L1: Physiology of Pregnancy Flashcards
Phases of Early developed pregnancy
Def of Fertilization
- Union of male gamete (mature capacitated sperm) +
female gamete (mature ovum) to form zygote.
Site of Fertilization
Ampulla of tube
Time of Fertilization
24 hours after ovulation.
Fertilizable Life Span of Ovum
12 - 36 hours
Fertilizable Life Span of Sperm
24-72 hours.
Oocyte journey During Fertilization
Sperms journey During Fertilization
Factors helping in ascending of sperms in female genital tract
Def of Sperm Capacitation
Method of Sperm Capacitation
Acrosomal Reaction
- Removal of decapacitating factors & activation of acrosomal
enzymes (neuroamidase, hyaluronidase & acrosin enzymes).
How is acrosomal Cap lost?
- May be attributed to proteolytic enzymes in estrogen dominant uterus.
Events occuring when sperm reach ovum
Events occuring when sperm reach ovum
- Sperms start to release …..
Events occuring when sperm reach ovum
- Sperms start to release ….. to penetrate corona radiata
Neuroamidase
Events occuring when sperm reach ovum
- Sperms start to release ….. to penetrate Zona pellucida
Hyaluronidase
Events occuring when sperm reach ovum
- Stimulation of Zona Pellucida receptor site
- Allowing penetration of zona by 1 sperm only
- Many sperms can penetrate corona radiata & participate in weakening of zona pellucida but only 1 sperm can penetrate zona).
Events occuring when sperm reach ovum
- Reblocking of Zona Pellucida Receptor Site
to prevent further sperms entrance.
Events occuring when sperm reach ovum
- Completion of 2nd Meiotic Division
(which was arrested in metaphase) → formation
of mature ovum & 2nd polar body.
Events occuring when sperm reach ovum
- Penetration of Oocyte Membrane
- Penetration of oocyte membrane (by acrosin) & only head & midpiece of sperm enter ovum.
Results of Fertilization
- Union of female pronucleus (contains 22 + X chromosomes) with male pronucleus (contains 22 + X or Y chromosomes) to form zygote (l-cell stage) which contains 46 chromosomes then zygote undergoes cleavage
Steps of Morula Formation
When does Morula reach the uterine cavity?
at 3rd - 4th post-fertilization day.
what is the morula?
16-cell stage
Blastocyst Formation
Def of Decidua
Thickened vascular endometrium prepared for implantation
(endometrium of pregnancy)
Layers of Decidua
Factors maintaning Decidua
Functions of Decidua
Def of Implantation
- Embedding of blastocyst in decidua
- (so, pregnancy is defined as implantation of blastocyst in decidua).
Normal Sites of Implantation
In Upper uterine segment UUS (60% posteriorly & 40% anteriorly).
Abnormal Sites of Implantation
- In Lower Uterine Segment LUS (placenta previa).
- Outside normal uterine cavity (ectopic pregnancy)
Time of Implantation
6th - 7th post fertilization day (one week post fertilization).
Mechanism of Implantation
Main Steps of Implantation
Differentiation of Decidua
Decidua Basalis
- Site
- Formed of
- Function
Decidua Capsularis
- Site
- Formed of
- Function
Decidua Parietalis (Vera)
- Site
- Formed of
- Function
Origin of Trophoblasts
Outer cell mass of blastocyst.
layers of Trophoblasts
Types of Chorionic Villi
Formation of 1ry Villi
Components of 1ry Villi
Foemation of 2ry Villi
Components of 2ry Villi
Formation of 3ry Villi
Components of 3ry Villi
Intervillous Space (Choriodecidual Space)
Functional Types of Villi
All are anchoring but not all are nutritive.
✓ Anchoring For supporting embryo.
✓ Nutritive For nutrition via choriodecidual space.
Fate of Chorionic Villi
-
Villi related to decidua basalis:
Form chorion frondosum (shares e decidua basalis in formation of placenta). -
Villi related to decidua capsularis:
Form chorion leave (forms outer layer of fetal membranes).
Origin of Embryo
From inner cell mass of blastocyst.
Def of Placenta
Unit of connection ( ) fetus & uterus ( mother)
Development of Placenta
Decidua basalis (maternal part)
+
Chorion frondosum (fetal part).
Anatomy of Placenta
Shape of Placenta
at full term, disc shaped or ovoid (circular cake - Discoid)
Diameter of Placenta
15-20 cm.
Thickness of Placenta
2 inch in center & thinner inch at periphery (1/2 inch)???
Weight of Placenta
300- 500 gm (at full term).
Color of Placenta
Dark red (due to maternal blood in intervillous space)
Surfaces of Placenta
Attachment of Placenta
Function of Placenta
- Respiratory function
- Nutritive function
- Secretory function
- Excretory function
- Hemopoietic function
- Mechanical function
Function of Placenta
- Respiratory
Function of Placenta
- Nutritive
Transport of glucose, lipids, proteins, vitamins & minerals.
Function of Placenta
- Secretory
Function of Placenta
- Secretory (Hormones)