Connective tissue Flashcards
Connective tissues are ……………. In origin
Mesodermal
Characteristics of connective tissues include;
- Usually have a good blood supply
- They compose of non-living extracellular matrix surrounding living cells
- Have good tensile strength; ability to stretch and recoil.
………….. cells appear temporarily in response to injury or infection
Wandering cells
Major functions of CT include;
- Binding and support
- Protection
- Insulation
- Transport of substances
Connective tissues are composed of;
- Fixed, and wandering cells
- Extracellular matrix; protein fibers, ground substances
Fibroblasts are derived from …………?
undifferentiated mesenchymal cells.
…………. synthesise the protein fibre and components of the ground substance?
Fibroblast
What are the three types of protein present in the extracellular matrix of the CT
Collagen fiber
Elastic fiber
Reticular fiber
What’s the distribution of collagen fibres?
Found in the skin, tendon, ligaments, bone, and cartilage
The subunit of the collagen fiber is a protein known as ……………….?
tropocollagen.
What is the composition of tropocollagen?
3 alpha chains intertwined about each other.
Collagen fibres stain …………?
Pink
What’s the distribution of reticular fibres?
liver, kidneys, lymph nodes, spleen, thymus and bone marrow
Define ground substance
Amorphous gelatinous material that house the protein fiber in the EM
They serve as a medium through which nutrients and other substances can diffuse between blood vessels and the cells.
What are ground substance composed of?
Composed of water and large organic molecules, such as GAGs,proteoglycans, and glycoproteins
What are GAGs?
Glycosaminoglycans (GAGs) are polysaccharides that trap water, giving the ground substances a gel-like texture
Outline the features of the components of ground substance
Glycosaminoglycans (GAG)
- linear (unbranched) polysaccharides, e.g. heparan sulfate, condroitin sulfate, keratan sulfate, hyaluronic acid
- very hydrophilic due to abundant negative charges (e.g. SO4- groups).
- except for hyaluronic acid, are usually bound covalently to protein core as part of a proteoglycan
Proteoglycans
- core protein + GAG side chains (like a bottle brush)
- bind cells, other proteins, and/or ECM components
Multiadhesive glycoproteins
- small glycosylated proteins containing NUMEROUS binding sites to cells, signaling molecules, and other ECM components
- examples include fibronectin and laminin: important for adhesion of epithelial cells to the basal lamina via transmembrane integrin receptors.
Name the supporting tissues
Bone, and cartilages
Classify ‘connective tissue proper’
General connective tissues
- loose CT
- Dense CT
Specialized connective tissue
- Elastic
- Reticular
- Adipose tissue
- Embryonic tissue
- Mesenchyme
- mucous
Where are loose areolar CT found?
- Respiratory and urinary tracts
- beneath dermis of skin
- Digestive tract
- between muscles
- around blood vessels
- Nerve
- around joints.
List the functions of loose areolar CT
- Cushions organs
- Provide support but permits independent movement
- Phagocytic cells provide defense against pathogens
A shot note on CT
Connective tissues are supportive, protective, binding and connecting tissues distributed everywhere in the body , there are made up of cells and extacellular matrix which developed from the embryonic mesenchymal cell of the mesoderm. They are very essential for life, forming an integral part of survival of the cell.
Apart from being disorders associated with CT, what do Granulomatosis with polyangiitis, Microscopic polyangiitis (MPA) and Churg-Strauss syndrome have in common?
They are characterised by the inflammation of blood vessels.
What causes Marfan syndrome?
Marfan syndrome is caused by a mutation in a gene called FBN1. The mutation limits the body’s ability to make proteins needed to build connective tissue.
A note on Polymyositis and dermatomyositis
Polymyositis and dermatomyositis are connective tissue disorders. These are types of myositis, which is the name for a group of conditions that cause weak, aching, and painful muscles. These diseases affect the body’s tendons, ligaments, and the collagen-based tissue that covers muscle ends.
What causes microscopic polyangiitis?
Microscopic polyangiitis (MPA) is a rare condition that results from blood vessel inflammation.
What is lupus?
An inflammatory disease caused when the immune system attacks its own tissues
An overview on Churg-Strauss syndrome
Churg-Strauss syndrome is a disorder marked by blood vessel inflammation. This inflammation can restrict blood flow to organs and tissues, sometimes permanently damaging them
What is granulomatosis with polyangiitis?
