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Question 1
Correct
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Where is leptin synthesized and secreted?
Your Answer: White adipose tissue
Explanation:Leptin is a hormone that helps regulate food intake and energy expenditure. It is synthetized by white adipose tissue and the gastric mucosa. It works by inhibiting the sensation of hunger, therefore, it opposes the actions of ghrelin, also known as the hunger hormone.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 2
Incorrect
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What is pendrin?
Your Answer: Na+/Cl- antiporter
Correct Answer: Cl-/i- antiporter
Explanation:Pendrin is an anion exchange transporter; it is a sodium-independent chloride-iodine exchanger which also accepts formate and bicarbonate. It is present in many different types of cells in the body, particularly the inner ear, thyroid, and kidney. Mutations in pendrin are associated with Pendred syndrome, which causes syndromic deafness and thyroid disease.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 3
Incorrect
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Choose the most correct missing words to complete the statement: A portion of circulating growth hormone is bound to the ____ receptor and activates the ____ pathway that mediates its effect.
Your Answer: Igf ii, jak 2stat
Correct Answer: Growth hormone receptor (extracellular domain), jak 2stat
Explanation:The growth hormone receptor is a transmembrane protein involved in the STATs, MAPK and PI3-kinase/Akt pathways. The JAK-STAT signalling pathway is activated by different ligands, such as growth hormone, interferon and interleukin. This pathway is involved in the expression of genes associated with oncogenesis, immunity, proliferation, differentiation and apoptosis. Errors in these pathways can produce leukaemia’s and other myeloproliferative disorders.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 4
Correct
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Which of the following stimulates glucagon release?
Your Answer: Exercise
Explanation:Studies have shown a small increase in glucagon levels during stress tests and exercise. This occurs in response to the reduction of blood glucose levels during physical activity; epinephrine levels are also a stimulus for the release of glucagon during exercise, since it suppresses insulin, which accounts for its stimulatory effects on glucagon. The use of stored fats for energy during exercise also stimulates the release of glucagon.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 5
Incorrect
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Periodic fevers occur in humans with mutations in the gene for pyrin. Pyrin is a protein found in which one of the following cells?
Your Answer: T lymphocytes
Correct Answer: Neutrophils
Explanation:Pyrin, also known as marenostrin or TRIM20, is a protein encoded by the Mediterranean fever (MEFV) gene, causing the autoinflammatory disease familial Mediterranean fever (FMF). Pyrin produces an increased sensitivity to intracellular signals. It is produced mainly in neutrophils, which display an increased ratio of cells entering apoptosis when exposed to pyrin.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 6
Correct
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Which of the following is not a feature of Liddle’s syndrome?
Your Answer: Autosomal recessive inheritance
Explanation:Liddle’s syndrome is a rare autosomal dominant condition characterized by early, and frequently severe, high blood pressure associated with low plasma renin activity, metabolic alkalosis, low blood potassium, and normal to low levels of aldosterone. Liddle syndrome involves abnormal kidney function, with excess reabsorption of sodium and loss of potassium from the renal tubule, and is treated with a combination of low sodium diet and potassium-sparing diuretic drugs (e.g., amiloride).
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 7
Correct
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The net effect of active Vitamin D on calcium and phosphate homeostasis is?
Your Answer: Increase in Ca, increase in phosphate
Explanation:Bone and its metabolism are regulated by several hormones, amongst which is vitamin D. It is heavily involved in the metabolism and homeostasis of calcium and phosphate through several processes. Vitamin D works in the intestine, kidney, bone and parathyroid glands to maintain levels of calcium and phosphate, promoting its absorption, bone resorption, and proper functioning of the parathyroid to maintain adequate serum calcium levels.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 8
Correct
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Select the correct statement regarding the macro anatomy of the thyroid gland.
Your Answer: It surrounds the trachea at the front of the neck.
Explanation:The thyroid is located around the trachea, in the anterior portion of the neck. It is formed by two lobes which are connected by an isthmus. The presence of a pyramidal lobe, or third lobe, is considered to be a normal anatomical variant. It originates from the primitive pharynx and the neural crest and has a rich vascular supply.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 9
Incorrect
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Which of the following stimuli increase growth hormone secretion?
Your Answer: Hyperglycaemia
Correct Answer: Ghrelin
Explanation:Ghrelin is a hormone which serves as an endogenous ligand for the growth hormone secretagogue receptor. It acts on the pituitary and the hypothalamus by affecting the vagus nerve. It acts on the somatotrophs of the anterior pituitary, GHRH-secreting neurons, and on GHIH-secreting neurons in the hypothalamus, causing a time-dependent and pulsatile stimulation over the secretion of growth hormone.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 10
Correct
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Pendrin is a Cl-/I- exchanger whose function is:
Your Answer: Transfer of iodide across the thyrocyte apical membrane into the colloid
Explanation:Pendrin is an anion transporter present in the inner ear, thyroid and kidney. It regulates the entrance of iodide from the thyroid cell to the colloid space. It has been proposed that its role could be the maintenance of the ionic composition of the endolymph.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 11
Incorrect
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Which enzyme is responsible for the conversion of testosterone to dihydrotestosterone?
