Urinary System Flashcards
what wastes do our bodies need to get rid of
lungs- heat, co2, water
skin- heat hco3-, water, urea, salt
digestive tract- food residue
urinary system-
what is the function of the urinary system
eliminate waste (nitrogenous wastes, water, salts, excess ions)
main functions of kidneys, ureters, urinary bladder, and urethra
kidneys:production
ureters:movement
urinary bladder:storage
urethra:elimination
ureters
smooth muscle tubes lines with mucous membrane, connect kidneys to bladder, peristaltic contractions move spurts of uring
bladder
expandable smooth muscle sac that stores urine, also lined with mucose
urethra
smooth muscle tube for exit of urine
average size of urethra
4 cm females 20 cm non erect males
control of urination by
nervous system, both voluntary and involuntary components, relaxation of internal and external sphincters
main function of kidneys
form urine and maintain homeostasis
other functions of the kidneys
- metabolic waste removal (mostly urea, creatinine, some uric acid)
- water-salt balance (NaCl, K+ and other ions)
- pH balance (H+ secretion)
- hormone secretion
- vitamin D conversion
parts of the kidneys
renal cortex, renal medulla, renal pelvie (look at figure 10.3)
nephron function (basic)
functional unit of the kidneys, make urine
structure of the nephron
renal corpuscle (glomerulus, glomerular capsule) renal tubule (proximal convulted, loop, distal convoluted) all in renal cortex, except for loop which goes into medulla
the nephron is surrounded by
capillaries
three functions of the nephron
glomerular filtration (glomerulus) tubular reabsorption (mostly in proximal tubule) tubular secretion (along length of tubule)
filtration in the nephron
happens in glomerulus which is a small tuft of capillaries, blood pressure forces water and small solutes out of capillaries into capsule
for filtration in the nephron higher pressure=
higher filtration rates
reabsorption in the nephron
occurs in the proximal tubule, filtrate items returned into blood
what is inside the tubule of the nephron
epithelial cells with microvilli for high surface area, made of 99% water and sodium, almost 100% glucose and amino acids
secretion in the nephrons
active transport of certain ions (H+,K+,NH4+)
removal of certain drugs (penicillin)
blood goes to renal veins
filtrate (now urine) empties into collecting ducts then renal pelvis
how much urine is made each day
1-2 liters of urine made each day from 180 liters of filtrate
how do the kidneys help conserve water in the arterioles of the glomerulus
arterioles of glomerulus lie next to distal convoluted tubule, detect low blood pressure and filtering, activate hormones to reabsorb more water and raise blood pressure
how do the kidneys help conserve water via concentration of urine
nephrons with long loops, tied to salt balance, collecting ducts
role of kidneys in pH balance
return bicarbonate ions during reabsorption, remove H+ during secretion
