Hormonal Regulation in the Menstrual Cycle

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Questions and Answers

What is an example of negative feedback in the body?

Ripening of fruit

Regulation of blood glucose levels (correct)

Contractions during childbirth

Amplification of hormone secretion

Which layer of the endometrium is responsible for building up new endometrial tissue?

Cuboidal ciliated epithelium layer

Myometrium

Basal layer

Functional layer (correct)

During which phase does the vaginal bleeding occur as the uterine endometrium is shed?

Proliferative phase

Menstrual phase (correct)

Luteal phase

Ovulation

What triggers positive feedback during childbirth?

The head of the fetus pushing against the cervix Signup and view all the answers

What is the average duration for the ovulation phase in a regular menstrual cycle?

13-15 days Signup and view all the answers

Which layer of the endometrium is the uppermost layer that covers the functional layer?

Ciliated epithelium layer Signup and view all the answers

What characterizes the proliferative phase of the menstrual cycle?

Thickening of the endometrium Signup and view all the answers

What is the primary function of positive feedback in the context of childbirth?

Amplification of body responses Signup and view all the answers

What happens to the functional layer of the endometrium if fertilization does not occur?

It is shed during menstruation Signup and view all the answers

What is the primary site of fertilization in the female reproductive system?

Ampulla of the fallopian tube Signup and view all the answers

What is the process that occurs after fertilization that involves cell division?

Cleavage Signup and view all the answers

How many sperm typically penetrate the zona pellucida to achieve fertilization?

Only one sperm Signup and view all the answers

What happens to the membrane of the ovum after one sperm successfully fertilizes it?

It is sealed to prevent further entry Signup and view all the answers

What is the name given to the 2nd cell stage reached after 30 hours of fertilization?

Blastomere Signup and view all the answers

What is the role of the decidua basalis in early pregnancy?

Supports the formation of the placenta Signup and view all the answers

Which layer of the decidua encapsulates the surface of the trophoblast?

Decidua capsularis Signup and view all the answers

What is the primary function of hyaluronidase enzymes released by sperm?

Dissolve the layer of acromal radiata Signup and view all the answers

What term describes the subjective signs that may indicate pregnancy?

Presumptive signs Signup and view all the answers

What refers to the portion of the decidua lining the uterine cavity outside the site of implantation?

Decidua vera Signup and view all the answers

What is the length of a fetus at the end of six lunar months?

28 to 36 cm Signup and view all the answers

Which of the following indicates the start of fetal viability?

End of the 24th week Signup and view all the answers

What major development occurs in the fetus at seven lunar months?

Conversion of fetal hemoglobin to adult hemoglobin Signup and view all the answers

What is the weight of a fetus at the end of seven lunar months?

1,200 gms Signup and view all the answers

Which characteristic is associated with a full-term baby?

Strong suck reflex Signup and view all the answers

At which week does the passive transfer of antibodies from the mother to the fetus begin?

20th week Signup and view all the answers

What is the period known as absolute fertility?

Ovulation time Signup and view all the answers

What triggers the luteal phase of the menstrual cycle?

Surge in LH Signup and view all the answers

What is the primary hormone secreted by the corpus luteum?

Progesterone Signup and view all the answers

During which phase does the endometrium mature in preparation for implantation?

Luteal phase Signup and view all the answers

What process refers to the embedding of a fertilized ovum in the uterus?

Implantation Signup and view all the answers

What is the average time after fertilization that implantation occurs?

6 to 9 days Signup and view all the answers

What is gametosis in the context of conception?

Formation of gametes Signup and view all the answers

What is the process of sperm formation called?

Spermatogenesis Signup and view all the answers

What is the term for the expulsion of an egg from the ovary?

Ovulation Signup and view all the answers

What occurs during the premenstrual phase of the menstrual cycle?

Endometrium matures until hormone levels drop Signup and view all the answers

What is the recommended drug of choice (DOC) for treating syphilis during pregnancy?

Benzathine penicillin Signup and view all the answers

At what point does the heart begin to beat during embryonic development?