Your Answer: 11β-hydroxylase
Correct Answer: 5α-reductase
Explanation:The enzyme 5α-reductase synthesizes DHT from testosterone in the prostate, testes, hair follicles, and adrenal glands. This enzyme reduces the 4,5 double-bond of the testosterone. Relative to testosterone, DHT is much more potent as an agonist of the androgen receptor.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 12
Correct
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During bone growth-the epiphysis are separated from the diaphysis by actively proliferating cartilage known as:
Your Answer: Epiphysial plate
Explanation:The epiphysial plate, physis, or growth plate, is a hyaline cartilage plate located near the ends of long bones; it consists of growing tissue. It is found in children and teenagers; in adults, it is replaced by an epiphysial line or epiphysial closure. The epiphysial plate is divided into zones: zone of reserve, proliferation, maturation and hypertrophy, calcification, and ossification.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 13
Correct
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Regarding the structure of the 3 pituitary glycoprotein hormones FSH, LH, and TSH, which of the following is true about the α- and β-subunits of each hormone?
Your Answer: Maximal physiological activity occurs only on their combination
Explanation:Glycoprotein hormones (GPHs) are the most complex molecules that function as hormones. They each consist of two different subunits, α and β, which are non-covalently associated. The combination of these subunits results in an increase in their activity and β structure.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 14
Correct
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In the microanatomy of the pituitary gland, the pituicytes present are in fact modified forms of which cells?
Your Answer: Astrocytes
Explanation:Pituicytes are glial cells present in the pars nervosa, the posterior pituitary gland. Their irregular shape resembles that of astrocytes, and their cytoplasm also has intermediate filaments. They differ from astrocytes in that they have large cytoplasmic lipid droplets.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 15
Incorrect
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The residual cleft of the intermediate lobe of the pituitary is lined by follicles resembling which human gland?
Your Answer: Adrenal medulla
Correct Answer: Thyroid
Explanation:The cells located between the two main pituitary lobes form what is known as the intermediate pituitary. This area secretes melanocyte-stimulating hormone and it is only a few cell layers thick. It is rich in follicles filled with colloid, and lined by basophilic cells. This configuration resembles that of another important gland: the thyroid.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 16
Correct
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What causes increased insulin sensitivity?
Your Answer: Exercise
Explanation:Physical activity, through its effect on insulin sensitivity, is one of the main modifiable risk factors for type 2 diabetes. It is estimated that by each weekly 500 kcal increment in exercise related energy consumption, the lifetime risk of suffering from type 2 diabetes is reduced by 9%. Up to two hours after exercise, glucose uptake is elevated due to insulin independent mechanisms; however, insulin sensitivity remains increased for at least 16 hours after exercising.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 17
Correct
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Which of the following skin coloration abnormalities occurs due to adrenal insufficiency due to primary adrenal disease?
Your Answer: Hyperpigmentation
Explanation:Addison’s disease, also known as primary adrenal insufficiency, or hypocortisolism is an endocrine disorder. Hyperpigmentation is one of its most common signs; it occurs as a result of an increase in pro-opiomelanocortin to produce more ACTH in response to the decreased levels of cortisol. Pro-opiomelanocortin is a precursor of melanocyte stimulating hormone (MSH), which stimulates melanocytes, causing darkening of the skin.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 18
Correct
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The febrile response to PGE2 will be impaired with the knockout of which one of the following prostaglandin receptors?
Your Answer: Ep3
Explanation:Prostaglandin EP3 receptor is a receptor for prostaglandin E2. Fever occurs as a result of the action of prostaglandin E2 and requires EP3 receptors in the preoptic area. Therefore, if there is an absence of EP3 receptors, fever caused by prostaglandin E2 will not occur.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 19
Correct
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To which protein is T3 mostly bound in the serum?
