Understanding the Menstrual Cycle

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Questions and Answers

What primarily characterizes the follicular phase of the menstrual cycle?

Dominance of progesterone

Luteinizing hormone predominance

Reduction in uterine gland size

Effect of oestrogens (correct)

What happens to the superficial parts of the endometrium just before menstruation?

It thickens due to increased blood supply

It experiences increased fluid content

It becomes more vascularized for implantation

It undergoes shedding due to cut-off blood supply (correct)

At what age does menstruation typically begin, a phenomenon known as menarche?

10 years

16 years

14 years

12 years (correct)

Which hormone primarily influences the changes during the luteal phase?

Progesterone Signup and view all the answers

What is the primary external manifestation of the cyclic changes occurring in the uterus during the menstrual cycle?

Menstruation Signup and view all the answers

What is the outermost layer of the uterine wall called?

Perimetrium Signup and view all the answers

Which part of the uterus undergoes changes during the menstrual cycle?

Endometrium Signup and view all the answers

What type of glands are found within the stroma of the endometrium?

Simple tubular glands Signup and view all the answers

During the menstrual cycle, which arteries supply the entire thickness of the endometrium?

Spiral arteries Signup and view all the answers

What is the primary function of the myometrium layer?

Assist in childbirth Signup and view all the answers

What phase of the menstrual cycle is primarily indicated by ovulation?

Ovulation phase Signup and view all the answers

Which layer of the uterus is composed mainly of smooth muscle?

Myometrium Signup and view all the answers

What type of epithelial cell is present during the postmenstrual phase?

Cuboidal Signup and view all the answers

Which of the following statements about the arteries during the menstrual cycle is true?

The arteries grow longer during the secretory phase. Signup and view all the answers

What change occurs to the epithelial cells at the end of the secretory phase?

Cells become more cuboidal. Signup and view all the answers

During which phase does glycogen accumulate in the basal portion of the epithelial cell?

Proliferative phase Signup and view all the answers

What happens to the lumen of the endometrium during the secretory phase?

It becomes highly irregular. Signup and view all the answers

Which part of the endometrium does not participate in the changes associated with the menstrual cycle?

Basal third Signup and view all the answers

What is the primary function of the secretory activity of the uterine glands?

To provide nutrition to the embryo Signup and view all the answers

How does the arrangement of stromal cells change during the postmenstrual phase?

They are uniformly distributed and compactly arranged. Signup and view all the answers

What is the characteristic of the endometrium at the end of the secretory phase?

It is thick and soft. Signup and view all the answers

What primarily triggers the onset of menstrual bleeding?

Constricted spiral arteries reducing blood flow Signup and view all the answers

What happens to the thickened endometrium in the absence of pregnancy?

The superficial layers are shed off Signup and view all the answers

At the end of menstruation, what is the approximate thickness of the remaining endometrium?

0.5 mm Signup and view all the answers

During the menstrual cycle, which phase involves the proliferation of cells in the basal parts of the uterine glands?

Secretory phase Signup and view all the answers

What occurs when the spiral arteries relax after becoming constricted?

Leaking blood comes from damaged blood vessels Signup and view all the answers

What does ischaemia of the endometrium specifically lead to?

Degeneration of the endometrium Signup and view all the answers

Which layers of the endometrium are primarily shed during menstrual bleeding?

Stratum compactum and stratum spongiosum Signup and view all the answers

What component of the endometrium is responsible for rapid reforming of the epithelial lining after menstruation?

Stratum basale Signup and view all the answers

What is the overall function of the thickened endometrium during the menstrual cycle?

To provide a suitable environment for a fertilized ovum Signup and view all the answers

Study Notes

The Menstrual Cycle

The menstrual cycle refers to cyclical changes in the endometrium (lining of the uterus) occurring monthly.
A key feature is menstruation, the monthly flow of blood.
The cycle is divided into postmenstrual, proliferative, secretory, and menstrual phases.
Another division is the follicular phase (estrogen-driven) and the luteal phase (progesterone-driven).
Endometrial changes include increased thickness, uterine gland growth, changes in epithelial cells, and thickened stroma.
Blood supply to superficial endometrial parts is cut off before menstruation, causing shedding and bleeding.
The cycle is influenced by hormones like estrogen, progesterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH).
The reproductive period is when a woman can bear children, marked by monthly menstruation (menses).
Menarche is the onset of menstruation at around 12 years of age.
Menopause is the cessation of menstruation around 45 years of age.

Phases of the Menstrual Cycle

The cycle is typically divided into postmenstrual, proliferative, secretory (or premenstrual), and menstrual phases, based on endometrial changes.
The follicular phase (first half) is characterized by actions of oestrogen from growing follicles, leading to endometrial changes.
The luteal phase (second half) is controlled by progesterone from the corpus luteum, with significant endometrial changes.

Uterine Structure and Changes

The uterus has three layers: perimetrium (outermost), myometrium (muscle), and endometrium (innermost).
The endometrium is the layer undergoing cyclical changes during the menstrual cycle.
The stroma (connective tissue) is found in the endometrium, and its structure varies in the different phases.

Hormonal Control of the Menstrual Cycle

Gonadotropin-releasing hormone (GnRH) from the hypothalamus stimulates the anterior pituitary gland.
The anterior pituitary releases follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which affect the ovaries.
FSH stimulates follicle growth and oestrogen production in the ovaries.
LH triggers ovulation and corpus luteum formation, leading to progesterone production.
Oestrogen and progesterone have significant effects on endometrial changes.
The cycles are closely interconnected. LH surge leads to ovulation, and in response, the corpus luteum forms and secretes progesterone.

Clinical Correlation

Understanding ovulation timing (e.g., using temperature charts) is pertinent for family planning.
Contraceptive pills often contain synthetic hormones mimicking oestrogen and/or progesterone, preventing ovulation.

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Description

This quiz explores the various phases of the menstrual cycle, including postmenstrual, proliferative, secretory, and menstrual phases. It highlights the hormonal influences, physiological changes, and significant events such as menarche and menopause. Test your knowledge of this essential aspect of female reproductive health.