Which features of the small intestine lining are primarily responsible for increasing the surface area for absorption?

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Multiple Choice

Which features of the small intestine lining are primarily responsible for increasing the surface area for absorption?

The key idea is how the lining of the small intestine maximizes contact with chyme to absorb nutrients. Circular folds (plicae circulares) and finger-like villi together dramatically expand the surface area available for absorption. The circular folds are folds of mucosa and submucosa that slow chyme and create more surface contact. The villi are small projections that increase surface area even further and house a rich network of capillaries and lacteals to transport absorbed nutrients. On the surface of the epithelial cells, microvilli form a brush border that provides yet more surface area for absorption. Goblet cells mainly secrete mucus and don’t increase absorptive surface. Lymphoid follicles are part of immune defense in the mucosa, not structural features that boost surface area. Smooth muscle layers help mix and propel contents but don’t contribute to the absorptive surface area.

The key idea is how the lining of the small intestine maximizes contact with chyme to absorb nutrients. Circular folds (plicae circulares) and finger-like villi together dramatically expand the surface area available for absorption. The circular folds are folds of mucosa and submucosa that slow chyme and create more surface contact. The villi are small projections that increase surface area even further and house a rich network of capillaries and lacteals to transport absorbed nutrients. On the surface of the epithelial cells, microvilli form a brush border that provides yet more surface area for absorption.

Goblet cells mainly secrete mucus and don’t increase absorptive surface. Lymphoid follicles are part of immune defense in the mucosa, not structural features that boost surface area. Smooth muscle layers help mix and propel contents but don’t contribute to the absorptive surface area.

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