The key difference between apodeme and apophysis is that apodeme is a ridge-like invagination which appears as a groove to the outside, while apophysis is a finger-like invagination found in the insect exoskeleton and visible as a tiny pit to the outside.
Arthropods, including insects, have an exoskeleton, which is a defining characteristic of this phylum. The exoskeleton is an external skeleton that protects the body of these insects. Moreover, it provides a large surface area for muscle attachment. In comparison to endoskeleton of vertebrates, exoskeleton affords a large surface area. There are invaginations present on the exoskeleton. They are inward growths of the cuticle. These invaginations further increase the surface area for muscle attachment in insects. In addition, they enhance the rigidity and strength of the exoskeleton.
So, in short, apodeme and apophysis are two types of invaginations. Ridge-like invaginations are apodemes while finger-like invaginations are apophyses. Both types support internal organs and also increase the surface area for the attachment of muscles.
CONTENTS
1. Overview and Key Difference
2. What is Apodeme
3. What is Apophysis
4. Similarities Between Apodeme and Apophysis
5. Side by Side Comparison – Apodeme vs Apophysis in Tabular Form
6. Summary
What is Apodeme?
Apodeme is an internal in-growth found in insect exoskeleton. In fact, it is a piece of the inflected cuticle of insects. Moreover, it is a calcified infold. It contains chitins as well. Hence they are stronger and stiffer than vertebrate tendons. Apodemes can stretch and store energy. Furthermore, apodemes provide attachment sites for muscles in the body of an insect, carrying out a similar function as tendons. Therefore, all muscles of insects are attached to exoskeleton mainly via these invaginations.
Figure 01: Insect Exoskeleton
Furthermore, apodeme supports internal organs. It is a ridge-like invagination. Generally, they are found in many arthropods. They are visible to outside as grooves.
What is Apophysis?
Apophysis is another type of inward fold found in insects. It is a finger-like invagination. It is visible externally as a tiny pit. Similar to apodeme, apophysis provides attachments points for muscle. Moreover, they increase the surface area of the exoskeleton for muscle attachment. Not only that, apophysis adds strength and rigidity to the exoskeleton.
What are the Similarities Between Apodeme and Apophysis?
- Apodeme and apophysis are two types of inward folds or invaginations found in insect exoskeleton.
- Both are important in providing strength and rigidity to the exoskeleton.
- Moreover, both invaginations increase the surface area for the attachment of muscles.
- Also, both support internal organs.
What is the Difference Between Apodeme and Apophysis?
Apodeme is an invagination of insect exoskeleton and is ridge-like. Meanwhile, apophysis is a type of invagination of insect exoskeleton and is finger-like. So, this is the key difference between apodeme and apophysis.
Moreover, apodemes appear as grooves to the exterior, while apophyses appear as tiny pits from the outside. Therefore, we can consider this as another difference between apodeme and apophysis.
Summary – Apodeme vs Apophysis
Apodeme and apophysis are two types of inward growths seen in arthropod exoskeleton. They are clearly visible in insect exoskeleton. Of these two types, apodemes are ridge-like invaginations, but apophyses are finger-like invaginations. So, this is the key difference between apodeme and apophysis. However, both invaginations provide points of attachments for muscles. Also, they both support the internal organs. Besides, they also add strength and rigidity to the exoskeleton of insects. Furthermore, the apodemes are visible as grooves to the outside, but the apophyses are visible as tiny pits. Thus, this is the summary of the difference between apodeme and apophysis.
Reference:
1. “The Exoskeleton.” ENT 425 | General Entomology | Resource Library (Tutorials), Available here.
Image Courtesy:
1. “insect exoskeleton” (CC0) via Peakpx.com