URINARY SYSTEM

FUNCTIONS

MAINTAIN HOMEOSTASIS OF pH, COMPOSITION AND VOLUME OF BODY FLUIDS

REMOVES: METABOLIC WASTE, EXCESS MATERIAL, FOREIGN SUBSTANCES (DRUGS)

PARTS

KIDNEYS URETER S URINARY BLADDER URETHRA FUNCTIONS?

http://miyessence.files.wordpress.com/2006/12/urinary.jpg

KIDNEYS

LOCATED RETROPERITONEALLY 12TH THORACIC TO 3RD LUMBAR

VERTEBRAE RENAL SINUS AT HILUM: BLOOD VESSELS,

URETER, NERVES, LYMPHATIC VESSELS RELEASES ERYTHROPOIETIN ? RELEASES RENIN ?

BLOOD PRESSURE ACTIVATES VITAMIN D ?

CALCIUM ABSORPTION

http://depts.washington.edu/ostomy/urostomy/urinary-sys.gif

http://www.biog1105-1106.org/demos/105/unit7/media/human-urinary-system.jpg

RENAL PELVIS FUNNEL SHAPED SAC AT URETER ORIGIN WHERE MAJOPR CALYCES MERGE

RENAL MEDULLA: RENAL PYRAMIDS MINOR CALYCES TO MAJOR CALYCES

RENAL CORTEX: OUTER LAYER DIPS IN BETWEEN PYRAMIDS = RENAL

COLUMNSRENAL CAPSULE

FIBROUS CONNECTIVE TISSUEPROTECTION, MAINTAIN SHAPE

BLOOD VESSELS

ARTERIES CAN CARRY 30% OF BLOOD TO KIDNEYS ?

RENAL ARTERY HAS _________________ BLOOD

RENAL VEIN HAS _________________ BLOOD

ARTERIES

Descending aorta Renal artery Interlobar artery Arciform arteries Interlobular arteries Afferent arterioles Glomerulus Efferent arteriole Capillary net

NEPHRON

FUNCTIONAL UNIT OF KIDNEY 1 MILLION PER PARTS

RENAL CORPUSCLE GLOMERULUS GLOMERULAR OR BOWMAN’S CAPSULE

2 LAYERS OF SQUAMOUS EPITHELIAL VISCERAL AND PARIETAL TO TUBULE VISCERAL CELLS: PODOCYTES

HAVE PROCESS AND SECONDARY PROCESSES = PEDICELS, INTERDIGITATE TO FORM SLIT PORES

FUNCTION AFFERENT AND EFFERENT ARTERIOLES

GLOMERULUS

http://www.jimstanis.com/images/glomerulus.jpg

http://www.life-enhancement.com/images/005glomerulus.jpg

PODOCYTES

http://www.life-enhancement.com/images/005glomerulus.jpg

RENAL TUBULE

PROXIMAL CONVOLUTED TUBULE NEPHRON LOOP/ LOOP OF HENLE

DESCENDING LIMB ASCENDING LIMB

DISTAL CONVOLUTED TUBULE COLLECTING DUCT/ COLLECTING TUBULE THROUGH RENAL PAPILAE TO MINOR

CALYX

RENAL TUBULE

http://www.dr-aschatterjee.com/renal.html

JUXTAGLOMERULAR APPARATUS

ASCENDING LIMB PASSES BETWEEN AFFERENT AND EFFERENT ARTERIOLE

MACULA DENSA = TALL DENSELY PACKED CELLS OF ASCENDING LOOP TOUCHING ASCENDING LIMB

JUXTAGLOMERULAR CELLS IN WALL OF AFFERENT ARTERIOLE (LARGE VASCULAR SMOOTH MUSCLE CELLS)

REGULATES SECRETION OF RENIN (CHAP 13)

JUXTAGLOMERULAR APPARATUS

http://www.cf.ac.uk/biosi/staffinfo/jacob/teaching/jga1.gif

NEPHRONS

CORTICAL 80% CORPUSCLE IN CORTEX CLOSE TO SURFACE SHORT NEPHRON LOOPS

JUXTAMEDULLARY 20% CORPUSCLE CLOSE TO MEDULLA LONG LOOP MOST RESPONSIBLE FOR H2O HOMEOSTASIS

BLOOD SUPPLY OF NEPHRON

AFFERENT ARTERIOLE DIAMETER LARGER THAN EFFERENT ?

