Studied by 4 people
Excludes Renal Physiology
Importance of the urinary system
excretory functions, maintain balance of water/salt, maintain balance between acids/bases (pH), and other metabolic functions
Major excretory organ of the urinary system
Kidneys
What things are regulated by the kidneys (4)
urea, creatinine, uric acid, and end products of hemoglobin breakdown
Urea
protein catabolism
Creatinine
muscle metabolism
Uric acid
nucleic acid metabolism
What functions of the urinary system are minute by minute?
maintenance of water/salt and acid/base balance
What other metabolic functions does the urinary system help with?
glycogenesis, activation of vitamin D, production of renin and erythropoietin
Renin
enzyme that helps regulate blood pressure
Erythropoietin
hormone that stimulates RBC production in bone marrow
What amount of water is added and taken away from the body daily?
2550ml
How is water added to the body?
ingestion (liquids/in food) and metabolically produced
How is water removed from the body?
insensible loss, sweat, in feces, and urine
Examples of insensible water loss
water lost through breathing or skin; NOT sweat
Kidneys location
superior lumbar region and retroperitoneal
Kidneys structure
adipose tissue capsule and tough renal fascia, surrounded by fibrous capsule
Function of adipose capsule and renal fascia for the kidneys
protects (cushions) and anchors kidneys in place
Function of fibrous capsule for the kidneys
anchor kidneys and prevents surrounding infections from spreading to them
Anorexia result on kidneys
breakdown of adipose capsule; kidney damage and urine backup
Ureters
slender tubes that extend from kidneys to urinary bladder; move urine through peristaltic contraction of muscular layers
Urinary bladder
hollow muscular sac just posterior to public symphysis
Function of the urinary bladder
store and expel urine (not by gravity)
Characteristics of the urinary bladder
very distensible (collapses when not full); has rugae; moderately full at 500ml, but can double that amount
Urethra structure and function
thin-walled tube from bladder to exterior that drains urine from bladder
Urethra in females
short and straight tube; more prone to urinary tract infections
Urethra in males
3 regions; long and curved tube; runs through prostate gland and has both urinary/reproductive function (carries semen and urine)
Cortex of the kidneys
bark, most superficial region
Medulla of the kidneys
inner core tissue composed of renal pyramids and columns
Renal pyramids
triangular masses that appear striped, houses collecting ducts
Collecting ducts
microscopic, parallel bundles of urine-collecting tubules
Renal columns
cortical tissue that surrounds renal pyramids
How many lobes (approx.) are in a kidney and what are they made up of?
about 8, pyramids and column pairs
Urine can be changed up to what point?
the end of the collecting duct/the minor calyx
What structures funnel urine from renal pyramids to the ureters?
minor calyx, major calyx, and renal pelvis
Nephron
structural and functional blood processing unit of the kidney; over 1 million per kidney
What makes up a nephron?
renal tubule and vascular component
What makes up a renal tubule (4)
glomerular (Bowman’s) capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule
Glomerular (Bowman’s) capsule
closed at one end, cup-shaped
What makes up the vascular component?
glomerulus and peritubular capillaries
Glomerulus
tuft of capillaries
What makes up a renal corpuscle?
glomerulus and glomerular (Bowman’s) capsule
Types of nephrons (2)
cortical and juxtamedullary
Cortical nephrons
represent 85% of nephrons; mostly in cortex; short loops of Henle that extend a short way into the medulla
Juxtamedullary nephrons
long loops of Henle; surrounded by vasa recta; key for concentrating urine
Blood supply to the nephron
aorta → segmental arteries → interlobar arteries → arcuate arteries → cortical radiate arterioles → afferent arterioles → glomerulus → efferent arteriole → peritubular capillaries
How does blood supply away from the nephron differ?
artery supply in reverse, except no segmental vein or efferent venules
Cortical radiate arterioles
supply cortical tissue, 90% of blood to kidneys
Functions of capillary beds of the nephron
production of filtrate and reabsorption
What is specialized for filtration and produces the filtrate?
the glomerulus
Structural differences that make the glomerulus specialized for the production of filtrate
fed/drained by 2 high resistance arterioles, afferent larger than efferent, large pores (fenestrations) in capillary walls
Increased diameter in the afferent has what function?
keeping the blood pressure in the glomerulus very high, fluid/solutes easily forced out of blood into glomerular capsule
What is specialized for reabsorption in the nephron?
peritubular capillaries
Peritubular capillaries
arise from efferent arteriole, wrap around adjacent renal tubule (proximal/distal), low-pressure and porous, secrete some substances into the renal tubule
Most of the filtrate (99%) is reabsorbed from tubule and returned to the blood (t/f)
true
The second capillary bed of the juxtamedullary nephrons tend to break up into peritubular capillaries (t/f)
false
Vasa recta
straight vessels formed instead of peritubular capillaries in juxtamedullary nephrons, surround tubules
The filtration membrane
allows free passage of water and solutes smaller than plasma proteins from blood into renal tubule
Three layers of the filtration membrane
fenestrations of endothelial cells, glomerular basement membrane, and podocytes
Fenestrations
allow all plasma components except blood cells
Basement membrane
restrict all but the smallest proteins, negatively charged to deter large anionic proteins
Podocytes
keep out other macromolecules that get through the basement layer, slit diaphragms
Where does filtrate switch to urine in the excretion of materials?
somewhere in the collecting duct
What structures only have blood in them?
glomerulus
What structures only have filtrate in them?
glomerular capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule, and beginning of collecting duct
What structures only urine in them?
end of collecting duct, minor/major calyx, renal pelvis, ureter, urinary bladder, and urethra
After filtrate has turned to urine, no more changes can be made (t/f)
true
Note 
Flashcard (130)