Question 1: Define the term 'hormone'.

Answer: A chemical messenger produced by endocrine glands that regulates activity of target organs.

Question 2: Explain how the pituitary gland controls the release of hormones from other endocrine glands.

Answer: The pituitary gland secretes hormones that stimulate other glands to produce their hormones, acting as a master gland to regulate bodily functions.

Question 3: Describe the mechanism by which the hormone insulin lowers blood glucose levels.

Answer: Insulin is secreted by the pancreas when blood glucose is high. It facilitates the uptake of glucose by cells, especially in the liver and muscles, and promotes the conversion of glucose to glycogen for storage, thereby reducing blood glucose levels.

Question 1: Calculate the amount of glucose (in grams) in 2 litres of blood if the blood glucose concentration is 5 mmol/dm³. (Molar mass of glucose = 180 g/mol)

Answer: 1.8 grams

Question 2: A person’s blood glucose level drops to 3 mmol/dm³. How many milligrams of glucose are in 1 litre of blood?

Answer: 540 mg

Question 1: Design a simple experiment to test the effect of insulin on blood glucose levels in a laboratory setting. Identify the independent and dependent variables, and outline safety precautions.

Answer: An experiment could involve injecting a sample of blood with insulin and measuring the glucose level before and after at regular intervals. The independent variable is the amount of insulin administered, and the dependent variable is the blood glucose level. Safety precautions include handling insulin carefully to avoid overdose, using sterile equipment, and disposing of biological waste properly.

Question 1: A group of patients with diabetes have their blood glucose levels monitored over a week. Patient A’s levels fluctuate between 4 mmol/dm³ and 8 mmol/dm³, while Patient B’s levels remain stable at around 6 mmol/dm³. Explain the possible reasons for these differences based on endocrine function.

Answer: Patient A’s fluctuations may indicate poor insulin regulation or insulin resistance, while Patient B’s stable levels suggest effective insulin production and regulation, possibly due to proper functioning of their endocrine system.

Question 1: Describe the role of the adrenal glands in the endocrine system and name one hormone they produce.

Answer: The adrenal glands produce hormones such as adrenaline, which helps the body respond to stress by increasing heart rate and energy availability.

Question 2: Explain how hormonal imbalance can affect homeostasis, giving an example related to blood sugar regulation.

Answer: Hormonal imbalance can disrupt homeostasis by either overproducing or underproducing hormones. For example, insufficient insulin production leads to high blood sugar levels, resulting in diabetes, which impairs the body’s ability to maintain stable glucose levels.

Question 1: Describe how hormone replacement therapy can be used to treat endocrine disorders, and mention one potential risk involved.

Answer: Hormone replacement therapy involves administering synthetic hormones to compensate for deficient endocrine function, such as insulin for diabetes. A potential risk is the development of side effects like hormonal imbalance or increased risk of certain cancers.