Chapter 47 Flashcards
What is the model organism for morphological development?
Sea urchin
Embryology
study of morphology over time
Developmental biology
genetics behind embryology
Fertilization
- syngamy
- fusion of 2 haploid cells into 1 diploid cell
H2O fertilization
Both the egg and sperm are in water
What are the four steps in fertilization?
- Acrosome reaction
- receptor binding of sperm and egg
- fusion of membranes
- deposition of sperm nucleus
What happens in the acrosomal reaction?
Hydrolytic enzymes pierce the membrane of the egg
What happens when the membrane fuse?
The DNA in the sperm is released into the egg producing a heterochariotic cell
Syngamy
Fusion of two haploid nuclei to form a diploid nucleus. Creates a zygote and initiates development
Blocks to polyspermy
- Fast block
2. Slow block
Fast block
Following the fusion of the sperm, rapid reversal of membrane potential
Slow block
Production of fertilization membrane by fusion of cortical granules
Ectoderm
- skin
- nervous system
- pituitary gland
- adrenal medulla
- germ cells
- jaws
- teeth
Mesoderm
- skeletal
- muscular
- circulatory
- lymphatic
- dermis
- excretory
- reproductive
Endoderm
- lining of digestive tract
- pancreas
- liver
- thymus
- thyroid
- parathyroid
Zygote
One cell
Cleavage
Cell division in which cell size decreases
Morula
32 cells
Gastulation
Transition from blastula to gastrula
Induction
Release cell signals that induce overlain ectoderm to differentiate to neural ectoderm which can form neural plates then neural folds then the neural tube
Archenteron
Becomes the digestive tract
Notochord
Show up in the gastrula
Trophoblast
Burrows into the endometrium
- becomes gastocyst when epiblast turns into germ layers
