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BIO 241: Anatomy & Physiology II > Urinary System > Flashcards

Flashcards in Urinary System Deck (73)
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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?

kidneys (2)
ureters (2)
urinary bladder


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?

Renal Cortex
Renal Medulla
Renal Sinus
Renal Pelvis


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

Responsible for:
- filtration
- reabsorption
- secretion


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?

Fatty acids
Amino acids
Nitrogenous wastes


What is the kind of epithelial cells are found in the:

Proximal tubule
Loop of Henle
Distal tubule
Collecting ducts

Proximal tubule = simple cuboidal + brush border (increase SA 90% reabsorption)

Loop of Henle = simple squamous
-water movement

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
sympathetic NS)


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


Where is the juxtaglomerular apparatus located?

next to glomerulus