URINARY SYSTEM
A&P
URINARY SYSTEM
• AKA EXCRETORY SYSTEM
• REMOVES WASTES & EXCESS WATER
• MAINTAIN ACID-BASE BALANCE
• HELPS MAINTAIN BODY’S HOMEOSTASIS
URINARY SYSTEM
PARTS OF THE URINARY SYSTEM:
2 KIDNEYS
2 URETERS
1 BLADDER
1 URETHRA
KIDNEYS
• BEAN-SHAPED ORGANS
• FOUND ON EITHER SIDE OF VERTEBRAL COLUMN
• LOCATED IN RETROPERITONEAL SPACE
• RETROPERITONEAL SPACE=AREA BEHIND UPPER PART OF
ABD CAVITY; SEPARATED FROM ABD CAVITY BY
PERITONEAL MEMBRANE
KIDNEYS
• PROTECTED BY RIBS & FAT CUSHION
• HELD IN PLACE BY CONNECTIVE TISSUE
• EACH KIDNEY IS ENCLOSED IN MASS OF FATTY
TISSUE=ADIPOSE CAPSULE
• EACH KIDNEY IS COVERED BY A TOUGH, FIBROUS
TISSUE=RENAL FASCIA OR FIBROUS CAPSULE
KIDNEYS
DIVIDED INTO 2 MAIN SECTIONS: CORTEX & MEDULLA
CORTEX=
oOUTER SECTION
oCONTAINS MOST OF THE NEPHRONS (NEPHRONS AID IN
PRODUCTION OF URINE)
KIDNEYS
MEDULLA=
oINNER SECTION
oCONTAINS MOST OF THE COLLECTING TUBULES
(COLLECTING TUBULES CARRY URINE FROM NEPHRONS
THROUGH THE KIDNEY)
KIDNEYS
• EACH KIDNEY HAS A HILUM
• HILUM=NOTCHED OR INDENTED AREA
• THE URETER, NERVES, BLOOD VESSELS, & LYMPH VESSELS
ENTER & LEAVE THE KIDNEY THROUGH THE HILUM
KIDNEYS
• NEPHRONS=MICROSCOPIC FILTERING UNITS OF THE
KIDNEY
• THERE ARE MORE THAN 1 MILLION NEPHRONS PER
KIDNEY
KIDNEYS
EACH NEPHRON CONSISTS OF A:
GLOMERULUS
BOWMAN’S CAPSULE
PROXIMAL CONVOLUTED TUBULE
DISTAL CONVOLUTED TUBULE
COLLECTING DUCT (TUBULE)
KIDNEYS
• THE RENAL ARTERY CARRIES BLOOD TO THE KIDNEY
• BRANCHES OF THE RENAL ARTERY PASS THROUGH THE
MEDULLA TO THE CORTEX
• THIS IS WHERE BLOOD ENTERS THE 1ST PART OF THE
NEPHRON, THE GLOMERULUS
• GLOMERULUS=CLUSTER OF CAPILLARIES
KIDNEYS
• WATER, MINERAL SALTS, GLUCOSE, METABOLIC
PRODUCTS, & OTHER SUBSTANCES ARE FILTERED OUT OF
THE BLOOD AS IT PASSES THROUGH THE GLOMERULUS
• RBCS & PROTEINS ARE NOT FILTERED OUT
KIDNEYS
• FILTERED BLOOD LEAVES THE GLOMERULUS & MOVES TO
THE RENAL VEIN WHICH CARRIES IT AWAY FROM THE
KIDNEY
• THE SUBSTANCES FILTERED OUT BY THE GLOMERULUS
ENTER THE NEXT SECTION OF THE NEPHRON,
BOWMAN’S CAPSULE
KIDNEYS
• BOWMAN’S CAPSULE=C-SHAPED STRUCTURE THAT
SURROUNDS THE GLOMERULUS
• IT IS THE START OF THE CONVOLUTED TUBULE
• BOWMAN’S CAPSULE PICKS UP THE FILTERED MATERIALS
& PASSES THEM INTO THE CONVOLUTED TUBULE
KIDNEYS
• AS THE FILTERED MATERIAL PASSES THROUGH THE
TUBULE, SUBSTANCES NEEDED BY THE BODY ARE
REABSORBED AND RETURNED TO THE BLOOD
CAPILLARIES
• THOSE SUBSTANCES ARE MOST OF THE WATER,
GLUCOSE, VITAMINS, AND MINERAL SALTS
KIDNEYS
• EXCESS GLUCOSE AND MINERAL SALTS, SOME WATER,
