Review the anatomy and physiology of the renal system and the GI system.
Kidneys- reddish brown kidney shaped organs measuring approx 5"x3" that weighs about 12-150g; Waste products of metabolism that collect in the blood are filtered in the kidneys; the blood is filtered in the glomerular capillaries which are porous and permit filtration of water and substances such as glucose, amino acids, urea, creatinine and major electrolytes; only 1% of glomerular filtration is excreted as urine and the rest is reabsorbed into the plasma; nl urine output is 1500-1700ml/24h and the kidney produces renin and erythropoietin.
Ureters- urine enters the renal pelvis from collecting ducts where ureters join them to the bladder; they are lumens approx 10-12" long and approx 1/2" in diameter; urine drainage from the ureter to the bladder is normally sterile; peristaltic waves cause the urine to enter the bladder in spurts rather than steadily
Bladder- is a hollow, muscular organ that is both a reservoir for urine and the organ of secretion; when empty the bladder lies behind the pubic symphysis; in men it lies on the anterior wall of the rectum; in women in the anterior wall of the uterus and vagina; the bladder capacity is about 600ml and nl voiding is 200-300ml
Urethra- urine travels from the bladder through the urethra and passes outside the body through the urethral meatus; normally the turbulent flow of urine through the urethra washes it free of bacteria; in women the urethra is 1.5- 2.5" in length; in men the urethra is approx 8" in length
Mouth- digestion begins in the mouth where mechanical and chemical breakdown of nutrients occur (mastication); food is broken down so it can be swallowed; salivary secretions contain enzymes that initiate digestion of certain food elements; saliva softens the bolus of food for easier swallowing
Esophagus- food passes from the mouth through the esophagus to the stomach where it is now referred to as chyme
Small Intestine- during normal digestion, chyme leaves the stomach and enters the small intestine; it is a tube approx 1" in diameter and 20' long which contains 3 divisions, duodenum, jejunum and ileum; chyme mixes with digestive enzymes while traveling through the small intestine; it travels slowly to allow the absorption of nutrients and electrolytes; the enzymes (bile and amalyse) in the small intestine break down fats, protein and carbs into simple elements; nutrients are almost entirely absorbed by the duodenum and jejunum; the ileum absorbs certain vitamins, iron and bile salts
Large Intestine- large in diameter then the small intestine and is 5'-6' in length; it is divided into 3 parts, the cecum, colon and rectum; it is responsible for the absorption of water and primary organ for bowel elimination; unabsorbed chyme enters the cecum at the ileocecal valve where it travels through to the colon; as watery chyme enters the colon the water volume decreases as it moves along;the colon is divided into 4 parts, ascending, transverse, descending and sigmoid colon; 4 fx of the colon are absorption, protection, secretion and elimination; a large volume of water and significant amounts of Na and Cl are absorbed by the colon daily; the amt of water absorbed from chyme depends on the speed at which colonic contents move; alterations in colon fx can cause diarrhea, electrolyte imbalance or constipation; the colon eliminates waste products and gas
Rectum- waste products that reach the sigmoid colon are called feces; this is the final division of the GI tract; its normally empty of feces until defecation; when a fecal mass moves into the rectum, the walls distend and defecation begins