Your Answer: Thyroxin-binding globulin
Explanation:In a normal person, approximately 0.03 per cent of the total serum T4, and 0.3 per cent of the total serum T3 are present in free or unbound form. The major serum thyroid hormone-binding proteins are: 1) thyroxine-binding globulin [TBG or thyropexin], 2) transthyretin [TTR or thyroxine-binding prealbumin (TBPA)], and 3) albumin (HAS, human serum albumin). TBG has highest affinity for T4, which is 50-fold higher than that of TTR and 7,000-fold higher that of HSA. As a result TBG binds 75% of serum T4, while TTR and HSA binds only 20% and Albumin 5%, respectively.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 20
Incorrect
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Choose the correct statement regarding trabecular bone:
Your Answer: Is located inside the cortical bone and makes up 20% of bone in the body
Correct Answer: All of the options are correct
Explanation:Trabecular, spongy or cancellous bone. It is located inside the cortical bone and makes up around 20% of all bone in the body. It is made of spicules or plates with a high surface to volume ratio, where many cells sit on the surface of the end plates. It receives its nutrients from the extracellular fluid (ECF), exchanging about 10 mmol of calcium every 24 hours.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 21
Correct
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Calcium is transported over the brush border in the gut, via which transporter / channel?
Your Answer: TRPV 6
Explanation:Transient Receptor Potential Vanilloid 6 or TRPV 6 is a calcium channel located in the cell membrane which is present in a variety of organs, including small intestine, oesophagus, stomach, colon, placenta, kidney, and uterus. In the intestine, it is located in the apical brush-border membrane of the enterocyte, regulating the entry of calcium into the cell.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 22
Incorrect
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Within the hypothalamus, the dopamine-secreting neurones of the intrahypothalamic system have their cell bodies in which nuclei?
Your Answer: Paraventricular
Correct Answer: Arcuate
Explanation:Arcuate nucleus dopaminergic neurons consist of a single group of neurons that project to the median eminence where they release dopamine into the hypophyseal portal circulation to inhibit pituitary prolactin secretion.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 23
Correct
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Where do the portal hypophysial vessels arise?
Your Answer: Median eminence
Explanation:The hypothalamic-hypophysial portal system connects the brain to the anterior pituitary. It is made up of two capillary beds, one in the median eminence and the other in the anterior pituitary. Blood from the plexus of the median eminence is carried by portal veins, draining into the cavernous and posterior intercavernous sinuses. This system delivers hypothalamic hormones to their target cells.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 24
Correct
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Which of the following may be a feature of primary hyperaldosteronism?
Your Answer: Muscular weakness
Explanation:Primary hyperaldosteronism or Conn’s syndrome is characterised by hypertension which may cause poor vision or headaches. Occasionally there may be muscular weakness, muscle spasms, tingling sensations, or excessive urination. Complications include cardiovascular disease such as stroke, myocardial infarction, kidney failure, and abnormal heart rhythms.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 25
Correct
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What is the most abundant hormone release by the thyroid?
Your Answer: T4
Explanation:T3 and T4 are the two tyrosine-based hormones produced and secreted by the thyroid gland. Although T3 is the active form of the hormone, and thus, it is much more potent; T4 is the most abundant hormone secreted by the thyroid (93% of the total thyroid secretion) and it also has a longer half life since it binds to proteins much more strongly.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 26
Correct
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A 14-year-old girl presents with short stature, webbed neck and primary amenorrhoea.Given the likely clinical diagnosis, which hormone replacement is most crucial over the longer term?
Your Answer: Oestrogen
Explanation:This girl most likely has Turner syndrome (TS) also known as 45,X, a condition in which a female is partly or completely missing an X chromosome. Signs and symptoms vary among those affected. Often, a short and webbed neck, low-set ears, low hairline at the back of the neck, short stature, and swollen hands and feet are seen at birth. Typically, they are without menstrual periods, do not develop breasts, and are unable to have children. Heart defects, diabetes, and low thyroid hormone occur more frequently. Most people with TS have normal intelligence. Many, however, have troubles with spatial visualization such as that needed for mathematics. Vision and hearing problems occur more often. Turner syndrome is not usually inherited from a person’s parents. No environmental risks are known and the mother’s age does not play a role. As a chromosomal condition, there is no cure for Turner syndrome. However, much can be done to minimize the symptoms including prescribing growth hormone, either alone or with a low dose of androgen, and oestrogen replacement therapy which is crucial long term for maintaining good bone integrity, cardiovascular health and tissue health
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 27
Correct
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The main efferent input of the posterior pituitary gland comes from:
Your Answer: Paracrine hormones secreted from the hypothalamus via axons.
Explanation:The posterior pituitary or neurohypophysis consists of a collection of axonal projections emerging from the hypothalamus. It releases hormones directly from these axonal endings into circulation; these hormones are oxytocin and vasopressin.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 28
Correct
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Which of the following factors is most likely to lead to an increase in serum cortisol levels?
