ENH220 Lec 7 Urinary and Gastrointestinal Tracts

kidneys

excretory organ via production of urine for removal of metabolic wastes ex. creatinine and urea; filters blood through the renal vein then goes through inferior vena cava to heart and then to lungs/other parts of body; located along the dorsal body wall below the diaphragm and adjacent to the vertebral column

Peritoneum

serous membrane sac that keeps abdominal organs in place

Psoas major muscle

erector muscle that runs up and down spine; keeps kidneys and spine in place

hillus

region where the blood vessels enter and leave and where the ureter exits to descend to the bladder

Renal pelvis

expanded upper end of ureter; divides into branches major calyces and minor calyces - calyces and pelvis convey urine into ureters which extend downward to enter posterior wall of bladder near its base in area called trigone

Renal pyramids

cone-shaped masses of renal tissue in the medulla that project into the minor calyces

Renal columns

Columns of cortical tissue that extend into the medulla between the pyramids

Ureters

long narrow tubes with muscular wall that propels urine toward bladder by wavelike contractions of the muscular walls (peristalsis); enters bladder at an angle - when bladder contracts, muscular wall compresses ureters to create a one-way valve as to prevent backflow of urine

Urine

Result of homeostasis; comes from blood; normal output is 1.4 L; 95% water

Bladder

distensible reservoir for urine lined by transitional epithelium continuous with lining of remainder of urinary tract

urethra

located at base of bladder with ureteral openings on either side/behind urethral opening

trigone

triangular area at base of bladder bounded by the 2 posterior ureteral orifices and anterior urethral orfice

Loop of Henle

the U-shaped tubule in the kidney where water and salt are reabsorbed into the bloodstream

Nephrons

basic structural and functional unit of kidneys; each kidney contains around one million; consists of glomerulus, renal tubule with draining collecting ducts and the associated vasculature

Glomerulus

Tuft of capillaries surrounded by Bowman's capsule in the nephron and is the main filtering unit of the kidneys; site where nitrogenous metabolic wastes are filtered from the blood

Vascular pole

site where afferent arteriole enters glomerulus and efferent arteriole exists

Bowman's capsule

expanded proximal end of the tubule of glomerulus that consists of tufts of capillaries and a visceral layer that is pushed in and becomes closely applied to capillaries of glomerulus; has long, footlike cytoplasmic processes usually called podocytes; has parietal layer (capsular epithelium/outer layer) and Bowman's space (space between 2 layers)

Bowman's space

Space between the two layers of Bowman's capsule into which the urine filters

Kidney formation

forms from masses of primitive connective tissue called mesoderm

Renal agenesis

failure of one or both kidneys to develop; bilateral or unilateral

hypertensive nephrosclerosis

complication of severe/chronic hypertension and progressive chronic renal disease; extreme elevation of blood pressure causes small arterioles and arteries in body to carry blood at much higher pressure, causing severe degenerative changes of blood vessels including thickening and narrowing of lumens - reduces blood flow through the narrowed arterioles; damage to nephrons and reduced blood flow to the glomerulus; sclerosis of the arterioles of the nephrons; common cause of chronic renal disease; reduced glomerular filtration - kidneys shrink; may progress to ESRD

Diabetic Nephropathy

glomerulus becomes damaged and leaks proteins due to change in blood vessels; higher levels of proteins in urine; manifests as progressive impairment of renal function and protein loss may lead to nephrotic syndrome

Glomerulonephritis

Nephropathy characterized by inflammation of the glomeruli caused by antigen-antibody reaction within the glomeruli; body mistakenly attacks itself in glomeruli - immune-complex

Nephrotic syndrome

marked loss of protein in urine; failure of filtration barrier in glomerulus; protein lost in urine and protein level in blood falls; causes edema due to low plasma osmotic pressure; manifests as marked leg edema and ascites; prognosis in adult is manifestation of progressive renal disease

