CONNECTIVE & ADIPOSE Basics

Question 1

What are 6 functions of connective tissue?

“Connective Tissue Will Do Plenty Stuff”

Answer 1

Protect - cushion between tissues and organs and shock absorber/insulation (adipose)
Transport - diffusion of nutrients and waste (loose CT)
Defence/Immune - against infection - (blood/lymph/wandering cells)
Connects - bone to bone, muscle to bone (cartilage, tendons)
Storage - fuel storage (adipose)
Wound Healing - fibroblasts, macrophages, myofibroblasts

Question 2

What are the 3 general components of CT?

Answer 2

Cells
Fibres
Ground Substance

Question 3

What is ground substance made up of?

Answer 3

A watery lubricating substance made of proteogylcans (long polysaccharide chains). GAGs bind to a core protein e.g. Along a hyaluronan molecule in hyaluronic acid which is a common GAG found in cartilage

Question 4

What is extracellular matrix made of?

Answer 4

Fibres and ground substance.

Question 5

What is loose CT formed of and what is it useful for?

Answer 5

Many cells, sparse collagen, lots of ground substance, it’s gel-like consistency good for Transportation - diffusion.

Question 6

What types of cells might you find in loose CT?

Answer 6

Many - fibroblasts, plasma cells, mast cells, endothelial cells, adipose cells, lymphocytes, eosinophils

Question 7

What 3 things/structures is loose connective tissue usually associated with? How does this help with it’s function?

Answer 7

1) Beneath epithelia for diffusion
2) Associated with epithelium of gland
3) Located around small BVs

These are all areas where pathogens can infiltrate - Loose connective tissue can swell during inflammation

Question 8

What kind of tissue is elastic fibres found in?

Answer 8

Most kinds of CT but where and how densely is different - e.g. Major component of Dermis, artery walls, lungs, elastic cartilage

Question 9

What are the 7 fixed cells and 5 wandering cells that can be present in connective tissue?

Answer 9

Fixed: macrophages, fibroblasts, myofibroflasts, mast cells, melanocytes, adipocytes, mesenchymal stem cells.

Wandering: monocytes, eosinophils, basophils, leucocytes, plasma cells

Question 10

What is the role of fibroblasts and myofibroblasts? What are their roles in wound healing?

Answer 10

Fibroblasts secrete ground substance and the fibres within it e.g. Procollagen - major role in wound healing and scar tissue formation

Myofibroblasts contain actin and play a major role in closing wounds ‘purse string’

Question 11

What are macrophages and two major roles?

Answer 11

Are migrated monocytes from blood to connective tissue - phagocytose foreign bodies and debris and also are professional antigen presenting cells (present antigens to T cells)

Question 12

What are mast cells, what coats them and name 2 things they release

Answer 12

Mast cells are found in CT near blood vessels. They release Histamine, Heparin They coat with IgE molecules that release their granule content on binding with an allergen. Role in allergic reaction/anaphylaxis.

Question 13

How is regular dense CT structure useful for it’s function?

Answer 13

It has dense parallel bundles of collagen fibres that withstand stress in a single direction.

Question 14

How is irregular dense CT suited to it’s function?

Answer 14

Dense irregular bundles of collagen fibres in all different directions - can withstand stress from many different directions e.g. Skin.

Question 15

What are Ghrelin and Leptin and where are they secreted from?

Answer 15

Ghrelin - appetite stimulant released from stomach

Leptin - appetite suppressor released from fat cells

Question 16

Give 3 examples of regular dense CT and 2 examples of irregular dense CT

Answer 16

Regular - tendons, ligaments, aponeuroses(e.g. Alba Linea)

Irregular - deep layers of dermis of skin, submucosa of intestine

Question 17

How many types of collagen are there? What is the main type?

Answer 17

28

90% is type I

Question 18

Describe and explain 4 common types of collagen

Answer 18

I - 90% - form fibres - tendons, capsules of organs, dermis
II- fibrils do not form fibres - hyaline and elastic cartilage
III - form fibres round muscle and nerve cells and within lymphatic tissues and organs (reticulin)
IV - Unique form found in basal lamina of basement membrane

Question 19

What are 3 common types of fibre found in connective tissue?

Answer 19

Collagen, reticular, elastic fibres

Question 20

What are reticular fibres? Where do they get secreted from?

Answer 20

Made of irregular network of collagen type III secreted by reticular cells

Question 21

What are elastic fibres?

Answer 21

Made of elastin which is enfolded and surrounded by fibrillin.

Question 22

What are 3 functions of adipose?

Answer 22

Fuel reserve, thermal insulation, shock absorber

Question 23

What is the different between unilocular and multilocular adipose?

Answer 23

Unilocular - white fat - one large lipid droplet inside, cytosol and nucleus pushed to periphery

Multilocular - brown fat - many small lipid droplets with central nucleus. Brown due to many mitochondria and blood vessels- high respiratory capacity to make heat - non shivering thermogenesis

Question 24

Where is brown fat found?

Answer 24

In babes - mainly scapula, sternum, axillae. In the adult there is some in the upper chest and neck.

Question 25

Give 4 examples form the lecture of what happens when CT can go wrong (disease)

Answer 25

Scurvy - lack of vit C that is needed to make procollagen
Osteogenesis imperfecta - Abnormal type I collagen
Marphans - autosomal dominant - abnormal expression of fibrillin gene so abnormal elastic fibres. Present as abnormally tall, arachnodactyly, dislocations, at risk of aortic rupture.
AAA - loss of elastin

Question 26

What does GAG stand for?

Answer 26

Glycosaminoglycan

Question 27

What are two functions of the ground substance gel made with GAGs and water

Answer 27

allow diffusion resist compression

Question 28

What are two main roles of loose connective tissue?

Answer 28

Diffusion - lots of Ground Substance

Can swell in immune response

Question 29

Which is the most common type of collagen in body?

Answer 29

Collagen I

90%

Question 30

How is type I collagen arranged, where in the body would you see it (4)?

Answer 30

Arranged in fibres, in tendons, bones, round organs and skin dermis

Question 31

How is type II collagen arranged? Where in the body is it found (2)

Answer 31

NOT in fibres, found in elastic and hyaline cartilage

Question 32

How is type III collagen arranged? Where in the body is it found?

Answer 32

Arranged in fibres. E.g.

muscle, nerves, and within lymphatic tissue and organs