Urinary System Phys (exam 5) Flashcards
What are the principle organs of the urinary system?
Kidneys
What are the accessory organs of the urinary system?
Ureter
Urinary bladder
Urethra
What are the jobs of the urinary system?
Filtration
Reabsorption
Secretion
Where does filtration occur?
Where is the filtrate moving, blood to tubules or tubules to blood?
In the glomerulus, which is inside bowman’s capsule
These are the parts of the renal corpuscle (in renal cortex)
Blood to tubules (blood to glomerulus), in renal corpuscle
What are the primary functions of the kidney?
cleanse and filter blood and regulate blood volume
filtration, reabsorption, secretion
What is filtered out during filtration?
Water, Electrolytes, urea, glucose, amino acids,
NO proteins
NO blood cells
Where does reabsorption primarily occur?
What direction are things moving, blood to tubule or tubules to blood?
PCT (mostly) into the peritubular (in the renal medulla)
Tubules to blood (tubules to peritubular capillaries, tubules to vasa recta)
What is reabsorbed?
Water!!!! Sodium!!! glucose (100% of what is filtered), amino acids (100% of what is filtered), some electrolytes (potassium, chloride, magnesium, calcium)
Where does secretion primarily occur?
What direction are things moving, blood to tubules or tubules to blood?
DCT (primarily)
Blood into tubules
What is typically secreted?
Ammonia (NH4+), urea, creatinine, hydrogen, potassium
What hormones regulate urine volume?
Where do they act?
Aldosterone, ANH, ADH
Act on the distal convoluted tubules (DCT)
What does aldosterone do?
Tells the DCT to reabsorb more sodium, which causes water to follow
Acts on DCT because there are sodium, potassium pumps that kick out potassium as sodium is reabsorbed
What does ANH do?
Tells the DCT to secrete more sodium, which causes water to follow
What does ADH do?
Tells the DCT and collecting duct to reabsorb more water
How much blood goes into the kidney per heart beat?
20-25% of blood every heart beat
What structure is the most frequent site of UTIs?
Trigone (in urinary bladder)
What is the number one bacteria that causes UTIs?
E coli
What muscles make up the urinary bladder?
Detrusor muscles
What is micturition?
The act of urinating
How many regions does the kidney have?
What are they?
2:
Renal Cortex
Renal Medulla
What occurs in the renal cortex?
What structures are in the renal cortex?
ALL filtration occurs here, reabsorption &some secretion
Renal corpuscle (glomerulus & Bowman’s capsule)
Proximal convoluted tubules (PCT)
Disatal convoluted tubules (DCT)
What occurs in the renal medulla?
What structures are in the renal medulla?
Some reabsorption, secretion Urine concentration (regulation of urine concentration and urine volume) Renal pyramids (contain the loop of henle, collecting duct)
What is the functional unit of the kidney?
Nephron
How many types of nephrons are there?
What are they?
2
Cortical nephrons
Juxtamedullary nephrons
Where are cortical nephrons?
What are they responsible for?
Primarily in the renal cortex
Loop of Henle dips very little into the medulla (renal pyramids)
Blood filtration & urine production
Where are juxtamedullary nephrons?
What are they responsible for?
Renal corpuscle is in the renal cortex
Loop of Henle dips deep into are all the way through the renal pyramids (renal medulla)
Urine concentration
What structure enters the glomerulus?
Exits the glomerulus?
Enters: Renal afferent arteriole
Exits: Renal efferent arteriole
What type of blood is in the afferent and efferent arterioles?
Oxygen rich blood
Gas exchange does not occur in the glomerulus
What does the efferent arteriole become once it exits the glomerulus?
Peritubular capillaries
Where are the peritubular capillaries located?
Around the PCT and DCT
What is the vasa recta?
What is it responsible for?
A special peritubular capillary that branches off and surrounds the loop of Henle
Countercurrent exchange with Loop of Henle (regulation of urine concentration and urine volume)
What is the renal corpuscle?
What does it do?
Where is it located?
Made of the glomerulus and Bowman’s capsule
Filtration
In the renal cortex
What is the glomerulus?
Where is it?
What does it do?
Capillary where gas exchange doesn’t occur
In Bowman’s capsule in the renal cortex
Filters the blood
What is Bowman’s capsule?
Where is it?
What does it do?
Surrounds the glomerulus
Collects the filtrate from the glomerulus
In the renal cortex
What is the glomerular filtration membrane?
Thin, negatively charged membrane that repels negative charged proteins from being filtered
What is the juxtaglomerular apparatus?
Where is it located?
Made of the macula densa and juxtaglomerular cells
Located between the afferent arteriole and the collecting duct
What does the macula densa do?
Measures pressure, sodium levels and oxygen levels
Detectors
What does the juxtaglomerular apparatus?
Secretes Renin (when low sodium, or low blood pressure or renal hypoperfusion, Renin increases sodium retention, increases BP) Secretes EPO (when low oxygen, hypoxic, EPO causes more RBCs to be made to carry oxygen)
What (primarily) occurs in the proximal convoluted tubules?
