0:00 Hello, in this video we're going to talk about connective tissues. 0:12 Connective tissue serves as the structural framework of the body, linking, 0:16 separating 0:17 and providing support to other tissue types. 0:21 It is unique among tissues because its cells are dispersed within an extrace 0:26 llular matrix 0:27 (ECM) that is more loosely organized than in other tissues, such as the muscle 0:33 or epithelial. 0:35 The extracellular matrix consists of a fluid compartment that surrounds the 0:43 cells. 0:45 There are primarily two types of connective tissue, and each place will categor 0:51 ize these 0:51 differently, but briefly speaking, the two are connective tissue proper and 0:57 specialized 0:58 connective tissue. 1:00 Connective tissue proper is further classified into loose and dense connective 1:06 tissue. 1:06 Specialized connective tissue includes reticular, blood, bone, cartilage, and 1:12 adipose tissues. 1:14 Though perhaps less glamorous than muscle or neural tissue, connective tissue 1:18 is vital 1:18 for maintaining the unity and function of the body's various systems. 1:28 So let's look at the components of what make up a connective tissue. 1:31 Connective tissue comprises three key elements, the cells, ground substance, 1:37 and fibers, all 1:38 of which form the extracellular matrix. 1:47 The cells itself, these are the fibroblasts which are the main cells and they 1:51 are responsible 1:52 for generating and sustaining the extracellular matrix. 1:56 Other cell types found in this area include immune cells like macrophages, 2:00 lymphocytes, 2:01 and mast cells, and adipose sites which are your fat cells. 2:05 Specialized forms of connective tissue have their own unique cells such as ch 2:09 ondrocytes 2:10 in cartilage and osteocytes in bone. 2:18 Now ground substance, which is the other part of connective tissue, this is 2:23 like a gel-like 2:24 medium which facilitates hydration and nutrient diffusion. 2:29 It contains water, proteoglycans, glycoproteins, and glycosaminoglycans. 2:36 Now the fiber is the other important part of the extracellular matrix together 2:41 with the 2:41 ground substance. 2:43 The fibers are what is produced by the fibroblasts, the cells, the main cells 2:47 in connective tissue. 2:50 There are three fiber types, collagen, elastic, and reticular fibers, each 2:55 contributing distinct 2:56 properties to the tissue. 2:58 Collagen is the most abundant and it is tough. 3:01 Connective fibers allows for stretching and recoil, whereas reticular are quite 3:06 strong 3:07 and rigid as well. 3:10 Now let's talk about the two types of connective tissue beginning with connect 3:13 ive tissue proper. 3:20 Connective tissue proper includes loose connective tissue, also known as areola 3:25 tissue. 3:26 These basically wrap and cushion organs. 3:29 These guys are the epitope of flexibility and softness. 3:32 It's like the body's version of packing material, filling spaces with a soft 3:36 matrix 3:36 that holds everything in place, while allowing for the exchange of nutrients 3:39 and waste between 3:40 the bloodstream and the cells. 3:42 Its composition is a balanced mix of cells such as the fibroblasts and macroph 3:47 ages. 3:48 All the three fibers are found and the ground substance, creating a loosely 3:52 organized, flexible 3:53 mesh that can withstand limited forces, but is primarily designed for cushion 3:58 ing and support. 3:59 Examples of loose connective tissue include what we find in the laminopropia of 4:04 the alimentary 4:05 canal and the respiratory tract, the mucus membranes of the reproductive and 4:10 urinary 4:10 tracts, the glands, the mesentree, and the dermis of the skin. 4:21 Next is dense connective tissue, which is again another type of connective 4:26 tissue proper. 4:27 Dense connective tissue, in stark contrast, dense connective tissue is a body's 4:32 equivalent 4:33 of reinforced concrete. 4:35 It's tougher, more compact, and designed to handle stress and strain. 4:41 It's comprised predominantly of collagen fibers, densely packed together, and 4:45 this tissue 4:46 type gives tendons and the ligaments their incredible tensile strength, 4:50 enabling them 4:51 to withstand the rigorous demands of movement and support. 4:55 The extracellular matrix is densely packed with collagen fibers. 5:00 Based on the arrangement of the fibers, there are two subtypes of dense connect 5:04 ive tissue. 5:05 These are dense regular and dense irregular. 5:09 Dense regular connective tissue has the collagen fibers aligned parallel to 5:12 each other. 5:13 This arrangement provides a tissue with high unidirectional resistance to 5:17 stress. 5:17 The best dense regular connective tissue example are your tendons and ligaments 5:22 . 5:23 Dense irregular connective tissue has collagen fibers randomly interwoven, 5:28 forming a three-dimensional 5:30 network resistant to distention in all directions. 