Which description best identifies the unique attributes of connective tissue? Connective tissues are hard and inflexible. Connective tissues, unlike other tissues, always lack blood vessels. Connective tissues transmit electrical signals from one part of the body to another. Connective tissues are generally characterized by a large amount of extracellular matrix. Question 25 Protein fibers and what: comprise the extracellular matrix that exists in the spaces between the cells of a typical connective tissue? Mesenchymal cells Fibroblasts Ground substance Leukocytes
The Correct Answer and Explanation is:
Correct Answers:
- Connective tissues are generally characterized by a large amount of extracellular matrix.
- Protein fibers and ground substance comprise the extracellular matrix that exists in the spaces between the cells of a typical connective tissue.
Explanation
Connective tissue is one of the four basic types of tissue in the human body, alongside epithelial, muscle, and nervous tissues. What uniquely defines connective tissue is the abundance of extracellular matrix (ECM) — a structural framework that supports the cells within the tissue. This matrix distinguishes connective tissues from other types that are primarily cellular, such as epithelial tissue.
The extracellular matrix is composed of two main components: protein fibers and ground substance. Protein fibers include collagen (providing tensile strength), elastic fibers (offering flexibility and resilience), and reticular fibers (forming supportive networks in soft tissues). The ground substance is an amorphous gel-like material composed of water, proteoglycans, glycoproteins, and other molecules. It fills the space between cells and fibers, allowing the diffusion of nutrients and waste products.
This structural composition allows connective tissue to perform diverse functions — from binding and supporting organs, to storing energy (as in adipose tissue), to providing immunity (as in blood and lymph). Contrary to one of the distractors in the question, most connective tissues are vascularized, meaning they contain blood vessels, although there are exceptions (e.g., cartilage is avascular).
Connective tissue is not specialized to transmit electrical signals — that function is specific to nervous tissue. Nor is connective tissue necessarily hard and inflexible; while bone is a rigid form of connective tissue, others like loose connective tissue and adipose tissue are soft and pliable.
Thus, the defining attribute of connective tissue is its abundant extracellular matrix, and that matrix is primarily made up of protein fibers and ground substance, not the cells themselves.
