What is the FUNCTION of the JOINTS

In humans, the locomotor system is made up of the osteoarticular system (bones, joints and ligaments) and the muscular system (muscles and tendons). This system is very important since it allows us not only to stand upright, but also to hold many other systems of our body, protect them and relate to the environment and the people who surround. Often one of the components that are overlooked within this system is the joints. In this lesson from a TEACHER we will see the joint function as well as what exactly are they. If you want to know more, keep reading!

Index

1. What are the joints?
2. Movement, the most important joint function
3. The joint as a growth point
4. Joint wear

The joints are the anatomical structures that allow junction between two bones or between a bone and cartilage. Joints are mainly made up of two bones that come together, although sometimes we can find a cartilage that gets between them and causes less wear and tear between the bones, which otherwise would rub. In the vicinity of the joints we find two other structures of the locomotor system: ligaments and muscles.

• The ligaments stabilize the union of the two bones, keeping them in position; This joint is relatively elastic and plastic, that is, within the position it maintains, it leaves a little margin of movement for the bones.
• The muscles meanwhile they give mobility to the joints. The muscles that are inserted in the vicinity of the joints produce the movement that, transmitted by the bones, allows the movement of the joints.

Sometimes, in joints with a lot of movement, the existence of cartilage is not enough to prevent its wear. In these cases, in the gap between the two bones (joint cavity), we can find a bag full of liquid. This liquid, called synovial fluidIt has a very specific composition and not only nourishes the cartilage, which is continually repairing itself, but also allows it to lubricate the movement.

This lubricant acts like the grease of an engine, preventing the parts of our joint from wearing out. One of the main components of synovial fluid is hyaluronic acid, which is capable of retaining large amounts of water, which is why it cushions joint friction very well.

Image: Slideshare

One of the most important functions of more than 360 joints that make up the human body is allow movement. As we have seen previously, the union that the joints carry out is not rigid. The union of our joints is not like a staple, which "sticks" to the two bones but is more similar to the joining of several papers with a paper clip: it keeps the two bones together but allows one to move over other.

The union between the two bones (the clip) can be more or less strong and leave more or less mobility. Thanks to these different degrees of mobility, the body can stay together but still have a plasticity and flexibility that allows us to move and move parts of our body in a Independent.

Types of joints

Depending on the force that holds the two bones together or the bone with the cartilage, we can distinguish three types joint basics: synatroses, amphiarthroses and diarthroses.

1. The synarthrosis they are the practically immobile joints, with less movement, and they are the ones that are, for example, between the teeth and the jaw.
2. The amphiarthrosis or cartilaginous joints They are joints in which the two bones have a medium movement; An example of amphiarthrosis is the joints between the vertebrae that make up our spine.
3. Finally, the diarthrosis or synovial joints they leave a great mobility to the bones; These bones usually have a lot of movement and a great variety of movements, so there is usually synovial fluid in their joint cavity. The elbow, shoulder, or ankle joints are diarthrosis.

Image: Slideshare

The second function of the joints is allow growth during childhood of certain regions of our body. In certain circumstances, the human body needs to protect a structure or organ through bones but at the same time this The protective structure must allow the growth of this "box" since the organ that is inside is still in increase. In other cases, the cartilage of the joint simply takes the place that will correspond to the adult bone and, when the moment is right, cartilage hardens and causes growth of one of the bones of the joint.

A example of this type of function is the one that occurs in the skull. The skull is made up of six different bones, which are joined by means of joints called sutures. During the first months of life, these joints are not firmly attached and allow the baby to come out through the birth canal when the woman gives birth, as well as the growth and total maturation of the brain once it is outside. Between the first and eighteen months of life, the sutures are closed until the joints are completely fused, thus protecting our brain.

As you have seen throughout the lesson, joints are a structure that is constantly renewed. Due to the large number of movements we make throughout our daily life, the bones, cartilage, membranes and synovial fluid that make up our joint are affected. In addition, over the years, our body loses the ability to renew cartilage and synovial fluid in the joints so quickly that it degrades with friction.

In joints such as the hips, knee or fingers, cartilage begins to lose faster than the body can replace it. This produces the little by little disappearance of cartilage and the bones of the joint wear out, becoming finer and finer. This process is usually more important in women, where diseases such as arthritis are more common than in men.

In joints such as the shoulder, mineral deposits, mainly calcium, can occur in and around the joints. This process, which is called calcification, leads to the joint becoming more rigid, "harden", with the consequent loss of mobility and discomfort and pain that this causes.

The wear and tear and degradation of the joints with age they can be very serious. Over the years, bad habits or poor diet can lead to the appearance of joint swelling, pain, stiffness, or deformities that greatly affect quality of life.

Image: Navalcan Pharmacy

If you want to read more articles similar to Joint function, we recommend that you enter our category of biology.

• Wikipedia (October 10, 2019). Joint (anatomy). Recovered from https://es.wikipedia.org/wiki/Articulación_(anatomía)
• Medline (October 2, 2019). Changes in bones, muscles and joints due to aging. Recovered from https://medlineplus.gov/spanish/ency/article/004015.htm
• Vattuone, L. D. (1977). Human Anatomy and Physiology.
• Rouvière, H., Delmas, A., & Delmas, V. (1987). Human anatomy: descriptive, topographic and functional (Vol. 9). Barcelona:: Masson.