Acute renal tubular injury

impaired renal blood flow; tubular necrosis caused by toxic drugs or chemicals; manifests as acute renal failure - oliguria, anuria; tubular function gradually recovers - treated by dialysis until function returns

Tubulointerstitial nephritis

both tubules and surrounding interstitium affected; often an allergic reaction to a drug

Renal Cysts

solitary cysts common - not associated with impairment of renal function; multiple cysts uncommon - may be associated with impaired renal function; congenital polycystic kidney disease; autosomal (adult) dominant polycystic kidney disease

Cortical tumors

renal tumors that arise from epithelium of renal tubules

adenomas

renal tumors - usually small and symptomatic

Renal carcinoma

first sign of aggressive carcinoma is blood in urine (hematuria) as result of ulceration of the epithelium of pelvis or calyces caused by growing tumor - tumor eventually invades renal vein

Transitional cell tumors

arise from transitional epithelium of urinary tract and are malignant; most arise from bladder epithelium, are low-grade malignancy and carry good prognosis; often quite vascular and bleed causing blood in urine

Nephroblastoma (Wilms Tumor)

unusual highly malignant tumor made of primitive cells; can arise in the kidney of infants/children; some resemblance to structure of embryonic kidney; neoplasm often metastasizes widely - treatment is by nephrectomy, radiotherapy/chemotherapy

Renal Calculi

stones that form anywhere in the urinary tract (kidney stones); urine becomes too concentrated and substances in urine crystallize to form stones

Staghorn calculus

renal calculus that increases in size to form large branching structures that adopt the shape of the renal pelvis and calyces where they have formed

Renal colic

paroxysms of intense flank pain radiating to the groin; usually reason for renal calculi being so painful

Chronic renal disease

classified as abnormal renal function for > 3 months; if number of functioning nephrons decreases to 30% of normal amount, renal function fails; remaining/surviving nephrons work harder at higher blood pressure and end up injured; in attempt to maintain GFR, decreased perfusion pressure is sensed by juxtaglomerular complex resulting in release of renin and activation of RAAS; often related to hemodynamic problems

Uremia/End-stage renal disease (ESRD)

retention of excessive by-products of protein metabolism in blood; fluid, electrolyte and acid-base regulation fail; metabolic acidosis occurs; lack of erythropoietin leads to anemia; level of urea in blood (blood urea nitrogen BUN) correlates with clinical condition - measurement of severity of renal failure

Renal failure

inability of kidneys to perform normal regulatory and excretory functions; uremia usually end stage; metabolic acidosis occurs; ketosis results from overproduction of acid ketone bodies, acetoacetic acid and beta-hydroxybutyric acid - derived from metabolism of fat; retention of urea in blood

Cystitis

most caused by gram-negative bacteria; affects only the bladder; sexual intercourse promotes transfer of bacteria from urethra to bladder; can be acute or chronic; common in older men since enlarged prostate interferes with bladder emptying

Gastrointestinal tract

includes mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus; digest and absorption of food, reabsorption of water, elimination of wastes

Cardiospasm (achalasia)

esophagus can erode and become scarred (Barrett's esophagus); squamous epithelia changes to columnar epithelia; incompetent cardiac sphincter

Esophageal obstruction

carcinoma in esophagus; stricture from scar tissue due to necrosis and inflammation from corrosive chemicals ex. lye

mucosal tears

caused by retching and vomiting; linear tears in mucosa or lining of esophagus leads to blood in vomit

Acute gastritis

inflammation of the gastric lining; self-limited inflammation of short duration; may be associated with mucosal ulceration/bleeding; associated with lifestyle and some medications

Helicobacter pylori gastritis

small, curved gram-negative organisms that colonize surface of gastric mucosa; grow within layer of mucus covering epithelial cells

Peptic ulcer

digestion of mucosa due to increased acid secretions or digestive enzymes (gastric acid and pepsin); usually in distal stomach/proximal duodenum; complications include hemorrhage, perforation, peritonitis, obstruction from scarring

