USMLE - First Aid

Question 1

Describe the epithelium of the esophagus in histological terms

Answer 1

Nonkeratinized stratified squamous cell epithelium

Question 2

Name a major histological difference between the duodenum and the colon

Answer 2

The duodenum has villi whereas the colon only has crypts

Question 3

The upper one-third of the esophagus is composed of _____ muscle

Answer 3

Striated

Question 4

The lower one-third of the esophagus is composed of ______ muscle

Answer 4

Smooth

Question 5

What type of muscle fibers make up the middle one third of the esophagus?

Answer 5

Both striated and smooth muscle

Question 6

Liver sinusoids are lined with what kind of endothelium?

Answer 6

Fenestrated

Question 7

Notably, the sinusoids of the liver are lacking what structure that most capillaries have?

Answer 7

Basement membrane

Question 8

Why is it advantageous to have fenestrated capillaries in the liver sinusoids?

Answer 8

They allow macromolecules to have access to the hepatocytes, thereby facilitating appropriate metabolism of these macromolecules