5:33 It is usually located in the capsules of joints and walls of organs. 5:44 So those were the connective tissue proper. 5:47 Let's look at the specialized connective tissue, beginning with reticular 5:51 connective tissue. 5:55 This type of connective tissue forms supportive framework of organs such as 6:00 your lymph nodes, 6:02 spleen and bone marrow. 6:04 It's characterized by a network of fibroblasts, specifically reticular sites, 6:11 as well as reticular 6:13 fibers. 6:15 These are the specific type of fiber. 6:20 Reticular connective tissue supports other cell types, specifically white blood 6:25 cells, 6:26 and that is why they are found predominantly in these organs and sites where we 6:31 find a 6:32 lot of white blood cells such as your lymph nodes and your spleen. 6:41 Next is adipose tissue, which is a specialized connective tissue. 6:45 Essentially it is body fat. 6:47 It's specialized in storing energy in the form of lipids. 6:50 Beyond energy storage, adipose tissue also provides insulation, protection, and 6:54 serves 6:55 as an endocrine organ, releasing hormones that regulate metabolism. 6:59 There are two types of adipose tissue, white and brown adipose tissue. 7:04 White adipose tissue is the most abundant, storing energy and cushioning organs 7:08 . 7:08 While brown, adipose tissue is rich in mitochondria and specializes in 7:12 generating heat, playing 7:14 a crucial role in thermoregulation, especially in infants. 7:18 Reticular connective tissue and adipose connective tissue has also been 7:22 classified as a loose 7:23 connective tissue, which is part of connective tissue proper, but we've 7:27 separated that into 7:28 its own category. 7:35 Then you have cartilage, which is also a connective tissue. 7:39 But unlike other connective tissues, cartilage is avascular, meaning it lacks 7:44 blood supply. 7:45 And it relies on diffusion through the matrix to receive nutrients and remove 7:50 wastes. 7:51 This feature combined with its unique extracellular matrix rich in water and 7:55 specialized fibers 7:56 allows cartilage to absorb shock and reduce friction in joints. 8:06 Cartilage comes in three main types. 8:09 These are your highline cartilage, which is the most abundant. 8:13 These are found in the ribs, nose, larynx, and trachea, as well as covering 8:18 bones at 8:18 joint surfaces. 8:20 It provides sturdy yet flexible support. 8:23 Elastic cartilage contains a high concentration of elastic fibers, giving it 8:29 enhanced flexibility 8:31 found in structures that require bending like the ear and the epic lotus. 8:36 Then you have your fibro-college, the toughest type. 8:39 It contains thick bundles of collagen fibers, the strong fibers. 8:44 It is found in areas subjected to heavy pressure and stretch, such as the inter 8:48 vertebral discs, 8:50 the meniscus of the knee, and the pubic synthesis. 8:59 The bone is also a connective tissue. 9:01 Bone tissue, or osteous tissue, forms the rigid structure of the skeleton. 9:06 It's a dynamic living tissue that continuously remodels itself. 9:11 Bones provide protection to vital organs, support the body, facilitate movement 9:16 by anchoring 9:17 muscles and serves as a reservoir for minerals like calcium and phosphate. 9:22 The extra cellular matrix of bone is rich in collagen fibers and mineral salts, 9:27 giving 9:27 its strength and rigidity while allowing for slight flexibility. 9:33 Bone cells include osteoblasts, osteocytes, and osteoclasts, are involved in 9:40 the formation, 9:41 the maintenance and resorption of bone tissue, showcasing the tissue's dynamic 9:47 nature in 9:47 growth and healing. 9:55 The final type of specialized connective tissue is the blood. 10:00 Blood is a fluid connective tissue, unlike any other. 10:03 It's tasked with the vital role of transportation within the body. 10:06 It transports oxygen, nutrients, waste products, and various cells throughout 10:11 the body play 10:12 a key role in immunity, regulation of pH, and temperature control. 10:18 Blood is composed of a liquid matrix called plasma, in which red blood cells, 10:22 white blood 10:23 cells, and platelets are suspended. 10:26 This composition allows blood to perform a wide range of function, from 10:30 delivery of oxygen 10:32 to wound clotting and immune defense. 10:41 So in summary, each type of connective tissue, with its unique composition and 10:46 arrangement 10:47 of cells, fibers, and ground substance, plays a crucial role in the body's 10:52 structure and 10:53 function, highlighting the interconnectedness and complexity of bodily systems. 11:00 We divided connective tissue into two broad types. 11:04 Connective tissue, proper and specialized connective tissue, which include a 11:09 whole lot, 11:10 include bone, cartilage, blood, and even adipose tissue. 11:16 Thank you for watching. 11:30 [BLANK_AUDIO]
