Urinary System Flashcards
How much cardiac output do the kidneys (combined) recieve?
20-25%
Where are the kidneys located compared to the vertebrae?
Between T12 - L3
What are the coverings of the kidneys from superficial to deep?
Renal fascia, adipose capsule, renal capsule
What kind of tissue comprises the renal fascia?
Dense irregular CT
What are the internal layers of the kidney?
Cortical layer and medullary layer
Which layer contains a majority of the nephrons?
The cortical layer
How many nephrons does each kidney contain?
~1.25 million/kidney
Describe the flow of blood from the abdominal aorta to the glomerulus.
Abdominal aorta -> renal artery -> segmental (lobar) arteries -> interlobar arteries -> arcuate arteries -> cortical radiate (interlobular) arteries -> afferent arterioles -> glomerulus
What nerves innervate the kidneys, what kind of fibers are they, and where do they come from?
Renal nerves, which are primarily postganglionic sympathetic fibers from the superior mesenteric ganglion
What is the function of the renal corpuscle?
Filtration of blood, emptying into the tubule
What is the function of the tubular system?
Turning filtrate into urine
What are the two types of nephrons?
Cortical and juxtamedullary
What are the percentages of the two types of nephrons?
Cortical: 85%
Juxtamedullary: 15%
Where are cortical nephrons located?
Almost entirely in the cortex of the kidney; their loops of Henle dip slightly into the medulla
Where are juxtamedullary nephrons located?
They lie near the cortical-medullary junction; their loops of Henle deeply invade the medulla
What is the relative function of cortical nephrons?
Perform more of the reabsorptive and secretory functions
What is the relative function of juxtamedullary nephrons? How do they achieve this?
Produce more concentrated urine due to longer loops of Henle
What structure is contained in Bowman’s capsule, and what s the name of the space?
The glomerulus, and Bowman’s space
What is the glomerulus?
A tuft of “leaky” capillaries
The fenenstrations of the glomerular capillaries retain what things? What do they allow to leak out?
Blood cells and larger proteins are kept; water and other solutes are released into the glomerular filtrate.
What are the histological layers of Bowman’s capsule and where are they?
Parietal, which surrounds the outer wall of the capsule; visceral, which covers the glomerular capillaries
What tissue is capsular epithelium (parietal layer) comprised of?
Simple squamous epithelium
What layers are deep to the glomerular epithelium?
Lamina densa (basement membrane) and glomerular endothelium
What cells make up the glomerular epithelium (visceral layer)?
Podocytes
What is the name of the processes of the glomerular epithelium? What are the openings called? What do they allow out?
Pedicels, which contain slit pores/filtration slits that allow the passage of dissolved ions and small organic molecules
Where does the filtrate in Bowman’s space drain into?
Proximal convoluted tubule
What is the lining of the PCT?
Simple cuboidal epithelium with microvilli
