Level 2 - Urinary System Part 2 Flashcards
A winding hollow tube from the renal corpuscle to the end of the nephron
Consists of 3 different regions
-proximal convoluted tubule
-Henle loop
-distal convoluted tubule
Renal tubule
First part of the renal tubule nearest to the Bowman’s capsule; follows a winding convoluted course; AKA the proximal tubule. Has one layer of epithelial cells with a brush border of microvilli to increase surface area because most of reabsorption is done here
Proximal convoluted tubule
Renal tubule segment just beyond the proximal tubule. Consists of a thin descending limb, a sharp turn and an ascending limb; the length of this loop is important for the production of concentrated urine
Dips into medulla
Henle (nephron) loop
Convoluted tubule beyond Henle loop; AKA distal tubule. Only minor reabsorption is done here. It conducts filtrate out of the nephron and into the collecting duct. Along with other distal tubules, it joins a common collecting duct
Distal convoluted tubule
Straight duct joined by renal tubules
Collecting duct
What is the order collecting ducts exit?
Collecting ducts of one renal pyramid converge at the renal papilla to release urine into:
-minor calyx
-major calyx
-renal pelvis
-out the ureter
Located where the afferent arteriole brushes past the distal convoluted tubule
Juxtaglomerular apparatus
What are the two main functions of the juxtaglomerular apparatus?
-important to maintain blood flow homeostasis by reflexively secreting renin when blood pressure in the afferent arteriole drops (JG cells)
-contributes to renal function homeostasis by influencing the ability of the kidney to produce concentrated urine (macula densa cells)
What 2 types of cells is the JG apparatus made of?
- Macula densa - sense the concentration of solute material in the fluid passing through the tubule contributing to producing concentrated urine
- JG cells - contain renin. Renin triggers angiotensin which causes blood pressure to increase in the afferent arteriole, maintaining homeostasis
Arteriole that enters glomerular capillary network
Afferent arteriole
Arteriole that leaves the glomerulus and extends to the peritubular blood supply
Efferent arterioles
A nephron with a Henle loop that does not dip much into the medulla but remains almost entirely within the cortex; they constitute approx. 85% of the total nephrons
Cortical nephron
A nephron with a renal corpuscle near the medulla and a Henle loop that dips far into the medulla and is responsible for concentrating urine
Juxtamedullary nephron
What are the chief functions of the kidney?
Process blood and form urine
What is the basic functional unit of the kidney?
Nephron
What are the 3 processes of urine formation?
Filtration
Tubular reabsorption
Tubular secretion
First step in blood processing; occurs in renal corpuscles
Occurs as a result of a pressure gradient between blood in the glomeruli and the filtrate in the capsule
Filtration
The rate of movement of fluid out of the glomerulus and into the capsular space, determined mainly by glomerular hydrostatic pressure and therefore directly related to systemic blood pressure
Glomerular filtration rate (GFR)
Why is glucose not excreted?
Needed for energy
Second step in urine formation; movement of molecules out of the tubule and into peritubular blood occurs as a result of passive and active transport mechanisms from all parts of the renal tubules; major portion of reabsorption occurs in the proximal convoluted tubules
Reabsorption
Mechanism in Henle loop concentrates sodium and chloride in the interstitial fluid of renal medulla
Countercurrent multiplier
*reabsorption in Henle loop
Mechanism in vasae rectae maintains high solute concentration in medullary interstitial fluid
Countercurrent exchange
*reabsorption in Henle loop
Where is the fluid most concentrated in the loop?
At the bottom
Where is the fluid least concentrated in the loop?
Coming out ascending side
*thicker wall
The movement of substances out of the blood and into tubular fluid to be excreted as urine
Tubular secretion
