Health Science Technology Dr. Halbert Urinary System Health Science Technology Dr. Halbert

Urinary system = excretory system Removes some wastes & excess water and maintains pH balance Consists of 2 kidneys, 2 ureters, bladder and urethra

Kidney On either side of vertebral column separated from the abdominal cavity by peritoneum Enclosed in a mass of fatty tissue called adipose capsule Also covered by tough fibrous tissue called renal fascia or fibrous capsule

Kidney structure 2 main sections Cortex Medulla Cortex: outer section, contains most of the nephrons Medulla: inner section, contains most of the collecting tubules, which carry the urine from the nephrons thru the kidney

Hilum Notched or indented area of the kidney thru which ureter, blood vessels & lymph vessels enter & leave kidney

Nephron Filtering unit of kidney One million nephrons per kidney Consists of Glomerulus Bowman’s capsule Proximal convoluted tubule Distal convoluted tubule Collecting duct

Glomerulus First part of nephron Cluster of capillaries As blood passes thru from renal artery, water, mineral salts, sugar are filtered out of blood RBCs & proteins are not filtered out Filtered blood makes its way to renal vein

Bowman’s capsule C-shaped structure that surrounds the glomerulus & is start of convoluted tubule Picks up filtered material from glomerulus & passes them to convoluted tubule

Passing through tubules Substances needed by body are reabsorbed & returned to blood capillaries Excess sugar, mineral salts; some water; & wastes remain in tubule & become urine Urine enters collecting ducts located in medulla

Renal Pelvis Collecting ducts empty into renal pelvis, funnel-shaped structure which is first section of ureter

Ureters Two muscular tubes About 10-12 inches Peristalsis moves urine through the ureter to the bladder

Bladder Hollow muscular sac that lies behind the symphysis pubis & at midline of pelvic cavity Mucous membrane lining arranged in folds, rugae which disappear as bladder expands with urine

Bladder wall Formed by three layers of smooth muscle Bladder stores urine until eliminated Urge to void occurs when bladder contains 250 cc (1 cup) of urine but bladder can hold much more

Sphincter Circular muscle controls opening of bladder to prevent emptying

Urethra Tube that carries urine from the bladder to the outside External opening is the urinary meatus

Urethra Male vs Female Female Male 3.75 cm (1½ in) Carries only urine Opens in front of vagina Male 20 cm (8 in) Carries urine & semen Passes through prostate & out through penis

Urine Liquid waste product produced by urinary system 95% water Waste products: urea (major waste product), uric acid, creatinine, mineral salts, pigments Urochrome: pigment giving urine its yellow color About 1½ to 2 quarts produced daily from 150 quarts of liquid that is filtered through the kidney

Terms Polyuria: excessive urination Oliguria: decreased amounts of urine Anuria: absence of urine Hematuria: blood in urine Pyuria: pus in urine Nocturia: urination at night Dysuria: difficult or painful urination Retention: inability to empty the bladder Incontinence: involuntary urination

Diseases of Urinary System

Cystitis Inflammation of the bladder Usually caused by pathogens entering urinary meatus More common in females

Glomerulonephritis Inflammation of the glomerulus Acute form: usually follows a streptococcal infection Chronic form: progressive disease that causes scarring of the glomeruli leads to kidney failure

Pyelonephritis Inflammation of kidney tissue & renal pelvis usually caused by bacteria

Renal calculus Kidney stone Calculus is formed when salts in the urine precipitate May become lodged in renal pelvis or ureter

Renal failure When kidneys stop functioning Acute renal failure (ARF): caused by hemorrhage, shock, poisoning, injury, dehydration Chronic renal failure (CRF): results from progressive loss of kidney function, caused by hypertension, toxins, endocrine disease, chronic glomerulonephritis

Uremia Toxic condition that occurs when kidneys fail & waste products are present in blood stream

Urethritis Inflammation of the urethra usually caused by bacteria, viruses or chemicals

Image Citations Slide 3: Anatomy of the urinary system, front view, 1/1/07, http://www.health.uab.edu/default.aspx?pid=65499 Slide 5: Illustration of the anatomy of the kidney, 1/1/07, http://www.uchospitals.edu/online-library/content=P01468 Slide 8: Glomerulus, 2/17/07, http://www.aic.cuhk.edu.hk/web8/Hi%20res/Glomerulus.jpg Slide 13: Male Bladder & urethra, 2/17/07, http://www.ivy-rose.co.uk/Topics/Urinary/Bladder_Urethra_Female_cIvyRose.jpg Slide 18: Urine, 2/17/07, http://www.open2.net/open2static/source/file/root/32/15/132078/urine.jpg Slide 21: Cystitis, 2/17/07, http://www.pathology.vcu.edu/education/renal/lab2.p.html