Bio II Lecture 3 PDF

Field of Basic Science Biotechnology and petroleum chemistry programs Biology II: BIO 241 Level 2 Connective Tissue Yasmine Hosny Hassan, PhD Date : 10/ 12 /2023 10/20/2024 Yasmine Hosny Hassan 1 Agenda….. Connective tissue. Components...

Field of Basic Science Biotechnology and petroleum chemistry programs Biology II: BIO 241 Level 2 Connective Tissue Yasmine Hosny Hassan, PhD Date : 10/ 12 /2023 10/20/2024 Yasmine Hosny Hassan 1 Agenda….. Connective tissue. Components of connective tissue. Types of connective tissue. 20/10/2024 Yasmine Hosny Hassan 2 Connective tissue The main function of connective tissue is to connect other tissues or organs together to support them. it consists of cells surrounded by a compartment of fluid called the extracellular matrix (ECM). However connective tissue differs from other types in that its cells are loosely, rather than tightly, packed within the ECM. They have a large amount of intercellular substance or matrix among their cells. 20/10/2024 Yasmine Hosny Hassan 3 Connective tissue  The connective tissues are made up of three main components: 1. Cells: widely separated from each other. 2. Fibers: different types. 3. Matrix: Amorphous ground substances. 20/10/2024 Yasmine Hosny Hassan 4 10/20/2024 Yasmine Hosny Hassan 5 Function of Connective tissues: 20/10/2024 Yasmine Hosny Hassan 6 Properties of connective tissue 1- Cellularity: cells are relatively few in connective tissue, and are widely separated by a prominent intercellular substance (Matrix). The intercellular substance is in the form of a ground substance within which there are numerous fibers. 2- Polarity: cells are scattered within the matrix; hence no polarity here. 20/10/2024 Yasmine Hosny Hassan 7 Connective tissue 3- Attachment: cells don’t rest on a basement membrane. 4- Vascularity: Connective tissue is well vascularized. 5- Regeneration: Contains mesenchymal stem cells. 20/10/2024 Yasmine Hosny Hassan 8 Classification of connective tissue connective tissue are classified according to the characteristics of their ground substance whether its solid or fluid and the types of fibers found within the matrix. 20/10/2024 Yasmine Hosny Hassan 9 Fibers of connective tissue 1. Collagen fiber is made from collagen protein. providing varying degrees of strength and rigidity to tissues. while flexible, have great tensile strength, resist stretching, and give ligaments and tendons their characteristic resilience and strength. These fibers hold connective tissues together, even during the movement of the body. 2. Elastic fiber contains the protein elastin. Each fiber can be stretched to approximately 150% of its resting length. The main property of elastin is that after being stretched or compressed, it will return to its original shape. Elastic fibers are prominent in elastic tissues found in skin and the elastic ligaments of the vertebral column. 3. Reticular fiber is made from reticulin; they are thin delicate fibers that form meshlike networks in organs such as the spleen, kidneys and lymph nodes. where they anchor and provide structural support to the parenchyma. 20/10/2024 Yasmine Hosny Hassan 12 A- Connective tissue proper what is function of connective tissues proper? connective tissue proper is found between many organs where it acts both to absorb shock and bind tissues together. It allows water, salts, and various nutrients to diffuse through to adjacent or imbedded cells and tissues. 