urinary system Flashcards
principal organs of the urinary system;
kidney
regulates the content of blood plasma to maintain “dynamic constancy,” or homeostasis, of the internal fluid environment within normal limits
urinary system
comprise much of the medullary tissue; papilla is at the tip of each pyramid and releases urine through multiple ducts
renal pyramids
where cortical tissue dips into the medulla between the pyramids
renal columns
kidneys are highly vascular
blood vessels of the kidney
large branch of the abdominal aorta; brings blood into each kidney (renal vein= blood away from kidney)
renal artery
extend to the nephrons(filter blood) and (microscopic functional units of kidney tissue)
afferent arterioles
Tube running from each kidney to the urinary bladder
2 of them
ureter
Reservoir for urine before it leaves the body
Aided by the urethra, expels urine from the body
function of urinary bladder
muscle contracts at first, then at appropriate time relaxes to release urine
External urethral sphincter
the microscopic functional units, comprise the bulk of the kidney; each nephron is made of two regions (renal corpuscle and renal tubule) and connects to a shared collecting duct
nephrons
made of the glomerulus tucked inside a Bowman capsule; located within the cortex of the kidney
renal corpuscle
cup-shaped mouth of the nephron
Formed by parietal and visceral walls with a space between them
bowman (glomerular) capsule
network of fine capillaries surrounded by Bowman capsule
glomerulus
formed by glomerular endothelium, basement membrane, and the visceral layer of Bowman capsule; function is filtration
Glomerular capsular membrane
Proximal convoluted tubule: first part of the renal tubule nearest to Bowman capsule; follows a winding, convoluted course; also known as the proximal tubule (most reabsorption happens here)
renal tubules
most absorption happens
renal tubules
henle (nephron) loop
Renal tubule segment just beyond the proximal tubule
convoluted tubule beyond the Henle loop; also known as the distal tubule
distal convoluted tubule
located where the afferent arteriole brushes past the distal convoluted tubule
Juxtaglomerular apparatus
Straight duct joined by the renal tubules of several nephrons
Collecting ducts of one renal pyramid converge to form one tube that opens at a renal papilla into a minor calyx
collecting duct
Afferent arteriole enters
glomerular capillary network
leaves glomerulus and extends to the peritubular blood supply
Efferent arteriole
straight arterioles that run alongside Henle loop
vase rectae
surround renal tubule
Peritubular capillaries
movement of water and protein-free solutes from plasma in the glomerulus into the capsular space of Bowman capsule
filtration
movement of molecules out of the tubule and into peritubular blood
tubular reabsorption
movement of molecules out of peritubular blood and into the tubule for excretion
tubular secretion
first step in blood processing
filtration
Filtration occurs as a result of a
pressure gradient
second step in urine formation
reabsorption
Reabsorption in the Henle loop
Two countercurrent mechanisms
Countercurrent multiplier mechanism
Countercurrent exchange mechanism
are reabsorbed from the filtrate in the ascending limb, where the reabsorption of salt makes the tubule fluid dilute and creates and maintains a high osmotic pressure of the medulla’s interstitial fluid
sodium and chloride
targets the cells of distal tubules and collecting ducts to make them more permeable to water
Antidiuretic hormone (ADH)
the movement of substances out of the blood and into tubular fluid
tubular secretion
hormone that targets the cells of the distal tubule and collecting duct cells; causes increased activity of the sodium-potassium pump
aldosterone
secreted by atrial muscle fibers, promotes loss of sodium by urine; opposes aldosterone, thus causing the kidneys to reabsorb less water and thereby produce more urine
Atrial natriuretic hormone
secreted by the adrenal cortex, increases distal tubule absorption of sodium, thereby raising the sodium concentration of blood and thus promoting reabsorption of water
aldosterone
influences water reabsorption; as water is reabsorbed, the total volume of urine is reduced by the amount of water removed by the tubules; ADH reduces water loss
ADH
rapid and effective regulation of GFR by changes in afferent arteriole smooth muscle contraction and relaxation
myogenic mechanism
also related to the total amount of solutes other than sodium excreted in urine; in general, the more solutes, the more urine
urine volume
approximately 95% water with several substances dissolved in it
urine composition
result of protein metabolism; include urea, uric acid, ammonia, and creatinine
Nitrogenous wastes
Disorders that interfere with normal urine flow from the kidney
Backing up of urine and may cause swelling in the renal pelvis
obstructive disorders
examples of obstructive disorders
renal calculi (kidney stones)
tumors
Caused by narrowing of the renal artery (stenosis) which may be caused by plaques
Leads to increases in renin
Insert stint into the renal artery to increase blood flow
renal hypotension
