Urinary system Flashcards
what 6 organs compose the urinary system?
2 kidneys, 2 ureters, 1 bladder, 1 urethra
What is the function of the urinary system?
To remove metabolic wastes from the blood and direct the waste out of the body.
Filters blood and creates waste
What do the kidneys do?
Filter blood and produce urine
What is the hilum?
Contains entry/exit for renal blood vessels, nerves, lymphatic vessels, and ureter.
What do the kidneys maintain?
Blood volume (ADH), blood composition, blood pH
What is a nephron?
functional unit of kidney.
What is the function of a nephron?
Filters blood and produces urine
What is a nephron composed of?
A renal corpuscle and a renal tubule.
What is a renal corpuscle composed of ?
Glomerulus and glomerular capsule
What is a glomerulus?
Filtration unit. Cluster of capillaries which contain pores/fenestrations.
What are afferent arterioles?
Lead to the glomerulus, which leads to the efferent arterioles.
What is the renal tubule composed of?
Proximal convoluted tubule,
descending limb, loop, ascending limb, distal convoluted tubule, collecting tubule/duct.
What is glomerular filtration?
blood plasma is filtered. substances move from the blood to the glomerular capsule.
What is tubular reabsorption?
return products filtered from the plasma back to the blood
What is tubular secretion?
puts waste products into the filtrate to be excreted from the kidney
What is glomerular filtrate?
stuff that passed through the glomerulus into the space within the corpuscle.
What is proximal tubular reabsorption?
the transfer of materials from peritubular capillaries to the renal tubular lumen
What is tubular secretion?
the transfer of materials from peritubular capillaries to the renal tubular lumen
What is the pathway of urine?
Nephrons, collecting ducts, renal papilae, minor and major calyces, renal pelvis, ureters, urinary bladder, urethra, outside world.
In what ways does the Urinary System maintain homeostasis?
-regulating blood volume, blood pressure, pH, and concentration (osmolarity) of electrolytes (Na+, K+, Ca2+, Cl-, HPO4-3, Mg2+, HCO3-)
-reabsorbing glucose and excreting wastes
-releasing certain hormones like renin and EPO
water conservation
n the collecting duct water is taken from the tubular fluid back into the blood.
renal corpuscle (Bowman’s capsule and glomerulus)
Filtration of blood to make filtrate.
proximal convoluted tubule
Mainly selective tubular reabsorption of glucose, amino acids, Na+ then Cl-, H2O follows by osmosis.
Reabsorption of bicarbonate.
Also tubular secretion of NH4+ and H+; tubular secretion of drugs (e.g. penicillin).
loop of henle (as a unit)
To create and maintain the concentration gradient across the medulla.
loop of henle (descending limb)
Impermeable to NaCl, permeable to H2O. Water leaves filtrate (in response to concentration of surrounding interstitial fluid) as it descends making the filtrate more concentrated.
loop of henle (ascending limb)
Impermeable to H2O, Na+ is pumped out of the tubule, (Cl- follows) so filtrate becomes less concentrated as it ascends.
distal convoluted tubule
H2O reabsorption depending on ADH. Tubular secretion of NH4, K+ and H+ depending on need. Reabsorption or secretion of bicarbonate depending on need.
collecting duct
Reabsorption of H2O depending on levels of ADH.
osmotic pressure
the amount of force applied to a solution that prevents solvent from moving across a semipermeable membrane.
Cortical nephrons
Cortical nephrons originate in the outer part of the cortex
these nephrons are concerned with solute reabsorption and production of filtrate;
Juxtamedullary nephrons
Juxtamedullary nephrons originate in the inner cortex close to the cortico-medullary boundary. These nephrons are concerned with creating and maintaining the concentration gradient across the medulla;
How is water gained in the body?
food
drink
metabolic water
How is water lost?
urination
defacation
evaporation (breath and sweat)
Function: renal cortex
Filters the blood
Function: renal medulla
Concentrates the filtrate
Involuntary control of urination
- stretch receptors in bladder wall activated
- signals travel to sacral spinal cord
- motor nerves cause contraction of bladder and relaxation of internal sphincter
Flow of filtrate
Nephron - papillary duct - minor calyx - major calyx - renal pelvis
What is hematuria?
Hematuria is blood in the urine, which can be visible or microscopic, and usually indicates an underlying issue with the urinary tract.
What does ADH do and where does it act?
- ADH helps the body conserve water by reducing the amount of water lost in urine.
- ADH acts primarily on the collecting ducts and distal tubules of the kidneys.
- High blood osmolarity
- Low blood volume or low blood pressure
How does alcohol increase the volume of urine?
alcohol increases urine volume by inhibiting ADH release, preventing the kidneys from reabsorbing water effectively, and resulting in greater, more dilute urine output.
How does ADH reduce the volume of urine?
ADH reduces urine volume by increasing the kidneys’ reabsorption of water in the collecting ducts and distal tubules, leading to less urine production and higher urine concentration.
What is the stimulus for ADH?
for ADH release are high blood osmolarity and low blood volume or pressure. ADH helps restore balance by conserving water, reducing blood osmolarity, and supporting blood pressure and volume.
