Connective Tissues

Question 1

Define connective tissue

Answer 1

A continuum throughout the body linking together muscle, nerve and epithelial tissues but also providing support in metabolic and physiological ways.

Question 2

What are the functions of connective tissue?

Answer 2

Provide substance and form to body and organs
Attach muscle and bone to bone 
Defend against infection
Aid in injury repair
Provide a medium for nutrients and waste
Cushion between tissues and organs

Question 3

What are the common cell types found in connective tissue?

Answer 3

Fibroblasts
Mast cells
Macrophages

Question 4

What is the function of fibroblasts?

Answer 4

Synthesise and secrete both ground substance and the fibres within ground substance

Question 5

What is the function of macrophages?

Answer 5

Degrade foreign organisms and cell debris, protecting agains infection
Phagocytic
Professional antigen presenting cells, can present foreign material to T lymphocytes

Question 6

What is the function of mast cells?

Answer 6

Coated in immunoglobulin E molecules which bind to specific allergens

Question 7

Describe the extracellular matrix

Answer 7

The extracellular matrix consists of ground substance,an amorphous matrix, within which lies collagen, reticulin and elastic fibres.

Question 8

What are the constituents of ground substance?

Answer 8

Hyaluonate proteoglycan aggregates
Glycosaminogylcan units (inc. hyaluronic acid)
Attached are proteoglycan monomers (protein ,lipids and glycoproteins)
Negative charges of GAGs attract water, forming a gel

Question 9

Describe the structure of type 1 collagen and say where it is found.

Answer 9

Collagen fibrils form fibres and fibre bundles
Each fibril has a unique banding pattern and consists of overlapping collagen molecules
Each collagen molecules consists of a triple helix of chains
In each amino acid chain, every third amino acid is a glycine
Found in tendons, organ capsules and skin dermis

Question 10

Describe Type 2 collagen and where it is found?

Answer 10

Collagen fibrils do not form fibres

Present in hyaline and elastic cartilage

Question 11

What is another name for Type 3 collagen and where is it found?

Answer 11

Reticulin

Fibrils form fibres around muscles and nerve cells and within lymphatic system and organs.

Question 12

Where is the only location of Type 4 collagen?

Answer 12

Basal lamina

Question 13

Describe the composition of elastin fibres and the locations where they are particularly important.

Answer 13

Elastin enfolded and surrounded by fibrillin microfibrils.

Artery walls, dermis and elastic cartilage.

Question 14

Describe the characteristics of dense connective tissue.

Answer 14

Close packing of fibres

Fewer cells and less ground substance than loose connective tissue

Question 15

What are the functions of dense connective tissue?

Answer 15

Mechanical support

Transmission of forces

Question 16

What distinguishes between regular and irregular dense connective tissue?

Answer 16

Irregular, bundles of collagenous fibres are interwoven and multidirectional allowing for multidirectional forces to act
Regular, bundles of collagenous fibres parallel to provide maximum tensile strength

Question 17

From where is loose connective derived?

Answer 17

Mesenchymal tissue in the embryo first becomes mucous connective tissue before becoming loose connective tissues seen in adults