PERITUBULAR CAPILLARY SYSTEM VASA RECTA AROUND JUXTAMEDULLARY

NEPHRON LOOP: LOW PRESSURE

URINE FORMATION

WASTES, EXCESS WATER, ELECTROLYTES GLOMERULAR FILTRATION

FILTERS INTO NEPHRON RATHER THAN INTERSTITIAL SPACE

PRODUCES 180 L OF FLUID/DAY SO MOST? TUBULAR REABSORPTION

PICKS UP RIGHT AMOUNT OF WATER, ELECTROLYTES, GLUCOSE

TUBULAR SECRETION REMOVES H+, TOXINS FASTER

URINARY SECRETION = GLOMERULAR FILTRATION + TUBULAR SECRETION – TUBULAR REABSORPTION

GLOMERULAR FILTRATION

MORE PERMEABLE TO SMALL MOLECULES: FENESTRATED CAPILLARIES

= WATER,GLUCOSE, AMINO ACIDS, UREA, URIC ACID, CREATINE, CREATININE, SODIUM, CHLORIDE, POTASSIUM, CALCIUM, BICARBONATE, PHOSPHATE, SULFATE

FENESTRATED CAPILARIES

http://www.jci.org/articles/view/23577/files/JCI0423577.f1/medium

FILTRATION PRESSURE

HYDROSTATIC PRESSURE CAUSES FILTRATION

ALSO AFFECTED BY HYDROSTATIC PRESSURE IN CAPSULE AND OSMOTIC PRESSURE IN PLASMA ?

NET FILTRATION RATE = GLOMERULAR CAPILLARY HYDROSTATIC PRESSURE – CAPSULAR HYDROSTATIC PRESSURE AND GLOMERULAR CAPILLARY OSMOTIC PRESSURE

NEPHRON RAP

http://www.youtube.com/watch?v=guOqyi5lUQQ

URINARY SYSTEM

http://www.natgeoeducationvideo.com/film/1115/the-urinary-system

DIALYSIS

http://www.youtube.com/watch?v=tQzqGHKkdE8&NR=1&feature=endscreen

FILTRATION RATE

FILTRATION RATE AFFECTED BY ANYTHING THAT AFFECTS GLOMERULAR HYDROSTATIC PRESSURE, GLOMERULAR PLASMA OSMOTIC PRESSURE, OR CAPSULAR HYDROSTATIC PRESSURE

GLOMERULAR HYDROSTATIC PRESSURE IS MOST IMPORTANT: ANY CHANGE IN DIAMETER OF ARTERIOLES, VASODILATION? VASOCONSTRICTION?

MORE FLUID IS FILTERED BECAUSE OF HIGHER HYDROSTATIC PRESSURE SO COLLOIND OSMOTIC PRESSURE DOESN’T AFFECT FILTRATION AS MUCH, UNLESS IT IS LOWERED ?

ANY OBSTRUCTION (?) WOULD BACK UP FLUID RAISING THE HYDROSTATIC PRESSURE OF CAPSULE AND REDUCING FILTRATION

FILTERS: 25% CARDIAC OUTPUT; 20% OF PLASMA = 125 ml/MIN; 180 L/DAY : SO PLASMA IS FILTERED 60X/DAY = 45G

SURFACE AREA OF GLOMERULAR CAPILLARIES = 2 sq m = SKIN’S SURFACE

CONTROL OF FILTRATION RATEGFR

MAINLY AUTOREGULATION BP/VOLUME DROP STIMULATES

SYMPATHETIC NS = VASOCONSTRICTION OF AFFERENT ARTERIOLES = ? IF BP/VOLUME INCREASE = ?

RENIN-ANGIOTENSIN SYSTEM: RENAL BAROMETERS OF AFFERENT ARTERIOLES STIMULATE SYMPATHETIC NS TO STIMULATE JUXTAGLOMERULAR CELLS SECRETE RENIN

DECREASING LEVELS OF SODIUM, POTASSIUM, CHLORIDE STIMULATE MACULA DENSA TO SECRETE RENIN

RENIN STIMULATES ANGIOTENSINOGEN ANGIOTENSIN I; ANGIOTENSIN-CONVERTING ENZYME CAHNGES ANGIOTENSIN I ANGIOTENSIN II

ANGIOTENSIN II: MAINTAINS SODIUM BALANCE, WATER BALANCE, BLOOD PRESSURE

CONSTRICTS AFFERENT OR EFFERENT ARTERIOLES, STIMULATES SECRETION OF ALDOSTERONE FROM ADRENAL CORTEX

ANGIOTENSIN II: VASOCONSTRICTOR OF AFFERENT AND

EFFERENT ARTERIOLES STIMULATE PRODUCTIN OF ALDOSTERONE:

