Week 12 Flashcards
What are the 4 basic stages of embryological development?
- Fertilisation.
- Zygote.
- Morula.
- Blastocyst.
What is fertilisation?
Fusion of haploid gametes (egg and sperm) to form the diploid zygote.
What is a zygote?
A eukaryotic cell formed by a fertilisation event between two gametes.
What is a morula?
Early-stage embryo.
What is a blastocyst?
Structure formed in the early development of mammals.
What is a diploid cell?
A cell that contains two complete sets of chromosomes.
What are the 3 main components of a blastocyst?
- Trophoblast.
- Blastocyst cavity.
- Embryoblast.
What are the 3 main components of a blastocyst?
- Trophoblast - Outer layer.
- Blastocyst cavity.
- Embryoblast - Inner cell mass.
What are embryoblasts?
True embryonic stem cells that are attached to the blastocyst wall.
What are the 2 layers the embryoblast develops into?
- Bilaminar embryonic disk.
2. Amniotic cavity.
What is implantation in embryology?
The stage of human reproduction at which the embryo adheres to the endometrium, occurs about 7 days after fertilisation.
What is gastrulation?
A phase early in the embryonic development where the bilaminar embryonic disk develops into the trilaminar disk.
What are the 3 trilaminar layers called?
- Ectoderm.
- Mesoderm.
- Endoderm.
What are the 4 main embryological membranes that support development?
- Yolk sac.
- Amnion.
- Allantois (becomes bladder).
- Chorion (becomes placenta).
What is the function of the yolk sac?
Important site of blood formation.
What is the function of the amnion?
Encloses the fluid that surrounds developing embryo.
How long is each of the 3 trimesters in human pregnancy?
13 weeks. (40 weeks total roughly)
What occurs in the trimester 1 of human pregnancy?
- Embryonic and fetal development.
2. All major organ systems appear.
What occurs in trimester 2 of human pregnancy?
- Organ system development.
2. Fetus looks human at end of this stage.
What occurs in trimester 3 of human pregnancy?
- Growth phase and maturation.
After how many weeks do babies have a significantly higher chance of surviving?
35 weeks.
What maternal changes are expected during pregnancy?
Increases in:
- Respiratory rate.
- Tidal volume.
- Blood volume.
- Nutrient and vitamin intake.
- Kidney filtration rate.
List the uterine changes during pregnancy.
- Progesterone inhibits uterine muscle contraction.
- Oxytocin, estrogens, prostaglandins excite uterine activity.
- Multiple factors and timing interact to produce contractions leading to labour.
List the stages of involved in labour.
- Uterus moves inferiorly.
- Contractions and cervix dilation.
- Expulsion.
- Placenta is expulsed.
