Endoskeleton vs Exoskeleton: Difference and Comparison

Every human body is made up of a skeleton system to provide a basic structure to the body and give it a shape. It is necessary to protect the internal organs and facilitate movement in the body.

The skeleton can be further classified into two types such as endoskeleton and exoskeleton. The structures of a few living beings are made up of an endoskeleton, whereas for the others, their structure is made up of an exoskeleton.

Endoskeleton is found in the internals of the body. It gives shape to the body and protects the organs.

It also facilitates the body for further movement. The exoskeleton, on the other hand, is located outside of the body.

It protects the living being from external threats and attacks from other predators. It also protects the outer climate and keeps the being safe.

Key Takeaways

1. Endoskeletons are internal support structures found in vertebrate animals, such as humans, composed of bone and cartilage; exoskeletons are external support structures found in invertebrate animals, such as insects and crustaceans, composed of chitin.
2. Endoskeletons provide support and protection for internal organs and muscle attachment; exoskeletons protect the body from external forces and provide muscle attachment points.
3. Endoskeletons allow for greater mobility and flexibility; exoskeletons limit mobility and require periodic moulting to accommodate growth.

Endoskeleton vs. Exoskeleton

Endoskeleton is an organized structure of bones present in the body of vertebrates like fish. It provides protection, sites for muscle attachment, and allows movement. Exoskeleton is the outer framework of bones present in invertebrates like insects. It protects from external threats.

Comparison Table

Parameter of Comparison	Endoskeleton	Exoskeleton
Meaning	Internal skeleton	External skeleton
Location	It is located inside the body	It is located outside the body
Organisms found in	Vertebrates	Arthropods
Developed from	Endoderm	Ectoderm
Made out of	Phosphorous and calcium	Calcifies shells and scales
Flexibility	It provides flexibility to the body	It does not provide much flexibility to the body
Growth	It grows with the body	It does not grow with the body
Support	It supports a larger body	It does not support larger body
Blood Supply	Bones enable blood supply	Bones do not facilitate blood supply
Examples	Humans, fish, birds	Spider, lobster, crabs

What is Endoskeleton?

Endoskeleton is a skeleton that is found inside the body of a living being. It provides support and protects the interior organs of the body.

It provides enough amount of support for the body to withstand its weight. It also facilitates the locomotory movement of the body and makes it flexible.

Most vertebrates have an endoskeleton, which helps them manage various aspects of the body. The endoskeleton grows along with the rest f the body.

It constantly grows as the living being grows from infancy to adulthood. There are two further types of bones in an endoskeleton: cortical bone (also known as compact bone) and cancellous bone (also known as trabecular bone).

The endoskeleton present in the body has several functions in the body that it caters they are- protecting the body and the internal organs, supporting the structure and the entire weight of the body, helping in flexible and free movement, storing excess nutrients, and providing it to the body when it needs any, manufacturing with the help of bone marrow.

What is Exoskeleton?

The exoskeleton is a skeleton located outside of an organism’s body. It is a rigid outer shell or coating that supports the body.

It also protects the muscles along with the internal organs of the body. The endoskeleton also protects the organisms against attacks from predators or external threats.

Most animals without a proper structural backbone have exoskeletons, such as cockroaches, lobsters, crabs, etc. The muscles are directly attached or cross-joined with the inside of the exoskeleton. Exoskeletons, unlike endoskeletons, do not grow inside the body; hence the arthropods periodically shed their exoskeleton.

The exoskeleton organisms have a heavy exoskeleton structure; accordingly, the size of the animals is relatively smaller. The outer shell of the exoskeleton is formed from several proteins, carbohydrates, and minerals.

Chitin, a substance secreted by the epidermal cells, is combined with the protein to form an exoskeleton. There are different types of exoskeleton animals, and they are classified under the following category- the arthropod cuticle and the shell.

Main Differences Between Endoskeleton and Exoskeleton

1. The endoskeleton is inside the body of the organism; it is an internal skeleton, whereas the exoskeleton is outside the body of the living organism; it is an external skeleton.
2. Endoskeleton is found in vertebrates, whereas the exoskeleton is found in arthropods.
3. The endoskeleton is made out of calcium and phosphorus. The outer shell of the exoskeleton is formed from several proteins, carbohydrates, and minerals.
4. Endoskeleton is developed from the endoderm, while the exoskeleton is developed from the ectoderm.
5. Endoskeleton provides the body with a lot of flexibility and movement, whereas in the exoskeleton, the body’s movements at certain times are restricted by the body.
6. The endoskeleton grows with the body from infancy to adulthood, whereas the exoskeleton does not grow with the body, and periodically the body sheds the exoskeleton.
7. Endoskeleton supports a larger body weight, whereas the exoskeleton does not support much weight of the organisms; hence, most are smaller.
8. In the endoskeleton, the bones do not enable and promote blood supply, whereas, in the exoskeleton, it does not facilitate any blood supply.

References

1. https://pubs.acs.org/doi/full/10.1021/cr0782630
2. https://kuscholarworks.ku.edu/bitstream/handle/1808/3715/paleo.paper.074.pdf?sequence=1
3. https://ieeexplore.ieee.org/abstract/document/4291584/
4. https://ieeexplore.ieee.org/abstract/document/1618670/