Cellular Development and Differentiation Flashcards
What is the male gamete?
Sperm cell (spermatozoan)
What is the female gamete?
Egg cell (ovum)
Where does fertilisation in humans occur?
In the ampulla of the uterine tube
What is the term that refers to the fusion of sperm and egg?
Syngomy
State the steps of blastocyst formation
1) One cell is fertilised
2) Cell undergoes cleavage to form 2 blastomeres
3) Division forms a morula (ball of cells) which enters the uterine cavity
4) Cavity in the morula (blastocoel) forms to give a blastocyst
What is the trophoblast of the blastocyst?
The layer of cells on the outside containing the blastocoel
What is the embryoblast/inner cell mass of the blastocyst?
Bundle of cells inside
What are the 3 parts of the blastocyst and what do they all produce?
Trophoblast - produces the placenta
Embryoblast - produces the offspring
Blastocoel - cavity in embryo
The inner cell mass is opposite what?
The sperm entry
What does the blastocyst undergo?
Gastrulation
What are the 3 germ layers?
- Ectoderm
- Mesoderm
- Endoderm
What are the four basic tissues?
- Muscle
- Connective
- Nervous
- Epithelial
Which germ layers produce which basic tissue?
- Ectoderm; epithelial
- Mesoderm; muscle, connective, epithelial
- Endoderm; nervous, epithelial
What 2 types of growth increase tissue volume in the developing embryo? What do each of them involve?
Hyperplasia - increase in cell number
Hypertrophy - increase in cell volume
Define differentiation
Unequal but controlled change in structure resulting in a functionally different area
What is meant if a cell is totipotent?
It can differentiate to form any type of cell in the body
What is the basis of differentiation in a developing embryo?
All cells contain ALL genes but will only express specific genes resulting in differentiation
Is differentiation reversible?
No, each ‘choice’ is unidirectional and irreversible
Stem cells in adults are determined, what does this mean?
They are committed to a particular developmental pathway
What is meant if a cell is unipotent?
It can only differentiate into 1 type of cell
What is meant if a cell is pluripotent?
It can differentiate into several types of cells
Other than selective gene activation, what other factors can influence gene activity?
Epigenetic influences
- Morphogens can result in gene activation in cells
What is terminal differentiation?
When a cell fully differentiates into one of the highly specialised cell types in the body
(following one path cuts out others until only one endpoint is left)
What can abnormalities in growth and differentiation cause in individuals?
- Cancer
- Deformities
