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URINARY SYSTEM. HST I SPRING 2010. Anatomy and Physiology. Urinary elimination depends on the function of the:. Kidneys Ureters Bladder Urethra. Kidneys. Paired Reddish-brown color Bean-shaped Lie on either side of the vertebral column
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URINARY SYSTEM HST I SPRING 2010
Urinary elimination depends on the function of the: • Kidneys • Ureters • Bladder • Urethra
Kidneys • Paired • Reddish-brown color • Bean-shaped • Lie on either side of the vertebral column • Extend to the 12th thoracic and third lumbar vertebrae • Left kidney is normally higher than the right due to the anatomical position of the liver
Kidneys • Waste products of metabolism that collect in the blood are filtered in the kidneys • Blood reaches the kidneys by a renal artery that branches from the abdominal aorta • Approximately 20-25% of the cardiac output circulates daily through the kidneys • Each kidney contains 1 million nephrons
Kidneys • Responsible for maintaining normal Red Blood Cell (RBC) volume • Produce erythropoietin, a hormone released primarily from specialized glomerular cells that sense decreased RBC oxygenation • After being released from the kidney erythropoietin functions within the bone marrow to stimulate erythropoiesis (production of mature RBCs)
Renin • Another hormone produced by the kidneys • Major role is the regulation of blood flow in times of renal ischemia (decreased blood supply)
Anatomy of Kidney • Cortex –hard outer layer • Medulla – fleshy portion • Pyramids – triangular shaped open areas • Nephrons – microscopic units that make urine. • Renal sinus or pelvis – collection basin for urine at base of kidney
Nephron • The functional unit of the kidney, forms urine • Composed of the glomerulus, Bowman’s capsule, proximal convoluted tubule, loop of Henle, distal tubule, and collecting duct
Glomerulus • Initial site of filtration of the blood and the beginning of urine formation • The capillaries here are porous and allow filtration of water and substances such as glucose, amino acids, urea, creatinine, and major electrolytes into the Bowman’s capsule • Large proteins and blood cells are not normally filter through
Glomerulus • The presence of large proteins in the urine (proteinuria) is a sign of glomerular injury • Filters approximately 125ml of filtrate per minute
Bowman’s Capsule • A C-Shaped structure • Surrounds the glomerulus • Is the start of the convoluted tubule • Passes the filtered materials into the convoluted tubule
Tubules • Filtered substances needed by the body are reabsorbed and returned to the blood through capillaries • Most of the sugar, water, and salts are reabsorbed • Urea, uric acid, and creatinine remain in the tubules
Ureters • Tubular structures measuring 25-30cm in length and 1.25cm in diameter • Extend from renal pelvis to bladder • Peristalsis of the muscular layer of the ureter transport urine through this structure
Bladder • Hollow, distendable muscular sac • Located behind symphysis pubis • Midline in pelvic cavity • Lined with mucous membrane • Reservoir for urine, minimum held usually 300ml
Urethra • Tube that carries urine from the bladder outside of the body • External opening is called the urinary meatus • Different in male and females • Normally the turbulent flow of urine washes it free of bacteria
Male Urethra • About 8 inches long • Passes through the prostate gland and through the penis • Carries both urine and semen
Female Urethra • About 1.5 inches long • Opens in above the vagina • Carries only urine outside the body
Urine • About 1500 to 2000ml (1 1/2 - 2 QTS) produced daily • 150 Quarts of liquid filtered through kidneys daily • Made up of concentrated liquid or urea, uric acid, creatinine, mineral salts, pigments, and 95% water • Liquid waste product produced by urinary system
Urine Consistency • Normal – clear, straw colored • Cloudy – white blood cells, pus – infection • Lighter the color – more water • Darker the color – more waste • Pink or red color – blood
Act of Urination • Several brain structures influence bladder function, including the cerebral cortex, thalamus, hypothalamus, and brainstem • Together they suppress contraction of the bladder’s muscles until a person wishes to void (urinate)
Act of Urination • The desire to urinate can be sensed when the bladder contains approximately 150ml of urine • As the volume increases, the bladder walls stretch, sending sensory impulses to the brain • Impulses from the brain then cause rhythmic contraction of the bladder muscles • The urethral sphincter relaxes so that urine can enter the urethra (although voiding does not occur yet)
