HIS - Fisiologi Kehamilan, Persalinan dan Laktasi

Summary

This educational video covers the physiology of pregnancy, labor, and lactation, focusing on fertilization, implantation, and placentation. The lecturer explains the process of fertilization in the fallopian tube, the formation of the zygote, and the early stages of embryo development. It also explores hormonal changes during pregnancy, the impact of these hormones on the body, and physiological changes such as increased blood volume and the growth of the uterus. The video delves into the mechanisms behind childbirth and lactation, emphasizing the roles of hormones like prolactin and oxytocin in milk production and the importance of early breastfeeding.

Takeaways

• 😀 Fertilization occurs in the fallopian tube, where sperm must enter the reproductive tract 5 days before ovulation and can survive for up to 5 days, while the ovum only survives for 12-24 hours.
• 😀 Sperm must undergo capacitation, where the tail moves like a whip, and enzymes are released from the acrosome to break through the zona pellucida of the egg.
• 😀 After fertilization, the zygote undergoes mitosis to form a morula, which then becomes a blastocyst that begins to differentiate into embryonic cells and eventually implants into the uterine wall.
• 😀 Twins can be either monozygotic (identical) or dizygotic (non-identical), with monozygotic twins forming from a single fertilized egg that splits, while dizygotic twins form from two separate eggs fertilized by different sperm.
• 😀 The trophoblast layer of the blastocyst plays a crucial role in implanting the embryo into the uterine wall and later developing into the placenta.
• 😀 The placenta develops fully by around 20 weeks of pregnancy and serves as the interface between maternal and fetal circulation, facilitating nutrient and oxygen exchange.
• 😀 Human Chorionic Gonadotropin (HCG) increases in the first trimester, maintaining the corpus luteum to produce estrogen and progesterone until the placenta can take over hormone production.
• 😀 Estrogen and progesterone levels rise throughout pregnancy, with estrogen playing a role in the prevention of ovulation and the development of uterine tissues.
• 😀 Physiological changes during pregnancy include increased blood volume, heart rate, and respiratory rate, as well as changes in the gastrointestinal system like constipation and morning sickness.
• 😀 Labor (partus) begins when the cervix softens (ripens) and the baby's head moves downward, initiating contractions which are fueled by hormonal signals, including oxytocin and prostaglandins.
• 😀 Lactation begins with prolactin stimulating milk production in the mammary glands, while oxytocin causes milk ejection through the contraction of myoepithelial cells in the breast.

Q & A

What is fertilization and where does it occur?

Fertilization is the process where sperm and egg combine to form a zygote. It usually occurs in the fallopian tube (tuba uterina), where sperm must be introduced into the reproductive tract within 5 days before ovulation to fertilize the secondary oocyte, which can survive for 12 to 24 hours.

What is capacitation in sperm, and why is it necessary for fertilization?

Capacitation is a process that enables sperm to fertilize the egg. During capacitation, the sperm undergo changes in the tail's movement and changes in the plasma membrane's structure, allowing the sperm to release enzymes from its acrosome to penetrate the zona pellucida of the oocyte.

What is the role of the zona pellucida in preventing polyspermy?

The zona pellucida is a protective layer around the oocyte. After one sperm successfully penetrates it, a calcium influx triggers the exocytosis of vesicles that harden the zona pellucida, preventing additional sperm from entering, thus avoiding polyspermy.

What happens after fertilization at the cellular level?

After fertilization, the secondary oocyte completes meiosis and becomes an ovum. This ovum then combines its chromosomes with the sperm’s, forming a zygote. The zygote undergoes mitosis to form a morula, which later becomes a blastocyst that implants in the endometrium.

How do identical and fraternal twins differ in terms of fertilization?

Identical twins, or monozygotic twins, come from a single fertilized egg (zygote) that splits into two embryos, resulting in genetically identical individuals. Fraternal twins, or dizygotic twins, result from two separate eggs being fertilized by two different sperm, producing two genetically distinct embryos.

What is implantation and how does it occur?

Implantation is the process where the blastocyst attaches to the uterine wall, specifically the endometrium, around the sixth day after fertilization. The trophoblast cells invade the endometrial lining, forming the placenta, which ensures nutrient and oxygen supply to the developing embryo.

What hormones play a crucial role in maintaining pregnancy?

During early pregnancy, human chorionic gonadotropin (HCG) maintains the corpus luteum, which secretes estrogen and progesterone. As the placenta develops, it takes over hormone production, ensuring the continuation of pregnancy and preventing ovulation.

How does the body respond hormonally to pregnancy?

Hormonal changes during pregnancy include increased levels of HCG, estrogen, and progesterone. These hormones affect various bodily systems, such as causing morning sickness, enlarging the uterus, increasing blood volume, and influencing the cardiovascular and respiratory systems.

What is the role of estrogen and progesterone during pregnancy?

Estrogen and progesterone are critical for pregnancy maintenance. Estrogen helps stimulate uterine growth and prepares the body for labor, while progesterone maintains the uterine lining and prevents ovulation during pregnancy.

How does lactation occur and what is the role of prolactin and oxytocin?

Lactation begins with prolactin, which stimulates the development of mammary gland cells to produce milk. Oxytocin is responsible for milk ejection by stimulating the contraction of myoepithelial cells around the alveoli in the mammary glands, pushing milk into the ducts for breastfeeding.