Connective Tissues Flashcards
What are ‘Connective’/’Supporting tissues’?
its supports , binds and connects other tissues and organs providing structural and metabolic support of them
General Properties of CT
- Strength – tensile strength afforded by structural proteins (e.g. various collagens)
- Space-filling / volume (due to glycoproteins and complex carbs – retain water
- Elasticity – can return to original shape after mechanical distortion – due to elastin fibrils
What are the constituent elements of Connective tissue?
- Cells
- Extracellular Matrix
* Ground substance: Hyaluronate and proteoglycan aggregates
- Fibrillar proteins e.g. Collagen fibres and Elastin
- Extracellular Matrix
Ground substance: highly hydrated – why?
- Composition: ‘Toilet-brushes’ of a proteoglycan core with covalently-bound glycosaminoglycan (GAG) ‘bristles’.
- These ‘brushes’ bind to long, linear hyaluronate (HA) molecules, to form hyaluronate - proteoglycan aggregates
what is CT derived from?
is derived from multipotent embryonic mesenchymal cells.
The mesenchyme
is a type of undifferentiated embryonic connective tissue that develops predominantly in the mesodermal layer of the embryo
what is Collagen
- Most abundant human protein – 30% of our whole body protein content
- 28 types of collagen known in humans
Different collagen types form fibrils and fibre, sheets e.g. Type IV or anchors.
List of the components of CT
1 - Cells: difference types
1. Fibroblasts
2. Macrophages
3. Mast cells
4. Plasma cells
5. Adipose cells
6. Leucocytes
2 - Fibers:
a. Collagenous
b. Elastic
c. Reticular
3 - Matrix:
* The *intercellular substance, in which cells and fibres
* Ground substance Hyaluronate and proteoglycan aggregates
Types Of C.T (Depending On Matrix):
- Soft = C.T Proper
- Rigid (rubbery , firm) = Cartilage
- Hard (solid) = Bone
Fluid (liquid) = Blood
Fibroblast Cells Structure
Flat branched cells (spindle-shaped) with basophilic cytoplasm.
* They can divide.
* Old fibroblasts are called fibrocytes . *fibrocytes are mainly inactive
Function of the plasma cells:
- Formation of proteins of C.T. fibres.
*the cytoplasm of these cells are rich in ribosomes which on the outer surface of Rough ER.
- Formation of C.T. matrix.
- Healing of wounds.
- Responsible for formation of 3 types of fibres (collagen , elastic , reticular ).
Most common cell and found nearly in all types of C.T. proper?
Fibroblasts
Macrophages
Structure?
Basophilic cytoplasm, rich in lysosomes
▪ Irregular outlines (cell membrane)
*pseudopodia of macrophages is the cause of its irregular outlines.
▪ They can divide.
▪ They originate from blood monocytes.
what is the function of macrophages?
phagocytosis
Mast cells structure
cytoplasm contains numerous basophilic cytoplasmic granules.
Function of mast cells
- Secrete heparin (anticoagulant)
- Secrete histamine (allergic reactions)
Active Plasma Cells Structure
- Basophilic cytoplasm with a negative Golgi image.
- *negative Golgi image : lack of ribosomes around Golgi apparatus.
- Nucleus: spherical, eccentric with a clock-face appearance of chromatin.
function of active plasma cells
Function: Secretion of antibodies (immunoglobulins).