| A | B |
|---|
| major responsibility of the kidneys | eliminate nitrogenous wastes and toxins |
| other responsibilities of the kidneys | regulate blood volume, produce renin and erythropoietin, and activate vitamin D |
| renin | enzyme that helps regulate blood pressure |
| erythropoietin | hormone that stimulates red blood cell production |
| urinary system | made up of the kidneys, ureters, bladder, and urethra |
| kidney location | retroperitoneal; extend from T12 to L3 |
| kidney size | about 12 cm (5 inches) long, 6 cm (2.5 inches) wide, and 3 cm (1 inch) thick |
| renal hilum | medial indentation where structures enter and leave the kidney |
| renal capsule | encloses each kidney |
| renal cortex | outer layer of kidney; light in color |
| renal medulla | layer deep to the cortex; reddish-brown in color |
| renal pyramids | triangular regions with a striped appearance |
| renal columns | cortex-like tissue that separates each pyramid |
| renal pelvis | basin-like cavity deep to the hilum |
| calyces | cup-shaped areas that enclose the tips of the pyramids |
| renal artery | arterial supply of each kidney |
| segmental arteries | divide off the renal artery |
| interlobal arteries | branch off a segmental artery |
| arcuate arteries | form from the interlobal arteries at the cortex-medulla junction |
| cortical radiate arteries | branch off the arcuate arteries |
| cortical radiate veins | drain into arcuate veins |
| arcuate veins | drain into interlobar veins |
| interlobal veins | drain into the renal vein |
| renal vein | emerges from the hilum |
| nephron | structural and functional unit of the kidneys |
| 2 main structures of a nephron | glomerulus and a renal tubule |
| Bowman's (glomerular) capsule | cup-shaped, closed-end of the renal tubule that surrounds the glomerulus |
| podocytes | octopus-like cells of Bowman's capsule that clings to the glomerulus |
| glomerulus | knot of capillaries; fed and drained by arterioles |
| peritubular capillaries | arise from the efferent arteriole, which drains the glomerulus |
| 3 regions of the renal tubule (from the capsule) | proximal convoluted tubule, loop of Henle, and distal convoluted tubule |
| most nephrons | located in the cortex |
| number of nephrons | roughly 1 million per kidney |
| filtrate | blood plasma without blood cells and blood proteins |
| portion of filtrate reclaimed by the tubule | roughly 99% |
| substances returned to blood | water, glucose, amino acids, and ions |
| tubular reabsorption | begins when filtrate enters the proximal convoluted tubule |
| nitrogenous waste products | urea, uric acid, and creatinine; are scarcely reabsorbed |
| urine under normal conditions | is sterile, slightly acidic, more dense than water, aromatic, and contains ammonia |
| ureter | connects the renal hilum to the bladder |
| ureter dimensions | 10 to 12 inches long and 1/4 inch in diameter |
| lithrotripsy | ultrasonic treatment for kidney stones |
| transitional epithelium | special epithelium that allows the bladder to expand |
| average adult bladder | moderately full with 500 mL (1 pint) of urine |
| urethra | transported from the bladder to the outside of the body |
| urethra length | 1.5 inches in females; 8 inches in males |
| internal urethral spincter | involuntary urethral spincter |
| external urethral spincter | voluntarily controlled spincter |
| micturition (voiding) | emptying the bladder |
| incontinence | occurs when we are unable to voluntarily control the external spiincter |
| hyperplasia of the prostate | when the prostate enlarges it narrows the urethra, making it difficult to void |
| quantity of blood filtered per day | between 150-180 liters |
| kidneys 4 major roles in blood composition | excretion of waste, water balance, electrolyte balance, and ensuring pH |
| water weight in a healthy adult | about 50% in women and 60% in men |
| total body water | approximately 40 L |
| intracellular fluid (ICF) | approximately 25 L |
| extracellular fluid (ECF) | includes interstitial fluid (IF) and plasma |
| interstitial fluid (IF) | approximately 12 L |
| plasma | approximately 3 L |
| thirst mechanism | when an increase in solute content excites osmoreceptors |
| osmoreceptors | sensitive cells in the hypothalamus |
| average daily beverage intake and urine output | approximately 1500 mL |
| additional ways that water leaves the body | through the lungs and perspiration |
| antidiuretic hormone (ADH) | prevents excessive water loss by promoting reabsorption in the collecting duct |
| aldosteone | regulates sodium ion concentration of the extracellular fluid |
| renin-angiotensin mechanism | focus is blood pressure regulation, not water/electrolyte balance |
| normal blood pH | 7.35 - 7.45 |
| bicarbonate buffer system | carbonic acid and salt that ties up positively charged hydrogen ions |
| when blood pH rises | the respiratory control centers of the brain are depressed |
| voluntary urethral sphincter control | related to nervous system control |
