pregnancy Flashcards
Relate what you have learned about the ovarian cycle with the menstrual cycle.
The ovarian cycle and menstrual cycle are interconnected processes. The ovarian cycle involves the development and release of an egg from the ovary, while the menstrual cycle involves changes in the uterus to prepare for potential pregnancy. The ovarian cycle has two phases: follicular phase and luteal phase. The follicular phase begins with the development of a follicle in the ovary, leading to ovulation. The luteal phase follows ovulation, during which the ruptured follicle transforms into the corpus luteum. The menstrual cycle consists of the menstrual phase (shedding of the uterine lining), proliferative phase (rebuilding of the uterine lining), and secretory phase (preparation for implantation). Hormonal changes during the ovarian cycle, primarily estrogen and progesterone, regulate the changes in the menstrual cycle.
Understand the hormonal mediated changes in reproductive tissues that prepare the body for pregnancy.
Hormones, particularly estrogen and progesterone, play crucial roles in preparing the reproductive tissues for pregnancy. Estrogen promotes the growth and thickening of the uterine lining (endometrium) to provide a suitable environment for implantation. Progesterone helps maintain the endometrium and prepare it for potential embryo implantation. It also promotes the development of glands and blood vessels in the endometrium to support the early stages of pregnancy. These hormonal changes create a receptive environment for the fertilized egg and facilitate the establishment of pregnancy.
Discuss the mechanisms for the maintenance of progesterone production.
The maintenance of progesterone production is primarily regulated by the corpus luteum, a temporary structure formed from the collapsed follicle after ovulation. The corpus luteum secretes progesterone under the influence of luteinizing hormone (LH) from the pituitary gland. LH stimulates the corpus luteum to produce progesterone, which helps prepare the uterine lining for implantation. If pregnancy occurs, the developing embryo releases human chorionic gonadotropin (hCG), which supports the maintenance of the corpus luteum and progesterone production during the early stages of pregnancy.
Learn about the broad range of actions related to hCG.
Human chorionic gonadotropin (hCG) is a hormone produced by the developing embryo after implantation. It has several important actions, including:
Maintenance of the corpus luteum and progesterone production in early pregnancy.
Stimulation of the testes in males to produce testosterone.
Detection of hCG in urine or blood is used in pregnancy tests.
Potential immunomodulatory effects that protect the fetus from rejection by the maternal immune system.
Some studies suggest hCG may play a role in fetal development and maternal adaptations during pregnancy.
What is the window of receptivity, and what happens during implantation of the embryo?
The window of receptivity refers to a specific timeframe when the endometrium is receptive to implantation. During implantation, the blastocyst (developing embryo) attaches to the uterine wall and begins to burrow into the endometrium. This process allows the embryo to establish a connection with the maternal blood supply for nourishment and support.
How does the placenta develop from the trophectoderm to late pregnancy?
The placenta develops from the outer layer of the blastocyst called the trophectoderm. As the blastocyst implants, the trophectoderm differentiates into two layers: the syncytiotrophoblast and the cytotrophoblast. These layers undergo further development and vascularization to form the placenta. During late pregnancy, the placenta functions as a vital organ for nutrient and gas exchange between the mother and the developing fetus.
How can inappropriate placental implantation/invasion lead to complications like preeclampsia?
Inappropriate placental implantation, such as shallow invasion of the placenta into the uterine wall, can disrupt normal blood flow and nutrient exchange. This condition is associated with complications like preeclampsia, characterized by high blood pressure and organ damage in the mother. Inadequate placental invasion may result in reduced blood supply to the placenta, leading to insufficient nutrient and oxygen delivery to the fetus, potentially causing growth restriction and other complications
Name two major placental hormones that mediate insulin production and secretion in pregnancy.
The two major placental hormones that mediate insulin production and secretion in pregnancy are human placental lactogen (hPL) and progesterone. These hormones increase insulin resistance in the mother, ensuring a steady supply of glucose to the growing fetus.
Describe the metabolic changes in pregnancy and how they support a healthy baby.
During pregnancy, there are metabolic adaptations to support the growing baby. These changes include increased insulin resistance, enhanced glucose uptake by maternal tissues, increased fat storage for energy reserves, and altered lipid metabolism. These adaptations ensure a continuous supply of nutrients, especially glucose, to meet the nutritional needs of the developing fetus
Provide an example of a disrupted endocrine system that may contribute to diabetes in pregnancy.
Gestational diabetes mellitus (GDM) is an example of a disrupted endocrine system in pregnancy. It is characterized by high blood sugar levels during pregnancy due to impaired insulin function. GDM typically resolves after childbirth but may increase the risk of type 2 diabetes in both the mother and child.
What are the two most abundant placental steroid hormones, and what roles do they play in pregnancy?
The two most abundant placental steroid hormones are progesterone and estrogen. Progesterone helps maintain the pregnancy by supporting the growth and development of the uterus and preventing contractions. Estrogen, particularly estriol, stimulates uterine growth, breast development, and the maturation of fetal organs.
How is steroid production coordinated between the fetal adrenal gland and the placenta?
The fetal adrenal gland produces a precursor hormone called dehydroepiandrosterone (DHEA), which is then converted by the placenta into estriol, a type of estrogen. This coordination allows for the production of estriol and other steroid hormones necessary for pregnancy.
How does CRH mediate the production of other hormones and the timing of labor?
Corticotropin-releasing hormone (CRH), produced by the placenta, stimulates the production of adrenocorticotropic hormone (ACTH) from the fetal pituitary gland. ACTH, in turn, triggers the production of cortisol from the fetal adrenal gland. Cortisol stimulates the production of estrogen by the placenta and plays a role in the maturation of fetal organs. Towards the end of pregnancy, elevated levels of CRH and cortisol contribute to the timing of labor by influencing the maturation of fetal organs and initiating uterine contractions.
How do prostaglandin and oxytocin contribute to labor, and what factors regulate the production of these hormones?
Prostaglandins are involved in the softening and thinning of the cervix and promoting uterine contractions during labor. Oxytocin, often called the “love hormone,” stimulates powerful contractions of the uterine muscles. The production of prostaglandins and oxytocin is regulated by various factors, including hormonal changes, mechanical stretching of the uterus, and positive feedback mechanisms during labor.
How does the endocrine system regulate parturition (the process of giving birth)?
The endocrine regulation of parturition involves the coordination of multiple hormones. Corticotropin-releasing hormone (CRH) from the placenta stimulates the production of cortisol, which triggers the production of estrogen by the placenta. Estrogen promotes the maturation of fetal organs and initiates the production of prostaglandins. Prostaglandins, in combination with oxytocin, stimulate uterine contractions and cervical changes, leading to the onset and progression of labor.
