Chapter 47 Animal Development Flashcards
What is fertilization?
Formation of a diploid zygote from a haploid egg and sperm
What two stages initiates embryonic development?
- fertilization
- cleavage
What is acrosomal reaction?
The triggering of when the sperm meets the egg
What is the acrosome?
Tip of the sperm head that releases hydrolytic enzymes to fertilize the egg
What is a fast block to polysperm?
a process that prevents additional sperm from entering an egg after the first sperm fertilizes it
What is the slow block to polysperm?
a process that prevents multiple sperm from fertilizing an egg by releasing material from the egg that creates a physical barrier to further sperm
What initiates the cortical reaction?
The fusion of the egg and sperm
What starts egg activation?
Increase in calcium in the cytosol –> increases the rates of cellular respiration and protein synthesis by the cell
What is the zona pellucida?
Extracellular matrix of the egg
Is fertilization in mammals and other terrestrial animals, internal or external?
Internal
What is cleavage?
A period of rapid cell division without growth
What are blastomeres?
The cytoplasm of one large cell that is split into many smaller cells
What is the blastula?
A ball of cells with a fluid-filled cavity
What is a blastocoel?
The fluid-filled cavity in the blastula
What is morphogenesis?
Process by which cells occupy their appropriate locations
What is involved with morphogenesis? (2)
- Gastrulation
- Organogenesis
What is gastrulation?
Movement of cells from the blastula surface to the interior of the embryo
What is organogenesis?
Formation of organs
What is the gastrula?
A three layered embryo that was originally the cells of the blastula
- rearranged by gastrulation
What are the 3 layers of the gastrula?
- ectoderm
- endoderm
- mesoderm
What does the ectoderm form?
Forms the outer layer
What does the endoderm outline?
Outlines the digestive tract
What does the mesoderm do?
Partially fills the space b/w the endoderm and the ectoderm
What is the blastocyst?
Human equivalent to the blastula
What is the inner cell mass?
Cluster of cells at one end of the blastocyst
What is the trophoblast?
Outer epithelial layer of the blastocyst and does not contribute to the embryo, but instead initiates implantation
What are amniotes?
Embryos that are surrounded by fluid in a sac called the amnion
What are the 4 extraembryonic membranes that form around the embryo?
- Chorion –> function in gas exchange
- Amnion –> Encloses amniotic fluid
- Yolk sac –> Encloses yolk
- Allantois –> Disposes of waste products and contributes to gas exchange
What begins neurulation?
The cell formation from the dorsal mesoderm that forms the notochord
What is the notochord?
A rod extending along the dorsal side of the embryo
What is induction?
When cells or tissues cause a developmental change in nearby cells
What is the nerual tube?
When a neural plate curves inward
What do neural crest cells develop into?
Found along the neural tube of vertebrates, it develops into various parts of the embryo
What is apoptosis?
Programmed cell death
What is determination?
Used to describe the process by which a cell or group of cells become committed to a particular fate
What is differentiation?
Refers to the resulting specialization in structure and function
What are fate maps?
Diagrams that show organs and other structures that arise from each region of the embryo
What is pattern formation?
Development of spatial organization
