A Endoskeleton Is a structure that holds the body of humans and some animals from the inside, allowing it to move and structure and shape the body.
Animals like fish, birds and mammals have endoeskeletons. In more complicated animals it serves as an anchor for muscle structures.
Image of different skeletons of animals.
In a human or a crocodile these muscles are anchored to the bones and interact with them to produce strength, flex and perform all the daily tasks necessary to ensure the health and survival of the body.
Other animals (such as sharks) develop very few bones and have endoskeletons composed largely of cartilage. They live throughout their adult lives with cartilaginous supports that leave no fossil record. These endoskeletons are generally more flexible than bone, but are less resistant.
Endoskeleton vs. Exoskeleton
The endoskeleton grows as the body grows, allows easy fixation of muscles and has many joints that give flexibility. This makes it different from the exoskeleton in several respects.
Many insects and crustaceans have exoskeletons, which are hard, shell-like structures that cover the body from the outside. These structures are static, meaning they do not grow.
Animals with exoskeletons remain at a constant size throughout their lives or move to their old exoskeletons in order to generate entirely new ones as they grow.
In contrast, endoskeletons are permanent parts of the bodies of Vertebrates . The endoskeleton begins to develop in the embryonic stage. The bones of animals are often made of cartilage, then over time they turn the bone through a process known as ossification. As the animal grows, bones become stronger, thicker, and lengthened to full size.
Parts of an Endoskeleton
The skeletal system of vertebrates is characterized by several easily identifiable parts. The first is the spine. All endoskeletons are built around a spine stacked with joined discs shaped like a column containing the animal's central nervous system.
At the top of the spine is a skull that houses the brain. The only exception to this rule is the echinoderms, which have no skulls or brains. Your movements are completely controlled by your central nervous system.
The limbs, fins and any other limb also extend from the spine. In most animals, the endoskeleton is covered in muscles, ligaments and tissues.
These coatings allow the endoskeleton to play an important role in body movement and motor control. The bone structure provided by the endoskeleton allows the body to stand, sit, bend, and swim with precision.
The protection of the organs is an equally important endoscopic function. The bodies of vertebrates are regulated by an intricate system of internal organs, including hearts, lungs, kidneys and livers. The endoskeleton protects these organs from damage, sheltering with a"cage"of rib bones.
Most important functions
The main functions of the endoskeleton are:
- Provide support to the body and help maintain the shape, otherwise the body will not be stable.
- Protect sensitive internal organs, such as the rib cage that protects the heart and lungs from damage
- It serves as a reservoir for calcium and phosphate in the body.
- It manufactures blood cells. The Red blood cells Are manufactured in the bone marrow and this maintains the constant supply of blood cells.
- It allows the body to stand, sit, bend and swim with precision.
Advantages of the Endoskeleton
The advantages include strong features that support weight and even growth. Endoskeletons are usually found in larger animals because of better weight support, since exoskeletons can limit growth because of weight.
The main advantage would be that an endoskeleton can be used as a lever and anchor points for muscles, which means that there is a biomechanical preeminence that is very important in our scale.
An ant or spider has a lot of force relative to its size on its own scale, but if it were the size of a human being it could hardly stand up because its musculature is confined within a rigid exoskeleton.
In addition, it is much easier for a creature with lungs to have an endoskeleton and a flexible rib cage, since it can easily take breaths without having to compress other organs.
Evolution
The earliest skeleton in the vertebrate lineage was a non-mineralized cartilaginous endoskeleton without collagen. It was associated mainly with the pharynx, in taxa such as lancets, lampreys and witch fish.
After the evolution of collagen II, collagen-based cartilage could be formed. In contrast to animals that did not have collagenous skeletons, some of the primitive condrictians (such as sharks) were able to form skeletal parts through the endochondral ossification process.
However, due to the lack of fossil records, the exact time of origin and the extent to which this mechanism was used is unclear.
From the evolutionary point of view, the Endochondral ossification Is the youngest of the 2 types of bone formation (the oldest dermal bone was formed by intramembranous ossification).
It occurred in vertebrate skeletons by replacing cartilage templates. The process of endochondral ossification evolved gradually, beginning with the perichondral bone deposition using the molecular tools that had evolved during the evolution of the bony shields in the skin.
This preceded the evolution of cartilage degradation processes and endochondral bone deposition, as demonstrated mainly by studies on shark skeletongenesis. The endochondral ossification provided structural support for the development of vertebrate members.
With the advent of terrestrial vertebrates, the skeletal function expanded in new directions. Although the bone was still a reservoir of calcium and phosphorus, and acted as a shield for vulnerable parts of the body, it also began to serve as a site for the production of Cells Of the blood, and allowed movement and mechanical support.
References:
- BBC Team (2014). Endoskeletons and exoskeletons. BBC. Retrieved from: bbc.co.uk.
- Darja Obradovic Wagner (2008). Where did bone come from?. Institute of Chemistry and Biochemistry, Berlin University. Retrieved from: archive.org.
- Sarah Meers (2016). Endoskeleton & Exoskeleton. Study. Retrieved from: study.com.
- Wise Geek Team (2017). What Is an Endoskeleton?. Wise Geek. Retrieved from: wisegeek.com.