Connective tissue Flashcards by Praise Tokode

Where do connective tissue cells come from?

The mesoderm

Mesenchymal stem cells

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What is the extracellular matrix composed of?

Ground substance
Structural glycoproteins
Fibres

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What are the 5 types of connective tissue?

Fibrocollagenous tissues
Adipose tissue
Cartilage
Bone
Blood

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What is the ground substance composed of?

Glycosaminoglycans (GAGs) – long unbranched polysaccaride chains

Proteoglycans – all GAGs except hyaluronic acid (hyuranan) link covalently to a protein core
- - proteoglycans can bind via a linker to hyaluronic acid to form even larger complexes (i.e. in cartilage)

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What are the main properties of Glycosaminoglycans (GAGs) and Proteoglycans:

Negatively charged, open conformations; retain water and positive ions (mostly Na+)
forms a hydrated gel which allows selective passage of molecules (e.g. nutrient diffusion)

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Describe the function of Structural glycoproteins, give examples

Functional molecules:
Many roles- linking, organising, catalysing processes

laminin, entactin, fibronectin (cell adhesion, part of basement membranes), fibrillin (elastic fibre formation); osteocalcin (bone mineralisation)

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Name the two types of fibers found in connective tissue. What are they used for?

Collagen
Elastic fibers
used for mechanical properties

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What is the precursor for collagen? Name the 4 different types and there properties

Precursor tropocollagen
Type I : thick bundles; very strong

Type II: thin, interwoven fibres- only in cartilage

Type III: delicate branching reticulin

Type IV: forms meshwork- basement membrane

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What is the precursor for elastic fibers? Describe there formation?

Precursor- Tropoelastin
Elastin + fibrillin = Fibrils
Fibrils form sheets

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Describe the cell(s), role and different types of Fibrocollagenous tissues

Cell: Fibroblast
Roles: Structural, supportive

Types:
A) Loose B) Dense (amount)
C) Reticular (type of loose, coll. III)

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Describe the morphology of the ECM forLoose (areolar) connective tissue , what is it made up of? What cells will you find there? What is there role? Give an example

ECM- relatively few fibres; abundant viscous ground substance (hyaluronic acid)

Type- Type I collagen with reticular and elastic fibers

Cells- Fibroblasts; also stem cells, adipocytes, defense and immune cells (lymphocytes, resident macrophages, mast cells)

Role:
Physical, metabolic and defensive support
Example:
Lamina propria

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Describe the morphology of the ECM for Dense connective tissue , what is it made up of? What cells will you find there? What is there role? Give an example

ECM- many fibres, little ground substance

Organisation-
random- dense irregular c.t.
structured- dense regular c.t.

Type- Type I collagen mainly +/- elastic fibers, reticulin

Cells:
Fibroblasts primarily
Role:
Mechanical support, tensile strength

Examples:
irregular- dermis,capsules
regular- tendon, ligament

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Describe the morphology of the ECM for Reticular connective tissue , what is it made up of? What cells will you find there? What is there role? Give an example

ECM- few fibres, little ground substance

Organisation- fine network
Type- Type III collagen

Cells:
Mainly fibroblasts
Role:
Structural support for epithelia in some highly cellular tissues
Examples:
Lymph nodes, spleen, liver and other glands

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What type of connective tissue does adipocytes contain? Name the two types

Contains supporting loose connective tissue (with fibroblasts)

white brown

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What is the difference between white and brown adipocytes?

White 
Unilocular- one space for lipid
Adult
Widespread
Energy store, shock absorber, insulator

Brown 
Multilocular- many spaces
Newborn
Restricted
Heat source

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Name the 3 types of cartilage and what they are made of?

Hyaline- type 2 collagen , Elastic- type 2 collagen and elastic fibers & Fibrocartilage- type 2 collagen and type 1

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Describe the ground substance of cartilage

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proteoglycans (aggrecan) containing chondroitin sulphate and keratan sulphate linked to hyaluronic acid– forming large complexes

and interacting with Type II collagen fibres

Name 2 cells you will find in cartilage and state there functions

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Chondroblasts (form cartilage)

Chondrocytes (maintain cartilage)

Describe the ECM of bone? What is it called? What will you find there?

