Human Skeletal System: Parts, Functions, Diagram, Facts

Definition of the Skeletal System

The human skeletal system forms a complex framework of bones and connective tissues functioning for structuring, protection, and mobility. The human adult skeleton is composed of 206 bones connected by a system of joints, yet held together with cardiovascular, cartilaginous, ligamentary, and tendinous parts.

It supports the body to take shape and maintain posture, protects vital organs like the brain, heart, and lungs and provides for movement via the articulation of bones and the associated action of bones and muscles. It is also relevant to the foremost physiological processes of human beings, offering storage for minerals and producing blood cells inside the bone marrow.

Skeletal System Anatomy

The structure is discussed below-

Number of Bones in the Human Body

An adult has 206 bones, whereas in a newborn it is about 270 bones. With increasing maturity, some of the bones fuse and hence the number decreases.

Classification of Bones Based on Shape

The bones can be simply classified into four major groups by their shapes:

• Long bones – femur

• Short bones – carpals

• Flat bones – skull

• Irregular bones – vertebrae

Major Components of the Skeletal System

The major components of the skeletal system are discussed below-

Axial Skeleton

The components of the axial skeleton system are:

Skull: This is made up of 22 bones, all together, protecting the brain, and generally forming the structure of the face.

Vertebral column: It is composed of 33 vertebrae, each supports the spinal cord and provides protection. These could be grouped into cervical-7, thoracic-12, lumbar-5, sacral-5 fused into the, and coccygeal-4 fused into the coccyx.

Rib cage: This structure is composed of 24 ribs in 12 pairs and the sternum, protects the heart and lungs and supports respiration or breathing.

Appendicular Skeleton

The components of the appendicular skeleton system are:

Pectoral girdle: This is made of the clavicles and scapulae. These bones serve to support the limbs of the upper part of the body, hence making wide-ranging movements at the shoulder possible.

Pelvic girdle: The hip bones are created by the ilium, ischium, and pubis. These bones convey the weight from the upper body to the lower extremities while on the same note serving to protect the pelvic organs.

Limbs: The upper limbs consisting of arms, forearms, wrists and hands and the lower limbs consisting of thighs, legs, ankles, and feet are made up of long and short bones that offer locomotion and contact with the environment

Skeletal System Physiology (Functions)

The functions are discussed below-

Support and Shape

The skeleton provides a great framework that helps to support the shape and structure of the body. Since the bones are the chief constituent structure of the body, they are easily able to provide support against the force of gravity and bear other external forces upon it.

Protection of Vital Organs

The skull covers, overlays, and protects one of the most important organs in the human body, the brain, against damage. The protective function of the rib cage shields from direct physical trauma heart and lungs—key molecular structures to cardiovascular and respiratory functions.

Movement and Locomotion

The skeletal system makes movements and locomotion possible through interaction with the muscular system. More precisely, bones are attachment sites for muscles. When these muscles contract, they will pull on the bones, generating movement at joints.

Mineral Storage

Bones act as a storage site for several crucial minerals, primarily calcium and phosphorus, both of which are critical to many bodily functions in general. This mineral content might then be resorbed back into the bloodstream when required and therefore help in the maintenance of mineral balance and metabolism.

Blood Cell Production

The process of hematopoiesis occurs within the red bone marrow in some bones. It is the area where blood cells are formed. Every day, millions of red blood cells are produced by this process for carrying oxygen, many white blood cells for immune defence, and thousands of platelets required for blood clotting

Human Skeletal System NEET MCQs (With Answers & Explanations)

Important questions asked in NEET from this topic are:

• Major components of skeletal system

• Physiology of skeletal system

Practice Questions for NEET

Q1. Which tissue is Avascular and Aneural?

1. Epithelium

2. Tendons

3. Cartilage

4. Epithelium and Cartilage

Correct answer: 3) cartilage

Explanation:

Cartilage is avascular and aneural. When cartilage lacks blood arteries it is said to be avascular. To absorb nutrients and eliminate waste it instead depends on diffusion from nearby tissues.

Aneural refers to cartilage that lacks a direct nerve supply because it lacks nerve cells. For this reason, under normal circumstances, cartilage is not responsive to pain.

An example of connective tissue is cartilage which gives joints, the nose, ears, and the respiratory tract support, flexibility, and cushioning. Compared to other bodily tissues, cartilage heals more slowly because it lacks blood arteries and nerves.

Hence, the correct answer is option 3) Cartilage.

Q2. The study of the skeletal system is known as

1. Osteology

2. Myology

3. Skeletology

4. Both a and c

Correct answer: 4) Both a and c

Explanation:

The human skeletal system is made up of a framework of bones and cartilage, providing structural support to the body. The study of this system is called osteology or skeletology. Besides offering protection to vital organs, the skeletal system plays a crucial role in enabling body movement by serving as points of attachment for muscles and acting as levers during motion.

Hence, the correct answer is option 4) both a and c.

Q3. The axial skeleton consists of

1. Skull

2. Vertebral column

3. Sternum and ribs

4. All of the above

Correct answer: 4) All of the above

Explanation:

In human beings, this system is made up of 206 bones and a few cartilages. It is grouped into two principal divisions –

• Axial skeleton: It is present on the median longitudinal axis of the body. It consists of the skull, vertebral column, sternum and ribs. It contains 80 bones.

• Appendicular skeleton: It is situated on the lateral sides which extend outwards from the principal axis. It consists of the pectoral and pelvic girdle and bones of arms and legs.

Hence, the correct option is 4) All of the above

Also Read:

• MCQs on Human Skeletal System

• List of the 206 Bones in Our Body

• Human Body and Its Movements

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