Elastic Tissue – Tutorial
Please read Unit 2 – Introduction to Connective Tissues prior to completing the activities in this chapter.
Introduction to Elastic Tissue
Elastic tissue is a type of connective tissue proper with an extracellular matrix containing a mixture of densely packed elastic and collagen fibers in a viscous (thick) ground substance. Elastic tissue possesses a high ratio of elastic fibers compared to collagen fibers which gives it a strong yet stretchy property. Widely spaced fibroblasts are the primary cell type found in elastic tissue, but they are difficult to identify since fibroblast nuclei stain the same dark color as elastic fibers which dominate the appearance of elastic tissue under a microscope. Fibroblasts secrete chemicals that thicken the ground substance and proteins that assemble to form elastic and collagen fibers in the extracellular matrix.
Since the extracellular matrix of elastic tissue is packed with large amounts of extremely flexible elastic fibers and smaller amounts of strong yet flexible collagen fibers it gives it a strong yet stretchy resilience which allows it to return to its original shape after repeated cycles of stretching or distortion. Elastic tissue is found in the walls of large arteries (known as elastic arteries) which allow them to stretch when the heart contracts and blood pressure surges and recoil back to a smaller diameter when the heart relaxes. Elastic tissue is also found in elastic ligaments that stabilize the position of vertebrae along the spine and in the walls of the urinary bladder and penis which allow them to expand and contract in volume without tissue damage.