Act of Urination • As the bladder continues to contract, nerve impulses travel to the brain making a person conscious of the need to urinate • If the person chooses not to void, then the external urinary sphincter remains contracted, and the urinary reflex is stopped. • If the person chooses to void, the external sphincter relaxes, nerve impulses stimulate the bladder to contract, and emptying of the bladder occurs
Cystitis • Inflammation of the bladder usually caused by pathogens entering the urinary system
Glomerulonephritis • Inflammation of the glomerulus of the kidney (two types) • Acute – follows a streptococcal infection • Chronic – a progressive disease causing scarring and sclerosing of the glomeruli
Pyelonephritis • Inflammation of the kidney tissue and renal pelvis caused by pyogenic ( pus forming) bacteria
Renal Calculus • A kidney stone • Formed when salts in the urine precipitate • Small calculi may be eliminated in the urine, but larger stones often become lodged in the renal pelvis or ureter
Renal Failure • When the kidneys stop functioning (two types) • Acute – caused by hemorrhage, shock, injury, poisoning, nephritis, or dehydration • Chronic – results from progressive loss of kidney function
Uremia • A toxic condition that occurs when the kidneys fail and urinary waste products are present in the bloodstream.
Urethritis • An inflammation of the urethra, usually caused by bacteria
Dialysis Technician • Operates machines that remove waste and excess fluids from the blood of patients whose kidneys can no longer carry out those functions.
Medical Laboratory Technician • Works under supervision of a medical technologist or physician to perform test on tissue, blood and body fluids to help physicians diagnose and treat diseases.
Medical Laboratory Technologist • A health care professional who performs test procedures in laboratories using sophisticated instruments to aid in the diagnosis, prognosis and treatment of diseases.
Nephrologist • A doctor who is a kidney specialist.
Urologist • A doctor who specially deals with the urinary system which includes the bladder, the urethra and possibly the ureters.
Bladder– vesicle that acts as the reservoir for the urine • Bowman’s capsule – part of the renal corpuscle in the kidney; picks up substances filtered from the blood by the glomerulus • Cortex – the outer section of the kidney
Excretory system – also known as the urinary system, responsible for removing certain wastes and excess water from the body and for maintaining the body’s acid- base balance • Glomerulus – microscopic cluster of capillaries in Bowman’s capsule of the nephron in the kidney
Hilum – a notched or indented area through which the ureter, nerves, blood vessels, and lymph vessels • Homeostasis – a constant state of natural balance within the body • Kidneys – bean-shaped organ that excretes urine; located high and in back of the abdominal cavity
Medulla – the inner section of the kidney; contains most of the collecting tubules which carry the urine from the nephrons • Nephrons – microscopic filtering units located in the kidneys; consists of a glomerulus, a Bowman’s capsule; a proximal convoluted tubule, a distal convoluted tubule and a collecting duct.
Renal pelvis – a funnel shaped structure that is the first section of the ureter • Ureters – tubes that carry urine from the kidneys to the urinary bladder • Urethra – tube that carries urine from the urinary bladder to outside the body • Urinary meatus – external opening of the urethra
Urine – the fluid excreted by the kidney • Void – to empty the bladder; urinate
Nephro (o) denotes kidney • Nephritis – inflammation of the kidney • Nephrohydrosis – disease condition of water in the kidney • Nephrolithiasis – disease condition of rock/stone in the kidney
Nephropathy – disease of the kidney • Nephroptosis – falling out/prolapse of the kidney • Nephrolithotomy – surgical incision to remove rock/stone in the kidney • Nephrosclerosis – disease condition of hardening of the kidney
Hydornephrosis – disease condition of water in the kidney • Nephrostomy – opening/mouth of the kidney
Pyel (o) denotes pelvis of the kidney • Pyelitis – inflammation of the pelvis of the kidney • Pyeloscopy – visual examination of the pelvis of the kidney • Pyelophlebitis – inflammation of the vein and pelvis of the kidney
Pyelectasis – dilatation of the pelvis of the kidney • Pyelotomy – surgical incision of the pelvis of the kidney • Pyelolithotomy – surgical incision to remove rock/stone in pelvis of the kidney