Digestion Overview

There are two parts to the mammalian digestive system:

  1. Alimentary canal
  2. Accessory glands
An overview picture of the human digestive system.

Figure 41.11, page 801, Campbell's Biology, 5th Edition

Focus on Protein Digestion

A globular protein Shows the eight essential amino acids, and how we can obtain them from grains and legumes together.

Unknown source; Figure 50.5, Purves's Life: The Science of Biology, 7th Edition

A Trip Through the Digestive Tract

Pre-protein Digestive Pathway

The Oral Cavity

Depicts the different types of dentition in carnivores, herbivores, and omnivores.

Figure 41.16, page 807, Campbell's Biology, 5th Edition

Pharynx to Esophagus

Swallowing is a Reflex

Shows the coordinated movement of the many organs needed for the swallow reflex.

Figure 41.12, page 802, Campbell's Biology, 5th Edition

Peristalsis: Moving Food Along

Shows the process of peristalsis.

Unknown source

Protein Digestion Begins Here


Shows the process of zymogen activation, with in this case the zymogen being pepsinogen. Zooms in on the process of autocatalysis, in which pepsin helps activate pepsinogen (positive feedback).

Figures 50.14 and 50.13, Purves's Life: The Science of Biology, 7th Edition

Small Intestine

Shows the interaction between the pancreas and the duodenum.

Figure 50.15, Purves's Life: The Science of Biology, 7th Edition

The Pancreas and Small Intestine: a Closer View

From the pancreas to the duodenum:

Shows the activation of certain enzymes from the pancreas in the duodenum. The chemical structure of a polypeptide, to give some context for these enzymes' actions.

Figures 41.14 and 5.16(b), pages 804 and 70, page 70, Campbell's Biology, 5th Edition

The Remaining Length of the Small Intestine

Depicts the multiple foldings that occur at many levels throughout the small intestine, so as to increase surface area.

Figure 41.15, page 805, Campbell's Biology, 5th Edition

Protein Digestion Review

A review of protein digestion, moving from a globular protein to individual amino acids, showing the enzymes that perform each breakdown step and where.

Unknown source