Placenta

During pregnancy, one or more offspring develop (gestate) in the womb of the pregnant woman. Multiple pregnancies result in multiple births, including twins. Although getting pregnant through sexual activity is most usual, there are additional procedures using assisted reproductive technologies. Pregnancies can end in one of four ways: live birth, spontaneous miscarriage (also known as abortion), artificial abortion (sometimes known as induced miscarriage), or stillbirth. The gestational age is the amount of time following the beginning of the last menstrual period (LMP) when childbirth typically takes place.

Placenta

Throughout pregnancy, the placenta serves as the fetus’s food source and guardian. It stands out because it is a temporary organ that develops along with the fetus throughout pregnancy before being expelled along with it at delivery.

• The placenta is occasionally referred to as the “afterbirth” since it is discharged vaginally after the fetus is delivered.
• Mammals have a temporary organ called the placenta that connects the mother’s uterus to the fetus during pregnancy.
• Only in the case of animals can it be found.
• Materials can be transported because of the umbilical cord’s connection between the placenta and the fetus.
• The uterus and placenta are typically connected at the top, bottom, side, front, or back.
• Placenta previa is a condition in which the placenta connects to the lower part of the uterus in extreme circumstances.

Types of Placenta

Depending on the Involvement of Embryo­nic Tissue

1. Yolk-Sac Placenta: The moment that the extraembryonic somatopleure and the midgut extension of the splanchnopleure encapsulating the yolk merge, allowing the embryo to make contact with the uterine wall. Examples: Mustelus.
2. Chorio-Allantok Placenta: In order to make touch with the uterine tissue, the extraembryonic somatopleure joins forces with the allantoic evagination of the hindgut. Examples include Eutherian animals and the Chalcides lizard.

Depending on the Distribution of Villi

1. Diffused Placenta: The villi are numerous and evenly dispersed over the entire chorion. Ungulates and Cetacea are two examples.
2. Cotyledonary placenta: In particular areas, the villi group together to create tiny tufts. Ruminants are an example.
3. Zonary Placenta: On the chorion, the villi are restricted to an annular zone. Examples include Carnivora (Pinnipedia).
4. Discoidal Placenta: Iruro-dents and insectivores can be seen with their villi constrained to a discoidal area. The placenta in humans and apes is of the metadiscoidal type.

Based on the Relationship of Villi with the Uterine Wall

1. Deciduate Placenta: The mucous membrane of the uterine wall, which emerges with the embryo at birth, develops an intimate connection with the villi.
2. Indeciduate or Adeciduate Placenta: The uterine walls, which detach from the uterus during birth, are weakly connected to the villi.

Based on the Degree of Involvement of Foetal and Maternal Tissues

1. Epitheliochortal Placenta: The uterine epithelium and the embryo’s chorion continue to be in simple apposition. Horse and pig, for instance.
2. Syndesmochorial Placenta: The uterine epithelium vanishes, and the chorion makes direct touch with either the glandular epithelium or endometrium. Consider sheep.
3. Vasochorial or Endotheliochorial Placenta: The endometrium and glandular epithelium vanish, and the chorion makes direct contact with the uterine capillary endothelium. Dogs and cats are two examples.
4. Haemochorial Placenta: The endometrium, glandular epithelium, and endothelium of the capillaries vanish, and the chorion is drenched in flowing matern­al blood. Example: A man.
5. Haemoendothelial Placenta: The glan­dular epithelium, endometrium, and endothelium of the maternal blood capillaries vanish, much like that of a placenta of the hemochorial type. The fetal endothelium divides the maternal and fetal circulating bloodstreams as a result of the removal of these maternal structures, which also causes the trophoblastic epithelium (the outer layer of the blastocyst) of the fetus to dissolve. Examples: A lot of mice.

Structure 

The placenta is a bodily organ that creates a solid connection between the mother and the fetus.

1. From the surface of the chorion, many finger-like projections called chorionic villi to develop into uterine tissue.
2. The placenta is formed when these villi puncture the mother’s uterine wall.
3. The foetal membrane is joined to the inner uterine wall by a connective tissue called the placenta.
4. As a result, the placenta is thought of as both maternal and embryonic.
5. Through the placenta, the developing embryo takes in oxygen and nutrients from the mother while exhaling carbon dioxide and nitrogenous waste.