(FROM?) CAUSES RETENTION OF SODIUM IN DISTAL TUBULE: LOSES LESS WATER

STIMULATES RELEASE OF ADH: INCREASES PERMEABILITY OF DISTAL TUBULE AND COLLECTING DUCT

ANP: (FROM?) RELEASED WHEN BLOOD VOLUME INCREASES: SO ?

TUBULAR REABSORPTION

REABSORPTION: MATERIAL TRANSPORTED OUT TO INTER STITIAL FLIUD AND DIFFUSE INTO PERITUBULAR CAPILLARIES

PASSIVE AND ACTIVE MECHANISMS CAUSED BY: LOW HYDROSTATIC

PRESSURE OF PERITUBULAR CAPILLARIES, HIGH PERMEABILITY OF CAPILLARIES, HIGHER COLLOID OSMOTIC PRESSURE OF PERITUBULAR CAPILLRIES

MOSTLY IN PROXIMAL TUBULE, HAVE MICOVILLI (?) GLUCOSE:

PROXIMAL: ACTIVE TRANSPORT UNLESS RENAL PLASMA THRESHOLD IN

REACHED (DIABETES) WATER:

PROXIMAL: OSMOSIS AMINO ACIDS:

PROXIMAL: ACTIVE TRANSPORT SMALL PROTEINS:

PROXIMAL: ACTIVE TRANSPORT: ENDOCYTOSIS CREATINE, LACTIC, CITRIC, URIC AND

ASCORBIC ACID: ACTIVE TRANSPORT

ACTIVE TRANSPORT REQUIRES CARRIER MOLECULES

SODIUM AND WATER RETENTION

WATER: OSMOSIS TIED IN WITH RETENTION OF SODIUM SODIUM PUMP IN PROXIMAL SECTION CHLORIDE, PHOSPHATE AND

BICARBONATE MOVE WITH SODIUM IONS MOST REABSORPTION IN PROXIMAL

TUBULE (70%) MOST SODIUM IS RETAINED (97-99%)

TUBULAR SECRETION

EPITHELIAL CELLS OF TUBULES SECRETE SUBSTANCES ACTIVE TRANSPORT:

ORGANIC COMPOUNDS LIKE PENICILLIN, HISTAMINE

HYDROGEN IONS: WHY? POTASSIUM: WHEN ALDOSTERONE CAUSES

REABSORPTION OF SODIUM = NEGATIVE CHARGE AND POTASSIUM IS SECRETED

REGULATION OF URINE CONTENT

HORMONES: ANP; ALDOSTERONE; ADH ADH FROM ?

POSTERIOR PITUITARY CAUSES DISTAL CONVOLUTED TUBULE AND

COLLECTING DUCTS TO ADD PROTEINS – AQUAORINS: WATER CHANNELS: OSMOSIS BECAUSE OF HYPERTONIC MEDULLA

COUNTERCURRENT EFFECT: ASCENDING LOOP IMPERMEABLE TO WATER BUT LETS ELECTROLYTES OUT SO INSIDE IS HYPOTONIC AND OUTSIDE IS HYPERTONIC

DECENDING LOOP IS PERMEABLE TO WATER NOT SOLUTES, HYPERTONIC OUTSIDE SO WATER DIFFUSES OUT: TUBULAR FLUID IS CONCENTRATED

