Urinary System
Urinary system = excretory system Responsible for removing wastes and excess water from body and maintaining acid-base balance Maintains homeostasis – state of equilibrium or constant state of the natural balance in the internal environment of the body Ex: increased water intake - increased urine output
urinary system anatomy part 1
Urinary System Two kidneys Two ureters Bladder urethra
Kidneys Bean-shaped organs located on either side of vertebral column – retroperitoneal Retroperitoneal – above waist and towards back Protected by ribs and fat
Kidney divided into 2 sections: cortex and medulla Cortex – outer section contains urine producing nephrons Medulla – inner section contains most of collecting tubules carrying urine from nephrons through kidney
Hilum – notched or indented area through which ureter, nerves, blood vessels, and lymph vessels enter and leave kidney.
Nephrons – microscopic filtering units of the kidney >1million nephrons per kidney Nephron consists of: Glomerulus, Bowman’s capsule, proximal convoluted tubule, distal convoluted tubule, collecting duct
Renal artery carries blood to kidney Connects to glomerulus (cluster of capillaries) which filter out water, mineral salts, glucose, metabolic products, etc RBC’s and proteins are not filtered out
Filtered blood leaves glomerulus and enters renal vein which carries it away from artery Substances filtered out enter Bowman’s capsule and then the convoluted tubule Substances (water, glucose, vitamins) needed by body are reabsorbed into bloodstream Excess glucose, mineral salts, some water and waste such as urea, uric acid and creatinine remain in tubule and become urine
structure and function of nephron
Urine then enters collecting ducts or tubules located in medulla These tubules enter in to renal pelvis
Ureters – muscular tubes approx 10-12 inches long extending from the renal pelvis in each kidney to the bladder Peristalsis moves urine through ureter to bladder
Bladder – hollow, muscular sac, containing rugae which allow bladder to expand to fill with urine Urge to void (urinate) occurs when bladder contains approx 250ml or 1 cup of urine Circular sphincter muscle controls opening to bladder
What makes us void? Circular sphincter muscle Receptors in bladder wall send out reflex action which opens muscle Infants can not control this muscle, older children learn to control this reflex
Urethra – tube which carries urine from bladder to outside of body Urinary meatus – external opening Females – carries only urine Males – carries urine and semen
Application Read DHO pgs 208-209 and define the following: Polyuria Oliguria Anuria Hematuria Pyuria Nocturia Dysuria Retention Incontinence Proteinuria Albuminuria
Uremia Toxic condition when kidneys fail and urinary waste products enter bloodstream S&S: headache, dizziness, N&V, ammonia odor to breath, oliguria and anuria, mental confusion, convulsions, coma, death
Cystitis Inflammation of bladder Usually caused by E.coli More common in females because have shorter urethra S&S : frequent urination, dysuria, burning sensation, hematuria, low back pain, bladder spasm, fever Tx: antibiotic and increase fluid intake
Renal Calculi Kidney stones Form when salts in urine precipitate (settle out of the solution) S&S: intense, acute pain, hematuria, N&V, frequent urge to void, Tx: strain urine, increase fluids, lithotripsy, surgical removal of stones
Kidney Failure Kidneys stop functioning Acute Renal Failure Chronic Renal Failure Waste products enter bloodstream dialysis
hemodialysis vs peritoneal dialysis