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Case 2: Connective Tissue 1 - Coggle Diagram
Case 2: Connective Tissue 1
Connective Tissue
Define Connective Tissue
Connective tissue is a diverse group of tissues where cells are distributed within the extracellular matrix, providing support, connection and separation between parts.
List the Functions of Connective Tissue
Structural and mechanical support:
Provide a framework in which body tissues are assembled
Anchor, connect or separate different parts of tissues and organs
Protection
Immunological Response (Communication)
Involved in the activation of the local immune response (Inflammation)
Mobilisation of the immune system
Growth and repair after injury (scar formation)
Storage of:
Water and Electrolytes
Act as energy-rich reserves (Adipose tissue)
Transport of Nutrients and Metabolites
Connective Tissue Composition
Outline the Composition of Connective Tissue
Connective Tissue consists of;
Ground Substance
Fibers:
Collagen Fibre
Elastic Fibre
Reticular Fibre
Extracellular Matrix which is made up of BOTH the Ground Substance and Fibers
ECM is any part of the organism's tissue that is located outside of the cells
Cell Types:
Macrophages
Fibroblasts
Lymphocytes
Mast Cells
Fat Cells
Neutrophils
Capillary
NOTE: All types and subtypes of connective tissue are classified according to the amount, type and proportion of components
Ground Substance
Define Ground Substance ?
Ground substance is the intercellular background material within which fibers and cells are embedded
Liquid/ Water in the ground substance is stabilised by proteins and polysaccharide mix of Proteoglycans and Glycoproteins
The consistency of ground substance is highly variable:
From fluid to gelatin-like to much more rigid material (bone)
List the function of Ground Substance
Allows for the diffusion of molecules and metabolites
Acts a protective barrier to slow the spread of pathogens
Fibers
Outline the Fibers found in Connective Tissue
Collagen Fibres
Collagen fibers are principle fibre type
They can combine to form bundles
Confer tensile strength with flexibility
When densely packed they provide resistance to tearing and stretching
Binds bones and other tissues to each other
Forms Scars
And are secreted by Fibroblasts
Reticular Fibers
Reticular fibres are a delicate branching form of collagen (Type 3 Collagen)
They are thinner and highly glycosylated
Provide a delicate supporting framework for loose cells in certain organs (Lymph Nodes, Spleen, Liver)
Elastic Fibers
Also known as Elastin
Confer resiliency for elasticity, meaning that they help restore normal shape after distortion
Characteristic of arterial walls, allows arteries to recoil
Cells Types
List the Cell Type in Connective Tissue as well as their respective Functions
Resident or Fixed Cells
Macrophages are Phagocytic and mobile
Fibroblasts which secret collagen and other intercellular material
Related cells include Chondroblasts which secrete matrix in cartilage and osteoblasts which secrete matrix into bone
Adipose Cells which are responsible for the synthesis and storage of reserve nutrients such as fat.
Mast Cells which are secretory alarm cells and trigger inflammation
Migrating Cells
Migrating cells are involved immune response and inflammation
Cells are
Monocytes
Lymphocytes
Plasma cells
Neutrophils
Eosinophils
Basophils
Classification of Connective Tissue
List the types of Connective Tissue
Ordinary/ Proper Connective
Specialised Connective Tissue
Ordinary/ Proper Connective Tissue
What is Ordinary/ Proper Connective Tissue ?
Ordinary Connective Tissue is a generalised form of connective tissue
It is a very large and diverse group of tissue
Found in between other tissues, everywhere in the body
It encompasses all organs and body cavities connecting one part with another, and equally important, separating one group of cells from another.
Example of Ordinary Connective Tissue
Loose, Irregular (Areolar) Connective Tissue
Dense Irregular Connective Tissue
Specialised Connective Tissue
Outline what is Specialised Connective Tissue ?
Specialised connective tissue is made up of highly differentiated and localized form of connective tissue
There are variations on the proportion of several components
List the example of Specialised Connective Tissue
Dense Regular Connective Tissue (Tendons and Ligaments)
Adipose (Fat) Tissue
Reticular Connective Tissue (Haemopoietic)
Cartilage
Bone
Blood
Ordinary/Proper Connective Tissue
Areolar (Loose Irregular) Connective Tissue
Outline what is Areolar (Loose Irregular) Connective Tissue ?
Most widespread connective tissue of the body
Connects the skin to underlying tissue
Fills spaces between various organs and holds them in place
Outline the composition of Areolar (Loose Irregular) Connective Tissue
It has a low fibre content (Collagen, some elastic)
Large proportion of ground substance in small spaces "areolar" (Moderately viscous matrix)
Contains many cells (Fibroblasts and Mast Cells)
Not stress resistance
Dense Irregular Connective Tissue
Outline what is Dense Irregular Connective Tissue ?
