Types Of Connective Tissue - What Is Connective Tissue - Functions Of Connective Tissue

In this video we discuss what is connective tissue, the different types of connective tissue and some of the functions of connective tissue. Transcript/Notes (partial) Connective tissue is the most widespread and diverse of all the tissues and they have three main components, cells, protein fibers and ground substance. Ground substance is produced by connective tissue cells, it is a non cellular material and it can be solid, semisolid, or viscous, meaning thick and sticky. The cells and protein fibers reside within this ground substance, and the ground substance and protein fibers together are often referred to as the extracellular matrix. There are many functions that the different types of connective tissues perform, such as in many cases it provides protection for internal organs, for instance the skull protects the brain. It can also provide structural support as bones provide the framework for the body. Connective tissues connect and bind certain structures, for instance ligaments bind bone to bone, and tendons bind muscles to bones. It is important in transportation as blood, which is a connective tissue, transports nutrients, gases and wastes throughout the body. And connective tissue helps with immune function, as many connective tissues contain white blood cells that protect the body from invaders. As you can see, there are three main classifications, connective tissue proper, supporting connective tissue and fluid connective tissue. Connective tissue proper, which is sometimes referred to as fibrous because it has many fibers in its extracellular matrix, is divided into 2 subgroups. Subgroup one is loose connective tissue and it has fewer cells and fibers and more ground substance than subgroup two, dense connective tissue. There are 3 main types of loose connective tissue. Areolar connective tissue has a viscous ground substance with both collagen and elastic protein fibers. It is highly vascularized, meaning it has a good blood supply, and it contains a large number of fibroblast cells, which produce many components of the extracellular matrix. Adipose connective tissue is also highly vascularized and is comprised primarily of adipocytes, which are fat cells, and have very little extracellular matrix. Reticular connective tissue has a viscous ground substance with a branching network of reticulin fibers within it. Reticular cells and the fibers provide a supportive framework in the spleen, lymph nodes and bone marrow. Now for dense connective tissue, which also has three main types. Dense regular connective tissue consists of tightly packed parallel collagen fibers with a limited amount of ground substance and fibroblast cells squeezed between the fiber layers. Dense irregular connective tissue consists of collagen fibers that are clumped together forming an irregular pattern. It also contains fibroblast cells, and has more ground substance and a much richer blood supply than dense regular connective tissue. Next, let’s look at the second classification of connective tissues, supporting connective tissue, which also has two subgroups, cartilage and bone, with cartilage having a semisolid matrix and bone having a solid matrix. There are 3 main types of cartilage. Hyaline cartilage consists of chondrocyte cells, which support and repair the cartilage matrix. It has a poor blood supply causing injuries to heal slowly, and sometimes not at all. Fibrocartilage consist of dense, wavy looking collagen fibers and it too has chondrocyte cells in lacunae. Fibrocartilage acts a great shock absorber and is resistant to compression. It is the toughest form of cartilage. The third type of cartilage is elastic cartilage. Elastic cartilage contains some collagen fibers, and a high number of elastic fibers, and it also has chondrocyte cells in lacunae. This cartilage has a high degree of flexibility. Bone is the second type of supporting connective tissue, and it is more solid than cartilage but less flexible and it has a rich blood supply. The extracellular matrix of bone consists of collagen fibers and mineral salt crystals and bone cells called osteocytes that occupy small spaces called lacunae and are scattered throughout the matrix. Timestamps 0:00 Overview of the main components of connective tissue 0:28 Functions of connective tissues 1:10 The types of connective tissues 1:28 Connective tissue proper 1:41 Loose connective tissue 1:52 Areolar connective tissue 2:12 Adipose connective tissue 2:48 Reticular connective tissue 3:00 Dense regular connective tissue 3:25 Dense irregular connective tissue 3:47 Elastic connective tissue 3:58 Supporting connective tissue 4:10 Hyaline cartilage 4:37 Fibrocartilage 4:55 Elastic cartilage 5:15 Bone 5:39 Compact bone 5:51 Spongy bone 6:01 Fluid connective tissue - blood 6:31 Lymph