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The Human Body: Skeletal and Muscular System - The Skeleton and its functions

Grade 5ICSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

The human skeleton is an internal framework consisting of 206 bones in an adult, providing shape and structural support to the body.

Support and Shape: The skeleton provides a rigid frame that supports the soft tissues and maintains the body's shape.

Protection: Vital organs are shielded by bony structures. For example, the skull protects the brain, and the ribcage protects the heart and lungs (responsible for O2O_2 and CO2CO_2 exchange).

Movement: Bones act as levers. Muscles are attached to bones by tendons, and their contraction allows for locomotion.

Storage of Minerals: Bones serve as a reservoir for essential minerals, primarily Calcium (CaCa) and Phosphorus (PP), which are released into the bloodstream when needed.

Blood Cell Production: The soft tissue inside large bones, known as bone marrow, is the site for producing Red Blood Cells (RBCsRBCs) and White Blood Cells (WBCsWBCs).

The skeleton is divided into the axial skeleton (Skull, Vertebral Column, Ribcage) and the appendicular skeleton (Limbs and Girdles).

📐Formulae

Total Bones (Adult)=206Total\ Bones\ (Adult) = 206

Calcium PhosphateCa3(PO4)2Calcium\ Phosphate \approx Ca_3(PO_4)_2

Hydroxylapatite (Bone Mineral)=Ca10(PO4)6(OH)2Hydroxylapatite\ (Bone\ Mineral) = Ca_{10}(PO_4)_6(OH)_2

💡Examples

Problem 1:

Identify the number of vertebrae in the human backbone and explain their function.

Solution:

33 vertebrae.

Explanation:

The vertebral column (backbone) is made up of 33 small, ring-like bones called vertebrae. They are stacked on top of each other to protect the spinal cord and allow the body to bend and twist.

Problem 2:

Which mineral is most essential for bone strength, and what is its chemical symbol?

Solution:

Calcium (CaCa).

Explanation:

Bones are primarily composed of Calcium salts. A deficiency in CaCa can lead to weak and brittle bones, a condition often referred to as osteoporosis in adults.

Problem 3:

How does the ribcage facilitate protection of internal organs?

Solution:

By forming a cage-like structure.

Explanation:

The ribcage consists of 12 pairs of curved bones. It protects the heart and the lungs from external injury while remaining flexible enough to expand during breathing.

The Skeleton and its functions - Revision Notes & Key Formulas | ICSE Class 5 Science