Histology: Organ-Specific Histology

What three structures constitute the portal triad located at the corners of a liver lobule?

A branch of the hepatic artery, a branch of the portal vein, and a bile duct.

Which lung cells are primarily responsible for gas exchange across the blood-air barrier?

Type I pneumocytes.

What are the four main layers of the GI tract wall from the lumen outward?

Mucosa, submucosa, muscularis externa, and serosa (or adventitia).

What is the primary function of the renal glomerulus?

Filtration of blood to form primary urine (ultrafiltrate).

What are the specialized resident macrophages found within the liver sinusoids?

Kupffer cells.

In which specific segment of the small intestine are Peyer's patches most prominent?

The ileum.

How can the proximal convoluted tubule (PCT) be histologically distinguished from the distal convoluted tubule (DCT)?

The PCT has a prominent brush border (microvilli) and a more eosinophilic cytoplasm compared to the DCT.

What is the primary function of Type II pneumocytes in the alveoli?

Production and secretion of pulmonary surfactant to reduce surface tension and prevent alveolar collapse.

Where are Brunner's glands located, and what is their primary function?

They are located in the submucosa of the duodenum and secrete alkaline mucus to neutralize acidic chyme.

Contrast the direction of blood flow and bile flow within a classic liver lobule.

Blood flows centripetally (toward the central vein), while bile flows centrifugally (toward the portal triad).