Excretory System

BY Lisa Kruk, Tara Quaghebeur, Duncan Kirk

Excretory System• The primary functions of the excretory system are; • Get rid of wastes from the human body• Eliminates useless by-products excreted from cells• Eradicates harmful chemical build-ups• Maintains a steady, balanced chemical

concentration• The excretory system consists of specialized

structures and capillary network

Kidney Structure

• The lateral surface of each kidney is convex, but its medial side is deeply concave. The medial depression leads into a hollow chamber; renal sinus. Hilum is the entrance of the sinus, which passes various blood vessels, nerves, lymphatic vessels, and the ureter. The superior end of the ureter is expanded to form a funnel-shaped sac; renal pelvis, which is located inside of the renal sinus. The pelvis is sub divided into two or three tubes; major calyces (sing, calyx) and subdivided into several minor calyces.

• Series of small elevations project into the renal sinus from its wall. The projections are called renal papillae, each are pierced by tiny openings that lead into a minor calyx.

Kidney Structure • The renal cortex forms a shell around the

medulla. Its tissue dips into the medulla between adjacent renal pyramids that from renal columns. The granular appearance of the cortex is due to the random arrangement of tiny random arrangement of tiny tubules that associate with the nephrons; functional units of the kidney.

Ureters Structure• Each ureter is a tubular organ that measures about twenty-five

centimeters in length and begin at the funnel-shaped renal pelvis.

• In the walls of the ureter there are three layers; inner layer, middle layer, and the outer layer.

• The inner layer or mucous coat is continuous with the linings of the renal tubules above and the urinary bladder below.

• The middle layer or the muscular coat is composed of large smooth muscle fibers.

• The outer layer or the fibrous coat is primarily composed of connective tissue.

Ureters Structure

• Each ureter enters the bladder through a tunnel in the bladder wall, which is angled to prevent the urine from running back into the ureter (reflux), when the bladder contrasts.

Bladder Structure• The bladder is a spherical shaped hollow, expandable,

muscular organ located in the pelvic girdle. • The shape is alerted by the pressures of surrounding

organs. When the bladder is empty, the inner walls of the bladder forms fold. When the bladder fills with urine, the walls become smoother.

• Internal floor of the bladder includes a triangular area; trigon. The trigone has three openings at each of its angles.

• The ureters are attached to the two posterior openings. The anterior opening, at the apex of the trigone, and contains a funnel-like continuation called the neck of the bladder.

Bladder Structure• Walls of the bladder consist of four bundles of smooth

muscle fibers. These muscle fibers, interlaced, form the detrusor muscle (surrounds the bladder neck) and comprise what is called the internal urethral sphincter.

• The internal urethral sphincter prevents urine from escaping the bladder until the pressure inside the bladder reaches a certain level.

• Parasympathetic nerve fibers in the detrusor muscle function in the micturition (urination) process.

Urethra Structure

• The urethra transmits urine from the bladder to the exterior of the body during urination.

• Urethra is held by the urethral s sphincter, a muscular structure that helps keep urine in the bladder until voiding can occur.

• The male’s urethra is about 8 Inches long and passes along the length of the penis before emptying. As its emergence from the bladder, the urethra passes through the prostate gland, and seminal ducts from the testes enter the urethra at each side, making it the pathway for the transmission of semen as well as for discharge of urine.

• The male urethra can be divided into three sections; the uppermost within the prostate, the next section within the urethral sphincter, and the lowermost and longest section with the penis.

Urethra Structure

• The female urethra is embedded within the vaginal wall, and its opening is situated between the labia. It is shorter than that of a male, it is one and a half inches long. It opens to the outside just after passing through the urethral sphincter.

PathologyUrethritisUrethritis is the physical examination of the males’ reproductive organ it is checked for inflammation or swelling of the urethra.

Causes are: • Engaging in sexual activity without using protection• Doing sexual activity with many sexual partners• Having history of STD’s

Symptoms include: • Painful of difficult urination• Purulent discharge in the reproductive organ.

Treatment: Azithromycin, doxycycline, erythromycin, levofloxacin, metronidazole, ofloxacin, or tinidazole are all possible drugs that will treat this.

PathologyKidney StonesKidney stones are essentially stones composed of minerals and calcium that leave the body through urination.

Causes: • Low fluid intake • Ingesting large amounts of animal protein• High intake of sodium, sugars and fructose

Symptoms: • Pain in flank and groin area • Sweating• Nausea• Vomiting

Treatment: Analgesia, expulsion therapy, extracorporeal shock wave lithotripsy, ureteroscopic surgery

Bibliography for pathology

• http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001475/

• http://www.cdc.gov/std/treatment/2010/urethritis-and-cervicitis.htm/