BL Connective Tissue

Question 1

What is connective tissue?

Answer 1

Tissue that supports, protects + connects other tissues and organs in the body
Made of cells, fibre + ground substance

Question 2

What are the 3 components of connective tissue?

Answer 2

Cells
Fibres
Ground substance

Question 3

What are the main cells in connective tissue?

Answer 3

Fibroblasts
Chondrocytes
Osteocytes/blasts/clasts
Stem cells
Adipocytes
Reticular cells - in lymphatic vessels

Question 4

What are the 3 fibres in connective tissue?

Answer 4

Collagen
Elastin
Reticulin

Question 5

What are the 3 groups of connective tissue?

Answer 5

Connective tissue proper
Fluid connective tissue
Supportive connecting tissue

Question 6

What are types of connective tissue proper?

Answer 6

Loose
Dense

Question 7

What are the types of fluid connective tissue?

Answer 7

Blood
Lymph

Question 8

What are the types of supportive connecting tissue?

Answer 8

Cartilage
Bone

Question 9

What is ground substance?

Answer 9

Gel containing protein glycoproteins, glycoaminoglycans, lipids + water

Question 10

What is extracellular matrix?

Answer 10

Ground substance and fibres linked to form a complex network

Question 11

Function of fibroblasts

Answer 11

Produce collagen + fibres of ground substance

Question 12

Functions of connective tissue

Answer 12

• Binding + supporting
• Protection
• Insulating
• Storage - bone marrow + adipose
• Transporting substances
  Separation of tissue

Question 13

What is the least specialised connective tissue in adults?

Answer 13

Loose/areolar connective tissue

Question 14

What are the two types of dense connective tissue?
Describe each type

Answer 14

Irregular - fibres running in different direction
Regular - fibres running parallel to each other

Question 15

Structure of loose connective tissue

Answer 15

• Cells - fibroblasts, macrophages, mast cells, adipocytes
• Fibres - collagenous + elastic
• Ground substance

Question 16

Functions of loose connective tissue

Answer 16

• Holds vessels
• Permits cell migration
• Involved in inflammation pathways
• Packaging around organs
• Shock absorber
• Stabilises organs - surrounds all organs

Question 17

What do mast cells contain?

Answer 17

Histamines - ^ blood vessel wall permeability
Heparin - anticoagulant
Cytokines - attract eosinophils and neutrophils

Question 18

Function of histamines

Answer 18

Increase blood vessel wall permeability

Question 19

What do mast cells look like?

Answer 19

Basophils
Many vesicles

Question 20

What is a unilocular adipocytes?

Answer 20

A large single lipid droplet
Nucleus, cytoplasm + organelles all sequenced to one side of cell

Question 21

Why do adipocytes appear white in H&E staining?

Answer 21

Xylene + toluene strip out the fats

Question 22

Function of white adipose tissue

Answer 22

Padding
Shock absorber
Insulation
Energy reserve

Question 23

What is a multilocular adipocyte?

Answer 23

Multiple small lipid drops
Nucleus, cytoplasm + organelle squeezed to centre of cell

Question 24

Function of brown adipose tissue

Answer 24

Insulation
Energy reserve

Question 25

Nucleus in white vs adipose tissue

Answer 25

- **white**: nucleus pushed to side - **brown**: central nucleus

Question 26

What type of adipose tissue has the most mitochondria?

Answer 26

Brown

Question 27

What are adipose cells generated from?

Answer 27

Immature fibroblasts Mesenchymal stem cells

Question 28

Who is brown adipose tissue found in?

Answer 28

Neonates Young children Upper backs of adults

Question 29

Lipid breakdown in white adipose tissue

Answer 29

Slow Heat only generated after shivering reflex

Question 30

Why do babies have brown adipose tissue?

Answer 30

Unable to shiver

Question 31

How does brown adipose generate heat?

