Da+Kidney+GMS

The Kidney 1. Describe the path of urine and the structure and function of each organ in this path. (detail). pp.188-189 Kidneys - paired organs located nera the small of the back, on either side of the vertebral column. Kindeys are bean shaped. The Ureters conduct urine from the kidneys to the bladder. They are small muscular tubes about 25 cm long and 5 mm in diameter. The wall of a ureter has three layers, inner mucosa a smooth muscle layer and an outer fibrous coat of connective tissue. The urinary bladder stores urine until until it is expelled from the body. The bladder has three openings: two for the ureters and one for the urethra which drains the bladder 2. Describe the four functions of the kidney and how they contribute to homeostasis (balance) (detail) p. 189 Excretion of metabolic wastes - the kidneys excrete metabolic wastes, notably nitrogenous wastes. Urea is the primary nitrogenous end product of metabolism in human beings. Maintenance of water-salt balance - A principal function of the kidneys is to maintain the appropriate water-salt balance of the blood. Blood volume is intimately associated with the salt balance of the body. Maintenance of Acid-base balance - The kidneys regulate the acid-base balance of the blood. In order for a person to remain healthy the blood pH should be just about 7.4 Secretion of hormones - The kidneys assist the enocrine system in hormone secretion. The kidneys rlease renin, a substance that leads to the secretion of the hormone aldosterone involved in regulating the water-salt balance of the blood 3. Trace the path of blood through the kidney. pp.191-192 Renal artery, afferent arrteriole, golmerular capsule, efferent arteriole, peritubular capillary network, venule, renal vein 4. What microscopic structure is responsible for the production of urine in the kidney? p. 191 nephrons 5. Describe the parts of the nephron (detail). pp.192-193 Each nephron has its own blood supply including two capillary regions. From the renal artery an afferent arteriole leads to the glomerulus a knot of capillaries inside the golmerular capsule. blood leaving the glomerulus enters the effernt arteriole. The efferent rteriole takes blood to the peritubular capillary network which surrounds the rest of the nephron 6. What are the major processes of urine formation and how does the nephron carry out each process? p. 195 Glomerular filtration - nephrons in the kidney filter 180 liers of water per day along with small molecules and ions Tubular Reabsorption - occurs as molecules and ions are both passively and actively reabsorbed from the nephron into the blood of the peritubular capillary network. the substances that are not reabsorbed become the tubular luid which enters the loop of the nephron. Tubular Secretion - occurs along the length of the kidney tubule. a second way by which substances are removed from blood and added to the tubular fluid 7. Explain how an artificial kidney cleanses the blood. p. 200 patients blood in pumped through dialysis tubing, it is sposed to a dialysate. wastes exit from the blood into the solution because of prestablished concentration gradiant. in this way blood is not only cleansed but its water salt and acid base balances can also be adjusted 8. How do the kidneys assist other body systems? p. 201-202 kidneys assist the endocrine system and also the cardiovascular system by producing erythropoietin. the kideys assist the skeletal, nervous and muscular systems by hellping to regulate the amount of calcium ions in the blood. The kidneys convert vitamin D to its active form needed for absoprtion by the digestive tract and they regulate the exretion of electrolytes. The kidneys also regulate the sodium and ptassium content of the blood