Renal Part I Flashcards
Where is the kidney located?
Deep to the 12th rib. Left kidney slightly higher due to downward projection of the liver.
Describe the urine collection system from minor calyces to the ureter.
Minor calyces each drain one pyramid. Each major calyx collects urine from several minor calyces. The major calyces converge into the renal pelvis, which drains into the ureter. The ureter carries urine to the bladder.
What makes up a nephron?
Nephrons are the functional unit of the kidney. There are around 1 million in each kidney, that decrease with age. The primary function is to filter blood and produce urine. The nephrons consist of glomerulus and tubules.
What are the different parts of the tubule?
Proximal convoluted - recovers 99% of what is filtered. Bulk re absorption of water, electrolytes, glucose, etc
Loop of Henle - determines urine concentration
Distal convoluted snd collecting tubule/duct - determines the fine control of re absorption via ADH and aldosterone
Collecting tubule/duct
What is the papilla?
The papilla is the opening through which the collecting ducts excrete urine.
What is the glomerulus?
The system of capillaries where the blood comes in and circulates.
Describe the relationship between the glomerulus and the Bowman’s capsule.
The glomerulus and Bowman’s capsule make up the renal corpuscle. This is where the capillaries meet the tubular system. Bowman’s capsule is a cup-like extension of the tubule. It is closed and similar to a bursa system. It’s function is to form a filtration barrier over the capillaries.
The glomerulus us a system of capillaries creates loops, which invaginate the closed end of Bowman’s capsule. It has both visceral and parietal layers. Blood is filtered from the capillary into capsular space.
What are the two types of nephrons?
Superficial nephrons: Short loops of Henle. Primary function is re absorption and secretion.
Juxtamedullary nephrons: long loops of Henle and functions to control the concentration of urine. The juxtamedullary nephrons control how much water to keep vs. how much to put in the urine. This helps control how much water is in the body.
Characterize the structure and transport mechanism if tubular cells.
Proximal, distal, and collecting parts of the tubule:
Consist of cuboidal cells linked by adhering junctions near their apices. The cells that transport water, ions, and nutrients have membranes that are heavily folded.
Apical membrane cells have microvilli and the basolateral membranes have basal invaginations.
Describe the vasculature of the kidneys.
21% cardiac output goes to the kidneys. Renal arteries branch from the aorta. Lobar arteries branch into interlobar, which branch into arterioles. Interlobar and arterioles extend between pyramids in the renal columns. Arcuate arteries surround the basal part of the pyramid and give off interlobular arteries. The pyramids can only tolerate capillaries. Veins drain in the same pattern.
How are substances carried across cell membranes?
Both transcellularly via transporters and paracellularly via tight junctions.
What type of cells are in the thin loop of Henle?
Simple squamous epithelium
What is the juxtaglimular apparatus (JGA)?
Junction of the distal convoluted tubule and the efferent and afferent arterioles. It is made up of modified smooth muscles cells that can respond and produce hormones. Includes the macula densa.
What is the macula densa
Cells of the JGA respond to osmolar levels of Na+ and secrete substances into the afferent arteriole. Juxta glomerular cells in the afferent arteriole respond to macula densa secretions with either changes in smooth muscle contraction or release of renin into the blood.
How does the glomular filtration filter by both size and charge?
Size is restricted by 3 layers: capillary endothelium, basement membrane, and podocyte layer.
Negative charges on the layers repel negatively charged proteins.
