skeletal system, supporting tissues

SKELETAL SYSTEM AND SUPPORTING TISSUES, Introduction to the skeletal system in living organisms

Living 0rganisms including plants and animals need tissues and other supporting systems to enable them to carry out life’s processes such as movement, respiration, feeding and reproduction.

Here is a typical example of what I am saying, without the various bones and tissues, vertebrates will not be able to stand, respire, move and carry out other life processes

Many multi-cellular organisms, mostly plants and animals need to support themselves in some way to enable them to maintain their shape.

It is also worthy of note that without the skeletal system, we as humans will not be able to stand upright, move about in search of food, carry loads, and raise our heads and other parts of the body.

As a result of the above-stated facts about the skeletal system of living organisms, we have no choice but to devote ample time to studying one of the essential parts of living organisms.


What is a skeleton? Why do we have skeletons in our bodies as living things?
The question will not be complete if we don’t ask how many bones are there in the human body or how can we count the number of bones in the body of humans. So here is a compact definition of the skeletal system


Skeleton is the bony framework of the body which provides support, shape and protection of the soft tissues and organs in animals.

Without the skeletal system, animals may not be able to carry out most of life’s processes such as movement, respiration and feeding. One of the most important functions of the skeletal system is that it enables animals to move from place to place

The skeletal system helps to determine the advancement and development of organisms, for instance, man is able to stand erects/upright because of our sophisticated skeletal system.


This is most confusing in trying to understand and name the various forms of the skeletal system. The issue here is what materials the creator of living organisms used in making the skeleton. Does the skeleton have components? So join me as I take deeper into the study of the skeletal system of living organisms.
There are three forms of skeletal materials found in animals. These are cuticles, bones and cartilage


The cuticles as a material of the skeletal system, are composed of chitin and a thin waterproof layer of wax. The chitin is a non-living substance, therefore animals with this type of skeletal material can only grow by moulting.

In this process of growth called moulting, an organism only sheds off it old skeletal system and puts on a new one. In order words, any organism with this type of skeleton will have put off the old skin.

The cuticle is an exoskeleton which is located externally on the body of the organism. An example of organisms with cuticles as their skeletal material system are mainly arthropods which are insects, crabs, scorpions and prawns


The bones as part of the skeletal system of organisms, are a tissue and a major component of the vertebral skeleton. It consists of living bone cells called osteocytes, protein fibres called collagen and minerals which are mainly calcium-phosphate and calcium-carbonate

The minerals, which are the non-living component of the bone are made up of the mass of a bone. As a result, bone is stronger and more rigid tissue than the cartilage.

A bone consists of a hard outer layer-shaft and a spongy or hollow cavity filled with bone marrow. A typical example of organisms which have bones are mainly vertebrates, which are bony fishes, toads, lizards, snakes, birds and mammals.


The cartilage, a form of material found in the skeletal system, is a tissue found in the skeleton of complex vertebrates.

The cartilage consists of living cells called chondroblasts, carbohydrates and protein fibres. The cartilage is a flexible and tough tissue that has great tensile strength.

The cartilage acts as a shock absorber, cushioning the effects of bone moving against bone during movement. Examples of organisms with cartilages are mainly cartilaginous fishes like wales, sharks and mammals generally.

In mammals, there are three types of cartilage. They are
i. Hyaline cartilages

This type of cartilage is found in the bronchi and trachea, surfaces of movable joints, the protruding part of the nose which supports it
ii. Fibro-cartilages

This type of cartilage is tougher than hyaline cartilage and it is found in the discs between the small bones of the vertebral column
iii. Elastic cartilages
This type of cartilage is found in the external ear called the pinnae and the epiglottis


Generally, it is said that growth is effective and consistent if certain activities which are supposed to propel it are in proportion to it. So these vitamins and mineral elements are

i. Vitamin-D Calciferol, Vitamin-C all form the cement of bone
ii. Mineral elements are calcium/phosphorus/magnesium

bones, buried, skeletal system

The difference between bones and cartilages


I. Bone is made up of living and non-living cells
II. Bones are flexible, especially in adults
III. Bone is made up of hard substance
IV. Bone can never be replaced by a cartilage
V. Bone is made up of mineral salts
VI. Bone is stronger, and it is a more rigid tissue

CARTILAGE Cartilage is made up of mainly living cells
ii. Cartilage is very flexible both in young and the adult
iii. Cartilage is made up of soft materials or substance
iv. Cartilage is not as strong as bone but it is a flexible tissue
Continue reading



As I highlighted in my previous post, here I will be treating the various types of skeletons in more advanced detail. As you read, if there is any topic or subject, or whatever question you would like me to clarify please don’t hesitate to use our comment box or search this blog using the search box.

