Embryology 1 Flashcards
what is some of the factors the drive embryogenesis
Driven by evolutionary, genetic, epigenetic and environmental factors
What are some of the things that errors can lead to
Embryonic death
Fetal death
Fetal mummification
Abortion
Stillbirth
Birth of nonviable neonates
Birth of viable offspring with defects
what is a multifactorial process and define what that means?
Embryogenesis, a system or process that is influenced by a range of factors
define Congenital
A disruption in development that results in a deviation of normal growth.
what are some key biological molecules which can affect growth
Carcinogens, mutagens and teratogens
what is a teratogen
agents or factors that cause the development of physical defects in the embryo or fetus. example: posion, radiation, heat effecture on mother ect.
define a critical period
Point of vulnerability of a specific area or system during development.
Utero crowding can lead to…
Congenital joint contracture (tissues around joints are shorter/tighter restricing movement)
Aggressive palpation of pregency can lead to….
limb deformities or disruption of the delicate vascular supply to the intestinal tract (atresia coli)
Physical effects during gestation can lead to….
embryonic or fetal abnormalities
define fertilisation
Process by which a spermatozoa and ovum fuse to form a single celled zygote.
desribe the layers of a ovum
When the ovum leaves the ovary it is surrounded by an accessory follicle (corona radiata) and below that is another layer (zona pellucida) then is the egg membrane
how do the sperm find the egg?
egg secrete chemical whitch attract the spermatazoa
describe the steps that take place in fetilisation
1 - sperm find egg via chemical signals secreted by the ovum
2 - sperm secrete enzymes from arcosome to break down zona pellucida
3- one sperm reaches egg membrane
4 - sperm bonds material with ovum and the head is guided into the eggs cytoplasm.
5 - vesicles reinforce the zona pellucida stoping others from entering
6 - sperm ‘activates’ the ovum, allowing embryogenesis to begin.
what happens if there is not enough sperm
not enough enzymes are secreted by the acrosome and the zona pellucida dose not break down, no fetilisation will occur.
abnormalities in the early development of the embry are typicallly major or minor
major
what sytem has the larget critcial period
neural tissue
abnormalities in the late development of the embry are typicallly major or minor
minor
