Introduction to connective tissues

Question 1

Two components of connective tissue

Answer 1

Cells and intracellular materials

Question 2

Cells found in connective tissue

Answer 2

Fibroblasts
Chondrocytes
Osteocytes
Osteoblasts

Question 3

Intercellular materials three categories

Answer 3

Fibres, matrix proteoglycans and glycoproteins

Question 4

Fibres in connective tissue

Answer 4

Collagen and elastic

Question 5

Matrix proteoglycans in CT

Answer 5

aggrecan, versican, biglycan, decorin, hyaluronan

Question 6

Glycoproteins in CT

Answer 6

Fibrinectin, osteonectin, laminin

Question 7

What is a proteoglycan

Answer 7

Proteins and carbohydrates joined together. Differs from a glycoprotein as there is more carbohydrate in proteoglycans in relation to its protein content, in glycoproteins there is more protein in relation to carbohydrate.

Question 8

Why are tendons white?

Answer 8

Because the have a reduced blood supply. Few capillaries. The CT of tendons don’t turn over frequently.

Question 9

Describe the structure of tendons and ligaments

Answer 9

Closely pack parallel bundles of collagen fibres, with intervening rows of often elongated fibroblasts, sparse capillary network. Contains some elastic fibres which may be more prominent in ligaments.

Question 10

What is a fibroblast

Answer 10

A CT cell that produces collagen and other fibres

Question 11

What is an essential feature of collagen molecules (found in tendons and ligaments)

Answer 11

Ability to withstand tension i.e. there is minimal elongation.

Question 12

What happens if tension is removed from a tendon?

Answer 12

Very quickly the collagen fibres become less aligned, cells become rounded and there is an increase in proteoglycan content. When there is tension the fibroblast don’t divide. When tension is removed the cells begin to divide

Question 13

Why do tendons become ‘puffy’ when there is a loss of tension?

Answer 13

Because there is an increase in proteoglycan content which binds water.

Question 14

What is a tenocytes

Answer 14

An elongated fibroblast type cell

Question 15

What happens to a tenacity when it is no longer under tension

Answer 15

Becomes a chondrocyte (cartilage forming cell also make collagen but more proteoglycan)

Question 16

Three types of cartilage

Answer 16

Hyaline
Fibrocartilage
Elastic cartilage

Question 17

Where is hyaline cartilage mainly found and what is its other name

Answer 17

Mainly in joints and called articular cartilage (because joints articulate)

Question 18

What is the proteoglycan content of articular cartilage

Answer 18

High-10% of dry weight

Question 19

Why is cartilage so good under pressure

Answer 19

Due to the aggrecan (a proteoglycan) molecules. These have a protein core with glycosaminoglycan side chains. The GAG side chain is negatively charged so proteoglycans repel each other resisting compressional force. H20 molecules also surround GAGs helping to withstand compressional force

Question 20

How are the proteoglycan molecules held in position (so they don’t squish out to the sides of joints)

Answer 20

With carbohydrate chains called hyaluronan. There are also collagen fibres which run parallel to the proteoglycans attaching with their positively charged amino acids to the negatively charged GAGS

Question 21

What is proteoglycan content in articular cartilage directly related to

Answer 21

Effectiveness of the joint to withstanding load. More PG better support.

Question 22

What happens if you take the pressure of the joint (in relation to PG content)

Answer 22

Nothing as long as you keep the joint moving

Question 23

Define anisotropic

Answer 23

Stretches more in one direction than other directions

Question 24

Define langers lines

Answer 24

The lines of maximum tension in the skin

Question 25

Layers of the skin

Answer 25

Epidermis- stratum corneum, stratum lucidum, sratum granulosm, stratum spinosum, stratum germinativum.
Basal lamina
Dermis- papillary layer, reticular layer.
Subcutaneous layer or hypodermis
Investing fascia

Question 26

What layer of the skin do scars form

Answer 26

Reticular layer

Question 27

What is the make up of the reticular layer

Answer 27

Basket weave of collagen

Question 28

How do scars form

Answer 28

When there is a tensional force pulling a wound apart collagen bands form in the reticular layer. This occurs when the wound is not in parallel with the langers lines (line of maximum tension)