2. Cell and Extra-cellular matrix during the morphogenesis of tissue and Organs

Question 1

How does morphogenesis of tissues and organs start?

Answer 1

Cell-and-matrix molecule interactions

Question 2

Morphogenesis is dependent on…

Answer 2

1. Changes in cell shape 2. Oriented cell division 3. Cells exchanging their neighbors

Question 3

What are some things the embryonic ectoderm gives rise to?

Answer 3

Epidermis Nervous System Retina of the Eye

Question 4

What are some things the embryonic endoderm gives rise to?

Answer 4

Endothelial linings

Question 5

What are some things the embryonic mesoderm gives rise to?

Answer 5

Smooth muscular coats CT Vessels Cardiovascular system Blood Bone marrow Repro and excretory organs

Question 6

In what week does organ-genetic period of development begin?

Answer 6

3rd Week (5 weeks after day of last normal menstrual period)

Question 7

What are the three phases of organ-genetic period of embryonic development?

Answer 7

1. Growth 2. Morphogenesis 3. Differentiation

Question 8

What is morphogenesis?

Answer 8

1. A complex interaction 2. Occurring in an order sequence - Cell movement - Cell transformation (EMT and MET) - Program cell death

Question 9

When does the skin begin to develop?

Answer 9

4-5 weeks

Question 10

Where is the epidermis derived and from where is the dermis derived?

Answer 10

Epidermis (melanocytes included) = Ectoderm Dermis = Mesoderm

Question 11

At what week does cartilage begin to develop?

Answer 11

5th week

Question 12

What is the process for the development of cartilage?

Answer 12

1. Paraxial Mesoderm 2. Somites 3. Condensation of mesenchymal cells 4. Chondrification centres 5. Chondroblasts - Hyaline - Fibro - Elastic

Question 13

What cell type has been shown to harbor positional identity?

Answer 13

The Blastema Cell

Question 14

What are the two types of bone development?

Answer 14

1. Intra-membranous ossification 2. intra-cartilaginous ossification (Endochondral Ossification)

Question 15

Where does Intra-membranous ossification primarily occur?

Answer 15

Flat bones, e.g. Skull

Question 16

Where does intra-cartilaginous ossification primarily occur?

Answer 16

In long bones

Question 17

What is the process for Intra-membranous ossification?

Answer 17

1. Membrane Sheath 2. Condensation of mesenchymal Cells 3. Vascularization 4. Osteoid Matrix deposition

Question 18

What is the process for Intra-cartilagionous ossification? (Endochondral ossification)

Answer 18

1. Condensation of mesenchymal cells 2. Cartilage tissue 3. Hypertrophic 4. Vascularization and osteoblast differentiation

Question 19

At what week does development of skeletal muscle begin?

Answer 19

7th week

Question 20

What is the process for the embryological development of skeletal muscle?

Answer 20

1. Mesenchymal cells in Myotome region of somites 2. Form myoblasts 3. These fuse to form Myotubes

Question 21

At what week does smooth muscle begin developing?

Answer 21

7th Week

Question 22

What is the process for embryological development of smooth muscle?

Answer 22

Same as that of skeletal muscle except for the cell origin 1. Mesenchymal cells = myoepithelial cells in glands - Somatic mesoderm = Smooth muscle in vessels - Splanchnic mesenchyme (located around endoderm) = Other 2. Form myoblasts 3. These fuse to form Myotubes Remain mononuclear

Question 23

In what week does caridac muscle develop?

Answer 23

4th Week

Question 24

From what does cardiac muscle develop?

Answer 24

Lateral splanchnic mesoderm

Question 25

From how many cells do cardiac muscle fibers arise?

Answer 25

Single cells

Question 26

In what week does the development of the PNS begin?

Answer 26

3/4th week

Question 27

What makes up the PNS?

Answer 27

Neural crest cells

Question 28

What does EMT stand for?

Answer 28

Epithelial - Mesenchymal transition (EMT)

Question 29

What is Epithelial - Mesenchymal transition?

