Introduction – Digestion and Absorption

00:02 Hello! In this particular lecture, we’re going to go through a number of very important topics.

00:07 We’re going to talk specifically about both absorption and digestion.

00:13 Here, we're going to specifically focus on understanding how carbohydrates, fats, proteins are digested and identify the enzymes that are primary involved in these processes.

00:26 We will also talk about the absorption of basic macronutrients, ions, and water as well as other electrolytes as they enter places like the portal vein or the lymphatic circulation.

00:38 Finally, we’re going to focus on the various portions of the splanchnic circulation that will help deliver this food stuff to the rest of the body and therefore provide the energy needed in undergoing normal daily activities.

00:53 So digestion, absorption, these are what our main topics will be for today’s lecture.

01:02 Just to give you an overall kind of review of what specific items are going to be most important.

01:10 Today, we’re going to discuss absorption and digestion.

01:14 This is primarily going to occur in places like the reaction vessel in the stomach, the catalytic and absorptive surface in the small intestine.

01:23 But we’re going to need some supply of enzymes from places like the enzyme supplier from the pancreas.

01:33 So digestion in a simplistic format is simply going to be taking a molecule from the intestinal lumen and moving it across the epithelial cells into the interstitial space so it can be picked up by the blood.

01:49 Using a classic example of glucose, glucose can simply travel through these enterocytes to be able to be absorbed.

02:00 Things that are a little bit more complex such as proteins, might need to broken down into individual amino acids or very short peptides to be able to be transported.

02:12 Complex carbohydrates or even simple carbohydrates such as sucrose still need to be broken down to their individual monosaccharides for absorption.

02:25 As you can see in this particular example, you might need to break down a peptide even to a greater extent within the enterocyte so that you can reabsorb the individual amino acid.

02:39 And finally, when we think of fats, which is going to be some of our most complex types of digestion and absorption.

02:46 Here, you need to break down triglycerides into individual fatty acids to absorb them.

02:53 But then it’s kind of odd, you have to repackage them for their transport out of the cell, but to get them across the intestinal lumen, you’ll need to have broken them down.

03:05 With that overview in mind, let’s specifically talk through the digestion of carbohydrates.