Overview
This lecture explores connective tissue, its types, structure, functions, and the impact of genetic disorders like Marfan Syndrome on it.
Flo Hyman & Marfan Syndrome
- Flo Hyman was an elite volleyball player whose sudden death was due to Marfan Syndrome, a connective tissue disorder.
- Marfan Syndrome is a genetic defect affecting connective tissue, leading to weakened joints, bones, eyes, lungs, and especially the heart and blood vessels.
- People with Marfan Syndrome are often tall, thin, with long limbs and fingers, and flexible joints.
Introduction to Connective Tissue
- Connective tissue is the most abundant and diverse of the four tissue types in the body.
- It is found throughout the body, varying greatly in amount depending on the organ.
- Four main classes: connective tissue proper (includes fat and ligaments), cartilage, bone, and blood.
Functions of Connective Tissue
- Connective tissue supports, binds, protects organs, and provides structure (skeleton).
- Fat (a type of connective tissue proper) insulates, stores energy, and holds organs in place.
- Blood transports hormones, nutrients, and other materials.
Common Properties of Connective Tissue
- All types develop from embryonic tissue called mesenchyme.
- Degrees of vascularity vary: some, like cartilage, have no blood vessels, while others are highly vascular.
- Mainly composed of extracellular matrix (ECM), a nonliving substance surrounding cells.
Structure of the Extracellular Matrix
- ECM has two main parts: ground substance (watery, rubbery, protective) and fibers (structural support).
- Ground substance contains proteoglycans and glycosaminoglycans (GAGs) that trap water.
- Three fiber types: collagen (strong, flexible), elastic (stretchy, recoil), and reticular (supportive network).
Connective Tissue Cells
- Immature cells (named with -blast) build matrix: e.g., chondroblasts (cartilage), osteoblasts (bone).
- Mature cells (named with -cyte) maintain the matrix and can revert to blasts for repair.
- Immune cells in connective tissue include macrophages and white blood cells for protection.
Effects of Marfan Syndrome on Connective Tissue
- Marfan Syndrome primarily affects elastic fibers in connective tissue, especially around the heart and aorta.
- Weakened elastic fibers can cause the aorta to enlarge and rupture, leading to life-threatening complications.
Key Terms & Definitions
- Connective Tissue — Tissue that supports, binds, or separates other tissues and organs.
- Extracellular Matrix (ECM) — Nonliving material outside cells, mainly ground substance and fibers.
- Mesenchyme — Embryonic tissue from which all connective tissues develop.
- Proteoglycans — Proteins with attached carbohydrates, part of ground substance.
- Glycosaminoglycans (GAGs) — Long carbohydrate molecules in ground substance.
- Collagen Fibers — Strong, flexible fibers providing tensile strength.
- Elastic Fibers — Fibers that stretch and recoil, providing flexibility.
- Reticular Fibers — Thin, branching fibers forming supportive networks.
- -blast Cells — Immature, matrix-secreting cells of connective tissue.
- -cyte Cells — Mature cells maintaining connective tissue matrix.
- Marfan Syndrome — Genetic disorder weakening connective tissue, especially elastic fibers.
Action Items / Next Steps
- Review the four main classes of connective tissue and their properties.
- Prepare for next lesson on connective tissue subtypes.
- Study definitions and be able to identify features of connective tissue in the body.