Excretory System (5/14) Flashcards
Key structures of the excretory system
Kidneys
Ureters
Urethra
Urinary bladder
Renal artery
supply each kidney with blood
Renal veins
where blood drains from kidneys
Renal capsule
protects kidney
Inside kidney
renal cortex and renal medulla
Nephron
function unit of the kidney
Renal corpuscle
where blood is initially filtered into the nephron
Renal tubule
filtrate travels to collecting duct through the tubule
Ureter
carry urine from kidneys to the urinary bladder
Urethra
carries urine from the bladder to outside of the body
In females, urine…
exits the body through the urethral orifice which is anterior to the vaginal orifice
In males, urine…
exits through the penis
Muscles involved with releasing urine
Internal (smooth-autonomic) and external urethral sphincter (skeletal- somatic)
Renal corpuscle
composed of the glomerulus and bowman’s capsule
Afferent arteriole
carries blood towards the glomerulus
Efferent arteriole
carries blood away from the glomerulus
Filtration
blood going through glomerulus causes water to be pushed into bowman’s capsule (this is the filtrate)- only small substances like water, salts, salt, ions
Renal tubule
adjusts volume of filtrate
reabsorbs valuable nutrients and expels wastes
contains proximal (reabsorption) and distal tubule and loop of henle (descending and ascending limb)
GLUCOSE is reabsorbed in large quantities
Loop of henle
allows for retention of large amount of water and solutes (mostly Na) medulla is more rich/increase in concentration
descending limb- permeable to water but not ions and this is how medulla gets very concentrated and vasa recta picks up ions to go back to blood
ascending limb- impermeable to water but is to ions (thin ascending- passive transport- bottom portion) (thick does active transport)
DCT and collecting duct
acted on by aldosterone and ADH (vasopressin)
in DCT
Na, Cl are reabsorbed while K ions are secreted
aldosterone increases Na reabsorption
Collecting duct
direct water reabsorption
Homeostasis of excretory system
blood pressure, osmoregulation, acid-base balance, nitrogenous waste
Blood pressure and osmoregulation
dehydrated- blood volume and pressure are low
hydrated- both high
Blood pressure and osmoregulation regulation by hormones
Aldosterone- increase Na reabsorption to increase volume and pressure
angiotensin II- increase pressure
Antidiuretic (ADH)- increases volume and pressure
atrial natriuretic peptide- decreases volume and pressure
Renin-angiotensin-aldosterone system
Renin comes in and acts on angiotensinogen to cleave and produce angiotensin I. ACE convert I to II and this triggers release of aldosterone
ADH/vasopressin
promotes water retension and vasoconstriction. reduce osmolarity
ANP
comes from atria of heart
decrease pressure and promotes sodium retention in the urine
