4. Examples of connective tissue are
(1) Bone and muscle                                                 (2) Bone and Blood
(3) Bone and cartilage                                      (4) Blood and skin

Introduction

Connective tissue is a fundamental tissue type in the human body that supports, binds, and connects other tissues and organs. Unlike tightly packed cells in tissues such as epithelium, connective tissue consists of cells dispersed within an extracellular matrix (ECM), which provides strength, flexibility, and resilience. This article explains the different types of connective tissue and clarifies which among the choices—bone, muscle, blood, cartilage, and skin—are true connective tissues. Specifically, bone and cartilage represent classic examples of connective tissue.

What Is Connective Tissue?

Connective tissue acts as the “glue” of the body, connecting various structures. It consists of cells and fibers embedded in a fluid or solid matrix, allowing it to perform diverse structural and metabolic functions. It can be broadly divided into:

• Connective tissue proper: Loose and dense connective tissues found throughout the body.

• Specialized connective tissue: Includes bone, cartilage, blood, adipose tissue, and lymph.

Examples of Connective Tissue

Bone and Cartilage

Bone and cartilage are specialized connective tissues that provide structural support, shape, protection, and mobility to the body.

• Bone is a rigid connective tissue with a mineralized ECM rich in calcium phosphate. It houses cells such as osteocytes, osteoblasts, and osteoclasts. Beyond support, bones store minerals and produce blood cells in the marrow.

• Cartilage is a flexible but firm tissue that cushions joints and shapes structures like the ear and nose. Types of cartilage include hyaline, elastic, and fibrocartilage, each with unique ECM composition.

Blood

Blood is a fluid connective tissue composed of red cells, white cells, platelets, and plasma (ECM). It facilitates transport of gases, nutrients, wastes, and immune cells throughout the body. Though liquid, it is classified as connective tissue because it originates from the mesenchyme and connects body systems via circulation.

Muscle and Skin Are Not Connective Tissue

• Muscle tissue is specialized for contraction and movement. It consists of tightly packed muscle fibers and does not qualify as connective tissue.

• Skin primarily consists of epithelial tissue (epidermis) and underlying connective tissue (dermis). Since skin is a composite structure, it itself is not connective tissue but contains connective tissues within it.

Correct Answer to the Query

• Among the given options:

  1. Bone and muscle — muscle is not connective tissue.

  2. Bone and blood — both are connective tissues.

  3. Bone and cartilage — both are connective tissues.

  4. Blood and skin — skin is not connective tissue (mostly epithelial).

Therefore, (3) Bone and cartilage is the best example of connective tissue pairs that both belong to connective tissue category.

Functions of Connective Tissue

• Support and structure: Bone and cartilage form the scaffold of the body.

• Protection: Bones protect vital organs; cartilage cushions joints.

• Transportation: Blood transports oxygen, nutrients, and immune cells.

• Storage: Bone stores minerals like calcium and phosphate.

• Immune defense: Blood cells fight infections.

• Binding tissues: Connective tissue proper binds organs and tissues together.