Intestinal microvilli as tiny helpers

Instructional Guide

After this lesson, the learners should be able to list the basic functions of the microvilli and where they reside within the body. The lesson will include a short story describing a day in the life of the microvilli, including its daily functions, activities, and location. The learners will also understand the basic structure of the microvilli. To supplement the lesson, students can use play-dough and pipe cleaners to make models of the intestinal lining.

Intended Grade Level

The intended grade level for this lesson is kindergarten or early elementary.

Learning objectives

• Students will understand the basic role of the GI system in breaking down food.

• Students will know where the microvilli are located within the GI tract.
• Students will be able to explain the basic functions of the microvilli.

Lesson Format

The lesson will take 35-60 minutes to complete and can be done with any size group. Students will be working both in pairs and in a large group. Materials needed include Play-Doh, pipe cleaners, and access to the narrated book, “Mike the Mighty Microvilli” (included).

• Have the learners pair up. Hand out the Play-Doh and pipe cleaners to the groups, and have them work on building the microvilli together. (15 mins)
• Once the students have completed their microvilli sculptures, encourage students to share their creations. (10 mins)
• Further exploration: play the Magic School Bus episode 10 – “For Lunch“.  (25 mins)

Lesson Background

The microvilli are finger-like projections that are present on cells that line the gastrointestinal tract. The microvilli are responsible for aiding in digestion by increasing the absorptive surface area.

Location

The microvilli heavily populate the small intestine of the gastrointestinal tract. This is because most of the food absorption occurs in the small intestine.

The most common spot to find microvilli within the small intestine will be on absorptive cells called enterocytes. Microvilli make up the surface of the enterocytes. Due to the finger-like projections of the microvilli, microvilli increase the surface area of the enterocytes, allowing the cells to absorb more nutrients.

Function

Microvilli have four main roles:

• increase absorption by increasing surface area
• enhance digestion by producing enzymes
• help transport nutrients
• protect the cell membrane from injury

Damage

Microvilli can be damaged due to infection, disease, and toxins. Damage to the microvilli will lead to malabsorption. Parvovirus is a common cause of microvilli damage in dogs.

Activities

Activity 1

Show the students the narrated book, “Mike the Mighty Microvilli”. Prior to showing the book, ask the students “Have you ever seen a dog eat its breakfast? What do you think happens to it inside its tummy?”. After the story, re-ask the question to see if their answer changed. Wrap up the question with discussing how the microvilli help digest the dog’s breakfast.

Activity 2

Have the students pair up. Hand out the supplies to each group, and instruct them to work together and build what they think the microvilli look inside the dog’s small intestine.

Supplies needed: scissors, Play-Doh, and pipe cleaners

Example of microvilli activity:

Wrap up the activity by going around in a circle and having each group describe and show their microvilli structure.

Common misconceptions and challenge points

Students may be curious if they have microvilli too. Yes we do! Humans also have microvilli that aid in digestion that are housed within the digestive tract. Another misconception that may need to be made clear is that microvilli are not their own cell, instead they are a part of the cell’s surface.

Assessment

The students will have their knowledge assessed at the end up activity 2 when they are describing their microvilli structures.

Further exploration

Play episode 10 of the Magic School Bus – “For Lunch“. This video will help the students get a deeper understanding of how food is digested. The students should try to point out the microvilli seen within the digestive tract. Link to episode:

Other chapters within this textbook may be interesting for students. Check out the link(s) below:

Spot’s Tummy Trouble