Endocrine System Practice Questions
19 free Endocrine System practice questions for the General Science. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which gland is often referred to as the 'master gland' because it regulates the activity of several other endocrine glands?
- A Thyroid gland
- B Adrenal gland
- C Pituitary gland
- D Parathyroid gland
Correct answer: Pituitary gland
The pituitary gland secretes several tropic hormones that signal other glands, such as the thyroid and adrenals, to produce their own hormones. It is physically connected to and controlled by the hypothalamus.
Which hormone is produced by the Beta cells of the Islets of Langerhans in the pancreas?
- A Glucagon
- B Somatostatin
- C Insulin
- D Ghrelin
Correct answer: Insulin
Insulin is secreted by Beta cells in response to high blood glucose levels, facilitating the uptake of glucose into cells. Glucagon, conversely, is produced by Alpha cells to raise blood sugar levels.
A deficiency in Iodine in the diet most directly affects the function of which endocrine gland?
- A Pancreas
- B Adrenal cortex
- C Thyroid gland
- D Parathyroid gland
Correct answer: Thyroid gland
The thyroid gland requires iodine to synthesize hormones like thyroxine (T4) and triiodothyronine (T3). Lack of iodine can lead to a condition known as goiter, which is an enlargement of the gland.
Which hormone is responsible for the 'fight-or-flight' response, increasing heart rate and blood glucose levels during stress?
- A Cortisol
- B Epinephrine
- C Aldosterone
- D Melatonin
Correct answer: Epinephrine
Epinephrine, also known as adrenaline, is released by the adrenal medulla during acute stress. It rapidly prepares the body for physical exertion by mobilizing energy stores and increasing cardiovascular output.
The hormone Melatonin, which regulates sleep-wake cycles, is secreted by which gland?
- A Thymus
- B Pineal gland
- C Pituitary gland
- D Hypothalamus
Correct answer: Pineal gland
The pineal gland produces melatonin in response to darkness, signaling to the brain that it is time for sleep. Light exposure inhibits its production, helping to maintain the body's circadian rhythm.
Which gland is primarily involved in the development of the immune system by maturing T-lymphocytes during childhood?
- A Thymus
- B Thyroid
- C Spleen
- D Adrenal
Correct answer: Thymus
The thymus gland is most active during childhood and puberty, serving as the site where T-cells mature. It gradually shrinks and is replaced by fat as a person reaches adulthood.
Hypersecretion of Growth Hormone (GH) in adults after the epiphyseal plates have closed results in which condition?
- A Gigantism
- B Dwarfism
- C Acromegaly
- D Cushing's Syndrome
Correct answer: Acromegaly
Acromegaly causes the enlargement of bones in the hands, feet, and face because the long bones can no longer grow in length. If hypersecretion occurs during childhood, it results in gigantism instead.
Which hormone increases blood calcium levels by stimulating osteoclast activity and reducing calcium excretion by the kidneys?
- A Calcitonin
- B Parathyroid hormone
- C Cortisol
- D Thyroid-stimulating hormone
Correct answer: Parathyroid hormone
Parathyroid hormone is produced by the parathyroid glands and is the primary regulator of calcium homeostasis. It acts in opposition to calcitonin, which works to lower blood calcium levels.
The adrenal cortex secretes which class of hormones responsible for regulating sodium and potassium balance?
- A Glucocorticoids
- B Mineralocorticoids
- C Catecholamines
- D Adrenal sex steroids
Correct answer: Mineralocorticoids
Mineralocorticoids, primarily aldosterone, regulate the balance of electrolytes and water in the body. They stimulate the kidneys to retain sodium and excrete potassium, which helps regulate blood pressure.
Which of the following is considered a 'mixed gland' because it possesses both endocrine and exocrine functions?
- A Adrenal gland
- B Pancreas
- C Pituitary gland
- D Thymus
Correct answer: Pancreas
The pancreas has an endocrine function (secreting hormones like insulin into the blood) and an exocrine function (secreting digestive enzymes through ducts into the small intestine).
Diabetes insipidus is a condition characterized by excessive thirst and urination caused by a deficiency of:
- A Insulin
- B Adrenocorticotropic hormone
- C Antidiuretic hormone
- D Aldosterone
Correct answer: Antidiuretic hormone
Unlike diabetes mellitus, which involves insulin, diabetes insipidus is related to antidiuretic hormone (ADH). A lack of ADH prevents the kidneys from concentrating urine, leading to the loss of large volumes of water.
Which hormone is responsible for stimulating uterine contractions during childbirth and the release of milk during breastfeeding?
- A Estrogen
- B Progesterone
- C Oxytocin
- D Prolactin
Correct answer: Oxytocin
Oxytocin is produced in the hypothalamus and released by the posterior pituitary. It plays a critical role in social bonding, labor, and the milk-ejection reflex.
Cushing's Syndrome is primarily caused by the hypersecretion of which hormone?
- A Thyroxine
- B Growth Hormone
- C Insulin
- D Cortisol
Correct answer: Cortisol
Cushing's Syndrome occurs when the body is exposed to high levels of cortisol for a long time. Symptoms include a rounded 'moon face,' high blood pressure, and a fatty hump between the shoulders.
Which hormone is secreted by the corpus luteum in the ovary to maintain the uterine lining for potential pregnancy?
- A Luteinizing hormone
- B Follicle-stimulating hormone
- C Prolactin
- D Progesterone
Correct answer: Progesterone
Progesterone prepares the endometrium for the implantation of a fertilized egg. If pregnancy does not occur, progesterone levels drop, leading to menstruation.
What is the primary target organ for the hormone Glucagon?
- A Skeletal muscle
- B Brain
- C Kidneys
- D Liver
Correct answer: Liver
Glucagon signals the liver to convert stored glycogen into glucose (glycogenolysis) and to synthesize glucose from non-carbohydrate sources (gluconeogenesis) to raise blood sugar.
Exophthalmos (bulging eyes) is a characteristic symptom of which endocrine disorder?
- A Graves' Disease
- B Hypothyroidism
- C Addison's Disease
- D Diabetes Mellitus
Correct answer: Graves' Disease
Graves' Disease is an autoimmune form of hyperthyroidism. In addition to an overactive metabolism, it can cause inflammation and swelling of the tissues behind the eyes, leading to protrusion.
Which hormone is produced by the heart and acts to reduce blood pressure by promoting sodium excretion?
- A Atrial natriuretic peptide
- B Angiotensin II
- C Renin
- D Vasoactive intestinal peptide
Correct answer: Atrial natriuretic peptide
Atrial natriuretic peptide is secreted by the atria of the heart when blood pressure is high. It inhibits the release of renin and aldosterone, leading to increased sodium and water loss in the urine to lower blood volume.
The second messenger system involving cyclic AMP (cAMP) is typically used by which type of hormones?
- A Steroid hormones
- B Thyroid hormones
- C Vitamin D and its active metabolites
- D Protein and peptide hormones
Correct answer: Protein and peptide hormones
Protein and peptide hormones are water-soluble and cannot cross the lipid bilayer of the cell membrane. They bind to surface receptors, which activate G-proteins and second messengers such as cAMP to elicit a cellular response, whereas steroid, thyroid, and vitamin D hormones act on intracellular receptors.
Which gland is located on the posterior surface of the thyroid gland and is usually four in number?
- A Adrenal glands
- B Islets of Langerhans
- C Thymus
- D Parathyroid glands
Correct answer: Parathyroid glands
The parathyroid glands are small, pea-sized glands embedded in the back of the thyroid lobes. Despite their proximity, they have a completely different function, focused on calcium regulation.