Mammalian sketeton function is so numerous and necessary in humans body and daily body activities but sometimes it is been overlooked when studying them, today I will be talking about another aspect in the sketeton system of mammals in study which is their function.
The functions of the mammalian skeleton
In vertebrates like us, the skeleton is a strong rigid structure found inside the body that has three major froles: support, protection and the productíon of bone marrow
Support is the major function of the skeleton, It provides a framework for your body and even helps to determine your shape. Many organs are attached to your skeleton for support and stability. The vertebrae that make up your spine and the bones of your legs are particularly important in supporting your body against gravity
People live on the land and like other land animals need skeletons to support their weight against gravity. Without a rigid internal skeleton, there is a limit on the size of land animals.
Another major function of your skeletal system is that of protection. Because it is strong and rigid, the skeleton protects your delicate internal organs from damage. The bones of the skull protect the Brain, the vertebrae (backbones) protect the spinal
Cord, the ribs protect the heart and lungs, and the pelvis protects some of the digestive rgans and the reproductive organs in the female.
A very strong, relatively rigid skeleton would work was support and protection,
well if all you needed in one place all the time. But animals while staying in one
need to move around in order to feed and escape.
The human skeleton is well adapted for
locomotion. Different types ot joints allow
different degrees of movement. If you look
carefully at the human skeleton, its adaptations for all these functions will become clear. Finally, the skeleton is very important tor the production of blood cells. Inside the bones of the skeleton is tissue known as bone marrow, and this
is where both red and white blood cells are formed.
Joints and their different types
When humans move, the bones move relative to each other. The point where two bones meet is called a joint. We say that the bones articulate at joints.
A movable joint such as the hip or elbow needs to have certain features.
These include the following:
.A way to keep the ends of the bones held
together, so that they don't separate (dislocate).
A means ot reducing friction between the ends of the moving bones
A shock-absorbing surtace between the two bones.
Movable joints are called synovial joints. They contain a liquid called synovial fluid, which is secreted by the synovial membrane, lining the space in the middle of the joint. Synovial fluid is oily, and acts as a lubricant, reducing the friction between the ends of the bones. The end of each bone has an articulating surface covered with a smooth layer of cartilage (gristle). Cartilage is a strong material, but it is not brittle. It acts as a shock absorber between the ends of the bones, rather like a rubber gym mat compresses to absorb
the shock when you fall over. It is smooth and Slippery so that it also reduces friction between the bones of the joint.
The joint is surrounded by a tough fibrous capsule, and held together by ligaments, which run from one bone to the other across the joint. Ligaments are composed of ibres that make them very tough.
They have great strength to resist stretching, called tensile strength. However, ligaments have some elasticity, so that they allow the joints to bend
and the bones to move without them becoming dislocated.
There are different types of joints which allow difterent amounts of movement. Synovial joints allow a considerable degree of movement. The ball and socket joints between the humerus and scapula, and between the femur and pelvis, allow
movement in three planes. These joints allow free movement of the limbs.
The hinge joints at the knee and elbow - allow movement in only one plane. However, this range of movement allows us to stand and walk without our legs buckling, and allows us to lift objects.
Between the vertebrae are slightly movable joints. These allow limited movement, but give flexibility and strength. Between the sutures or fixed joints in the skull there is almost no movement when a baby is born, so the head can squeezed as it is born- but by the time you are an adult the joints are completely fused and there no movement in them at all.
Muscles and Movement at joints
Muscles are organs that are attached to bones. Muscles move the bones by contracting, puliing on the bone. At the end of a muscle there are tendons. A tendon attaches the muscle to the bone. Tendons
have very high tensile strength, like ligaments, but unlike ligaments they are not very elastic. This means that they dont stretch when the muscle contracts. The correct definition of an 'elastic material is one which, when you bend or stretch it,
will return to its original shape. The word 'elastic' to mean 'easily stretched.
The word we use to mean 'not very elastic' is inelastic. Both ligaments and tendons have a high tensile strength, but ligaments are fairly elastic, while tendons are inelastic. Ligaments join bone to bone across a joint, while tendons join
muscle to bone.
In mammals, there are three types of muscle tissue:
Skeletal (or striated) muscle, which moves the muscles about and allows whole body movement
Smooth muscle, which is part of the internal organs and the blood vessels and moves the food through the gut
Cardiac muscle, which contracts regularly to give the heart beat.
Muscle tissue is made up of protein fibres that contract when they are supplied with energy from respiration. ln mammals, muscles can make up as much as 40 percent of body weight. They contract in response to messages from the nervous they enable us to respond to the world around us. Muscle fibres usually occur in big blocks or groups known as muscles.
The contraction of muscles holds us upright against the pull of gravity and allows us to make the millions of tiny adjustments to Our posture that keep us upright throughout the day. The
contraction of muscle fibres is also responsible for the much larger movements our bodies make as
we move around, carrying out all the normal functions of life. Movement, whether the tiniest twitch of a finger or the explosive burst of speed of a sprinter, is brought about by the action of muscles on bones. Each of your skeletal muscles
is attached to two different bones, spanning at least one joint. They are attached by tendons. The attachment nearest to the heart is known as the origin of the muscle and it does not move when
the muscle contracts. The attachment furthest away is called the insertion and this is on the bone that will be moved.
Muscles are attached to bones in pairs. Muscles fibres are always either contracted or relaxed. When muscle contracts, it shortens and pulls on the
bones to which it is attached, moving one of them. When it relaxes, it is capable of being stretched to its original length, but it cannot push the bone back into place. This can only be done by anothe
muscle, contracting and pulling in the opposite direction to the first one. This is why muscles always come in pairs one pulls the bone in one direction, the other pulls it back to its original
position. Because they work in direct opposition to each other, these muscles are known as antagonistic pairs
References
. https://www.livestrong.com/article/115165-functions-skeleton/
. https://opentextbc.ca/anatomyandphysiology/chapter/6-1-the-functions-of-the-skeletal-system/
. https://sciencing.com/five-main-functions-skeletal-system-5084078.html
. https://www.healthline.com/health/how-many-joints-in-human-body#synovial-joints
. https://courses.lumenlearning.com/wm-biology2/chapter/types-of-synovial-joints/
. https://www.britannica.com/science/joint-skeleton