Connective tissue

Question 1

What is the mesenchyme? Where does it come from?

Answer 1

Mesenchyme are pluripotent stem cells that give rise to many connective tissue cells, such as fibroblasts, chondroblasts, osteoblasts, etc. All connective tissue is derived from mesenchyme that comes from the mesoderm, but not all the mesenchyme comes from mesoderm.

Question 2

What is the importance of fibroblasts. What 3 things do they generate?

Answer 2

Fibroblasts secrete the components of the ECM. Specifically, they create glycoproteins, fibers (ie collagen), and ground substance.

Question 3

Describe the difference between an active and inactive fibroblast?

Answer 3

Active fibroblasts are swollen b/c they are generating the ECM. Inactive fibroblasts are narrow and called fibrocytes.

Question 4

Describe the amino acid composition of collagen.

Answer 4

proline, glycine, hydroxyproline, hydroxylysine, and lysine

Question 5

What is the most abundant protein in the body?

Answer 5

collagen

Question 6

What are the different types of collagen and where are they found?

Answer 6

1. most abundant- fibrocartilage, tendons, ligaments, bones, dermis
2. Hyaline and elastic cartilage
3. Reticular fibers/organ stromas
4. Basement membrane

Question 7

Describe the production of type 1 collagen.

Answer 7

Starts in the RER and golgi-3 alpha chains combine to forms procollagen. Procollagen is secreted into fibroblast cove where it is cleaved into tropocollagen. Tropocollagen self assembles into fiber types 1,2,3. Vitamin C is necessary to facilitate collagen assembly.

Question 8

Why is vitamin C important in connective tissue?

Answer 8

It is important in facilitating the collagen assembly.

Question 9

Name some disorders that are related to collagen dysfunction.

Answer 9

Scruvy - lack of vitamin c
Ehlers-Danlos
Osteogenesis imperfecta

Question 10

Describe the composition and purpose of elastic fibers.

Answer 10

They are made up of elastin protein surrounded by fibrillin fibers. Together, they add elasticity to cartilage.

Question 11

What does elastin do?

Answer 11

Amorphous core of elastic fibers

Question 12

What does fibrillin do?

Answer 12

Forms shealth around elastin in elastic fibers

Question 13

Name the two most common glycoproteins found within CT ECMs.

Answer 13

fibronectin and laminin- specifically found along the with collagen 4 in basement membranes

Question 14

Describe the composition of ground substance.

Answer 14

hydrated gel that allows the diffusion of nutrients and signals. Made of proteoglycans (protein cores with glycosaminoglycans attached) and proteoglycan aggregates bound to hyaloronan.

Question 15

Describe the differences between loose and dense connective tissue

Answer 15

Loose- lots of cells, irregular fibers, a lot of ground substance

Regular- few cells, lots of fibers (regular or irregular) little ground substance

Question 16

List connective tissue with special properties

Answer 16

mucous, adipose, bone

Question 17

What is the purpose of adipose?

Answer 17

energy storage, insulation, protection, endocrin secretion

Question 18

What are the differences between white and brown fat?

Answer 18

Brown fat is found in infants for creating more heat (problem with SA to volume). Brown appearance is created by mitochondria (thermogenin inside mitochondria create heat)

Question 19

Describe the importance of mast cells.

Answer 19

Very important for anaphalactic shock. Recognize IgE. Contain vesicles with vaso and immuno active substances which degrade upon IgE binding, creating immediate hypersensitivity. Modulated by heparine and histamine.

Question 20

Why are heparin and histamine important?

Answer 20

Modulate mast cells

Question 21

Which cells are clock faced?

Answer 21

plasma cells- creating antibodies.

Question 22

What are the two major constituents of connective tissue, and what are they comprised of?

Answer 22

Cells and ECM. Cells can be either resident or wandering cells. The ECM is comprised of ground substance, fibers, and glycoproteins.