10. Endocrine Sytem Flashcards
- Which statement below about hormones is true?
A. Hormones are enzymes that catalyse reactions.
B. Hormones are released into the blood circulation.
C. Hormones affect all cells of the body.
D. Hormones are released by neurones at synapses.
Answer is B: Hormones are circulating messengers that are transported in blood. A particular hormone does not necessarily affect every cell in the body. Some (but not all) hormones are released by neurones, for example, in the hypothalamus.
- Which hormones are soluble in blood?
A. Steroid hormones
B. Hormones produced by the adrenal cortex
C. The sex hormones
D. Those released by the pituitary gland
Answer is D: The pituitary gland releases peptide hormones which are soluble in blood. The other choices refer to steroid hormones which are insoluble in blood. They require transport via plasma proteins.
- Which statement about the hypothalamus is correct?
A. The hypothalamus is connected to the brain by the infundibulum.
B. The hypothalamus is composed of glandular epithelial tissue.
C. The hypothalamus secretes “releasing hormones”.
D. The hypothalamus secretes epinephrine and norepinephrine.
Answer is C: The hypothalamus is part of the brain so is composed of neural tissue. Epinephrine and norepinephrine are released from the adrenal medulla.
- What hormone does the thyroid produce?
A. Thyroid-stimulating hormone
B. Calcitriol
C. Thyroxine
D. Parathyroid hormone
Answer is C: Thyroxine (or tetraiodothyronine) is converted to triiodothyronine in target tissues.
- What hormone(s) does the adrenal medulla produce?
A. Aldosterone
B. Epinephrine and norepinephrine
C. Corticosteroids
D. Glucocorticoids
Answer is B: Epinephrine and norepinephrine are produced in the adrenal medulla (the deep or inside part). Aldosterone is a mineralocorticoid, which like corticosteroids and glucocorticoids, as the “cortico” in the name suggests, are all produced in the adrenal cortex.
- What is produced by the beta cells of the pancreas?
A. Angiotensin-converting enzyme
B. Glucocorticoids
C. Glucagon
D. Insulin
Answer is D: Beta cells of the pancreatic islets produce insulin. The alpha cells produce glucagon.
- Which gland or organ releases erythropoietin?
A. The kidneys
B. The adrenal glands
C. The anterior pituitary D. The pancreas
Answer is A: Kidneys produce erythropoietin (EPO) – which signals the red bone marrow to increase production of RBC.
- What effect does parathyroid hormone have?
A. It increases plasma Ca2+ concentration.
B. It decreases plasma Ca2+ concentration.
C. It increases the rate of ATP formation.
D. It stimulates the thyroid gland to produce thyroxine.
Answer is A: PTH increases plasma Ca2+ (calcitonin aids in lowering blood calcium).
- Which one of the following is NOT part of the endocrine system?
A. The islets of Langerhans (pancreatic islets)
B. The thyroid gland
C. The acini cells of the pancreas
D. The parathyroid glands
Answer is C: The acini cells produce digestive enzymes.
- What is the difference between an exocrine gland and an endocrine gland?
A. An endocrine gland secretes neurotransmitters (an exocrine gland does not).
B. An endocrine gland secretes via a tube to the destination (an exocrine gland does not).
C. An exocrine gland secretes into the blood (an endocrine gland does not).
D. An endocrine gland secretes into the blood (an exocrine gland does not).
Answer is D: Endocrine glands secrete “circulating” hormones, that is, secrete into the blood.
- By what term are hormones derived from tyrosine also known?
A. Amino acid derivatives B. Peptide hormones
C. Steroid hormones
D. Corticosteroids
Answer is A: Catecholamines (adrenaline, noradrenaline), dopamine and thyroid hormone are all derived from tyrosine.
- Which hormones have their receptors inside their target cell?
A. Amino acid-based hormones
B. Hormones with a membrane carrier mechanism or that are lipid soluble
C. Steroid hormones and peptide hormones of less than 50 amino acids
D. Lipid-soluble hormones
Answer is B: Choice D is also correct, but B is the better answer as thyroid hormones cross membrane by a carrier mechanism.
- Where in the body is the hypothalamus located?
A. On the inferior surface of the brain
B. In the cortex of the adrenal gland
C. In the anterior pituitary gland
D. On the dorsal surface of the thyroid gland
Answer is A: The hypothalamus is below the thalamus, more or less on the “floor” of the brain, but above the pituitary gland.
- From where are antidiuretic hormone and oxytocin released?
A. The anterior pituitary B. The posterior pituitary C. The adrenal cortex
D. The adrenal medulla
Answer is B: ADH and OT are produced in the hypothalamus and transported to the posterior pituitary.
- Which hormone has the element iodine as part of its molecule?
A. Calcitonin
B. Haemoglobin
C. Thyroxine
D. Parathyroid hormone
Answer is C: Thyroxine or thyroid hormone contains iodine.