very little ADH is released, If you are hydrated, very little ADH is released, pee copiouslypee copiously

If you are dehydrated, lots of ADH is released, If you are dehydrated, lots of ADH is released, pee brown highly concentrated urinepee brown highly concentrated urine

MECHANISMS FOR MECHANISMS FOR REABSORBTIONREABSORBTION

Regulation of urine concentrationRegulation of urine concentration Volume of urine reaching distal convoluted tubule Volume of urine reaching distal convoluted tubule

has been 92% reabsorbed (remaining has been 92% reabsorbed (remaining 8% under 8% under control of ADH)control of ADH)

PATHWAY OF BLOOD PATHWAY OF BLOOD THROUGH THE KIDNEYTHROUGH THE KIDNEY

VesselVessel DescriptionDescription

1. RENAL ARTERY1. RENAL ARTERY Branches off the aortaBranches off the aorta

2. LOBAR ARTERIES2. LOBAR ARTERIES

(segmental arteries outside (segmental arteries outside the kidneys)the kidneys)

5 sections (one for each lobe) 5 sections (one for each lobe) that branch off of renal artery that branch off of renal artery and enters the kidneyand enters the kidney

3. INTERLOBAR 3. INTERLOBAR ARTERIESARTERIES

Numerous sections that branch Numerous sections that branch from each lobar artery and pass from each lobar artery and pass around renal pyramids (in renal around renal pyramids (in renal column) to cortex column) to cortex

PATHWAY OF BLOOD PATHWAY OF BLOOD THROUGH THE KIDNEYTHROUGH THE KIDNEY

PATHWAY OF BLOOD PATHWAY OF BLOOD THROUGH THE KIDNEYTHROUGH THE KIDNEY

4.4.

ARCUATE ARTERYARCUATE ARTERY

Artery that loops Artery that loops throughout the renal cortex throughout the renal cortex near the renal pyramidsnear the renal pyramids

5.5.

INTERLOBULAR INTERLOBULAR ARTERIESARTERIES

Tiny branches off of Tiny branches off of arcuate artery deeper into arcuate artery deeper into the renal cortexthe renal cortex

6.6.

AFFERENT ARTERIOLEAFFERENT ARTERIOLE

Small vessel that enters the Small vessel that enters the Bowman’s Capsule and Bowman’s Capsule and will form the will form the GLOMERULUSGLOMERULUS

PATHWAY OF BLOOD PATHWAY OF BLOOD THROUGH THE KIDNEYTHROUGH THE KIDNEY

PATHWAY OF BLOOD PATHWAY OF BLOOD THROUGH THE KIDNEYTHROUGH THE KIDNEY

7.7.

EFFERENT ARTERIOLE EFFERENT ARTERIOLE (much smaller in diameter (much smaller in diameter and causes pressure needed and causes pressure needed for filter)for filter)

Extremely small vessel that Extremely small vessel that leaves the Bowman’s leaves the Bowman’s CapsuleCapsule

8.8.

PERITUBULAR PERITUBULAR CAPILLARIESCAPILLARIES

Efferent arteriole forms Efferent arteriole forms capillary bed that reabsorbs capillary bed that reabsorbs along the PCT, Loop of along the PCT, Loop of Henle, and DCT Henle, and DCT

PATHWAY OF BLOOD PATHWAY OF BLOOD THROUGH THE KIDNEYTHROUGH THE KIDNEY

9.9.

INTERLOBULAR VEININTERLOBULAR VEIN

Capillary beds come back Capillary beds come back together and moves back together and moves back toward inner edge of renal toward inner edge of renal cortexcortex

10.10.

ARCUATE VEINARCUATE VEIN

Circles round the cortex to Circles round the cortex to interlobar veininterlobar vein

11.11.

INTERLOBAR VEININTERLOBAR VEIN

Travel back between renal Travel back between renal pyramids and exits the kidneypyramids and exits the kidney

12.12.

RENAL VEINRENAL VEIN

Attaches to inferior vena cavaAttaches to inferior vena cava

CHARACTERISTICS OF URINECHARACTERISTICS OF URINE

Normal yellow color is due to UROCHROME, a Normal yellow color is due to UROCHROME, a pigment that results from the breakdown of pigment that results from the breakdown of hemoglobinhemoglobin

pH- slightly acidic around 6pH- slightly acidic around 6

SPECIFIC GRAVITY- how heavy urine is SPECIFIC GRAVITY- how heavy urine is compared to water- compared to water-

Specific gravity is between 1.001-1.035 depending Specific gravity is between 1.001-1.035 depending on the amount of solutes compared to 1.000 for on the amount of solutes compared to 1.000 for pure waterpure water

