Dr. Amam Ali Amam PhD: Periodontal Disease Connective Tissue

How are we going to study connective tissue? Study connective tissue components Focus on different cell types characters and properties Where and when to find these cells.

What’ r we going to study in these cells 1.Properties, characterization and shape 2.Function. 3.Origin (from where they are derived?)

Epithelial tissue Epithelial tissue Connective tissue Connective tissue Muscular tissue Muscular tissue Nervous tissue Nervous tissue The human body is composed of only 4 basic types of tissue Cells Molecules of the extracellular matrix They are formed by:

The main characteristics of these basic types of tissue: Main Function Extracellular matrix CellsTissue Transmission of nervous impulses NoneIntertwining elongated processes Nervous Lining of surface or body cavities, glandular secretion Very small amountAggregated polyhedral cells Epithelial MovementModerate amountElongated contractile cells Muscle Support and protection Abundant amountSeveral types of fixed and wandering cells Connective

Epithelial, Muscle & Nerve Tissues are formed mainly by: Epithelial, Muscle & Nerve Tissues are formed mainly by: Cells Extracellular matrix Connective Tissue The major constituent is: Connective Tissue The major constituent is:

Characterized by: The abundance of extracellular material produced by its cells. Characterized by: The abundance of extracellular material produced by its cells. Connective Tissue Present in all systems Specialized connective tissue: 1- Adipose tissue. 2- Cartilage. 3- Bone. Present in all systems Specialized connective tissue: 1- Adipose tissue. 2- Cartilage. 3- Bone. Originate from the mesenchyme. The mesenchyme develops from middle layer of the embryo Originate from the mesenchyme. The mesenchyme develops from middle layer of the embryo

 Definition: They are responsible for providing and maintaining form in the body.  Function: They are providing the matrix that: 1- connects. 2- binds the cells & organs, 3- gives support to the body.  Definition: They are responsible for providing and maintaining form in the body.  Function: They are providing the matrix that: 1- connects. 2- binds the cells & organs, 3- gives support to the body. Connective Tissues

Fibroblasts: Fibroblasts and Fibrocyte, Other cells Fibers: structure & the most resistant componant of stroma. In some organs they form walls & the trabecular. Ground substance: macromolecules & multiadhesive glycoproteins. –They are the storage of controls of the cells. –Medium for nutrition and wastes. Fibroblasts: Fibroblasts and Fibrocyte, Other cells Fibers: structure & the most resistant componant of stroma. In some organs they form walls & the trabecular. Ground substance: macromolecules & multiadhesive glycoproteins. –They are the storage of controls of the cells. –Medium for nutrition and wastes. Connective Tissues Components & Function

Structure of Connective Tissue 3 classes of components Structure of Connective Tissue 3 classes of components Collagen Elastic Reticular multiadhesive glycoproteins multiadhesive glycoproteins macromolecules 3- Ground substance 2- Fibers Extracellular matrix 1-Fibroblast. 2-Macrophage. 3-Mast cell. 4-Plasma cell. 5-Lymphocytes. 6-Leukocytes. 7-Adipose cell. 1-Fibroblast. 2-Macrophage. 3-Mast cell. 4-Plasma cell. 5-Lymphocytes. 6-Leukocytes. 7-Adipose cell. 1- Cells

Extracellular matrices Consist of different combinations of: Extracellular matrices Consist of different combinations of: 2- Ground substance 2- Ground substance Collagen 1- Protein Fibers Elastic Reticular macromolecules multiadhesive glycoproteins multiadhesive glycoproteins Elastin = Amine Acid + Cholesterol

1-Fibroblast. 2-Macrophage. 3-Mast cell. 4-Plasma cell. 5-Lymphocytes. 6-Leukocytes. 7-Adipose cell. 1-Fibroblast. 2-Macrophage. 3-Mast cell. 4-Plasma cell. 5-Lymphocytes. 6-Leukocytes. 7-Adipose cell. Cells seen in connective tissue

Fibers composed of: Collagen Constitute Tendons Constitute Tendons Aponeuroses Capsules of organs Capsules of organs Membranes That envelop CNS (meninges) Membranes That envelop CNS (meninges)