Granulomatosis with polyangiitis is an uncommon disorder that causes inflammation of the blood vessels in the nose, sinuses, throat, lungs and kidneys.
What is scleroderma?
A chronic hardening and contraction of the skin and connective tissue, either locally or throughout the body.
What is the distribution of fibrocartilage?
Intervertebral discs
Pubic symphysis
Discs of knee joint
Where is adipose tissue usually found?
Deep to the skin, especially at sides; buttocks, breasts, padding around eyes and kidneys.
Mention the functions of adipose tissue
- Provides padding and cushions shocks
- Insulation (reduces heat loss)
- Store energy reserves.
Reticular fibres are distributed in ……………?
Liver
Kidney
Bone marrow
Thymus
Lymph node
Spleen.
What is the major function of reticular fibres
Fiber forms soft internal skeleton (stroma) that support other cell types including white blood, mast cell and macrophages.
Outline characteristics of dense CT
- Characterized by close parking of fibers
- Has fewer cells and less amorphous ground substance
- In most region collagen are the principal fibers but in few ligaments elastic fibers predominate
- Dense connective tissue can divided into regular dense and irregular dense
Dense irregular connective tissues are characterised by;
- Interlacing fibers which form a coarse tough felt work
- Little GS and cells among the fiber; collagen, elastic and reticular fiber
-Principal cells- fibroblast
Dense irregular connective tissues are located in;
- Capsules of organs or joints
- Dermis of skin
- Submucosa of GIT
- Periosteum
- Perichondrium
What is the function of dense irregular CT?
Provide structural strength, able to withstand tension exerted in any direction.
Dense regular CT are found in?
- Tendons
- Ligaments
- Aponeurosis
Dense regular CT function by?
Attaching muscles to bones or to muscles, bones to bones, withstand great tensile stress from any direction.
Describe dense regular CT
Densely park fibers that lies parallel to each other forming structures of great tensile strength. Collagen* and Elastic fiber. Major cell type- fibroblast
What is mesenchyme?
The first connective tissues to appear in developing embryo-tissue. They give rise to other connective tissues
Mucous CT are also called …………..
Wharton’s jelly
Mucous CT and mesenchyme are both ………….
Embryonic connective tissues
Mucous CT is a loose connective tissue present in the ………
Umbilical chord
Describe bone (osseous tissue)
They are hard, calcified matrix containing many collagen fibers; osteocytes lie in lacunae, and are very well vascularized .
What are the functions of osseous tissues
- Supports and protects by enclosing
- Provides levers for the muscles to act on
- Stores calcium and other minerals and fat
- Marrow inside bones is the site for blood cell formation (hematopoiesis)
Describe hyaline
Amorphous but firm matrix; collagen fibers form an imperceptible network, chondroblasts produce the matrix and when mature lie in lacunae
Functions of hyaline include;
- Supports and reinforce
- Serves as resilient cushion
- Resists compressive stress.
What is the distribution of hyalin
- Forms most of the embryonic skeleton
- Covers the ends of long bones in joint cavities
- Form costal cartilages of ribs
- Cartilages of the nose, trachea, and larynx.
Describe elastic cartilage
Similar to hyaline cartilage, but more elastic fibers in matrix
Where can elastic cartilage be found?
- Epiglottis
- Supports the external ear
What’s the function of elastic cartilage?
Maintains the shape of a substance while allowing great flexibility
What collagen is found in all basement membranes?
Collagen IV, they help in support and filteration
What collagen is associated with type I and II fibrils?
Collagen VI and IX
They function in fibril-fibril, fibril-ECM binding
What collagen is found in the epithelia?
Collagen VII, they help in connecting the epidermis to basal lamina
………….. is the most abundant fibril-forming collagen
Collagen I
Where is collagen I found?
Skin, tendon, bone, dentin
What is the function of collagen I?
Resistance to tension
What collagen is found in the cartilage and vitreous of the eye, and what is its function?
Collagen II. It functions in resistance to pressure
Reticulin, collagen III is found in ……………
Skin, muscle, blood vessels, liver.
Examples of the FACITs
VI, IX
……………… is an example of anchoring collagens?
Collagen VII
………… is a network-forming collagen
Collagen IV
Mention some fibril-forming collagens
Collagen I, II, III
