Connective Tissue- soft connective tissue Flashcards
What is connective tissue ?
It is the extracellular matrix and the supporting cell population
What are the three forms connective tissue is found in- giving details?
Soft
Semi Hard (cartilage)- can be deformed but readopts to original structure
Hard (Bone) -
What are the functions of soft connective tissue?
Space filler and mechanical support- separates 2 types of tissue and mechanical support in the outer layer of dermis of the skin
Attachment and proteins- attachment of other cell types and other cells + dermis of the skin gives good protection
Highway for nutrients- large arteries and large arterioles branch into capillaries- the blood supply supplies nutrients for CT and epithelial cells. The connective tissue provides protective tissue layer for artery.
Storage- fat and calcium
adipose cells- hyperdermis
calcium stores for muscle contraction
Site of immunological defence- the dermis and hyperdermis in skin, respiratory airways and gut
What type of cells are found in the connective tissue ?
Fibroblast
macrophage
mast cells
capillary epithelial
What is the function of fibroblast ?
synthesis and secretion of the ECM components
the ECM components are variable hence this determines the function of the ECM
What are the types of the soft connective tissue?
Mesenchyme- (embryonic)- undifferentiated cells- look like fibroblasts, becoming more specialised
Loose- (mesentery and under the dermis )
Dense-( tendon, dermis and capsules)
Reticular- (bone marrow, lymph nodes)
describing the types of the cells in the CT which look like stars
Adipose (fat cell found in the hyperdermis of the skin and body organs)
What does the ECM consist of?
Proteins- glycoproteins
Glycosaminoglycans - GAGs
Forms of a large hydrated gel
What are the types of Proteins
Adhesive proteins
Collagen
Elastic fibres
Describe adhesive proteins
DIts presence in a cells surface membrane of a cell will determine whether the cell will adhere to the cell or will pass through.
It binds to transmembrane receptors called integrins which attaches cell to ECM
It is associated with actin filaments- holding a cell in place.
eg. Fibronectin- abundant in all cells in CT
Tenasin- produced in wounds
laminin- found in the basal lamina, binds the epithelial cells to BM
Describe collagen
Tensile strength of the ECM
Not extensible
Both of the above will result in the molecule not being stretching end to end- but can deform.
It is found in cells where there needs to be resistance to deformation
It is a polymer- 3 collagens polypeptides in a triple helix
Can vary the function due to the shape/size of collagens
eg. in the upper part of the skin- the collagen is very thick
however the diameter of the collagen will decrease going down.
What are the different types of collagen
Fibrous- inextensible shape
Type I- skin bone tendons and dentures
Type II- cartilage
Type III- blood vessels, skin
Sheet Collagens-
Type IV BM (NOT TRIPLE HELIX)
Describe elastic fibres
Complimentary to the function of the collagen as it allows for the readopting of the original structure
Elastic proteins are in random confirmation- joining end-to-end by covalent bonds to form elastic fibres
As the pressure is applied, the elastic will stretch out but remain attached- THIS STORES ENERGY
as soon as the pressure is released It will recoil
eg. found in blood vessels close to the heart, this is because they are subject to the greatest changes in blood pressure.
Increase in BP elastic fibres will expand and as the BP decreases the elastic fibres recoil
Comment on elastic fibres in regards to age
Although elastic fibres are resilient and long lived- less is produced in adults so the skin of adults is less elastic in adults
What is the function of the basement membrane?
Separates the CT from the epithelial layer- acts as the physical barrier to the cells maintaining the integrity of the tissues
What is the difference between proetoglycans and GAGs
GAGs are attached to a core protein to form proteoglycans