Functions

The placenta acts as a conduit for nutrition from the mother’s body to the foetus, ensuring that the foetus gets the resources it needs to survive. It also serves as a barrier, shielding the fetus from a number of maternal infections. The placenta carries out the following tasks:

1. Gas exchange is possible, ensuring that the foetus gets enough oxygen.
2. It aids the foetus is getting enough nutrition.
3. The placenta helps control the foetus’ bodily temperature.
4. It takes waste away from the foetus through the mother’s body for processing.
5. Some potentially infectious bacteria are filtered away by the placenta.
6. The mother’s antibodies are passed from her to the foetus through the placenta, offering some immune defence.
7. It generates hormones that keep the mother’s body prepared for conception.
8. The placenta effectively performs the functions of several organ systems for the foetus because it is unable to breathe, eat, or evacuate waste while within the womb.

Purpose of the Placenta 

The placenta’s functions include:

• Nutrition: The placenta is responsible for transferring nutrients from the mother’s blood to the fetal blood.
• Storage: Before the liver matures, the placenta stores nutrients such as fat, glycogen, and other substances for the fetus.
• Human chorionic gonadotropin, progesterone, and estrogen are among the hormones secreted by the placenta, which also function as an endocrine gland (HCG).
• Protein digestion: Proteins are broken down by the trophoblast of the placenta before entering the fetal bloodstream.
• Excretion: The placenta transfers nitrogenous wastes like urea into the mother’s blood, where the kidneys of the mother filter them out.
• Respiration: The placenta moves carbon dioxide from the fetal blood to the maternal blood as well as oxygen from the maternal blood to the foetal blood.
• Barrier: The placenta serves as an effective defensive wall and barrier, allowing beneficial aerials to reach the blood. Drugs that are addictive like heroin and toxic substances like nicotine from cigarettes can cross the placenta. Therefore, pregnant women should refrain from using drugs and smoking. The placenta can permit the passage of germs and viruses.

FAQs on Placenta

Question 1: What is placenta?

Answer:

A mammalian organ that grows during pregnancy is the placenta. The placenta supplies the developing foetus in the mother’s uterus with oxygen and nutrients.

Question 2: What does placental filtering mean?

Answer:

Transferring nutrients, oxygen, and other beneficial substances from the mother to the foetus is made easier by the placenta. Some bacteria and poisons can be eliminated by it, but not all of them. Pregnant women are recommended to stay away from toxins and disease-causing substances because of this.

Question 3: What purpose does the placental anatomy serve?

Answer:

The placenta divides the mother’s and foetus’ blood supplies to prevent the mother’s immune system from attacking foetal blood cells. However, it does permit the exchange of some molecules, including gases, antibodies, and nutrients.

Question 4: What is the placenta made of?

Answer:

The placenta starts to develop when a fertilised egg known as a blastocyst implants in the mother’s endometrium. The blastocyst’s outer layer is what eventually develops into the placenta. The overlaying syncytiotrophoblast and the underlying cytotrophoblast are the two layers that follow this one. In the latter, a multinucleated cell layer covers the placenta. The differentiation and fusion of cytotrophoblast cells lead to its development. The syncytiotrophoblast performs the primary function of the placenta, which is to serve as a barrier. Pregnancy causes the placenta to enlarge. By the conclusion of the first trimester, the placenta has received all the cells it needs from the mother’s blood.

Question 5: What is the structure of the placenta?

Answer:

The placenta is a bodily organ that creates a solid connection between the mother and the foetus.

1. From the surface of the chorion, many finger-like projections called chorionic villi develop into uterine tissue.
2. The placenta is formed when these villi puncture the mother’s uterine wall.
3. Materials can be transported because of the umbilical cord’s connection between the placenta and the foetus.
4. The uterus and placenta are typically connected at the top, bottom, side, front, or back.
5. The foetal membrane is joined to the inner uterine wall by a connective tissue called the placenta.
6. The placenta is therefore both maternal and embryonic.
7. The placenta assists the developing embryo in absorbing oxygen and nutrients from the mother while also removing carbon dioxide and nitrogenous waste.

Question 6: What percentage of the placenta does the embryo contribute?

Answer:

The membrane known as the chorion surrounds the developing foetus. The chorion is the placenta’s component that the embryo contributes.