A: Histology of connective tissue

Question 1

Functions of connective tissue

Answer 1

• Structure
• Protection
• Storage
• Transportation
• Defense

Question 2

Fibroblasts

Answer 2

• Flat cells with elongated nuclei.
• Produce fibres + ground substance
• Help in wound healing (mesenchymal cells develop into fibroblasts and enter a wound site. They secrete ground substance + fibres to make a collagenous scar which replaces damaged tissue).

Question 3

What are the dark blue things

Answer 3

Fibroblasts

Question 4

Mast cells

Answer 4

• Common beneath membranes + along small blood vessels
• In their cytoplasm there are granules with histamine (causes capillaries to leak, causing oedema which dilates blood vessels causing warmth + redness) and heparin (inhibits blood clotting)

Question 5

Identify

Answer 5

Mast cells

Question 6

Plasma cells

Answer 6

• Derived from B cells
• Large, granular + round nucleus
• Secrete specific antigens.

Question 7

Identify

Answer 7

Plasma cell

Question 8

Adipocytes

Answer 8

• Synthesise + store fat
• Release cytokines

Question 9

White adipocytes

Answer 9

large lipid droplets push nucleus to edge of cell

Question 10

Brown adipocytes

Answer 10

found in newborn mammals, used for thermoregulation. Are smaller, central nucleus + many small lipid globules.

Question 11

Identify

Answer 11

White adipocyte

Question 12

Identify

Answer 12

Brown adipocyte

Question 13

Collagen

Answer 13

• Strong + inelastic
• Produced by fibroblasts
• Tropocollagen (3 collagen a-fibres) come together to make collagen microfibrils which make collagen fibres

Question 14

What is E, L and Ma?

Answer 14

Elastin
Collagen
Mast cells

Question 15

Ehlers-Danlos syndrome

Answer 15

Mutated gene forming abnormal collagen.
- Hypermobile ligaments
- Hyperelastic skin bruises easily

Question 16

Osteogenesis imperfecta

Answer 16

• Mutation in gene for collagen synthesis –> abnormal collagen
• Extremely fragile bones
• More likely to be deaf.
• Blue sclera

Question 17

Elastin fibres

Answer 17

• Branched fibres, can stretch + recoil
• Synthesised by fibroblast
• Made of protein elastin + fibrillin (which forms scaffolding for elastin)

Question 18

Marfan’s syndrome

Answer 18

• Mutation in fibrillin gene
• Makes skeleton tall + thin with arachnodactyly
• Risk of developing aortic dilation or aortic aneurysm
• Leaky heart valves
• Myopia in eyes

Question 19

Reticular fibres

Answer 19

• Fine, highly branched collagen fibres
• Form structural framework
• Found in lymph nodes + spleen

Question 20

Ground substance:

Answer 20

• Semi-fluid gel in between cells + fibres
• Made of glycosaminoglycans (polysaccharides), proteoglycans (bind water, giving gel-like properties), water and salt
• Size of spaces between glycosaminoglycans determines permeability of tissue
• Delays spread of infection through tissue

Question 21

Types of general connective tissue

Answer 21

• Loose connective tissue: low density of fibres
• Dense connective tissue: dominated by fibres

Question 22

Dense connective tissue:

Answer 22

Dominated by fibres
Dense regular: fibres run parallel
Dense irregular: fibres have no clear orientation

Question 23

Identify

Answer 23

Areolar connective tissue

Question 24

Loose connective tissue:

Answer 24

Low density of fibres
- Areolar
- Adipose

Question 25

Identify

Answer 25

Adipose loose connective tissue

Question 26

Identify

Answer 26

Regular dense connective tissue

Question 27

Identify

Answer 27

Irregular dense connective

Question 28

Identify

Answer 28

Elastic dense connective tissue

Question 29

Identify

Answer 29

Mesenchymal

Question 30

Identify

Answer 30

Reticular connective tissue

Question 31

Identify

Answer 31

Reticular connective tissue

Question 32

Identify

Answer 32

Brown adipose tissue

Question 33

Identify

Answer 33

Mesenchymal connective tissue