Acute Enteritis

intestinal infections; common; of short duration; causes nausea, vomiting, abdominal discomfort, loose stools

Chronic enteritis

less common and more difficult to treat; 2 common types are chronic ulcerative colitis and Crohn's disease

Meckel's Diverticulum

Outpouching at distal ileum, 12-18 inches proximal to cecum; from persistence of a remnant of the vitelline duct, narrow tubular channel connecting small intestine with yolk sac embryologically

Colitis

inflammation of the inner lining of the colon; symptoms are abdominal pain, diarrhea, rectal bleeding

chronic ulcerative colitis

Targets the colon, not the small intestine; inflammation of rectal mucosa that may spread progressively; in severe cases ulcerated mucosa may bleed profusely leading to bloody diarrhea/perforation of colon with escape of bowel contents into peritoneal cavity; can cause carcinoma of colon/rectum

Crohn's disease

Chronic inflammation and ulceration of the bowel mucosa with marked thickening and scarring of entire bowel wall; inflammation affects scattered areas of small bowel (skip lesions); severe thickening/scarring of bowel causes lumen to narrow/become blocked which impedes passage of bowel contents; often localized to distal ileum but can involve colon/parts of small intestine

Infectious colitis

can be viral, bacterial, parasitic; inflammatory condition of colon usually caused by eating/drinking contaminated food/water; salmonella & E.coli common causes

Ischemic colitis

inflammation/injury of large intestine due to inadequate blood supply to large intestine/colon

Irritable bowel syndrome

episodes of cramping/abdominal discomfort, loud gurgling bowel sounds, disturbed bowel function with structural/biochemical abnormalities; excessive mucous secreted by colonic mucosal glands; also called spastic colitis or mucous colitis

Appendicitis

most common inflammatory lesion of the bowel; generalized/localized right lower abdominal pain; rebound tenderness

High Intestinal obstruction

severe, crampy abdominal pain from vigorous peristalsis due to blockage of normal passage of intestines

low intestinal obstruction

mild crampy abdominal pain due to mild obstuction in intestines

Common causes of intestinal obstruction

adhesions, hernia, tumor, volvulus, intussusception

Diverticulosis

outpouchings or diverticula of colonic mucosa through weak areas in the muscular wall of large intestine; acquired, usually asymptomatic; seen in older people; commonly site - sigmoid colon

Diverticulitis

inflammation incited by bits of fecal material trapped within outpouchings; complications include inflammation, perforation, bleeding, scarring, abscess

Hemorrhoids

varicose veins of hemorrhoidal venous plexus that drains rectum and anus

Internal hemorrhoids

varicose veins of the lower rectum; may erode and bleed, become thrombosed, or prolapse

external hemorrhoids

varicose veins of the anal canal and perianal skin; may become thrombosed, causing discomfort

Pedunculated polyps

benign frequent tumors of colon; tip may erode causing bleeding; removed by colonoscopy

Cecum/right half of colon carcinoma

does not cause obstruction because caliber is large and bowel contents are relatively soft

Left half of colon carcinoma

causes obstruction and symptoms of lower intestinal obstruction

Grade I Vesicoureteral Reflux

Reflux into nondilated ureter

Grade II Vesicoureteral Reflux

reflux into nondilated ureter, pelvis and calyces

Grade III Vesicoureteral Reflux

mild to moderate dilated ureters, pelvis and calyces, minimal blunting of fornices

Grade IV Vesicoureteral Reflux

moderate tortuous ureter, dilation of pelvis and calyces

Grade V Vesicoureteral Reflux

gross ureteral dilation and tortuosity, pelvis and calyces, loss of papillary impressions

Vesicoureteral reflux (VUR)

defective valve mechanism where ureters enter the bladder results in urine flowing back (reflux) into one or both ureters when bladder contracts during urination; predisposes to UTIs by preventing complete emptying of bladder; predisposes to pyelonephritis since bacteria may be carried through reflux of urine into upper urinary tract