Question

Which of the following statements about progesterone is fulse? a. Progesterone is secreted by the corpus luteum b. Progesterone is secreted by the placenta. c. Progesterone decreases the basal body temperature. d. Progesterone secretion drops towards the end of the nonfertile luteal phase.

Short answer

The false statement is "c. Progesterone decreases the basal body temperature". Progesterone actually increases the basal body temperature.

Step-by-step solution

Statement a

Progesterone is secreted by the corpus luteum. This statement is true. The corpus luteum is formed in the ovaries after the release of an egg, and it produces progesterone to prepare the uterus for a possible pregnancy.

Statement b

Progesterone is secreted by the placenta. This statement is also true. During pregnancy, the placenta takes over the production of progesterone to support the developing fetus and prevent the uterine muscles from contracting.

Statement c

Progesterone decreases the basal body temperature. This statement is false. Progesterone actually increases the basal body temperature. After ovulation, the release of progesterone causes the body temperature to rise, which can be measured to help track fertility.

Statement d

Progesterone secretion drops towards the end of the nonfertile luteal phase. This statement is true. Progesterone levels decrease during the nonfertile luteal phase, and if no pregnancy occurs, the corpus luteum degenerates, causing a drop in progesterone levels, which in turn triggers menstruation. In conclusion, the false statement is "c. Progesterone decreases the basal body temperature".

Key concepts

Corpus Luteum

The corpus luteum plays a critical role in human physiology, especially concerning female reproductive health. After an egg is released from an ovary during ovulation, the follicle from which it originated transforms into the corpus luteum. This temporary gland is responsible for secreting progesterone, a hormone crucial for maintaining the lining of the uterus and creating a supportive environment for a potential pregnancy.

The lifespan of the corpus luteum depends on whether or not fertilization occurs. If the egg is not fertilized, the corpus luteum degenerates within about two weeks, leading to a decrease in progesterone levels. This decrease signals the body to begin menstruation, marking the start of a new menstrual cycle. However, if fertilization takes place, the corpus luteum continues to secrete progesterone until the placenta can take over, ensuring the maintenance of the uterine lining for the growing embryo.

Basal Body Temperature

Basal body temperature (BBT) refers to the lowest body temperature attained during rest, usually measured immediately after waking up and before any physical activity has been undertaken. This temperature can be an indicator of ovulation and the menstrual cycle phase a person is in. After ovulation, due to the increased production of progesterone by the corpus luteum, there is a slight but noticeable rise in BBT. This thermal shift may continue until the end of the menstrual cycle.

Charting BBT can be a valuable tool for individuals trying to conceive or those wishing to avoid pregnancy, as it can help them understand their cycle patterns. Elevated BBT typically indicates the luteal phase, during which the uterus is primed for a potential pregnancy. If conception does not occur, the corpus luteum will fail, resulting in a drop in progesterone levels and a subsequent decrease in BBT right before menstruation begins.

Luteal Phase

The luteal phase is one segment of the menstrual cycle that starts after ovulation and ends when menstruation begins. It typically lasts around 14 days but can range from 11 to 17 days in a normal menstrual cycle. This phase is characterized by the dominance of progesterone, produced by the corpus luteum.

During this phase, the uterine lining is further thickened and enriched with nutrients in preparation for a potential embryo to implant. If implantation does not occur, the corpus luteum will eventually degenerate, leading to a sharp decline in progesterone levels. This decline is one of the physiological triggers that precipitate the shedding of the uterine lining, manifesting as the menstrual period. Understanding the luteal phase is essential for addressing issues related to fertility and menstrual health.