ASCENDING LOOP REABSORBS MORE SALT, SALT CONCENTRATION KEEPS MULTIPLYING: COUNTERCURRENT MULTIPLIER

MORE THAN 4X SOLUTE CONCENTRATION THAN PLASMA

SALT DIFFUSES INTO DESCENDING VASA RECTA BUT DIFFUSES OUT OF ASCENDING: MAINTAINS SALT GRADIENT IN MEDULLA

mhhe.com

UREA AND URIC ACID PRODUCTION

UREA AMINO ACID BREAKDOWN FOR

GLUCONEOGENESIS URIC ACID

METABOLISM OF A AND G 10% EXCRETED/ MOST REABSORBED

URINE COMPOSITION

VARIES ? 95% ?;UREA, URIC ACID, CREATINE,

TRACE AMINO ACIDS, ELECTROLYTES DIET & PHYSICAL ACTIVITY

VOLUME

.6-2.5L 50-60 ml/MIN LESS THAN 30 ml/min = KIDNEY FAILURE

RENAL CLEARANCE

DEFINITION: KIDNEY’S EFFICIENCY AT REMOVING A SUBSTANCE

TESTED TO SEE IF DISEASE OR DAMAGE INSULIN CLEARANCE TEST: GFR CREATININE CLEARANCE TEST: GFR:

KIDNEY FUNCTION: USUALLY ALL REMOVED FROM BLOOD TO URINE

URETERS 25 cm BEHIND PARIETAL PERITONEUM TO URINARY

BLADDER 3 LAYERS:

MUCOUS COAT: TRANSITIONAL EPITHELIUM MUSCULAR COAT: SMOOTH MUSCLE: CIRCULAR

AND LONGITUDINAL LAYERS FIBROUS COAT: CONNECTIVE TISSUE

MOVES BY PERISTALSIS: STARTED BY PRESENCE OF URINE

VALVE AT URINARY BLADDER ? KIDNEY STONE COULD INCREASE PERISTALSIS OR

SYMPATHETIC NS CONSTRICTS URETER AND KIDNEY SHUTS DOWN

URINARY BLADDER

HOLLOW, BEHIND PARIETAL PERITONEUM TRIGONE: OPENINGS TO URETER AND

URETHRA MUCOUS COAT: TRANSITIONAL

EPITHELIUM SUBMUCOSA: CONNECTIVE TISSUE WITH

GLAND CELLS MUSCULAR COAT: SMOOTH MUSCLE:

DETRUSOR MUSCLE: FORMS INTERNAL URETHRAL SPHINCTER @ NECK

ALWAYS SUSTAINED CONTRACTION PARASYMPATHETIC NS: REFLEX FOR

URINATIONSEROUS COAT: PARIETAL PERITONEUM AT

TOP, FIBROUS CONNECTIVE TISSUE REST

URETHRA

MUCOUS MEMBRANE LONGITUDINAL SMOOTH MUSCLE FIBERS URETHRAL GLANDS: MUCOUS GLANDS MALES: PROSTATIC URETHRA PASSES

THROUGH PROSTATE; MEMBRANOUS URETHRA EXTERNAL URETHRAL SPHINCTER; PENILE URETHRA

MICTURITION

MICTURITION REFLEX: STRETCH RECEPTORS STIMULATED; SIGNAL

MICTURITION REFLEX CENTER: IN SACRAL SPINAL CORD

PARASYMPATHETIC NS IMPULSE TO DETRUSOR MUSCLE TO CONTRACT

CAN STILL BE CONTROLED: EXTERNAL URETHRAL SPHINCTER, IMPULSES FROM BRAIN STEM AND CEREBRAL CORTEX

EXTERNAL URETHRAL SPHINCTER RELAXES: IMPULSES FROM HYPOTHALAMUS AND PONS

DETRUSOR MUSCLE CONTRACTS: MICTURITION IMPULSES STOP; DETRUSOR MUSCLE RELAXES,

BLADDER FILLS

LIFE SPAN CHANGES

KIDNEY CELLS START TO DIE AT 20 BUT NOT NOTICED TILL AFTER 40; 1/3 LOSS BY 80

GLOMERULI SHUT DOWN: LOSS; DAMAGE; GFR DROPS AT 40; 75: 125ml 60ml RENAL TUBULES THICKEN WITH FATTY

ACIDS; DON’T PROCESS DRUGS AND ORGANICE MATERIAL AS WELL

BLOOD FLOW DECREASES BY 50% @ 80

SLOWER TO RESPOND FOR HOMEOSTASIS: ARTERIOLES DON’T DILATE AS QUICK RELEASE OF RENIN DECREASES CAN’T ACTIVATE VITAMIN D

URETER, URINARY BLADDER AND URETHRA AREN’T AS ELASTIC: BLADDER HOLDS 50% LESS AND RETAINS MORE: MORE FREQUENT URINATION AND MORE URGENT

INCONTINENCE: LOSS OF MUSCLE TONE OF BLADDER