Increases in urine specific gravityIncreases in urine specific gravity

1.1. Due to inadequate fluid intakeDue to inadequate fluid intake

2.2. FeverFever

3.3. Pyelonephritis- inflammation of the kidneyPyelonephritis- inflammation of the kidney

Decreases in urine specific gravityDecreases in urine specific gravity

1.1. Excessive fluid intakeExcessive fluid intake

2.2. Use of diureticsUse of diuretics

3.3. Chronic Renal Failure- kidney cannot take in Chronic Renal Failure- kidney cannot take in ions ions

NORMAL URINE COMPONENTSNORMAL URINE COMPONENTS

1.1. NITROGENOUS WASTESNITROGENOUS WASTES

A. A. UREAUREA- - formed by liver in formed by liver in breakdown breakdown of proteins of proteins

B. B. URIC ACID-URIC ACID- formed by liver in formed by liver in breakdown of nucleic acidbreakdown of nucleic acid

C. C. CREATININECREATININE-- waste from waste from metabolism of metabolism of creatine in the creatine in the musclesmuscles

NORMAL URINE COMPONENTSNORMAL URINE COMPONENTS

2.2. SODIUM AND POTASSIUM IONSSODIUM AND POTASSIUM IONS

3.3. AMMONIAAMMONIA

4.4. BICARBONATE IONSBICARBONATE IONS

ABNORMAL Urine Components ABNORMAL Urine Components (should not appear)(should not appear)

1.1. Blood- RBC-Blood- RBC- bleeding in urinary tract due to bleeding in urinary tract due to kidney stones or trauma kidney stones or trauma

2.2. Pus- WBC/Bacteria-Pus- WBC/Bacteria- urinary tract infection urinary tract infection3.3. GlucoseGlucose- diabetes mellitus or excess sugar intake- diabetes mellitus or excess sugar intake4.4. ProteinsProteins-(albumin) - hypertension, -(albumin) - hypertension,

glomerulonephritis, physical exertion, pregnancyglomerulonephritis, physical exertion, pregnancy5.5. BileBile- liver disease- liver disease6.6. RENAL CALCULI-RENAL CALCULI- (kidney stones) concentrated (kidney stones) concentrated

uric acid salts that crystallizeuric acid salts that crystallize

Components of Urine OutputComponents of Urine Output

1.1. Diet of individualDiet of individual

2.2. Cellular metabolism of individualCellular metabolism of individual1.1. Will decrease if excessive sweating- (keep water Will decrease if excessive sweating- (keep water

and ions to compensate)and ions to compensate)

2.2. Water loss from lungs during respirationWater loss from lungs during respiration

3.3. Water loss from feces during excretionWater loss from feces during excretion

Components of Urine OutputComponents of Urine Output

3.3. Presence of ADHPresence of ADH

4.4. Presence of Aldosterone- major factor in Presence of Aldosterone- major factor in reabsorbing certain ions- when aldosterone reabsorbing certain ions- when aldosterone levels are high sodium will be reabsorbed-levels are high sodium will be reabsorbed-(and potassium will be lost)(and potassium will be lost)

EMPTYING THE BLADDEREMPTYING THE BLADDER MICTURITION (VOIDING)-MICTURITION (VOIDING)- is the term for emptying is the term for emptying

bladder !!bladder !!

Bladder collects approx 200 ml before “stretch receptors” are Bladder collects approx 200 ml before “stretch receptors” are activated.activated.

Reflex contractions of the bladder result and forced the stored Reflex contractions of the bladder result and forced the stored urine past the involuntary urethral sphincterurine past the involuntary urethral sphincter

Micturition will reoccur after another 200ml have been Micturition will reoccur after another 200ml have been collected- will typically max out at 600mlcollected- will typically max out at 600ml

External (voluntary) urethral sphincter feels added pressure External (voluntary) urethral sphincter feels added pressure and at some point will relax whether one wills it or notand at some point will relax whether one wills it or not

INCONTINENCEINCONTINENCE

Unable to voluntarily control the external Unable to voluntarily control the external urethral sphincterurethral sphincter1. typical in toddlers under 2 yrs of age (if 1. typical in toddlers under 2 yrs of age (if older usually a sign of emotional problems, or older usually a sign of emotional problems, or pressure (pregnancy), or nerve problems pressure (pregnancy), or nerve problems (stroke, spinal cord injury)(stroke, spinal cord injury)2.2. also occurs in older children who sleep also occurs in older children who sleep heavily through micturition stimulusheavily through micturition stimulus3.3. also can occur in older adultsalso can occur in older adults

URINARY RETENTIONURINARY RETENTION

Bladder is unable to expel urineBladder is unable to expel urine

Primarily caused by an enlargement of the Primarily caused by an enlargement of the prostate glandprostate gland

CATHETER- tube inserted in the urethra to CATHETER- tube inserted in the urethra to void the bladder-void the bladder-

DIALYSIS-DIALYSIS-