Answer 31

1- noradrenaline released in response to cold 2- noradrenaline activates lipase: TAG > fatty acids 3- fatty acids activate UCP1 (thermogenin) 4- UCP1 uncouples ETC 5- H+ transported back to mitochondria 6- energy released as extra heat

Question 32

What does brown adipose tissue contain that allows heat generation?

Answer 32

Thermogenin (UCP1) - physiological uncoupler

Question 33

What are the 4 types of collagen?

Answer 33

- **Type I** - most common - in tendons, skin dermis - **Type II** - fibrils don’t form fibres - in hyaline + elastic cartilage - **Type III** - reticulin - fibres around muscles + nerves + within lymphathic tissues -**Type IV** - in basement membrane

Question 34

What is the most common type of collagen?

Answer 34

Type I

Question 35

What collagen is present in hyaline + elastic cartilage?

Answer 35

Type II

Question 36

What type of collagen is reticulin?

Answer 36

Type III

Question 37

What type of collagen is in the basement membrane?

Answer 37

IV

Question 38

What fibre is absent in loose connective tissue?

Answer 38

Reticulin

Question 39

Functions of the fibres in connective tissue

Answer 39

- **collagen** - flexible with high tensile strength - **reticulin** supportive framework - **elastin** - recoil after stretch

Question 40

Where is loose connective tissue located?

Answer 40

Around small blood vessels Beneath epithelia Associated with epithelium of glands

Question 41

What is proteoglycans?

Answer 41

Large macromolecule consisting of a core protein which glycoaminoglycans are covalent bound

Question 42

What are glycoaminoglycans? Example

Answer 42

Long chained polysaccharides *hyaluronic acids*

Question 43

Function of irregular dense tissue

Answer 43

- **Prevents tearing** - Irregular arrangement resists forces in multiple directions - **Stretch + recoil** - due to elastic fibres

Question 44

Structure of mucoid connective tissue

Answer 44

- **Cells** - immature fibroblasts - **Fibres** - collagen II fibres - **Ground substance** - hylauronic acid

Question 45

Where is mucoid connective tissue found?

Answer 45

Umbilical cord Vitreous humour of eye

Question 46

Examples of locations dense irregular connective tissue

Answer 46

Deep layer of dermis Submcosa of intestine

Question 47

Examples of locations of dense regular connective tissue

Answer 47

Tendons Ligaments Aponeuroses

Question 48

What type of collagen is in dense connective tissue?

Answer 48

Collagen I

Question 49

Types of fascia

Answer 49

Superficial Deep Visceral or parietal

Question 50

Structure of fascia

Answer 50

Sheet of fibrous connective tissue containing closely packed bundles of collagen fibres orientated in a wavy pattern parallel to direction of pul

Question 51

What clinical conditions result due to connective tissue issues?

Answer 51

Scurvy Marfan’s syndrome Osteogenesis imperfecta

Question 52

What is elastin surrounded by?

Answer 52

Fibrillin

Question 53

Distinguish between the structure of loose and dense connective tissue

Answer 53

Loose - many cells - sparse collagen fibres - abundant ground substance Dense - few cells (nearly all fibroblasts) - many collagen fibres - little ground substance

Question 54

Where is connective tissue located?

Answer 54

At the sites where pathogens can be destroyed by cells of the immune system

Question 55

2 examples of loose connective tissue

Answer 55

Superficial dermis of skin Submucosa of colon

Question 56

Describe the structure of ligaments

Answer 56

Collagen bundles densely packed in parallel arrangements Are arranged in fascicles

Question 57

What germ layer to most connective tissue cells originate from?

Answer 57

Mesoderm

Question 58

Structure of collagen

Answer 58

- 3 alpha polypeptide chains - repeating structure with glycine in every 3rd position - glycine lie in middle of helix

Question 59

What does abnormal collagen type I result in?

Answer 59

Osteogenesis imperfecta

Question 60

What are the layers of the basement membrane?

Answer 60

Basal lamina Reticular lamina