Question

Which of the following is NOT contained in menstrual discharge? A. Blood B. Cells previously lining the vagina C. Stratum functionalis D. Zygote

Short answer

D. Zygote

Step-by-step solution

Understand the Composition of Menstrual Discharge

Menstrual discharge consists of blood, cervical mucus, vaginal secretions, and the shedding of the endometrial lining (stratum functionalis).

Analyze the Given Options

Consider each option to see whether it is typically a component of menstrual discharge:

Option A: Blood

Blood is a key component of menstrual discharge as it involves the shedding of the uterine lining. Thus, option A is contained in menstrual discharge.

Option B: Cells previously lining the vagina

Cells from the vagina can mix with the menstrual discharge, thus option B is also contained.

Option C: Stratum functionalis

Stratum functionalis is the top layer of the endometrium that sheds during menstruation. Therefore, option C is present in the discharge.

Option D: Zygote

A zygote is a fertilized egg and is not a component of menstrual discharge. Thus, option D is not contained in menstrual discharge.

Identify Final Answer

Based on the analysis, identify which option is not part of menstrual discharge.

Key concepts

menstrual cycle

The menstrual cycle is a natural process that happens in the female body, usually every 28 days. It prepares the uterus for pregnancy.
If no pregnancy occurs, the body sheds the uterine lining, leading to a menstrual period. The menstrual cycle has several key phases:

• Menstrual Phase: This is when bleeding happens, lasting 3-7 days. The uterine lining sheds, causing menstrual discharge.
• Follicular Phase: It starts on the first day of menstruation and lasts until ovulation. Follicles in the ovaries grow, and one egg matures.
• Ovulation: Around mid-cycle, an egg is released from the mature follicle and travels down the fallopian tube.
• Luteal Phase: It follows ovulation. The body prepares for possible pregnancy. If fertilization doesn't happen, the cycle starts over with a new period.

Understanding these phases helps to know why and how the body undergoes different changes during the cycle.

endometrial shedding

Endometrial shedding is a fundamental part of the menstrual cycle. It involves the shedding of the endometrial lining, which is the inner layer of the uterus.
This layer, called the stratum functionalis, thickens throughout the cycle to prepare for a potential pregnancy.
If the egg is not fertilized, the hormone levels drop, and the stratum functionalis is no longer supported.
Here are the steps of endometrial shedding:

• Hormone Shift: The decline in estrogen and progesterone signals the body to start shedding the lining.
• Shedding Process: The top layer of the endometrium (stratum functionalis) breaks down and exits the body through the vagina as menstrual blood.
• Healing Phase: After shedding, the endometrium begins to repair itself in preparation for the next cycle.

This process is crucial for maintaining a healthy reproductive system.

menstrual blood

Menstrual blood is a mixture of different substances that are expelled from the body during menstruation. It is more than just blood.
Here's what it consists of:

• Blood: Makes up about 36-72% of menstrual flow. It's the main component and comes from the blood vessels in the endometrium.
• Endometrial Cells: These cells are part of the stratum functionalis that shed during menstruation.
• Cervical Mucus: It helps in the flow of menstrual blood out of the body and can vary in consistency.
• Vaginal Secretions: These are fluids produced by the vaginal walls that mix with the discharge.

Menstrual blood does not contain a zygote as it happens only when an egg is fertilized, leading to pregnancy.
Menstrual discharge is entirely a sign that no fertilization happened, and the body is resetting for the next cycle.