Urinary System (Filtration (proximal tubule . ( nephron loop (loop of…
Filtered out of the renal corpuscle is everything BUT blood cells and proteins.
proximal tubule .
nephron loop (loop of henle)
filltration generally remains constant even with the changes of BP
filtration coordinates with cardiovascular system to change BP.
In the renal tubule the following takes place: the filtration flows out the impurities remaining in the tubules.
The Bowman's capsule is located in the renal corpuscle and it is known as the filter media; it is surrounded by the glomerular capsule
main function of urinary system is filtration of blood
the difference in the size of the afferent and efferent arterioles provides the needed pressure to force blood plasma into Bowman capsule. Once this happens, the fluid is no longer plasma but is called filtrate.
bowmans capsule = double-walled cup shaped structure in the upper end of a nephron that encases the glomerulus and collects the filtrate from the blood.
Renal Corpuscle = the part of a nephron that consists of a glomerulus enclosed by a Bowmen's Capsule; site of production of filtrate
Glomerular Filtration Rate (GFR) =
amount of filtrate the kidneys produce each minute
Glomerular Filtration Rate (GFR) is determined by the:
balance of the forces pushing fluid out and pulling fluid back into the glomerular capillaries
Blood pressure in the glomeruli
pushes fluid out (hp)
Colloid osmotic pressure (OP) in the capsule
pulls fluid back in
regulation of of blood volume, blood composition, blood pressure, pH level, water and electrolyte, & acid-base balance, consevation of nutrients, and regulation of the production, storage, & elimination of urine
Salvage of essential compounds (from filtrate)
Regulation of ion levels
Maintenance of stable osmolarity
Regulation of plasma volume (BP)
Production of hormones
Mainly occurs in the the proximal convoluted tubules
Water and solutes needed by the body are reabsorbed by renal tubule
water is reabsorbed
all along the renal tubule
The DCT and collecting ducts do not absorb water unless:
Anti-diuretic hormone (ADH) is present
increase in ADH = increase in water reabsorption =
increase in urine concentration & decrease in urine vol.
removal of organic waste products from body fluids
urea and uric acid
urinary system excretes nitrogenous waste
uric acid a nitrogenous waste formed when proteins are used in cells. It is excreted by the kidneys in urine.
ammonia a small, very toxic molecule made up of three hydrogen atoms and one nitrogen atom; produced by nitrogen fixation and as a metabolic waste product of protein and nucleic acid metabolism.
Creatinine a waste product of muscle metabolism, filtered out of the blood by the kidneys and excreted in urine
elimination of waste products especially nitrogen-containing wastes (by-products from the break down of nucleic acids in the body), urea, creatine, uric acid, toxins, drugs, and excessive water & electrolytes
Regulates concentrations of Na, K, and Cl in blood plasma
Regulates Ca2 levels with calcitriol
Stabilizes blood pH
Conserves valuable nutrients
ADH is secreted by the pituitary gland. Secreted when BP or ion concentratipn not normal.
Increases permeability of distal tubule.
Urinary Bladder temporary storage before elimination of waste products
Stretch receptors are activated in the bladdder wall when the volume of urine reaches 200 to 300 mL.
Signals are sent along the sensory neurons to the cerebral cortex and to the micturition center in pons
Micturition center sends nervous signals that cause contraction of the bladder and relaxation of internal urethral sphincter( parasympathetic system).
The urination will take place if the voluntary control is undeveloped. Conscious control involves relaxation to the external sphincter; facilitated by voluntary contraction of abdominal and expiatory muscles.
If urinaiton is not activated at the time of first reflex > micturition reflex will be activated again after another 200-300m: added urination will occur involuntariy between 500-600 mL
Mainly occurs in the distal convoluted tubules
-Especially waste products and drugs
secrets ions to help regulate pH