AND WASTES (UREA, URIC ACID, AND CREATININE)
REMAIN IN THE TUBULE
• THESE EXCESS SUBSTANCES ARE A CONCENTRATED
LIQUID=URINE
KIDNEYS
• URINE ENTERS COLLECTING DUCTS (TUBULES) LOCATED
IN THE MEDULLA
• THE COLLECTING DUCTS EMPTY INTO THE RENAL PELVIS
(RENAL BASIN),
• RENAL PELVIS=FUNNEL-SHAPED STRUCTURE THAT IS THE
1ST SECTION OF THE URETER
URETERS
• 2 MUSCULAR TUBES
• 10-12 INCHES LONG
• RENAL PELVIS=FUNNEL-SHAPED 1ST SECTION OF URETER
• ONE URETER EXTENDS FROM THE RENAL PELVIS OF EACH
KIDNEY TO THE BLADDER
URETERS
• PERISTALSIS MOVES URINE THROUGH URETER FROM
KIDNEY TO BLADDER
BLADDER
• HOLLOW, MUSCULAR SAC
• FOUND BEHIND SYMPHYSIS PUBIS
• LOCATED AT MIDLINE OF PELVIC CAVITY
• RECEIVES URINE FROM URETERS
• STORES URINE UNTIL IT IS VOIDED
• VOID=URINATE=MICTURATE
BLADDER
• LINED WITH MUCOUS MEMBRANE
• MUCOUS MEMBRANE HAS RUGAE (FOLDS)
• RUGAE DISAPPEAR AS BLADDER EXPANDS TO FILL WITH
URINE
• BLADDER WALLS ARE MADE OF TRIPLE LAYER OF
VISCERAL (SMOOTH) MUSCLE
BLADDER
• CIRCULAR SPHINCTER MUSCLE CONTROLS THE BLADDER
OPENING TO PREVENT EMPTYING
• RECEPTORS IN BLADDER SEND OUT A REFLEX ACTION
WHICH OPENS THE MUSCLE
• URGE TO VOID OCCURS WHEN BLADDER HAS 250ML
BUT IT CAN HOLD MUCH MORE
BLADDER
• INFANTS CANNOT CONTROL THE REFLEX ACTION
• AS CHILDREN GROW, THEY LEARN TO CONTROL THE
REFLEX
URETHRA
• TUBE THAT CARRIES URINE FROM BLADDER TO OUTSIDE
OF BODY
• URINARY MEATUS=EXTERNAL OPENING OF URETHRA
URETHRA
FEMALE URETHRA:
1.5 INCHES LONG
OPENS IN FRONT OF VAGINA
CARRIES ONLY URINE
URETHRA
MALE URETHRA:
8 INCHES LONG
PASSES THROUGH THE PROSTATE GLAND
EXISTS THE PENIS
CARRIES BOTH URINE & SEMEN (NOT AT THE SAME
TIME)
URINE
• LIQUID WASTE PRODUCT OF URINARY SYSTEM
• APROX 95% WATER
• CONTAINS DISSOLVED WASTE PRODUCTS:
UREA, URIC ACID, CREATININE, MINERAL
PIGMENTS
SALTS,
URINE
• EXCESS USEFUL PRODUCTS (LIKE SUGAR) CAN ALSO BE
FOUND IN URINE
• WHEN USEFUL PRODUCTS ARE IN URINE, IT USUALLY
INDICATES DISEASE
URINE
• KIDNEYS FILTER ABOUT 150 QUARTS OF LIQUID DAILY
• ABOUT 1,500-2,000 ML (1.5-2 QUARTS) OF URINE ARE
PRODUCED DAILY
URINATION TERMS
TERMS USED TO DESCRIBE CONDITIONS THAT AFFECT
URINATION:
POLYURIA=EXCESSIVE URINATION
OLIGURIA=BELOW NORMAL AMOUNT OF URINE
ANURIA=ABSENCE OF URINATION
HEMATURA=BLOOD IN URINE
URINATION TERMS
PYURIA=PUS IN URINE
NOCTURIA=URINATION AT NIGHT
DYSURIA=PAINFUL URINATION
RETENTION=INABILITY TO EMPTY BLADDER
INCONTINENCE=INVOLUNTARY URINATION
URINATION TERMS
PROTEINURA=PROTEIN IN URINE
ALBUMINURA=ALBUMIN (A BLOOD PROTEIN) IN URINE