University:
Western Sydney University
Course:
MEDI 2003 | Clinical Sciences 2
Academic year:

2024
Views:

447

Pages:

4
Author:

Mariam A. A.

Organisation of the Urinary System Functional anatomy • • • • The hilus opens into the renal sinus. - The renal sinus is completely surrounded by renal parenchyma expects when it connects to the ureter. - The renal sinus includes urine filled spaces: renal pelvis proper and its extensions, the major and minor calyces. - Blood vessels and nerves also pass through the sinus. - The renal capsule reflects into the sinus at the hilus so that the inner layers line the sinus and the outer layers anchor to the blood vessels and renal pelvis. The cortex appears granular due to the presence of glomerulus there. The renal artery divides into anterior and posterior branches. - This is referring to the segmental arteries, which supply the segments of the kidney, and how one of the segments is located on the posterior. Very small branches of the arcuate artery supply a subpopulation of the juxtamedullary glomeruli, that are located near the junction of the cortex and the medulla. - The efferent arterioles of these nephrons descend to form the vasa recta. 90% of the blood entering the kidney perfuses superficial glomeruli and cortex, and only 10% perfuses the juxtamedullary glomeruli and the medulla Difference between the cortical nephron and the juxtamedullary nephron • • Cortical nephron: glomerulus located at the cortex. - Also, knowns as superficial nephrons. Juxtamedullary nephron: glomerulus located near the juxtamedullary junction. - Play an important role in concentrating the urine Lymphatics and the kidney • • Drain fluid that is rich in renal hormones. Not present in the medulla, because if they were present there then they will drain high osmolarity fluid, which will disturb the urine concentration. The Renal Corpuscle • • • Site of glomerular filtration formation. The glycocalyx has negatively charged glycosaminoglycans which prevent the leakage of negatively charged micronutrients. The basement membrane separates the endothelial layer from the epithelial layer. - Has heparan sulfate proteoglycans which restricts the entry of negatively charged molecules. The juxtaglomerular apparatus • • The region where the TAL is in contact with its glomerulus. It has two main regulatory roles: - It the amount of NaCl and water increase then it will help decrease the GFR (see mechanism on tubuloglomerular feedback mechanism) - When the baroreceptors detect low blood pressure, it will increase renin release. Measuring Single Nephron Rates of Clearance and Filtration • • • • This is made possible by microscopic techniques. - Allows us to know how single nephrons function, and to understand how individual nephron segments contribute to overall nephron function. Allows us to determine which segments of the nephron are doing what. It is impossible to determine which nephrons are responsible for overall urinary excretion. To apply the concept of clearance to a single nephron site, we have to use the free flow micropuncture approach and measures the concentration of solutes in the tubule fluid at that site [TFx] volume flow at that site and plasma concentration [Px] - A pipette for collection of fluid is inserted into a superficially located tubule in the kidney, which in this case is the PCT.