Digestive Processes (Nursing)

00:01 So when we are processing food during the digestive process, there are six essential activities that are going to take place.

00:09 First we have ingestion or eating.

00:12 This is where we're going to take the food into the mouth.

00:16 From there we're going to have propulsion.

00:19 We need to be able to move the food from the mouth through the alimentary canal.

00:24 This is going to involve the process of swallowing as well as a process known as peristalsis.

00:30 Which is our major means of propelling food and involves alternating waves of contraction and relaxation in one direction.

00:41 Also, we have mechanical breakdown which we sometimes refer to as mechanical digestion.

00:48 And this is going to include things like chewing, mixing food with saliva, the churning of food in the stomach and segmentation.

00:57 Segmentation is a process that is going to take place in the intestines and involves local constriction of the intestine and the mixing of food with digestive juices.

01:10 A fourth process in the digestive process is digestion.

01:14 This is going to be a series of catabolic steps that are going to involve the enzymes that break down our complex food molecules into chemical building blocks that we can use for other metabolic activities in the body.

01:28 After we digest or break down the food.

01:31 We then absorb it, this involves the passage of the digested fragments from the lumen of the GI tract into the blood or lymph.

01:41 Finally, We must get rid of whatever was not digested.

01:45 This is referred to as defecation or the elimination of our indigestible substances by way of the anus in the form of feces.

01:55 Two processes that involve the movement of food through the GI tract are peristalsis and segmentation.

02:02 While they have some similarities, they also have some differences In peristalsis adjacent segments of the alimentary canal are going to alternately contract and relax.

02:15 This causes food to be moved distallyalong the tract and it's the primary propulsion mechanism of the digestive system.

02:25 While it is going to mainly be propelling food through the GI tract, there is also some mixing that does take place.

02:33 Segmentation on the other hand is when non adjacent segments of the alimentary canal are going to contract and relax.

02:42 Food does move forward but it also moves backward.

02:46 The primary function of segmentation is going to be mixing food and breaking it down mechanically, although some propulsion may occur.

02:56 So as you can see, peristalsis is mainly for propelling food forward and segmentation is mainly for mixing food through mechanical digestion.

03:09 So now let's look at the journey that food takes through our digestive system.

03:15 Starting with ingestion or eating of food, food is going to be taken into the mouth.

03:21 From there, we're going to propel the food through the GI tract through multiple different processes.

03:28 First, in the oropharynx at the back of the mouth and in the throat, we have swallowing.

03:35 Following swallowing we have peristalsis where we're going to prepell the food through the remainder of the GI tract by way of the esophagus, the stomach, the small intestine and the large intestine.

03:50 Once we get into the lower parts of the GI tract mainly the the stomach, although some of this does take place in the mouth.

03:58 We're going to have mechanical breakdown.

04:01 So starting in the mouth.

04:02 We're going to chew the food which is going to start breaking it down into smaller parts.

04:07 Once we get to the stomach, We're going to turn the food and then once we get to the small intestine, we're going to mechanically break down the food using segmentation.

04:19 Along with mechanical breakdown, we also have a chemical breakdown of our food from the larger biomolecules to the smaller biomolecules.

04:31 After we break the food down, we have absorption.

04:35 Absorption is going to take place mostly in our small intestine and our large intestine.

04:42 In this process, nutrients and water are going to be absorbed into the blood vessels or the lymph vessels.

04:50 Water is also going to go into the blood vessels mainly in the large intestine.

04:56 Finally, we have defecation of any substances that were not digested or absorbed.

05:03 This is in the form of feces that is going to exit the body by way of the anus.