Wk 2: Connective Tissue Flashcards
1
Q
4 Functions of CT
A
- Structural support
- Medium for exchange of nutrients & waste products
- Defence, protection & repair of the body
- Fat storage
2
Q
What are the 3 functions of the Extracellular Matrix
A
- Provides tissue w strength to resist tensile & compressive forces
- Directs cells to proper positions within tissue & holds cells in place
- Regulates development, mitotic activity & survival of cells in a tissue
3
Q
Composition of ECM
A
- Ground substance
- Protein fibres
(gel like ground substance w fibres embedded throughout)
4
Q
The ground substance of ECM is made up of what 3 families of macromolecules
A
- Glycosaminoglycans (GAGs)
- Proteoglycans
- Cell adhesive glycoproteins (CAGs)
5
Q
What are glycosaminoglycans (GAGs)
A
Polysaccharides, made of sugars including glycosamine
6
Q
Function of proteoglycans in ground substance of ECM
A
- Bind to a long GAG forming proteoglycan aggregates.
- These make ECM firmer, more solid, resistant to compression.
7
Q
Function of Cell Adhesive Glycoproteins (CAGs)
A
- Holds everything in place - adhere cell to cell and cells to surroundings
- Maintain normal tissue architecture
8
Q
Function of collagen in CT
A
Provides tensile strength & elasticity
9
Q
Type 1 collagen
A
- Main structural collagen
- Fibrous supporting tissue
- Skin (dermis), tendons, ligaments & bone
10
Q
Type 2 collagen
A
- Hyaline cartilage
- Consists of fibrils in the cartilage ground substance
11
Q
Type 3 Collagen
A
- Liver, bone marrow & lymphoid organs
- Forms reticular supporting mesh work, prominent in liver
12
Q
Type 4 collagen
A
- Constituent of basement membranes
- Network mesh forming collagen
13
Q
Type 7 collagen
A
- Anchoring fibrils
- These link ECM to basement membranes
14
Q
What can be seen in histological analysis of collagen
A
Characteristic cross banding (due to polymerisation of the tropocollagen monomer)
15
Q
What is the elasticity of a tissue due to
A
Due to the presence of elastic fibres in the ECM
16
Q
What is the precursor monomer of elastin and what synthesises it
A
- The precursor monomer of elastin is tropoelastin
- Tropoelastin is synthesised by fibroblasts
17
Q
What is tropoelastin polymerised by
A
Lysyl oxidase
18
Q
Where in the body is elastin found (4)
A
- Lung
- Skin
- Urinary bladder
- Blood vessels
19
Q
What is CT derived from (what precursor cells)
A
Mesenchyme
20
Q
5 fixed cells in CT
A
- Fibroblasts
- Myofibroblasts
- Adipose cells
- Mast cells
- Macrophages
21
Q
What are fixed cells
A
Cells that develop & remain in the CT where they carry out their function
22
Q
7 transient cells in CT (& what are transient cells)
A
- Plasma cells
- Lymphocytes
- Neutrophils
- Eosinophils
- Basophils
- Monocytes
- Macrophages
* Transient cells originate in the bone marrow, circulate in the bloodstream and migrate into CT to perform function when given the signal
23
Q
Funtion of active fibroblasts (3)
A
- Specialise in tissue repair
- Support wound healing
- Create new ECM
24
Q
Function (1) of inactive fibroblasts
A
- Maintain structural integrity - synthesise ECM
25
Appearance of unilocular (white) adipocyte
* Large spherical cells
* Contain a single large lipid droplet that pushes the cytoplasm to the edge of the cell
* More abundant
26
Appearance of multilocular (brown) adipocytes
* Smaller & more polygonal
* Less abundant
* Contain several small lipid droplets
27
2 subdivisions of macrophages
1. Phagocytes
2. Antigen presenting cells
28
Function of macrophages
* Remove cellular debris
* Protect against foreign invaders
29
the 2 primary mediators in mast cells & their functions
* Histamine & heparin released by mast cells
* Function in the initiation of the inflammatory response
30
What is mast cell activation induced by
Foreign antigens - pollen, certain drugs
31
How is the inflammatory response initiated - detailed
First exposure to foreign antigen
* IgE antibody formation
* IgE antibodies bind to Fc receptors on mast cells, sensitising the mast cells
Subsequent exposure:
* Antigen binds to IgE
* Release of primary mediators from granules of mast cells
* Inflammatory response initiated
32
What are plasma cells derived from
B lymphocytes
33
Function of plasma cells
* Part of adaptive immune system
* Produce antibodies for specific antigens
(found in greatest numbers in areas of chronic inflammation & in areas where foreign substances or m/os have entered tissues)
34
What is loose (areolar) CT made of - cells & other substance
* Mainly ground substance
* Houses fibroblasts, adipocytes, immune cells
* Contains the 3 types of protein fibres - collagen, elastin, reticular
* Extensive blood supply
35
Where is loose (areolar) CT found
* it surrounds blood vessels, nerves, muscles, organs
* Separates skin from deeper structures
36
What is dense irregular CT made of
* Predominantly disorganised collagen bundles
* More fibres & fewer cells than loose CT
37
Function of dense irregular CT
* Strong
* Resists tension in movement
38
Where is dense irregular CT found (3)
High tension areas:
* Dermis of skin
* Surrounding organs & joints
* Sheaths of nerves
39
What is dense regular collagenous made of
* Predominantly organised into parallel collagen bundles
* Fibroblasts between collagen bundles
40
Where is dense regular collagenous CT found
* Constitutes tendons & ligaments that are subject to tension
41
What is dense regular elastic connective tissue made of
* Composed of parallel elastic fibres
* Randomly oriented collagen fibres
* Few fibroblasts scattered throughout
42
Where is dense regular elastic CT found (2)
In walls of organs that must stretch to perform function - large blood vessels & certain ligaments
43
WHat is reticular CT composed of
Reticular fibres produced by fibroblasts
44
What does reticular CT form & hence what can it support
* A fine network
* That can support small structures - blood & lymphatic vessels
45
Where can reticular CT be found
* Lymph nodes
* Spleen
(forms weblike nets trapping old & foreign cells)
* Part of basement membrane that supports all epithelia
46
What is adipose CT made of
* Adipocytes
* Surrounding fibroblasts
* ECM
47
Function of adipose CT (4)
* Fat storage
* Insulation
* Shock absorption
* Protection
48
Where is adipose CT found
* Buttocks
* Breast
* Abdomen