Answer 29

Process where epithelial cells lose polarity and cell-cell adhesion, Gain invasive and migratory properties to become MSCs MSCs differentiate into many cell types

Question 30

What does MET stand for?

Answer 30

Mesenchymal - Epithelial Transition

Question 31

What does MET form?

Answer 31

Kidney, tubules Nephrogenic blastema Endocardium Somites

Question 32

What is MET?

Answer 32

Mesenchymal-epithelial transition forms polarized epithelia from motile, multipolar mesenchymal cells

Question 33

What cadherin do Mesenchymal cells express?

Answer 33

N-Cadherin

Question 34

What cadherin do Epithelial cells express?

Answer 34

E-Cadherin

Question 35

What type of matrix proteins are there?

Answer 35

1. Fibrous structural proteins 2. Specialized proteins 3. Proteoglycans 4. Matrix degrading Enzymes

Question 36

What are some types of Fibrous Structural proteins?

Answer 36

Collagen Laminis Fibrinextin Vitronectin Elastin

Question 37

What are some types of specialized proteins?

Answer 37

Growth factors Small matricellular proteins Small integrin-binding glycoproteins

Question 38

What are some types of matrix degrading enzymes?

Answer 38

Matrix Metalloproteinase (MMP) Serine protease Cysterine protease

Question 39

What are the factors involved in cell and matrix molecule interactions?

Answer 39

Growth factors (BMP/TGFB, Wnt signalling) Cell adhesion molecules Cell-ECM interactions Matrix molecules and their ligands

Question 40

What does BMP stand for and what is it?

Answer 40

Bone Morphogenetic Proteins ## Footnote It regulates: 1. Cell type specification 2. Maturation 3. Apoptosis 4. Chemotaxis 5. Mitosis 6. Differentiation 7. Extracellular matrix production

Question 41

What does BMP (Bone morphogeneic protein/s) bind to?

Answer 41

Heparitin sulfate Heparin Type 4 Collagen

Question 42

BMP-2 K/O is?

Answer 42

Embryonic Lethal. Impacts Heart

Question 43

BMP-4 K/O causes?

Answer 43

No mesoderm induction

Question 44

BMP-7 K/O results in?

Answer 44

Kidney, eye development anomolies

Question 45

What functions do Cadherins form?

Answer 45

Mediate homophilic interaction during EMT/MET

Question 46

What occurs if N-cadherin is K/O?

Answer 46

Ill formed somites Abnormal neural tubes Loosely organised myocardium no EMT

Question 47

What occurs if E-Cadherin is K/O?

Answer 47

No MET Trophectoderm fails to form Basolateral domain of epithelium

Question 48

What are cantenins?

Answer 48

They are cadherins partners found in complexes Can be phosphorylated Alpha and B cantenins

Question 49

Do cadherins work with integrins to achieve cell adhesion?

Answer 49

Yesum

Question 50

Can integrins act as receptors?

Answer 50

Yes

Question 51

What is the structure of an integrin?

Answer 51

Heterodimeric trans membrane protein with aB subunits

Question 52

How many subtypes of integrins are there?

Answer 52

15 of a and 8 of B

Question 53

Which transmembrane receptor bridges cell-cell and cell-extracellular matrix interactions and often consists of an Arginin-glycine-aspartate (RGD) sequence?

Answer 53

Integrins!

Question 54

What are semaphorins?

Answer 54

Secreted or membrane associated proteins characterized by conserved sema domain Axonal guidance molecules that direct neuronal axons to appropriate targets

Question 55

What are some of hte physiological functions of semaphorins?

Answer 55

Cardiogenesis Angiogenesis Vasculogenesis Tumour Metastasis Immune Regulation Osteoclastogenesis

Question 56

How many classes of semaphorins are there?

Answer 56

8 classes acting on 3 main receptors Plexins (Most classes act on this receptor) Neurophilins Integrins

Question 57

What does remodelling involve?

Answer 57

Assembly/Degradation

Question 58

What does Regeneration involve?

Answer 58

Remodelling (Assembly \> degradation) X Time

Question 59

What does Organogenesis involve?

Answer 59

Regeneration + EMT + MET