Reabsorption (of water, sodium, 100% of filtered glucose & amino acids, some electrolytes
What (primarily) occurs in the loop of Henle?
Regulation of urine concentration and urine volume
Part of countercurrent exchange
What (primarily) occurs in the distal convoluted tubules? What affects the function of the DCT?
Secretions (end product secretions)
Aldosterone, ANH, ADH work at DCT
Where does the collecting duct lead to?
Drips into the papilla (cup like structure at the bottom of the renal pyramids)
Trace the final urine product pathway
Drips from collecting duct into papilla of renal pyramid
Moves from papilla into minor calyces
Moves from minor to major calyces
All major calyces drain into the renal pelvis
Renal pelvis drains into the ureter
Ureter to urinary bladder to urethra
Trace the RAAS pathway
Macula Densa cells detect low sodium or low BP
Juxtaglomerular cells secrete Renin from the kidney
RENIN: converts angiotensinogen into angiotensin 1 in the blood
ANGIOTENSINOGEN: is released from the liver, is a “ProProEnzyme”, is converted into angiotensin 1 by renin
ANGIOTENSIN 1: is a “ProEnzyme”, is converted from angiotensinogen by renin, converted to angiotensin 2 by ACE
ANGIOTENSIN CONVERTING ENZYME (ACE): is released by the lungs, converts angiotensin 1 into Angiotensin 2
ANGIOTENSIN 2: is converted from angiotensin 1 by ACE, the bad mamajama, affect the system, hypothalamus, posterior pituitary, and adrenal cortex
SYSTEMIC VASOCONSTRICTION: angiotensin 2 causes this to increase BP, most important effect
THIRST: angiotensin 2 acts of the hypothalamus, increasing thirst, increasing water content, increasing blood volume, increasing BP
ADH: angiotensin 2 affects the post pit to secrete ADH to increase reabsorption of water, to increase blood volume to increase BP
ALDOSTERONE: angiotensin 2 affects the adrenal cortex to secrete aldosterone to increase reabsorption of sodium and water, to increase blood volume to increase BP
What is the purpose of the RAAS system?
To increase BP
What does the body secrete to counteract the RAAS system?
ANH to increase secretion of sodium and water to decrease blood volume and decrease BP
What pathologies arise from an overactive RAAS system?
Hypertension (chronic high BP)
Overactive angiotensin 2: increased BP & increased blood volume causes hypertrophy of the heart which can cause congestive heart failure, increased endothelial damage leading to atherosclerosis or increased vascular inflammation or increased coagulation cascade (thrombus production), decreased apoptosis putting you at risk for cancer, increased thrombosis
What happens to urine pH when hydrogen excretion is increased? Decreased?
Excrete more hydrogen, blood becomes more basic, retain more bicarb
Excrete less hydrogen and blood becomes more acidic, excrete more bicarb
What is ammonia? What is it converted into? What does it do? What happens when excretion is increased? Where does ammonia come from?
Ammonia (NH4+) is a base Converted into urea in the liver Urea is neutral Helps maintain normal blood pH Increase ammonia excretion, blood becomes more acidic Ammonia comes from protein metabolism
What is the normal pH range of the blood?
7.35-7.45
What is the normal pH range of the urine?
4.6-8.0
What do natriuretic peptides (ANH) do?
What is an example of a synthetic ANH?
Decrease BP
Inhibits sodium and water reabsorption
Urodilation is a synthetic ANH
What affect does vitamin D have on reabsorption?
Released by the kidney
Acts on the intestine
Absorb more calcium
What tests measure renal function?
Creatinin Clearance test (urine test)
Plasma creatinine concentration (blood test)
Blood urea nitrogen (BUN) (blood test)
What is the creatinin clearance test?
When does it indicate renal failure?
Want creatinine in the urine, so we want high creatinine clearance
It is how we measure GFR
Decrease creatinine clearance indicates a bad kidney
What do we want on a plasma creatinine concentration test?
What indicates a bad kidney?
Want a low number
Increased blood creatinine indicates a bad kidney
What do we want on a BUN test?
What indicates a bad kidney?
Want less in blood, more in urine
Increased BUN indicates a bad kidney
What are the 4 pressures of the kidney?
Glomerular Hydrostatic Pressure (BP driving, push glomerulus into capsule)
Glomerular Oncotic Pressure (albumin driven, pull from capsule into glomerulus)
Capsular Hydrostatic Pressure (push from capsule into glomerulus, important when theres an obstruction then increases)
Capsular Oncotic Pressure (pull from glomerulus into capsule, negligible)
If we increase BP what happens to the glomerular filtration rate?
It increases
If we increase CHP what happens to the glomerular filtration rate?
It decreases because it is pushing back into the glomerulus
Does a decreased glomerular filtration rate indicate a good or bad kidney?
Bad kidney functioning
What is the first step in renal functioning?
Filtration
Where does reabsorption pull fluid and electrolytes from and into?
From blood (peritubular capillaries/ vasa recta) into the tubule
What effect does increased secretion of fluid have on the blood?
Decreased blood volume
