The urinary system part 5

Lecture Objectives
By the end of this lecture, students are expected to:
1. List and describe the walls of nephrone.
2. Outline the histological features of the nephron .
3. Compare the local function and histological features of proximal and distal convoluted tubules.
4. Outline the different types of epithelium within urinary passages.
5. Summarize the functional and histological structure of medulla of kidney.
6. Relate the functional to histological feature of the of cells of proximal and distal convoluted tubules.
7. Outline the structural and functional adaptations of the gastroesophageal glands.
8. Outline the difference in histological features of outer layer of esophagus along its course.
Nephron
Comprises a renal corpuscle, a proximal convoluted tubule, a loop of Henele, and a distal convoluted tubule. A renal corpuscle is composed of a glomerulus and a Bowman capsule.
(1) A glomerulus consists of a spherical knot of capillaries, which is fed by an afferent arteriole and drained by an efferent arteriole at the vascular pole.
(2) A Bowman capsule consists of a visceral layer and a parietal layer.
a) The visceral layer is composed of podocytes, which cover the capillaries of a glomerulus. These cells have long, interdigitating cellular processes and play an important role in blood filtration. The interstitial tissues surrounding the glomerular capillaries contain cells called intraglomerular mesangial cells.
b) The parietal layer of the Bowman capsule is a hollow spherical structure lined