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Flashcards in ToB - Connective Tissues Deck (12):
0

What is connective tissue?

A tissue which forms a continuum through the body, linking together muscle, nervous and epithelial tissue. It has mesodermal origin.

1

What are the 3 basic components of connective tissue?

Ground substance
Fibres
Cells

2

What are the functions of connective tissue and an example of each?

1). Link bone to muscle, bone to bone - ligaments/tendons
2). Defend the body (immunity) and transport gas - blood
3). Provide substance and form to the body and organs - cartilage/bone

3

What does the extracellular matrix in CT define?

Defines whether the CT is of mechanical importance, or is simply a loose packaging material.

4

What is ground substance in extracellular matrix and its function?

It is a gel matrix made of proteoglycans, glycoproteins and GAGs, in which fibres and cells are embedded.
It allows tissue fluid to diffuse through it.

5

What fibres are found in the extracellular matrix and their features?

Collagen
- synthesised in RER by fibroblasts
- usually type I

Reticular
- type III collagen
- provide structural framework around organs, smooth muscle, epithelia and viscera.

Elastic
- enfolds and is surrounded by Fibrillin
- important in dermis and artery wall.

6

What are the resident cells of connective tissue?

Fibroblasts - synthesise and maintain the ground substance and fibres (so have lots of RER)

Mesenchymal cells - these are undifferentiated cells that can differentiate to maintain extracellular materials. They are embryonic.

Macrophages - derived from monocytes, these move from the blood to the tissue to ingest foreign material and be professional antigen presenting cells.

7

What vistant cell types are found in connective tissue?

Mast cells - contain granules of histamine (increases vascular permeability), heparin (anticoagulant) and substances that attract eosinophils and neutrophils. These are not found in the CNS as this may cause oedema.

Plasma cells - WBCs derived from lymphocytes

Leukocytes - a type of WBC from blood vessels that produces immunocompetent cells.

Adipocytes - occur in clusters, acting as shock absorbers.

8

How do adipocytes develop?

Mesenchymal cells differentiate into pre adipocytes which form lipoblasts. These develop lipid droplets in cytoplasm, which fuse to form one large droplet n white adipose tissue, or remain in brown.

9

How can connective tissue be classified and what are the features of each classification along with an example.

1). Loose CT
- Decreased fibres
- Increased ground substance
- Good for stretching/movement
= submucosa of colon, lamina propria between crypts of lieberkühn.

2). Dense irregular CT
- Increased unorganised fibres
- Decreased cells
- Decreased ground substance
- Good for resisting forces in multiple directions
= dermis of skin, capsules of some organs

3). Dense regular CT
- Decreased cells
- Decreased ground substance
- Increased, organised fibres
- Good for tensile strength
= tendons, ligaments

10

Why does brown adipose tissue appear brown?

Many mitochondria for dissipating energy to produce heat

11

How do reticular fibres appear?

They form an anastomosing network