Connective Tissue

Question 1

What are the 3 components of connective tissue?

Answer 1

Cells, Extracellular fibres and Ground Substance

Question 2

What is the function of connective tissue?

Answer 2

To support organs, filling spaces between them and forming tendons and ligaments

Question 3

What are the resident cell types of the connective tissue and what is their function?

Answer 3

Fibroblasts, mesenchymal cells and macrophages.

Fibroblasts synthesise extracellular materials. Fibrocytes are older, mature cells that are less active

Mesenchymal cells are undifferentiated cells that differentiate and maintain extracellular materials

Macrophages are derived from monocytes. They ingest foreign materials.

Question 4

What are the visitant cell types and what are their functions?

Answer 4

Mast cells, plasma cells, fat cells and leukocytes.

Mast cells release pharmacologically active molecules

Plasma cells are derived from lymphocytes

Fat cells are for storage and insulation

Leucocytes are white blood cells that produce immunocompetent cells

Question 5

What is the extracellular matrix made up of?

Answer 5

Fibres, amorphous aground substance and extracellular fluid. The composition of the extra cellular matrix determines the function.

Question 6

What are the 3 types of fibres found in the extracellular matrix?

Answer 6

Collagen, elastic fibres and reticular fibres.

Question 7

What are reticular fibres and where are they found?

Answer 7

Type three collagen. They are found around organs and some cell types (supportive function)

• liver
• kidney
• spleen
• lymph nodes
• bone marrow.

Question 8

What are elastic fibres made up of?

Answer 8

Amorphous protein and elastin. surrounded by fibrillin

Question 9

What is the amorphous ground substance?

Answer 9

• Gel-like matrix
• fibres and cells are embedded
• Tissue fluid diffuses through it.

Question 10

Where is loose connective tissue found?

Answer 10

-submucosa of alimentary tract

septa and trabeculae that make up framework of organs

Question 11

What is the composition of loose connective tissue?

Answer 11

• fibroblasts widely dispersed; secrete strong fibrous proteins and proteoglycans as an extracellular matrix.
• The cells of this type of tissue are generally separated by quite some distance by a gelatinous substance primarily made up of collagenous and elastic fibers.
• Can contain adipose cells
• Reticular fibres

Question 12

What is mucous connective tissue?

Answer 12

It is a form of loose connective tissue

Question 13

What is the composition of mucous connective tissue?

Answer 13

• Large fibroblasts
• few macrophages
• few lymphocytes
• Fine mesh of collagen fibres.
• Soft and jelly like ground substance, with a high concentration of hyaluronic acid.

Question 14

Where is mucous connective tissue found?

Answer 14

• Umbilical cord

- Subdermal connective tissue of the embryo

Question 15

Where is areolar connective tissue found?

Answer 15

• Deep under skin
• in the submucosa
• below the mesothelium of the peritoneum
• associated with adventitia of blood vessels
• surrounding the parenchyma of glands

Question 16

How does the composition of dense connective tissue affect its function?

Answer 16

There are closely packed fibres and less ground substance, meaning there is more mechanical support

Question 17

How is dense regular connective tissue arranged?

Answer 17

Parallel so high tensile strength

Question 18

What is the composition of ligaments?

Answer 18

• Collagen fibres interspersed with fibroblasts.

- Elastic ligaments contain elastin mainly, they are less regularly arranged then tendons

Question 19

What is the composition of tendons?

Answer 19

• collagen fibres interspersed with flattened fibroblasts
• fascicles (bundles of collagen and fibroblasts) separated by endotendineum (loose CT) and held together by peritendineum.
• A fibrous sheath surrounds the whole tendon.

Question 20

Where is dense irregular connective tissue found?

Answer 20

• Capsules
• large septa and trabeculae of many organs
• deep fascia of muscles
• dermis of skin
• periosteum
• perichondrium
• dura mater.

Question 21

What is the structure of dense irregular connective tissue?

Answer 21

• Interwoven bundles of collagen, which criss-cross each other in many directions.
• This counteracts multi-directional forces to which the tissues are subjected.
• Mainly collagen with small amount of elastic and reticular fibres.

Question 22

What are keloids?

Answer 22

scars of the skin caused by abnormal amounts of collagen.

Question 23

What is systematic sclerosis?

Answer 23

• organs have excessive accumulation of collagen (fibrosis).
• This occurs in skin, digestive tract, muscles and kidneys
• causing hardening and functional impairment.

Question 24

What is Marfan’s syndrome?

Answer 24

• genetic defect in chromosomes that code for fibrillin, which means elastic fibres aren’t developed
• Large elastic arteries (e.g. aorta) rupture because there’s high blood pressure due to bulging in the arteries causing a smaller lumen.
• sufferers could be very tall, with long digits

Question 25

What is Ethlers-Danlos disease?

Answer 25

deficiency in type III collagen (reticular fibres) causing ruptures in tissues with high reticullin content.

Question 26

How is scurvy linked to collagen?

Answer 26

- deficiency in vitamin C - hydroxyproline important part of collagen structure due to forming hydrogen bonds - enzyme that converts proline to hydroxyproline (proline hydroxylase) requires vitamin C - less hydroxyproline so less hydrogen bonds and weaker collagen - leading to degeneration of connective tissue. - Periodontal ligament (with a high collagen turnover) is affected in scurvy, loosening of teeth in their sockets with subsequent loss (bleeding gums)