GENITOURINARY SYSTEM
KIDNEY
Characteristics:
• Bean-shaped paired organs
• 150 grams
• Right kidney slightly lower than the left
• Receive 20% of cardiac output (at rest)
• Receive 2-4% cardiac output (under stress)
Location:
• Posterior abdominal wall, retroperitoneal
• T12-L3 (iliac crest)
Functions:
• Urine formation
• Excretion of waste products
• Regulation of electrolytes
• Regulation of acid-base balance
• Control of water balance
• Control of blood pressure
• Renal clearance
• Regulation of red blood cell production
• Synthesis of vitamin D to active form
• Secretion prostaglandins
• Regulates calcium and phosphorus balance
v Renal circulation
Renal Artery (hilum) branches into afferent arterioles
(Glomerular Capillary beds)
Efferent Arterioles
Renal Vein
NEPHRON
v Anatomic & functional unit of the kidney
v 1 million per kidney
v Process:
l Urine is formed in the nephrons in a three-step process:
ü Filtration – transfer of water and waste from blood to glomerulus
ü Reabsorption – water and necessary ions are transferred back into the blood
ü Excretion – excess substances and wastes are removed and transferred into urine
l Water, electrolytes, and other substances, such as glucose and creatinine, are filtered by the glomerulus;
varying amounts of these substances are reabsorption in the renal tubule or excreted in the urine.
Parts
l Glomerulus
ü Urine filtration (water & solutes except blood, albumin & fibrinogen)
ü Is a unique network of capillaries suspended between the afferent and afferent blood vessels.
l Bowman’s capsule (Glomerular capsule)
ü Collects the filtrate
ü Epithelial structures that encloses the glomerulus
l Proximal convoluted tubules (PCT)
ü Reabsorption (peritubular capillaries)
ü Glucose (active transport)
ü Sodium (active transport)
1 TOPRANK REVIEW ACADEMY- NURSING MODULE
, NURSING*RADTECH*DENTISTRY*CRIMINOLOGY*MIDWIFERY*MEDTECH
LET*PSYCHOMET*RESPIRATORY THERAPY*CIVIL SERVICE*NAPOLCOM
NCLEX*DHA*HAAD* PROMETRIC* UK-CBT
ü Chloride & Bicarbonate (diffusion)
ü 80% of water (osmosis)
l Loop of Henle
ü Reabsorption
Ø Water (osmosis)
Ø Chloride (active transport)
Ø Sodium (diffusion)
l Distal convoluted tubule (DCT)
ü Reabsorption
Ø Sodium (active transport aldosterone)
Ø Water (osmosis-ADH)
Ø Secretion (active transport)
Ø Hydrogen
Ø Potassium
Ø Ammonia
l Collecting tubules
ü Final osmotic reabsorption of water (ADH)
URETERS
v 10 -12 inches (25-30 cm)
v Expands as it enters the kidney to form the renal pelvis (subdivided into calyces each containing renal papillae)
v Collects urine secreted by the kidney & propels it to the bladder by peristaltic wave
URINARY BLADDER
v Hollow, spherical, collapsible bag of smooth muscle
v Behind the symphysis pubis
v Reservoir for urine
v Capacity of the adult bladder 300-500 mL
v Influenced by Automatic Nervous System
URETHRA
l Musculo-membranous tube lined with mucosa opening to urinary meatus
v Female
l Behind the symphysis pubis
l Anterior to the vagina
l 3-5 cm
l Passageway for expulsion of urine
v Male
l Extends through the prostate gland and semen
URINE VOLUME CONTROL
v Glomerular filtration rate (GFR)
v Constant (125 ml/min)
v Renin-Angiotensin-Aldosterone-System
v Specialized juxtaglomerular cells called densa cells secrete the hormone renin.
v Renin converts angiotensinogen to angiotensin I.
v By Angiotensin-converting enzyme (ACE) in lungs, Angiotensin I is converted to Angiotensin II the most
powerful vasoconstrictor.
v Angiotensin II causes the blood pressure to increase.
v The adrenal cortex secretes Aldosterone in response to poor perfusion or increasing serum osmolality.
v Aldosterone causes sodium retention and potassium excretion.
v “Where sodium goes, water follows.”
v The result is an increase in Blood volume and Blood pressure.
v Antidiuretic hormone (ADH)
v Plasma/Urine osmolarity
2 TOPRANK REVIEW ACADEMY- NURSING MODULE
, NURSING*RADTECH*DENTISTRY*CRIMINOLOGY*MIDWIFERY*MEDTECH
LET*PSYCHOMET*RESPIRATORY THERAPY*CIVIL SERVICE*NAPOLCOM
NCLEX*DHA*HAAD* PROMETRIC* UK-CBT
NORMAL URINE VALUES
Color: amber/straw (light yellow)
Odor: aromatic
Consistency: clear or slightly turbid
pH: 4.5-8
Specific gravity: 1.010-1.020
WBC/RBC: (-)
Albumin: (-)
E coli: (-)
Mucus thread: few
Amorphous urate: (-)
DISORDERS OF THE GENITO-URINARY TRACT
CYSTITIS
v Infection of urinary bladder
v Usually caused by an ascending bacterial infection (E.coli)
v Most common route is transurethral
v Female (shorter urethra, childbirth, anatomic proximity of urethra to rectum)
v Male (due to epididymitis, prostatitis, renal calculi)
v Predisposing factors:
l Microbial invasion - E.coli
l High risk - women
l Obstruction
l Urinary retention
l Increase estrogen levels
l Sexual intercourse
v Clinical Manifestation:
l Pain- flank area
l Hematuria
l Nocturia
l Dysuria
l Pyuria
l Fever
l Urgency
l Chills
l Suprapubic pain
l Urinary frequency
v Diagnostic Tests:
l Urine culture & sensitivity (+) to E.coli
v Management
l Pharmacologic Management
ü Antibiotics
Ø Co-trimoxazole - drug of choice
ü Antispasmodics
ü Analgesic
l Nursing Management
ü Force fluid / hydration
ü Diet
Ø Cranberry/orange juice
Ø Avoid urinary tract irritants
Ø (coffee, tea, alcohol)
ü Warm sitz bath
ü Empty bladder after sexual intercourse
ü Good hygiene
ü Encourage frequent voiding
3 TOPRANK REVIEW ACADEMY- NURSING MODULE
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