Hormones: Maintaining Blood Homeostasis (AQA GCSE Combined Science: Trilogy: Biology): Exam Questions

Higher Tier Only

Both the liver and pancreas are involved in maintaining blood glucose concentration within a narrow range.

The blood glucose concentration of an athlete was monitored over the course of a day. One hour after the athlete has eaten a meal, their blood glucose concentration rises.

Explain why it is important that negative feedback brings a raised blood glucose concentration back down.

Figure 1 shows some of the blood vessels associated with the liver.

The two veins associated with the liver are:

• The portal vein, delivering blood from the small intestine to the liver

• The hepatic vein, which connects the liver to the vena cava.

The concentration of glucose can be measured from samples of blood taken from the hepatic vein and the portal vein.

Suggest and explain how the concentration of glucose in these two blood vessels would differ 1 hour after a meal.

Higher Tier Only

Three hours after having eaten, the athlete runs on a treadmill for one hour.

The athlete’s blood glucose concentration decreases as he runs.

Describe how the body responds when the blood concentration begins to decrease.

Individuals with diabetes cannot control their blood glucose levels. There are two types of diabetes: Type 1 and Type 2.

Compare and contrast the causes of, and treatments for, each type of diabetes.

A blood test can be used to see how the body responds to glucose. The blood glucose concentration can be measured before and after drinking a glucose drink.

It is important that patients do not eat or drink anything other than water before the blood test.

Suggest why.

Figure 1 shows the results of a blood glucose tolerance test for two people (A and B).

Figure 1

Which patient has diabetes?

Justify your answer.

Look at the data in Table 1.

Table 1

Calculate the percentage (%) of the population of the USA estimated to have diabetes.

You should include both diagnosed and undiagnosed people in your calculation.

Give your answer to 2 significant figures.

Many functions of the human body are controlled by chemicals called hormones.

What is a hormone?

The endocrine system, in combination with the nervous system, play a key role in regulation of many internal conditions in the human body.

Describe how the detection of a stimulus by a receptor of the nervous system can result in stimulation of the endocrine system. 

(i) Identify the gland referred to as the 'master gland' in the endocrine system.

[1]

(ii) Suggest why this gland is referred to as the 'master gland'.

[1]

Table 1 shows some features that can be found in the endocrine system. 

Table 1

Complete Table 1 by listing descriptions for each feature of the endocrine system.

Androgenic anabolic steroids are synthetic derivatives of the male hormone testosterone.

They have approved medical uses in male patients with disorders of the testicles or pituitary gland.

Some of the effects of these substances are shown below in Figure 1.

Figure 1

Suggest why androgenic anabolic steroids are a banned substance in sport.

Pancreatic cancer is a lethal disease characterised by progressive weight loss, fatigue and a sudden-change in previously well-controlled blood sugar levels.

Suggest what causes these symptoms.

The hypothalamus is the section of the brain that links the nervous system and the endocrine system in order to maintain homeostasis.

Suggest which gland in the endocrine system the hypothalamus targets?

Some individuals suffer from starvation even though they eat sufficient amounts of food.

Identify which condition of A - D could explain this.

Higher Tier Only

Figure 2 shows the blood glucose levels of a healthy individual.

Explain the events that most likely occur at points A to D.

Figure 2

The insulin receptor (INSR), is a transmembrane receptor that is activated when insulin binds to it. The binding of insulin triggers a signalling pathway that activates glucose transporters in the cell membrane. 

Some people suffer from a mutation in the INSR gene. 

Suggest the effect of such a mutation. 

Glucose tolerance tests can be used to assess if a patient has diabetes. During the test, a patient (who has fasted for eight hours) drinks a sugary solution and the glucose concentration of the blood is measured at regular intervals.

Figure 2 shows the results of a blood glucose tolerance test for a patient with diabetes (patient A).

Figure 2

Patient B who does not suffer from diabetes, undertook the same glucose tolerance test. The glucose concentration in their blood prior to drinking the sugary solution was 5 mmol / L .

Draw a curve on the graph in Figure 2 to show the results you would predict for patient B.

In the glucose tolerance test, diabetes is diagnosed if the concentration of glucose in the blood is higher than 7 mmol / L from at least two different tests.

Explain why the results may sometimes be inaccurate.