ToB - Connective Tissues

Question 0

What are the 3 basic components of connective tissue?

Answer 0

Ground substance
Fibres
Cells

Question 1

What is connective tissue?

Answer 1

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

Question 2

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

Answer 2

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

Question 3

What does the extracellular matrix in CT define?

Answer 3

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

Question 4

What is ground substance in extracellular matrix and its function?

Answer 4

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.

Question 5

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

Answer 5

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.

Question 6

What are the resident cells of connective tissue?

Answer 6

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.

Question 7

What vistant cell types are found in connective tissue?

Answer 7

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.

Question 8

How do adipocytes develop?

Answer 8

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.

Question 9

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

Answer 9

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

Question 10

Why does brown adipose tissue appear brown?

Answer 10

Many mitochondria for dissipating energy to produce heat

Question 11

How do reticular fibres appear?

Answer 11

They form an anastomosing network