14th day Signup and view all the answers

Which of the following anomalies is characterized by the absence of the head or brain?

Anencephaly Signup and view all the answers

What screening test should be conducted during the first prenatal visit to check for syphilis?

VDRL test Signup and view all the answers

What is a possible consequence of untreated syphilis in the fetus beyond the 18th week of pregnancy?

Deafness Signup and view all the answers

What major development occurs by the end of the first lunar month (4th week)?

Heart chambers are formed Signup and view all the answers

At what age of gestation are the external genitalia distinct but not yet distinguishable by simple observation?

8 weeks Signup and view all the answers

What is one of the first significant physical developments observed in the fetus during the second month?

Gestational sac visibility on ultrasound Signup and view all the answers

Which treatment is recommended for women with genital lesions during pregnancy?

CS (Cesarean section) Signup and view all the answers

At what week does the nervous system begin to appear during embryonic development?

3rd week Signup and view all the answers

Study Notes

Hormonal Feedback Mechanisms

Negative feedback regulates blood glucose levels and osmoregulation.
Positive feedback amplifies the body's response to stimuli, such as the stretching of the cervix during childbirth, leading to increased hormone secretion.
Examples of positive feedback: uterine contractions during labor and the ripening of fruit.

Endometrium Structure

Composed of three layers:
- Basal layer: 1 mm thick, lowermost, above the myometrium, includes rudimentary structures for new endometrium development.
- Functional layer: 2-5 mm thick, middle layer containing tubular glands, varies under hormonal influence.
- Cuboidal ciliated epithelium: uppermost layer, covers the functional layer and lines the tubal glands.

Menstrual Cycle Phases

Menstrual phase: lasts 3-5 days with vaginal bleeding as the endometrium sheds.
Ovulation: release of a mature ovum from a Graafian follicle, usually occurs 13 to 15 days prior to menstruation.
Luteal phase: 15 to 28 days, prompted by LH surge, leading to corpus luteum formation and secretion of progesterone and estrogen.
If fertilization occurs, endometrium becomes thicker and more vascular to support implantation.

Conception Process

Conception occurs when the fertilized ovum embeds in the uterus.
Sequence includes: gametosis, ovulation, copulation, fertilization, development of fertilized ovum, and implantation.
Egg expulsion from ovary signifies ovulation, followed by sperm transportation to the fallopian tube.
Sperm encounter challenges in the vaginal acidic environment; only a few survive to fertilize the ovum.

Sperm Penetration and Fertilization

Capacitance allows sperm to penetrate the outer barriers of the egg, with only one sperm fertilizing the ovum.
After fertilization, the zygote undergoes cleavage, dividing into blastomeres.
Early development includes stages of division leading to a multi-celled structure (16 to 32 cells).

Signs and Symptoms of Pregnancy

Presumptive signs include subjective experiences, such as missed periods or nausea.
First lunar month: heart forms and beats by the 14th day; limb buds and primary lung buds appear.
Two lunar months: embryo begins to take human form; sex organs distinct but not identifiable.
Six lunar months: surfactant production begins, and passive antibody transfer from mother starts.
Ten lunar months (full-term): all newborn characteristics develop; average weight about 3200g, and length between 48-52 cm.

Key Pregnancy Milestones

Fetal viability begins around the 24th week.
Infants born around 28 weeks can survive with expert care, measuring 35-38 cm and weighing approximately 1,200 g.
Meconium can be present in the rectum as early as 20 weeks.

Maternal Infections and Complications

Syphilis, caused by Treponema pallidum, can lead to severe fetal outcomes if untreated.
Infections may prompt recommendations for cesarean sections; acyclovir (Zovirax) is the drug of choice for genital lesions.
Evidence suggests that timely treatment during the first trimester can prevent complications.

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Description

This quiz focuses on the hormonal changes and feedback mechanisms involved in the menstrual cycle, particularly during the proliferative phase. It covers the structure of the endometrium and examples of both negative and positive feedback related to hormone production. Test your understanding of these vital biological processes!