Lecture notes on decidua in embryology

Decidua:

Definition : Deciduas means gravid endometrium

Decidua reaction:

 i) cells of the endometrium polyhedral and loaded with glycogen and  lipids

  ii) intercellular spaces are filled with extravasate

  iii) the tissues is edematous

At first it occur at the site of implantation but soon spread throughout the endometrium 

Parts of deciduas : it is divided into three parts

1.      decidua basalis : parts of decidua deep to the developing embryo which contributes to the development of placenta

2.      decidua capsularis : part of decidua which surround the embryo and it is separated from the uterine cavity

3.      decidua parietalis : rest of the decidua excluding decidua basalis and decidua capsularis 

Lecture notes on implantation

Implantation:

Definition: The process during which the blastocyst attaches to the endometrium and subsequently embeds in it.

It occurs at 6 days after fertilization and

by the 11 th to 12^th days of development the blastocyst is completely embedded in the endometrial stroma.

Bleeding may occur at the implantation site as a result of increase blood flow into the lacanar spaces.

 This bleeding occur near the 28^th day of menstrual cycle, it may confused with normal menstrual bleeding.

Q: In which phase of menstrual cycle implantation is occurred?

Ans: The secretory phase, during which time uterine glands and artery become coiled.

What are the phases of menstrual cycle?

1.      Menstrual phase

2.      proliferative(follicular)  phase

3.      secretory (progestational) phase

What is ovarian cycle?

It is a regular monthly cyclic changes in the ovaries (which start at puberty )

Phases are:

i)                    follicular development

ii)                  ii) LH surge (ovulation)

Normal sites of implantation: The blastocyst implants in the endometrium along the anterior or posterior wall of fundus of uterus. (Trophoblast cells of blastocyst invade the epithelium and underlying endometrial stroma with the help of proteolytic enzymes.)

Abnormal implantation:

1.      implantation in abdominal cavity

2.      implantation in the pouch  of Douglas

3.      implantation in the ampullary region of f. tube (most common)

4.      Implantation in the internal os

5.      Ovarian implantation

6.      Interstitial implantation

7.      Tubal implantation

Decidua : pregnant endometrium

Decidua:

Definition : Deciduas means gravid endometrium

Decidua reaction:

 i) cells of the endometrium polyhedral and loaded with glycogen and  lipids

  ii) intercellular spaces are filled with extravasate

  iii) the tissues is edematous

At first it occur at the site of implantation but soon spread throughout the endometrium
 

Parts of deciduas : it is divided into three parts

1.      decidua basalis : parts of decidua deep to the developing embryo which contributes to the development of placenta

2.      decidua capsularis : part of decidua which surround the embryo and it is separated from the uterine cavity

3.      decidua parietalis : rest of the decidua excluding decidua basalis and decidua capsularis

Easy summary of RNA

RNA: the nucleic acid which is found mainly in the nucleolus and ribosome

Composition of RNA : it is formed by single stand nucleotide . Each nucleotide contain pentose suger , phosphate, four nitrogenous bases :  (A), cytosine (C), guanine (G), or uracil  (U). Adenine

There are three types of RNA: 1. mRNA  2. tRNA  3.rRNA

Messenger RNA (mRNA): it transfers genetic information from the nucleus to the ribosomes in the cytoplasm and also acts as a template for the synthesis of polypeptides.

Transfer RNA: transfers activated amino acids from the cytoplasm to messenger RNA.

Ribosomal RNA :  (rRNA) is responsible for the translation of mRNA to protein.

itis the RNA component of the ribosome which is essential for protein synthesis in all living organisms. rRNA is the predominant RNA in most cells, composing around 80% of cellular RNA. Ribosomes are approximately 60% rRNA and 40% protein by weight.