Connective Tissue PDF

Tissues of the human body: Connective tissue Dr Fraser Philp Intended learning outcomes Tissue Describe and define tissue Classify and describe the tissues of the body into the principal types Connective Tissue Identify the distinguishing features of connective tissue Discuss the cells, fi...

Tissues of the human body: Connective tissue Dr Fraser Philp Intended learning outcomes Tissue Describe and define tissue Classify and describe the tissues of the body into the principal types Connective Tissue Identify the distinguishing features of connective tissue Discuss the cells, fibres and intercellular substance that constitute connective tissue Describe the structure and function of different types of connective tissue indicating their locations Tissues in the body Loading… Tissue S “a group of cells that usually have a common ① embryonic origin and function together to carry - - - out specialised activities” Organisation ⑧ Loading… Tissues in the body Structure and properties of a specific tissue are influenced by factors such as Nature of the extracellular matrix Connections between cells that compose the tissues Tissues in the body may be Hard (bone) * Semisolid (fat) * Tissues in the body (Principal types) Connective tissue - Overview  Functions 1- Binds together, supports & strengthens other body tissues. 2 E Protect and insulate internal organs 3 - Compartmentalize structures, such as skeletal muscle 4 6 Major transport system – blood G Ofat Store energy reserves – adipose 6- Main source of immune response –# platelets/lymph Connective tissue - 2 basic elements Cells Extracellular matrix Loading… Connective tissue - 2 basic elements Extracellular matrix CELL NUCLEI Material located between the widely spaced cells, consists of * protein fibres and PROTEIN GROUND ground substance FIBRES SUBSTANCE 2 EXTRACELLULAR (material between the MATRIX Connective tissue - cells Cells – Types and Immature Resident and fluctuating ↓by Immature cells suffix = blast = bud or sprout fibroblasts – loose and dense connective tissue Chondroblasts – cartilage Osteoblasts – bone Retain the capacity for cell division and secrete the extracellular matrix ⑳ Cells - Mature Once the extracellular matrix is produced the immature cells differentiate into mature cells. Mature cells suffix = cyte Reduced capacity for cell division and extracellular matrix Mostly involved with maintaining the matrix  Cells – connective tissue types There are 6 types of connective tissue cells mentioned here. Vary according to the type of tissue 1. 2. Fibroblasts Adipocytes / Lipocytes 6 3. Macrophages 4. Lymphocytes Mast cells 5. Mast cells Cells Present in general connective tissue, most numerous. Secrete extracellular matrix e.g. T Fibroblasts ① collagen, active during wound repair – forms granulation tissue Resident ② Adipocytes / Lipocytes Store and synthesise fats Macrophages ① Engulf and digest bacteria or foreign bodies (Phagocytosis) Immunological response * Involved in defence mechanism, migrate to sites of parasitic invasions and allergic Lymphocytes ② responses Fluctuating Mast cells ③ Produce histamine (vasodilation), Involved in defence mechanism Plasma cells ⑪ Involved in defence mechanism, secrete antibodies * May be resident e.g. lungs or fluctuating Extracellular matrix Extracellular matrix – ground substance Ground substance (material between the cells and fibres) Fluid Semifluid Gelatinous Calcified Contains water and a series of large organic molecules complex combination of polysaccharides (glycosaminoglycans (GAG’s) and proteins proteoglycans Extracellular matrix – Role of ground substance Support cells, provides a medium through which substances are exchanged between the blood and cells Important for tissue development, migration, proliferation, changing of shape and metabolism Acts as a mechanical barrier Adhesion proteins present, main one being  fibronectin, which binds collagen fibres and Extracellular matrix – Fibres Three fibre types 1. Collagen 2. 3. Elastic Reticular 3 Embedded in the extracellular matrix Extracellular matrix – Fibres - Collagen Collagen (colla = glue) Very strong, resist pulling forces, allow for flexibility Many different types Cartilage attracts more water than bone giving cartilage a cushioning effect Occurs in parallel bundles Orientation of the fibres depends on stresses/direction of force Extracellular matrix – Fibres - Elastic Smaller diameter than collagen Branch and join together forming a network Made up of protein molecule elastin surrounded by a glycoprotein named fibrillin Strong can be stretched up to 150% of relaxed strength Able to return to original shape (elasticity) Common in skin, blood vessel  walls & lung tissue Extracellular matrix – Fibres - Reticular Reticul = net Consisting of collagen arranged in fine branching bundles Coated in glycoprotein Provide support in blood vessel walls and forms a network around cells for some tissues e.g. areolar (breast), adipose & smooth muscle Produced by fibroblasts c = capillary Thinner than collagen and immature High proportion in bone, Collagen cartilage, tendons and ligaments Common in skin, blood vessel Elastic walls & lung tissue forms the supporting framework Reticular of many soft tissue organs e.g. spleen and lymph nodes Classification of connective tissue We can then use this information to understand what makes up connective tissue and how to classify the different types of connective tissue. We will cover this in the next lecture. We can also look in greater detail at the structure and function of connective tissue and where it is found This will help us to differentiate between connective tissue and