Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Endocrine glands are ductless glands that secrete chemical messengers called hormones directly into the blood stream to reach a target organ.
The Pituitary Gland is the 'Master Gland' located at the base of the midbrain. It secretes hormones like Growth Hormone (), Thyroid Stimulating Hormone (), and Antidiuretic Hormone ().
The Thyroid Gland requires Iodine to produce Thyroxine. Hyposecretion in adults leads to Myxoedema, while in children it causes Cretinism. Hypersecretion leads to Exophthalmic Goitre.
The Pancreas contains the Islets of Langerhans. -cells secrete Insulin (lowers blood glucose), -cells secrete Glucagon (raises blood glucose), and -cells secrete Somatostatin.
The Adrenal Glands consist of the Cortex (secretes Cortisone/Aldosterone) and Medulla (secretes Adrenaline). Adrenaline is the 'Fight or Flight' hormone that prepares the body for emergencies.
The Feedback Mechanism regulates hormone levels. For example, a rise in blood glucose levels triggers the secretion of insulin, which then lowers the glucose level, subsequently reducing insulin production.
Diabetes Mellitus is caused by deficiency, leading to high blood sugar (). Diabetes Insipidus is caused by deficiency, leading to frequent urination.
📐Formulae
💡Examples
Problem 1:
A patient presents with a swollen neck, increased heart rate, and protruding eyeballs. Identify the condition and the hormone responsible.
Solution:
The condition is Exophthalmic Goitre (a form of Hyperthyroidism), caused by the over-secretion of Thyroxine.
Explanation:
Hyperthyroidism increases the (Basal Metabolic Rate), causing the heart to beat faster and leading to the deposition of fat behind the eyes, which results in protruding eyeballs.
Problem 2:
Explain the biological response when a person is suddenly frightened by a wild animal.
Solution:
The Adrenal Medulla secretes Adrenaline () into the blood.
Explanation:
Adrenaline increases the heart rate, diverts blood flow from the digestive system to the muscles, and increases the conversion of to provide immediate energy for 'fight or flight'.
Problem 3:
Why is the Pituitary gland often called the 'Master Gland'?
Solution:
Because it produces 'Tropic Hormones' that regulate the activities of other endocrine glands.
Explanation:
For example, stimulates the Thyroid gland and stimulates the Adrenal Cortex. Its function is coordinated by the Hypothalamus.