There are three main types of skeleton.

They are
1. Hydrostatic skeleton
2. Exoskeleton and
3. Endoskeleton

The Hydrostatic fluid skeleton

The hydrostatic skeleton is the type of skeleton possessed by soft-bodied animals– read more here. They have fluid pressure to provide support. The fluid is secreted to fill the spaces in the body.

The fluid presses against the body wall, causing the muscles to contract, and exerting pressure against the fluid.

This helps to maintain the shape and form of the animal. Examples of organisms with this type of skeleton the earthworms and anemones


The exoskeleton is the type that is found in the outside or the external part of the body of some animals. Most vertebrates also possess cuticle which is composed of chitin.

The Chitin is a non-living substance commonly found covering the outer parts of the body of some animals. Such external skeletal tissues enclose, support, give shape, protect and enable the animals to move about from place to place.

Here is a skeletal system of human
Examples of organisms with exoskeletons are invertebrates like Euglena, Paramecium, Hydra, Tapeworm, Snails, Prawns, Crabs, Spiders, Crayfish, millipedes and earthworms.

Organisms with this type of skeleton can only grow by a process called moulting or ecdysis. In this process, an organism sheds off its old skeleton and is covered with a new one as it grows.


An endoskeleton is the type of skeletal system that is found in the body of the animal. The endoskeleton exists in the bony or cartilaginous skeleton of fishes, toads, lizards, birds and mammals.

The endoskeleton in vertebrates is made up of cartilage and bones. Endoskeleton in mammals are the skull, vertebral column or backbone, ribs and the bones of the fore-limbs and hind limbs


The skeletal system or bones in mammals like that of rabbits are grouped into two major parts. These are the Axial and Appendicular skeletons which are the main parts of the skeletal system

1. Axial skeleton
The Axial skeleton is made up of the skull, vertebral column or backbone, the ribs, sternum/breastbone

2. Appendicular skeleton
The Appendicular skeleton is made up of the limb girdles (pectoral and pelvic girdles) and the limbs (forelimbs and hind limbs)


The mammalian skull is made up of several flat bones which are joined together by means of joints called sutures

There are three major parts of the skull
i. The cranium is often called the brain box. This part of the skull houses the brain

ii. The facial skeleton, supports the nose, eyes and the muscles of the cheek.
iii. The jaw. This part of the skull is made up of the upper jaw called MAXILLA and the lower jaw known as the mandible in the teeth is also fixed.

The functions of the skull as part of the skeletal system

i. The skull gives protection to the brain
ii. The skull gives shape to the head
iii. The skull protects vital organs like eyes, nose and ears
iv. The skull bears the teeth which are used for the grinding of food


The vertebral column, also known as the backbone or spinal column, is the central supporting structural system of the skeleton. The vertebral column forms the backbone of vertebrate animals and houses the spinal cord.

It is made up of five groups of bones known as the vertebrae=== singular vertebra. In humans, it consists of 33 vertebrae while in rabbits it consists of 46 vertebrae. The vertebrae are held on the other with a strong ligament having compressible cartilage pads called INVERTEBRAL DISC between consecutive vertebrae.

In mammals, the five different vertebrae are

1. Cervical vertebrae===== this found in the neck region
2. Thoracic vertebrae=====this type of vertebra is found in the chest region
3. Lumber vertebrae====this type of vertebrae is found along the upper abdomen

4. Sacral vertebrae=== This type of vertebrae is found around the lower abdomen
5. Caudal vertebrae===== This type of vertebrae is found around the tail region.

The features of typical vertebrae as part of the skeletal systems

All vertebrae, even though they have different functions, have certain features in common. So a typical vertebrae has the following features in common

Neural carnal:

this is for the passage of the spinal cord

Neural spine:

this projects upwards dorsally for the attachment of muscles

Transverse process:

they project from each side of the vertebrae for the attachment of muscles and ligaments



it is a solid piece of bone below the neural canal
v. Facet: this is a small, smooth and slightly depressed area on a bone that is usually a point of contact with another bone.

vi. Zygapophysis: these are articular surfaces for the articulation of successive vertebrae. They are grouped into two parts. Pre-zygapophyses face inward and upwards while post-zygapophysis faces outward and downward

Don’t get tired friend, read about the various types of vertebrae here
Types of vertebrae and their functions

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