Connective Tissue (1)

Question 1

Define a tissue

Answer 1

A collection of cells containing a predominant cell type that work together and perform the same function form a tissue.

Connective Tissue (CT) = network of fibres in a ground substance + cells in the following relative proportions which characterise a

CT:- few cells, large amount of extracellular matrix with many fibres and abundant ground substance

Question 2

Define an organ

Answer 2

An organ is a collection of tissues joined in a structural unit to serve a common function

Question 3

What 3 components make up a tissue?

Answer 3

cells + fibres + extracellular substance

Question 4

Name the 4 basic (primary) tissues

Answer 4

Question 5

What is the function of connective tissue?

Answer 5

Functions to ‘connect’ and mechanically support other tissues of the body. (Also called Support Tissue).

Question 6

What are the 2 classifications of connective tissue?

Answer 6

CT ‘Proper’

Specialised CT

Question 7

Define CT ‘proper’

Answer 7

provides mechanical support to tissues and organs whilst also carrying blood vessels and nerves to and from these.

Question 8

Define specialised CT

Answer 8

bone, cartilage, blood, adipose tissue, ligaments and tendons. (Bone & cartilage to be given in separate lecture).

Question 9

What are the 2 subclasses of CT ‘proper’?

Answer 9

loose (areolar) CT
dense CT

Question 10

What can dense CT be subclassed into?

Answer 10

dense irregular and dense regular

Question 11

What differentiates dense regular and regular?

Answer 11

dependent on arrangement of collagen fibres

Question 12

What are the identifying characteristics of connective tissue?

Answer 12

• Few cells
• Cells apart from each other
• Spaces filled with fibres + ground substance + fluid = extracellular matrix (ECM)
• Connects and supports

Question 13

What are the spaces between cells in connective tissue filled with?

Answer 13

ECM

Question 14

What does the ECM define in CT?

Answer 14

defines structural and functional

e.g. solid to liquid connective tissue… bone and blood

Question 15

Describe the appearance of loose (areolar) CT?

Answer 15

An aggregation of loosely arranged fibres and many cells of differing types.

Picture showing histology of skin

Question 16

What is the role of loose CT?

Answer 16

Primary location beneath epithelia that cover surfaces or line tubes/cavities

Question 17

What is the role of loose CT?

Answer 17

Initial site of defence against bacteria, so many transient cell types migrate to loose CT from local blood vessels.

Question 18

What classification of CT does adipose tissue fall under?

Answer 18

specialised CT

Question 19

What are the characteristics of adipose tissue?

Answer 19

Specialised Loose CT with abundant fat storing adipocytes

Single, large droplet of lipid pushes nucleus to one side and flattens cytoplasm to a thin rim

Rich blood supply

White fat (most adult) and brown fat (mostly foetal)

Mostly in CT under skin -insulation - and also for protection around organs and neurovascular bundles

Question 20

What type of CT tissue is shown?

Answer 20

adipose tissue

Single, large droplet of lipid pushes nucleus to one side and flattens cytoplasm to a thin rim

C = capillaries
N = nucleus

Question 21

Does adipose tissue have a rich blood supply?

Answer 21

YES

Question 22

What is the difference between white and brown fat?

Answer 22

White fat (most adult) and brown fat (mostly foetal)

Question 23

Where is adipose tissue located in the human body?

Answer 23

Mostly in CT under skin -insulation - and also for protection around organs and neurovascular bundles

Question 24

Define fat

Answer 24

Fat = adipose cells in amongst some CT cells and fibres macroscopically has yellowish colour

Question 25

What is adipose tissue abundant in?

Answer 25

Specialised Loose CT with abundant fat storing adipocytes

Question 26

What is adipose tissue mainly made up of?

Answer 26

adipocytes (fat cells)

Question 27

What bone marrow made up of?

Answer 27

red marrow, which produces red and white blood cells and platelets, and yellow marrow, which contains fat and connective tissue. A = adipocytes purple = capillaries

Question 28

Describe dense irregular CT?

Answer 28

Thick collagen fibres that run in all directions

Question 29

What is the function of dense irregular CT?

Answer 29

Able to withstand tension exerted in many directions; provides structural strength

Question 30

What is the location f dense irregular CT?

Answer 30

Dermis of the skin; submucosa of digestive tract; fibrous capsules or organs and of joints

Question 31

What CT is this?

Answer 31

dense irregular CT

Question 32

What are structures A and B

Answer 32

dense irregular tissue

Question 33

Describe dense regular tissue

Answer 33

closely packed collagen fibres all running in the same direction poorly vascularised

Question 34

Describe the function of dense regular tissue

Answer 34

attaches muscl;es to bones or to muscles; attaches bones to bones; withstands great tensile stress when pulling force is applied in one direction

Question 35

What is the location of dense regular CT?

Answer 35

tendons and ligaments

Question 36

What CT is this?

Answer 36

CT dense regular

Question 37

Name fibres A and B

Answer 37

CT dense regular

Question 38

What are the components of connective tissue?

Answer 38

CT = cells + ECM

Question 39

What makes up ECM?

Answer 39

1. Fibres - 'rope-like' 2. Ground substance - 'jelly-like' 3. Tissue fluid - liquid

Question 40

What are the major fibres in the ECM?

Answer 40

collagen reticular and elastin

Question 41

What is the ground substance in the ECM?

Answer 41

carbohydrate linked to protein (e.g. hyaluronic acid - joints)

Question 42

How would you describe fibres in the ECM?

Answer 42

rope-like

Question 43

How would you describe ground substance in the ECM?

Answer 43

jelly-like

Question 44

What fibre is this?

Answer 44

collagen protein

Question 45

What fibre is this?

Answer 45

Reticular lymph

Question 46

What fibre is this?

Answer 46

Elastic aorta

Question 47

What is the most abundant fibre in CT?

Answer 47

collagen

Question 48

Describe collagen in the ECM

Answer 48

Strong, flexible with good tensile strength Exhibits ultrastructural periodicity

Question 49

Describe the appearance of collagen fibres

Answer 49

LM looks like wavy structures of variable width and length

Question 50

What fibre is this?

Answer 50

collagen

Question 51

What fibre is this?

Answer 51

reticular fibres Arrows indicate the reticular fibres supporting lymphoid tissue, eg. in lymph node, spleen, thymus

Question 52

Describe the characteristics/structure of reticular fibres

Answer 52

Are collagen fibrils but only 20nm in diameter and greater amount of sugar Do not form large bundles Often found singly, dispersed in an extensive matrix of ground substance or in a mesh/network

Question 53

In adults what do reticular fibres support?

Answer 53

In adults also the supporting stroma of haemopoietic and lymphatic tissue; in the liver and other glands

Question 54

What fibre is the arrow pointing to?

Answer 54

elastic fibre

Question 55

Are elastic fibres thinner than collagen?

Answer 55

YES

Question 56

Are elastic fibres arranged more randomly than collagen?

Answer 56

yes

Question 57

What is the property of elastic fibres?

Answer 57

elastic properties

Question 58

What are the microfibrils like in elastic fibres?

Answer 58

straight and thin (12nm diameter)

Question 59

How does the composition of elastic fibres change with age?

Answer 59

Composition changes with age (more microfibrils in youth, more amorphous elastin as we age)

Question 60

Give 2 examples of where elastic fibres are located/involved in?

Answer 60

Elastic ligaments of the spinal column Fenestrated lamellae in concentric rings in the walls of elastic arteries