Page 615 - Atlas of Histology with Functional Correlations

Overlying Peyer patches are specialized M cells, which are not found

anywhere else in the intestine
Peyer patches and the lymphatic aggregations are part of gut-associated
lymphatic tissue (GALT)
M cells show deep invaginations or microfolds that contain macrophages and
lymphocytes

M cells sample intestinal antigens and present them to underlying
lymphocytes for immunologic responses

LARGE INTESTINE

Situated between anus and the terminal end of ileum
Shorter and less convoluted than small intestine

Consists of cecum and ascending, transverse, descending, and sigmoid
sections
Semifluid chyme enters through ileocecal valve
At terminal end, semifluid residues become hardened or semisolid feces

Main function is the absorption of water and electrolytes
Epithelium consists of simple columnar epithelium with increased number of
goblet cells
Goblet cells produce mucus for lubricating the canal to facilitate passage of

feces
No enzymes or chemicals produced, but enteroendocrine cells are present in
the epithelium
No plicae circulares, villi, or Paneth cells; intestinal glands are deeper

Increased numbers of solitary lymphatic nodules with cells are present in
lamina propria
Muscularis externa contains inner circular layer with outer layer arranged in
three strips, the taeniae coli

Contractions of taeniae coli form sacculations or haustra

Review Questions

QUESTIONS

In the following multiple choice questions, choose the letter corresponding to the
one best answer.

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