Urinary System Flashcards
Describe the basic function of the urinary system
- homeostasis
- excrete waste
- water balance
- filter blood
- activate vitamin D
- Regulates blood pressure
- erythropoiesis regulation
List the major components of the urinary system
- Kidneys
- Ureters
- Urinary bladder
- urethra
Define retroperitoneal as it relates to kidney
-external to parietal peritoneum to hold the kidneys in place
List the 3 protective layers of the kidney
- Renal capsule (immediately surrounding kidney)
- adipose capsule
- renal fascia (anchors kidney to abdominal wall)
Describe the Hilus
-External concave area where blood vessels, urters enter/exits kidney
Describe the cortex
-the outer portion of the kidney
Describe the renal medulla
-the inner part of the kidney
Describe the pyramid
- the inner medulla has triangular shaped regions
Describe the renal papillae
- is the apex of each pyramid is a papilla (makes urine)
Describe the renal pelvis
-is the funnel like structure inside the kidney in the region of the hilus collecting urine from the pyramids
Describe the renal calyces
- the extensions into the pyramids
- collecing urine and empty into ureter
- major calyx (8-18)
- minor calyx (2-3)
Describe the blood flow to the kidney
- there is A LOT
- via the renal arteries, about 1/5 of the cardiac output
Name the functional microscopic unit of the kidney and describe its specific parts
Nephron
- glomerulus and glomerular capsules
- renal tubules
- proximal convoluted tubule
- descending limb of the loop of nephron
- loop of nephron
- ascending limb of loop of nephron
- distal convoluted tubule
- collecting ducts
Describe the glomerulus and the renal corpuscles
- glumerulus is a netowrk of permeable blood capillaries
- surrounded by the (bowmans) capsule
- these two structures make the renal corpuscle
- renal= Kidneys
Describe the overall nephron physiology. Define urine
- Nephrons filter blood to make liquid waste (urine)
- control blood pressure, volume, and pH
- remove waste from the bloodstream
- Protein metabolic waste (urea)
Describe glomerular filtration
- Filtration occurs from the glomerulus into the glomerular capsule
- passive process
- influenced by size of the particles and if they can fit through the process of the glomerulus
- not based off of need
- blood pressure in the glomerulus is the driving force
Describe the factors that favor and oppose glomerular filtration.
- glomerular hydrostatic pressure (blood pressure) drives filtration
- the opposing factors are not strong enough to oppose filtration, but include the osmotic pressure in the glomerular as well hydrostatic pressure in the glomerular capsule
Discuss the effects of increased blood pressure and decreased blood pressure (as in hemorrhaging) on glomerular filtration
- Increased pressure increases filtration
- decrease pressure decreases filtration
Describe active and passive tubular reabsorption and give examples
- active reabsorption requires ATP, passive does not
- Glucose is reabsorbed from the proximal convoluted tubule to the bloodstream by active transport
- water flows passively
discuss the significance of an increasingly concentrated intrstitial fluid as you descend from the cortex to the medulla. Describe how this concentration is maintained.
- as you descend into the medulla, the interstitial fluid is very concentrated which offers some great drawing power for pulling water out of the kidney tubules
- the concentration is maintained by having the vasa recta operate in the countercurrent mechanism so that all the solutes are not removed from the interstitial region
- urea adds to the interstitial concentration, as does differential permeability of the different proportions of the nephron
Describe the reabsorption and secretion that occurs in all parts of nephron
- the proximal convoluted tubule
- most reabsorption occurs (water and nutrients)
- descend the limb of the nephron
- permeable to water, water reabsorbed
- the loop
- urea enters the loop from the interstitial region and is recycled back into urine
- Ascending limb is permeable to salt but not h20
- as you ascend into a weakly concentrated interstitial region, the sal will not reabsorb
- Distal convoluted tubule
- ADH and Aldosterone dependent
- If ADH is present, what is reabsorbed
- Aldosterone is present, sodium is reabsorbed and water passively flows
- Collecting duct is also hormone dependent
- ADH present, significant water reabsorption resulting in small amounts of highly concentrated urine
- it gets so concentrated, that neat the bottom of the collecting duct, even urea is reabsorbed into the interstitial region
- secretions of substances such as hydrogen ions, ammonia, and drugs occur primarily in the convoluted tubules
- here substances can pass directly from blood stream into these tubules
Describe juxtaglomerular apparatus. Name the enzyme made here and describe its function.
- juxta=near
- these are the cells of the wall of the distal convoluted tubule that make renin
- Renin is an enzyme that activates angiotensinogen (leads to increased blood pressure)
Describe the function of ADH. Where is it made and stored
- ADH is made by the hypothalamus and stored in the posterior pituitary gland
- it causes water reabsorption in the nephron
Describe the countercurrent multiplication mechanism of the kidneys
- 2 Parallel tubes running in opposite directions benefit each other
- for example if salt is pulled out of one tube, it facilitates pulling water out of the parallel tubes
