Hormones, Homeostasis & Reproduction (DP IB Biology: HL)

The following graph shows the hormones involved in the menstrual cycle.

Which line represents the hormone responsible for ovulation?

Polycystic ovary syndrome (PCOS) is a condition which may affect certain women during their childbearing years. Some of the most common symptoms of this condition is a failure to ovulate and irregular menstrual cycles. Women with PCOS have an increased risk of developing endometrial cancer.

What would be the most appropriate explanation for this?

The endometrium will:

A person is admitted to hospital after suffering a stroke. It was found that the suprachiasmatic nucleus in the hypothalamus of the brain was damaged by the event. This resulted in the pineal gland secreting less melatonin into the bloodstream.

Which of the following changes would be observed in the patient?

A condition known as congenital adrenal hyperplasia (CAH) may affect the development of the genitals in female fetuses. These children lack an enzyme necessary to produce the hormones cortisol and aldosterone. Without these hormones the fetus will produce more male sex hormones, such as testosterone, during their development.

What effect would this have on the development of a female fetus?

The diagram shows the female reproductive system.

Which row correctly identifies the structures?

The following diagram shows the steps followed during in vitro fertilization.

Which row correctly identifies the steps?

Which of the following are roles of thyroxin?

1. Targets metabolically active regions, such as adipose tissue.
2. Increase the rate of protein synthesis.
3. Inhibits the appetite and reduces food intake.
4. Increase the generation of body heat.

An obese patient participated in a drug trial to test the effectiveness of leptin injections to promote weight loss. After 12 weeks of receiving weekly leptin injections, the patient failed to lose any weight.

What could be the most plausible explanation for this outcome?

A one year old child displays fatigue and excessive thirst over a period of time. A urine test reveals the presence of glucose.

Which of the following would be the most likely diagnosis?

In which of the following scenarios would there be an increase in the breakdown of glycogen in the liver?

Which of the following statements about melatonin are correct?

I. Melatonin secretion increases in the evening in response to darkness and decreases at dawn in response to light.

II. Increasing melatonin levels stimulate the body, preparing it for waking up and staying awake during the day.

III. Melatonin is secreted by the hypothalamus.

IV. The night-time drop in core body temperature triggers an increase in melatonin secretion.

V. Melatonin levels vary during a 12-hour cycle known as a circadian rhythm.

Which of the statements below describe the hormone leptin?

I. This hormone is secreted by fat storage cells known as adipose cells.

II. This hormone's main role is to regulate the basal metabolic rate.

III. This hormone circulates in the blood and targets groups of cells in the hypothalamus.

IV. This hormone targets almost all cells in the body.

V. A deficiency in this hormone can lead to weight gain despite the loss of appetite.

Four hormones all interact to control the menstrual cycle via both negative and positive feedback.

Which of the below is an example of a negative feedback mechanism that occurs during the menstrual cycle?

Identify the set of images that correctly shows follicle development during the course of the menstrual cycle.

Which of the following statements is the most biologically correct?