20/10/2024 Yasmine Hosny Hassan 15 1- Areolar Connective tissue It has almost equal amounts of cells, fibers and ground substance. Chief cells are the fibroblasts. However, immune system cells are also present. Collagen fibers are the principal fibers of the ECM. They are sparsely distributed within the ECM, Besides the collagen fibers, moderate amounts of reticular and elastic fibers are present as well. Cells: fibroblasts Fibers: collagen fibers loosely scattered in the ECM 20/10/2024 Yasmine Hosny Hassan 16 Cells of Connective tissue proper 20/10/2024 Yasmine Hosny Hassan 17 10/20/2024 Yasmine Hosny Hassan 18 2- Adipose Connective tissue is the energy-storing connective tissue. It consists of adipocytes, cells filled with lipids (fats). This tissue has a small amount of ECM made of only a few collagen fibers that keep the cells together. Depending on how the lipids are distributed within the cell; there are white and brown adipose tissues. Cells: Adipocytes ECM: no ECM 20/10/2024 Yasmine Hosny Hassan 19 3- Reticular Connective tissue is a mesh-like, supportive framework for soft organs such as lymphatic tissue, the spleen, and the liver. Cells: reticular cells Fibers: reticular fibers organized in delicate networks 20/10/2024 Yasmine Hosny Hassan 21 4- Fibrous Connective tissue Cells: fibroblasts Fibers: collagen fibers are predominant, elastic fibers are few. 20/10/2024 Yasmine Hosny Hassan 24 10/20/2024 Yasmine Hosny Hassan 25 B- Skeletal tissue: Two major forms of supportive connective tissue, cartilage and bone, allow the body to maintain its posture and protect internal organs. 20/10/2024 Yasmine Hosny Hassan 28 1-Cartilage is the avascular connective tissue that connects bones at joints and comprises walls of upper respiratory airways and external ear. Chief cells: chondrocytes, lodged into cavities within the ECM called lacunae. The ECM: is vast, rich in water bound to glycosaminoglycans. This ECM structure makes cartilage flexible in various degrees but resilient to mechanical stress. 20/10/2024 Yasmine Hosny Hassan 29 10/20/2024 Yasmine Hosny Hassan 30 10/20/2024 Yasmine Hosny Hassan 31 2-Bone  Bone is the hardest connective tissue. It provides protection to internal organs and supports the body.  bone is composed of cells within an extracellular matrix of fibers (predominantly collagen fibers) and ground substance.  The extracellular bone matrix is mineralized and arranged in circular layers called lamellae. These lamellae circumvent around a central canal (Haversian canal) which serve for the passage of neurovasculature that supplies the bone and house the cells. 20/10/2024 Yasmine Hosny Hassan 32 Bone Bone’s rigid extracellular matrix contains mostly collagen fibers embedded in a mineralized ground substance containing a form of calcium phosphate. Cells: osteoblasts, osteocytes,. ECM: calcified lamellae 20/10/2024 Yasmine Hosny Hassan 33 10/20/2024 Yasmine Hosny Hassan 34 10/20/2024 Yasmine Hosny Hassan 35 10/20/2024 Yasmine Hosny Hassan 36 C- Vascular tissue: Blood and lymph are fluid connective tissues. Cells circulate in a liquid extracellular matrix (Plasma). Erythrocytes (red blood cells) transport oxygen and some carbon dioxide. Leukocytes (white blood cells) are responsible for defending against potentially harmful microorganisms or molecules. Platelets are cell fragments involved in blood clotting. Some white blood cells have the ability to cross the endothelial layer that lines blood vessels and enter adjacent tissues. Nutrients, salts, and wastes are dissolved in the liquid matrix and transported through the body. 20/10/2024 Yasmine Hosny Hassan 37 C- Vascular tissue: Blood and lymph are fluid connective tissues. Cells circulate in a liquid extracellular matrix (Plasma) It consists of water and solutes (proteins, electrolytes, nutrients, gases, hormones and waste products).. Erythrocytes (red blood cells) transport oxygen and some carbon dioxide. Leukocytes (white blood cells) are responsible for defending against potentially harmful microorganisms or molecules. Platelets are cell fragments involved in blood clotting. Nutrients, salts, and wastes are dissolved in the liquid matrix and transported through the body. 20/10/2024 Yasmine Hosny Hassan 38 Cells: erythrocytes, leukocytes, platelets. ECM: blood plasma. 10/20/2024 Yasmine Hosny Hassan 39 10/20/2024 Yasmine Hosny Hassan 40 10/20/2024 Yasmine Hosny Hassan 41