 Synthesize collagen, elastin, glycosaminoglycans, protyoglycans, and multiadhesiveprotiens.  The most common cells in the connective tissue and most important.  They can go from resting to activating phase depending on: Stimulation such as: body injury (inflammation, trauma). Involved in the production of growth factors, etc.  Synthesize collagen, elastin, glycosaminoglycans, protyoglycans, and multiadhesiveprotiens.  The most common cells in the connective tissue and most important.  They can go from resting to activating phase depending on: Stimulation such as: body injury (inflammation, trauma). Involved in the production of growth factors, etc. Fibroblast properties:

Fibroblast

The comparison between Fibroblasts (active) & Fibrocytes (rest) The quiescent Fibroblasts (Fibrocyte) Smaller than the active Fibroblasts. Spindle shape. Fewer processes. Darker. Elongated nucleus. Acidophilic cytoplasm. Small amount of rough endoplasmic reticulum. The quiescent Fibroblasts (Fibrocyte) Smaller than the active Fibroblasts. Spindle shape. Fewer processes. Darker. Elongated nucleus. Acidophilic cytoplasm. Small amount of rough endoplasmic reticulum.

Fibroblasts & Fibrocytes Active Quiescent

Representative Function Representative Product or ActivityCell Type StructuralProduction of fibers & ground substanceFibroblast, chondroblast, Osteoblast. Immunological (defense) Production of antibodies.Plasma cell Immunological (defense) Production of immunocompetent cellsLymphocyte (several types) Immunological (defense) Participation in allergic & vasoactive reactions, modulation of mast cell activities and the inflammatory process. Eosinophilic leukocyte Defense.Phagocytosis of foreign substances, bacteria Neutrophilic leukocyte Defense.Secretion of cytokines and other molecules, phagocytosis of foreign substances and bacteria, antigen processing and presentation to other cells. Macrophage Defense (participate in allergic reactions Liberation of pharmacologically active molecules (eg, histamine) Mast cell & basophilic leukocyte Energy reservoir, heat production. Storage of neutral fats.Adipose (fat) cell Function of connective tissue cells

Connective tissue cells

Main FunctionLocationCell Type Precursor of macrophagesBloodMonocyte Production of cytokines, chemotactic factors, and several other molecules that participate in inflammation (defense), antigen processing and presentation. Connective tissue, Lymphoid organs, Lungs, Bone marrow Macrophage Same as macrophages.LiverKupffer cell Same as macrophages.Nerve tissue of the CNSMicroglia cell Antigen processing and presentation. SkinLangerhans cell Antigen processing and presentation. Lymph nodesDendritic cell Digestion of bone.Bone (fusion of several macrophages) Osteoclast. Segregation and digestion of foreign bodies, Connective tissue (fusion of several macrophages). Multinuclear giant cell Function of connective tissue cells

Macrophage Surface: irregular. The cytoplasma: granular Nucleus: oval eccentric nucleus or kidney. Age: long life. Characterization Property& shape A phagocytic ability & Secrete cytokines Defense. Function Bone marrow, then from monocytes then immigrates to connective tissue Origin (derived)

Special names of Macrophage Kupffer cell in the Liver. Microglial cells in the CNS. Langerhans cells of the Skin. Osteoclasts in Bone tissue. Monocytes & Macrophage are the same cell in different stages of maturation. Distributed throughout the body & constitute the mononuclear phagocyte system

Macrophage

 Cells: Round to oval.  The cytoplasma: filled with basophilic granules.  Nucleus: spherical centric. Characterization Property& shape storage of mediators of the inflammatory response. & liberation of pharmacologically active molecules. Defense as allergic reaction. Function Bone marrow (from progenitor cells), then immigrates to connective tissue. Origin (derived) Mast cell

The surface of mast cells contains specific receptors for immunoglobulin E ( IgE ). IgE is a type of immunoglobulin produced by Plasma cells.

