Flashcards in Urinary System Deck (73)
What is excretion and secretion?
“Excretion” is the removal of material from a living thing while “secretion” is the movement of material from one point to another
Why do we need a urinary system?
protein catabolism yields toxic nitrogenous wastes
- NH2 → NH3 → Urea
water and essential ions tend to accumulate
What organs contribute to waste removal?
lungs: CO2, water vapor
gastrointestinal tract (fiber or undigestible material, water,)
sudoriferous glands (sweat - salt, urea, water)
What organs does the urinary system consist of?
What are the general functions of the kidneys?
regulate blood volume and composition
regulate blood pressure (renin)
regulate RBC numbers with erythropoietin
synthesize vitamin D (calcitriol)
How do the kidneys regulate blood volume and composition?
water in excess will be filtered out
How do the kidneys regulate blood pressure (renin)?
water removal/retension affects BP
renin controls vasoconstriction too
How do the kidneys regulate RBC numbers with erythropoietin?
erythropoietin produced by kidneys
25% of blood passes through kidneys
monitors if you have enough O2 or not
not enough triggers erythropoietin secretion = more RBCs
How do the kidneys synthesize vitamin D (calcitriol)?
calcitriol: hormone version of vitamin D
controls absorption/reabsorption of calcium
produced by kidneys
Where are the kidneys located?
in between, retroperitoneal and abdominal wall, posterior to liver
What is the hilum?
indented side of kidney
- where ureter, lymphatic, arteries/veins enter/exits
What are the coverings of the kidneys?
renal fascia - anchor
adipose capsule - packing
renal capsule - thin layer of dense connective tissue on surface of kidney
- barrier to outside of kidney to protect it
What components comprise the internal anatomy of the kidney?
What is the Renal Cortex?
Outer layer of the kidney
Renal Columns: spaces in between the pyramids
- still part of renal cortex
Nephrons begin in the renal cortex
What is the Renal Medulla?
Inner layer of the kidney
renal pyramids: in the medulla the corn shaped striated sections of medulla
- lots of ducts creates striated texture
- base of pyramid faces cortex
- apex of pyramid is called the renal papillae
Renal papillae: where pyramids empty urine into the minor calyx
What is the Renal Sinus?
space between everything entering/exiting hilum is called renal sinus
What is the Renal Pelvis?
Renal Pelvis big area right before ureter
Minor caliyce: cup like opening at end of renal pyramid (renal papillae)
Major calyce: Larger area that contains multiple minor calyces
What is the pathway of urine in the kidney?
Renal papillae → Minor Calyx → Major Calyx → Renal Pelvis → Lumen of Ureter
What is the nephron?
Functional unit of the kidney
What are the types of nephrons?
cortical (85%) located mostly in the cortex
juxtamedullary (15%) located close/adjacent to medulla
- start in cortex but tube dips down close to medulla
- the nephrons responsible for water retention or
What is the renal corpuscle?
glomerulus + bowmans capsule
What is the glomerulus?
glomerulus: bundle of capillaries (in kidneys, oxy blood enters as arteriole and leaves as arteriole too (different))
- afferent arteriole: brings oxy blood in
- efferent arteriole: leads blood away from glomerulus
What is the bowmans capsule?
filters the blood
surrounds the tuft of capillaries but has 2 layers
parietal layer: outer layer
capsular space between layers (par/visc): everything that is filtered out
see the filtrate inside the capsular space
from capsular space, filtrate travels into tubed ductwork of nephron (renal tubule)
visceral layer: innermost layer, covers every capillary in the glomerulus
What is the renal tubule? What are its parts?
renal tubule: filtrate from capsular space arrives here
proximal convoluted: filtrate from capsular space arrives here first
loope of henle: becomes much thinner and dips down and comes back up
- Proximal Straight (descending loop)
- Distal Straight (ascending loop)
distal convoluted tubule
- leads right into the collecting duct for filtrate
What can pass through the membrane of the nephrons?
What is the kind of epithelial cells are found in the:
Loop of Henle
Proximal tubule = simple cuboidal + brush border (increase SA 90% reabsorption)
Loop of Henle = simple squamous
Distal tubule = simple cuboidal + basal foldings (SA)
Collecting ducts = simple cuboidal
aquaporins in collecting ducts (ADG)
distal cells = secretion into filtrate (urine)
How does blood get supplied to the kidneys
~25% of cardiac output via
aorta → renal arteries →
segmental arteries →
interlobular arteries →
arcuate arteries →
afferent arteriole →(arrive)
glomerular capillaries →
efferent arteriole →(exit)
peritubular capillaries and
vasa recta capillaries →
ultimately the renal veins →
inferior vena cava
How is the kidney innervated?
Nerve supply = sympathetic fibers
What is the juxtaglomerular apparatus?
specialized structure formed by the distal convoluted tubule and the glomerular afferent arteriole
- regulates blood pressure and the filtration rate of the glomerulus