Connective Tissue Overview

Study Notes

Connective Tissue

Connective tissues are diverse tissues with multiple functions, including binding & supporting, protection, insulation, storage, and transport.
Four main types: connective tissue proper, cartilage, bone, and blood.
Originate from mesenchyme (embryonic tissue).
Vary in vascularity.
All have an extracellular matrix separating living cells, providing resistance to stress.
Comprised of three main components: ground substance, fibres, and cells.

Ground Substance

Unstructured material filling spaces between cells.
Contains interstitial fluid, cell adhesion proteins (e.g., holding cells to the matrix), and proteoglycans.
Proteoglycans have a protein core with glycosaminoglycans (GAGs).
GAGs are negatively charged, trapping water, increasing viscosity (e.g., hyaluronic acid).

Fibres

Provide support to structures.
Collagen: Strongest and most common, most abundant animal protein. Forms bundles, cross-links for high tensile strength. Types differ in structure and location.
- Type I: skin, tendons, bone, ligaments, dentin
- Type II: cartilage, vitreous humor
- Type III: skin, muscle, blood vessels
- Type IV: basal laminae
- Type IX: cartilage, vitreous humor
Elastic: Long, thin, branching network. Allow stretch (elastin) limited by collagen. Return to original shape when relaxed. Found in skin, lungs, blood vessels.
Reticular: Continuous, branched network of collagen fibers. Provides support around blood vessels and soft tissues.

Cartilage

Resists tension and compression.
Density falls between connective tissue and bone.
Lacks nerves and blood vessels (repair slow).
Calcifies (turns to bone) with age.
Types:
- Hyaline: Most common; supports, reinforces. Found in ends of long bones, nose, larynx, trachea.
- Elastic: Similar to hyaline but with more elastic fibers. Maintains shape while flexible; found in ear (pinna), epiglottis.
- Fibrocartilage: Less dense than hyaline. Compressible and resists tension; absorbs compressive shock, withstands pressure. Found in intervertebral discs, knee.

Bone

Also called osseous tissue, provides support and protection.
Contains cavities for fat storage & blood cell synthesis.
Matrix similar to cartilage but denser.
Contains calcium salts (bone salts).
Has central canals with blood vessels and nerves.

Bone Functions

Anchorage: Attachment site for skeletal muscles. Forms levers.
Production: Haematopoiesis (blood formation) in bone marrow.
Hormones: Influences insulin secretion, glucose homeostasis, and energy use.
Storage: Triglycerides (energy store), calcium, and phosphates (blood ions replenishment).

Skeleton

Two groups:
- Axial: Forms central axis of the body (skull, vertebral column, ribcage). Provides protection and support.
- Appendicular: Includes upper and lower limbs, and girdles (shoulders and hips). Primarily for locomotion and movement.

Description

This quiz covers the essential elements of connective tissues, including their types, functions, and structural components like ground substance and fibers. Dive into the roles of collagen in providing strength and the significance of the extracellular matrix. Test your knowledge on the varied nature and origins of connective tissue.