Mast cell

Plasma cell  Cells: large & ovoid.  The cytoplasm: basophilic.  Nucleus: spherical eccentric, with dense compact chromatin.  Age: short life (10-20 days). Characterization Property& shape Synthesis of antibodies. Defense (immunological).Function B lymphocyte.Origin (derived)

Plasma cell

Lymphocytes, Leukocytes ( white blood corpuscles)  to be discussed later ( lymphoid organs). Characterization Property& shape  Defense: when there is inflammation they immigrates to connective tissue Function  Bone marrow (they migrate from the blood vessels by diapedesis). Origin (derived)

Collagen fibers Basesd on their structure & functions they can classified into 4 groups 1-Collagen that form long fibrils 2- Fibril- associated Collagen. 3-Collagen that form a network 4-Collagen that form anchoring fibrils

Collagen fibers

Elastin fibres

Reticular fibres

Glycosamino glycans Called acid mucopolysaccharides Glycosamino glycans Called acid mucopolysaccharides multiadhesive glycoproteins multiadhesive glycoproteins Ground substance 3 classes of components Proteoglycans a core protein with 4 main Glycosaminoglycans 1- dermatan sulfate. 2- chondroitin sulfate. 3- keratan sulfate. 4- heparan sulfate. Proteoglycans a core protein with 4 main Glycosaminoglycans 1- dermatan sulfate. 2- chondroitin sulfate. 3- keratan sulfate. 4- heparan sulfate.

Adipose tissue Characterization, Property& shape  Adipose tissue is a special connective tissue in which adipose cells predominate.  Often called Fat cells.  Adipose cells (Adipocytes) predominate.  Isolated in small groups within connective tissue or found in large aggregates.  It’s one of the largest tissue in the body.  In men % of the body weight. In women % of the body weight.  It’s a very efficient storage tissue.  Fills up spaces between other tissues, keep some organs in place.  Both types of adipose tissue have a rich blood supply.  It spreads all over the body.  Adipose tissue is a special connective tissue in which adipose cells predominate.  Often called Fat cells.  Adipose cells (Adipocytes) predominate.  Isolated in small groups within connective tissue or found in large aggregates.  It’s one of the largest tissue in the body.  In men % of the body weight. In women % of the body weight.  It’s a very efficient storage tissue.  Fills up spaces between other tissues, keep some organs in place.  Both types of adipose tissue have a rich blood supply.  It spreads all over the body.

Adipose tissue Functions It is the largest storage of energy of the body (triglycerides), the other organs are liver & skeletal muscle (glycogen). Energy reservoir, heat production. It is the largest storage of energy of the body (triglycerides), the other organs are liver & skeletal muscle (glycogen). Energy reservoir, heat production.

Types of Connective Tissue

Section of Loose Connective Tissue Proper

Section of immature dense irregular Connective Tissue Proper

Longitudinal section of dense regular Connective Tissue

Dense supporting tissue

Mucous Tissue of an embryo

Adipose tissue

1- Unilocular adipose tissue Common or yellow 2- Multilocular adipose Tissue brown

1- Unilocular adipose tissue Common or yellow  Color: white to dark yellow.  Distribution : all the body except the eyelids, the scrotum, etc.  Uniform: In newborn has a uniform thickness throughout the body.  Cells: spherical (if isolated), polyhedral (in adipose tissue, closely packed).  The cytoplasm: thin ring (single ring cell), contains a Golgi complex, mitochondria, free polyribosomes.  Nucleus: eccentric & flattened.  Surrounded by a basal lamina. Characterization Property& shape In Starving and Obesity: release or storing fat, that’s mean, cell size differs not cells numbers! Function Lipoblast from ( Mesenchymal cell).Origin (derived)

Unilocular adipose tissue

Unilocular & Multilocular adipose tissue, Origin (derived)

2- Multilocular adipose tissue Brown fat Cell: Polygonal and smaller cells (than Unilocular). Nucleus: spherical & central. Color & Called : Brown fat (large number of blood capillaries & numerous mitochondria (colored cytochromes). The cytoplasm: great number of lipid droplets (various sizes). Distribution: Limited ( animals; hibernating gland). Characterization Property& shape  Produce heat.  In newborn and hibernating animals: to raise the body heat as this tissue is a well- innervated tissue. Function  Lipoblast from ( Mesenchymal cell). mesenchemical cells that resemble epithelial cells. Origin (derived)

Distribution of adipose tissue Multliocular adipose tissue in a human newborn

Multiocular adipose Tissue

Brown adipose tissue