Dense irregular connective tissue is found in organ capsules, dermis of the skin and around muscles
Outline the composition of Dense Irregular Connective Tissue
High density of randomly aligned extracellular fibres, mostly Collagen
Relatively smaller proportions of cells and ground substance (viscous matrix)
Less Flexible
Has Impact Resistance
Involved in Scar Formation
Specialised Connective Tissue
Dense (Fibrous) Regular Connective Tissue
Outline what is Dense (Fibrous) Regular connective Tissue ?
Dense (Fibrous) Regular Connective Tissue is found in the dermis, tendons and ligaments
List the function of Dense (Fibrous) Regular Connective Tissue
To anchor skeletal muscles to the bone
To attach bone to bone, and stabilise bones within a joint
Provides strength, and resistance to tearing and stretching
Outline the composition of Dense (Fibrous) Regular Connective Tissue
Fibres are organised in a regular, parallel pattern
Abundance of collagen fibres, and few elastic fibres
Little intercellular ground substance
Few cells: Fibroblasts, Arranged in rows between fibres
Adipose Connective Tissue
Outline what is Adipose Connective Tissue ?
Adipose Connective Tissue is loose connective tissue dominated by adipocytes
Adipocytes are cells which contain a large internal fat droplet
Outline the functions of Adipose Connective Tissue ?
Synthesis and storage of energy-rich reserves of fat
Acts as pad to protect organs
Reticular Connective Tissue
Outline what is Reticular Connective Tissue ?
Reticular Connective Tissue is loose connective tissue with a large number of lymphocytes and often reticular fibers
Where is Reticular Connective Tissue Found ?
Reticular Connective Tissue is found in the:
Lymph Nodes
Spleen
Cartilage
Outline the composition of Cartilage
Cartilage has:
Chondrocytes isolated in small lacunae within a rigid matrix
Ground substance has a firmly, gelated consistency, for smooth gliding movements between surfaces
What is the function of Cartilage ?
Cartilage:
Facilitates bone movement
Provides slightly flexible support
3.Structural Reinforcement
List the 3 types of cartilage
Hyaline Cartilage
Elastic Cartilage
Fibrocartilage
Bone: Specialized Connective Tissue
Outline the Composition of the Bone
Bone consists of:
Cells such as Osteoblasts which are bone forming cells, Fibers and a Large ground substance
Matrix is impregnated with Calcium Phosphate (85%), Calcium Carbonate (7%) and Inorganic Salts
Outline the function of Bone ?
Support
Protection
Calcium Homeostasis
Provides maximal strength for its weight bearing functions with minimum weight
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Extracellular Matrix
Outline what is the Extracellular Matrix ?
The ECM is a complex network of secreted macromolecules located in the extracellular space
List the function of ECM
ECM plays a central role in cellular processes such as
Cell to cell interactions
Proliferation
Differentiation
Migration
Survival
Outline the Macromolecular Structure of ECM
Ground Substance
Proteoglycans: Core proteins to which Glycosaminoglycans (GAG's) attach
Glycoproteins: Proteins to which branched oligosaccharide chains attach eg: Fibronectin and Laminin
Fibres
Collagen fibers
Elastic fibers
Reticular fibers
Ground Substance: Proteoglycans and Glycoproteins
Outline the Similarities and Differences between Glycoproteins and Proteoglycans
Similarities
Both contain protein and carbohydrate units
Carbohydrate units are bonded covalently to protein molecules, varying in size from monosaccharides to polysaccharides
Differences
Glycoproteins
Composition: Greater Protein content than Carbohydrates
Carbohydrate Chain Length: Short with 2-10 Sugar residues
Serial Disaccharide Repeats: None, very Heterogenous
Branching of Carbohydrates: Yes
Location: Mainly in cellular membranes
Function: Cellular recognition, such as cell to cell and cell to ECM interactions
Negatively Charged Carbohydrate Chains: Not always
Proteoglycans
Composition: Greater Carbohydrate content that protein
Carbohydrate Chain length: very Long
Serial Disaccharide Repeats: Yes
Branching of Carbohydrate Chain: No
Location: Mainly in connective tissue
Function: Gel forming, Modulation of cellular development processes
Negatively Charged Carbohydrate Chain: Yes, due to presence of sulfate and uronic acid groups
Glycoproteins in the ECM
List the types of Glycoproteins
Fibronectin
Laminin
What is Fibronectin ?
Fibronectin is a Dimer with 2 identical subunits
It has multiple domains to which other matrix macromolecules (Collagen fibres, Proteoglycans etc.) and cell surface molecules (integrins) can bind
What is Laminin ?
Laminin is a large Heterometric molecule
Found in the basement membrane
and Interacts with itself, other matrix components and cells