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Ground substance called osteoid

Collagen type I fibres- layers (lamellae) in mature bone
Mineralised

List the cell types found in bone and state there function

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Osteocytes- maintain bone
Osteoblasts- secrete osteoid, form bone
Osteoclasts- resorb bone

Describe the ECM in blood

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Plasma fluid

Fibres: Fibrin of clots- made by liver as soluble fibrinogen

Which cells will you find in blood?

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Circulating blood cells formed in bone marrow

What secretes fiber precursores

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connective tissue cells

What is a hematoma?

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A collection of blood, usually clotted, outside of a blood vessel that may occur because of an injury to the wall of a blood vessel

What is Ehlers-Danlos syndrome?

A group of disorders that affect connective tissues supporting the skin, bones, blood vessels, and many other organs and tissues.

How many types of Ehlers-Danlos syndrome is there?

(2017 classification) 13

Name features found in most Ehlers-Danlos syndrome types?

Hyperbomility, frequenct joint dislocations, soft velvety skin, very stretchy and elastic skim

Name the 2 different ways Ehlers-Danlos syndrome can be inherited?

Mainly Autosomal dominant can be recessive

What is the normal role of collagen type 5 in connective tissue?

It regulates the diameter of collagen type I fibrils

What type of joint is the shoulder joint?

Synovial ball and socket

What is the role of the Children and Family Court Advisory and Support Service in cases of suspected child abuse?

1. To ensure that decisions are made in the child's best interest. 2. They get involved in the case and become known as the childs guardian 3. The guardian is the independent voice of the child in court

Which is the tissue type of the epdermis? What is the major cell type?

Tissue type- stratifued squamous epithelial Cell type- keratinocyte

Which is the tissue type of the dermis? What is the major cell type?

Tissue type- dense irregular connective tissue Cell type- Fibroblast

How is classic EDS diagnosed?

``` 3 symptoms from major criteria - Skin hyperextensibility -Widened atrophic scarring -Joint hypermobility -positive family history 1 from minor criteria -smooth velverty skin -easy bruising -Muscle hypotonia -complications of joint hypermobility and skin (dislocations) and tissue extensibility (hiatal hernia) ```

How many people with EDS are diagnosed?

5% (incidence may be higher than we assume)

Name other symptoms nor related to connective tissue that might suggest EDS

IBS, chronic pain, Fibromyalgia

Which mutation is responsible for EDS

A nonsense mutation in COL5A1 gene (substitution of glutamine causing a premature stop codon). (result- truncated protein)

How does a mutation in the COL5A1 gene lead to EDS?

A component of type V collagen called the pro-α1(V) chain is produced from the COL5A1 gene. Collagen is rope like made from 3 chains. 2 combinations of chains can be produced, three pro-α1(V) chains or two pro-α1(V) chains and one pro-α2(V) chain. The mutation reduces the amount of pro-α1(V) chains that cells produce. Fibrils containing type V and tyoe 1 callagen are disorganised and larger than usual. This weakens the connective tissue causing EDS.

Which laboratory tests are used to diagnose EDS?

A skin fibroblast biopsy can be taken and analysed in 2 ways 1- Assess the Electrophoretic pattern of the (pro)collagen type I, III and V (normal in PBL) 2. SDS-PAGE of collagen from dermal fibroblasts.Crude detection of protein Different proteins have different weights and thus they can be separated on the gel by weight (does not tell you if mutated or functional)

What leads to abnormal wound healing in EDS?

Collagen type 1 is looser with few bundles

Describe the wound healing stages.

1. Haemostasis Vascular constriction and clotting. 2. Inflammation Release of cytokines and growth factors WBC – remove dead cells and provide defence against microbes 3. Proliferation Fibroblasts and kerantinocytes proliferate and start to make new ECM 4. Remodelling -scar formation

Which stage if wound healing is affected in EDS?

Stage 4 - remodelling Due to mutation collagen synthesis is affected collagen 3 is chnaged to 1 water is reabsorbed and fibers lie closer together wound contracts so fibers do not gape

Connective tissue Flashcards

(42 cards)