PP1.H1.6 +D1 +D2 Kidney Tubules
Kidney Tubules:
- The tubular part of the nephron has three parts:
- Proximal convoluted tubule
- This part lies in the cortex of the kidney
- It is composed of a simple cuboidal epithelium
- It receives the glomerular filtrate from the Bowman's space
- Resorption of water, glucose, various ions, amino acids and small proteins occurs in this part of the nephron
- The luminal surface of the proximal convoluted tubule has numerous microvilli to increase the surface area for absorbtion to take place
- Loop of Henle
- This starts in the cortex but passes into the medulla and then "loops back" into the cortex
- The middle part of the Loop of Henle is formed of a simple squamous epithelium
- This thin part is located in the medulla and forms part of a structural association with blood capillaries and collecting ducts which is essential for the concentration of the urine (countercurrent mechanism)
- Distal convoluted tubule
- This part lies in the cortex of the kidney
- It is composed of a simple cuboidal epithelium
- Ion resorption takes place in this part of the nephron
- The luminal surface has no significant microvillous border
Electron Micrograph of Cell of Proximal Convoluted Tubule:
- Nucleus
- Microvilli
- Area containing endocytic vesicles and small lysosomes
Micrograph of Kidney Cortex:
- Renal corpuscles
- Proximal convoluted tubules These cells are more densely stained than the cells of the distal convoluted tubules due to the large number of organelles and inclusions they contain
- Notice that the luminal surface of the cells of the proximal convoluted tubule appears fuzzy
- What surface projection is causing this fuzziness?
- Distal convoluted tubules
