Chapter 2 — Hormonal Co-ordination in Living Organisms · Biology. These are 10 questions from the Magmo3 bank on this lesson, from easy to hard. Solve each one, then open "Show answer and explanation". Magmo3 has 39 questions on this lesson, each with an explanation.
The hormone that raises the level of sugar in the blood by converting glycogen into glucose is...
Correct answer: (B) Glucagon
Explanation: Glucagon (from the alpha cells) raises blood sugar and works in the opposite way to insulin.
Parathormone, secreted by the parathyroid glands, regulates the level of which element in the blood?
Correct answer: (D) Calcium
Explanation: Parathormone regulates the level of calcium (and phosphorus) in the blood; it raises calcium when it falls.
The hormone known as the emergency hormone (fight or flight), which is secreted during fear and danger, is...
Correct answer: (D) Adrenaline
Explanation: Adrenaline (from the medulla of the adrenal gland) is secreted during danger and increases the heart rate and blood sugar to prepare the body.
An excess in the secretion of growth hormone during childhood causes...
Correct answer: (C) Gigantism
Explanation: An excess of growth hormone during childhood causes an exaggerated increase in height (gigantism).
A deficiency of thyroxine in children causes cretinism, whose symptoms include...
Correct answer: (C) Retarded physical and mental growth
Explanation: Cretinism results from a deficiency of thyroxine during childhood and causes short stature and retarded mental development.
An excess in the secretion of thyroxine causes Graves' disease, whose characteristic symptoms include...
Correct answer: (C) Bulging eyes, a rapid heartbeat, and thinness
Explanation: An excess of thyroxine raises the metabolic rate, causing thinness, a rapid heartbeat, and bulging eyes (exophthalmic goiter / Graves' disease).
The beta cells in the islets of Langerhans in the pancreas secrete...
Correct answer: (A) Insulin
Explanation: The beta cells secrete insulin (which lowers sugar), and the alpha cells secrete glucagon (which raises sugar).
After a meal very rich in calcium, the calcium level in a person's blood rises above normal. Which hormonal response returns it to normal?
Correct answer: (D) More calcitonin from the thyroid, which helps deposit calcium in the bones
Explanation: Calcitonin, secreted by the thyroid gland, lowers blood calcium by promoting its deposition in bone. Parathormone has the opposite effect, raising blood calcium by drawing it from the bones, so it would be reduced in this situation.
A patient's tests show low sodium and high potassium in the blood, with low blood pressure. A deficiency of which hormone, from which part of the body, best explains these results?
Correct answer: (A) Aldosterone from the adrenal cortex
Explanation: Aldosterone, secreted by the adrenal cortex, makes the kidney keep sodium and excrete potassium. Its deficiency leads to sodium loss, potassium retention and lower blood volume and pressure. Cortisone is from the same region but mainly affects blood sugar, while ADH affects water, not the sodium–potassium balance.
A few days after an operation to remove part of her thyroid gland, a patient develops painful muscle spasms and becomes irritable for the slightest reason. Which explanation fits these symptoms best?
Correct answer: (D) Parathyroid lobes on the sides of the thyroid were damaged, so her blood calcium has fallen
Explanation: The four lobes of the parathyroid glands lie two on each side of the thyroid, so they can be damaged in thyroid surgery; less parathormone lowers blood calcium, causing painful convulsions, muscle spasms and increased nervous excitability. Calcitonin lowers blood calcium, so losing some of it could not make calcium fall.
The first 10 questions in every subject are free, each with an explanation.