Lecture 4: Cell Morphogenesis

Question 1

Morphogenesis

Answer 1

Change in cell shapes, location, and interactions

Question 2

Epidermis

Answer 2

Epithelial cells of the skin

Question 3

Dermis

Answer 3

Connective tissue

Question 4

Embryogenesis

Answer 4

This refers to the formation and development from fertilization all the way to just before birth

Question 5

What are the key stages for embryogenesis for development.

Answer 5

1. Fertilization and cell proliferation
2. Bastula (sphere of cells)
3. Gastrulation and cell differentiation along with morphogenesis

Question 6

Outline of morphogenesis (shapes)

Answer 6

1. Cell internalization
2. Elongation
3. Fine repositioning of cells

Question 7

Describe the processes that occur in cell internalization of morphogenesis

Answer 7

Gastruction will occur, turning the blastula into an embryo and 3 tissue layer.

Ectoderm: epidermis and nervous system
Mesoderm: muscles, connective tissue, bones, blood, kidneys
Endoderm: pancreas, gut, liver and lungs

Question 8

Which cells indent and start forming the anus

Answer 8

Endoderm

Question 9

Which cells crawl around inner surface

Answer 9

Mesoderm

Question 10

Fill in the blank.

Cell internalization by ________________form the mesoderm

Answer 10

Ingression and delamination

Question 11

Ingression

Answer 11

Individual cells from the outer layer detach and move inwards
This is known as an epithelial to mesenchymal transition because epithelial cells will transition to mesenchymal cells

Question 12

Why is the EMT transition carefully regulated

Answer 12

Because abnormal epithelium can start to develop and move inwards

Question 13

Fill in the blank.
Cell internalization by __________________form the endoderm

Answer 13

Invagination and involution

Question 14

What is an important example of invagination/involution in human development?

Answer 14

The neural tube formation-
After the endoderm is formed, specific signals will tell part of the ectoderm to start becoming the neural tube and through invagination the neural tube will form.

Question 15

what is involved during elongation process of morphogenesis

Answer 15

the cell undergoes convergent extension where cells crawl towards each other and then extend outwards

Question 16

besides convergent extension, what is another way that the cell undergoes elongation

Answer 16

mass migration, where cells, move individually or as a group.

There are two types of migration, sheet migration (lots of cells stuck together that have a lot of adherents) or chain type migration- clusters

Question 17

What are the three most common ways cells undergo cell elongation

Answer 17

1. cell growth
2. cell division
3. matrix deposition (plants)

Question 18

Describe elongation in plant cell growth

Answer 18

plant cells grow asymmetrically via cellulose because it constricts plant growth forcing expansion in one direction

Question 19

how do disorganized microtubules disrupt plant cell elongation

Answer 19

Microtubules are responsible for positioning cellulose complexes in plants and when microtubules are disorganized, so are the cellulose complexes, which will prevent elongation in one direction causing cell swelling- because there is growth in many directions

Question 20

Give an example of the final stage of morphogenesis, fine repositioning

Answer 20

the cerebral cortex are repositioned by whole cell migrations and the oldest cells are in the deepest layer `

Question 21

how are axons positioned in the body

Answer 21

by migration of cell extension