Your Answer: Severe emotional stress
Explanation:Cortisol is widely known as the stress hormone. Alterations in cortisol levels have been found in relation to mood disorders, illness, trauma, pain, fear, exertion, and anxiety, amongst other stimuli.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 29
Correct
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The apical enzyme responsible for the oxidation and reaction of iodide with thyroglobulin is:
Your Answer: Thyroid peroxidise
Explanation:Thyroid peroxidase is an enzyme that is secreted into the thyroid colloid. It works by oxidizing iodide ions into iodine which are incorporated into thyroglobulin, in order to produce T3 and T4.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 30
Correct
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Compact/cortical bone makes up
Your Answer: The outer layer of most bones and accounts for 80% of bone in the body
Explanation:Cortical, lamellar, or compact bone, is more dense than spongy bone and it forms the rigid, outer layer of bones, also called cortex. It consists of packed osteons, with a central osteonic canal surrounded by concentric rings. Spaces called lacunae are filled with osteocytes, and channels called canaliculi go from the lacunae to the osteonic canal. The strength of cortical bone allows it to support the body and protect organs. It also stores different elements, such as calcium.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 31
Correct
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Which one of the following is most likely to be seen in a patient with multiple endocrine neoplasia (MEN) type I?
Your Answer: Insulinoma
Explanation:Multiple endocrine neoplasia type 1 (MEN-1 syndrome) or Wermer’s syndrome is part of a group of disorders, the multiple endocrine neoplasias, that affect the endocrine system through development of neoplastic lesions in the ‘three P’s’:Parathyroid (>90%): hyperparathyroidism due to parathyroid hyperplasiaPituitary (15-42%)Pancreas (60-70%, e.g. insulinoma, gastrinoma)
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 32
Correct
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Which of the following features is least commonly seen in Gitelman’s syndrome?
Your Answer: Hypertension
Explanation:Gitelman syndrome is an autosomal recessive kidney disorder characterized by hypokalaemia metabolic alkalosis with hypocalciuria, and hypomagnesemia. In contrast to patients with Gordon’s syndrome, those suffering from Gitelman’s syndrome are generally normotensive or hypotensive.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 33
Correct
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The net effect of parathyroid hormone on calcium and phosphate homeostasis is?
Your Answer: Increase in Ca, decrease in phosphate
Explanation:Parathyroid hormone’s main target organs are the kidneys, bone, and intestine. In the kidney, it decreases reabsorption of phosphate and increases calcium reabsorption. It also promotes absorption of calcium from bone. PTH release results in a small drop in serum phosphate concentrations.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 34
Correct
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Select the correct statement about the microanatomy of the thyroid gland.
Your Answer: The capillaries adjacent to thyroid cells have a fenestrated endothelium.
Explanation:Fenestrated capillaries have a very thin endothelium, which is perforated by numerous fenestrations or pores. Hormones are usually released into these capillaries, reaching their target cells through the circulatory system.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 35
Correct
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As assessed by immunocytochemistry and electron microscopy, the anterior pituitary gland contains how many different types of cells?
Your Answer: 5
Explanation:The pituitary is divided into three sections
-the anterior lobe which constitute the majority of the pituitary mass and is composed primarily of five hormone-producing cell types (thyrotropes, lactotropes, corticotropes, somatotropes and gonadotropes) each secreting thyrotropin, prolactin, ACTH, growth hormone and gonadotropins (FSH and LH) respectively.
There is also a sixth cell type in the anterior lobe -the non-endocrine, agranular, folliculostellate cells.
The intermediate lobe produces melanocyte-stimulating hormone and endorphins, whereas the posterior lobe secretes anti-diuretic hormone (vasopressin) and oxytocin.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 36
Correct
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Where is the melanocortin system located?
Your Answer: Hypothalamus
Explanation:The melanocortin system is a group of hormones which include hormones from the pro-opiomelanocortin (POMC)-expressing neurons, the neuropeptide Y (NPY) and agouti-related peptide (AgRP)-co-expressing neurons. This system is located in the hypothalamic arcuate nucleus; it also includes the hypothalamic arcuate nucleus and the melanocortin 4 receptor (MC4R)-expressing neurons located in the hypothalamic paraventricular nucleus. The system regulates energy expenditure and food intake.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 37
Incorrect
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What microscopic changes are visible in an active thyroid gland?
Your Answer: Colloid is abundant.
Correct Answer: Follicle lining cells are cuboid or columnar.
Explanation:Active follicles are lined by cuboidal or columnar cells; this is because active follicles are smaller and have less colloid. Their cells are tall because they are actively secreting hormones, whereas older follicles have a flat epithelium and are filled with more colloid.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 38
Correct
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Which are the main hormones secreted by the posterior pituitary gland.
Your Answer: Oxytocin and vasopressin
Explanation:The posterior pituitary gland secretes oxytocin and vasopressin (antidiuretic hormone). These hormones are stored in Herring bodies before being secreted into the bloodstream.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 39
Correct
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Which of the following is least recognised as a potential complication of acromegaly?
Your Answer: Mental retardation
Explanation:Acromegaly is a condition that results from excess growth hormone (GH) after the growth plates have closed. It is typically due to the pituitary gland producing too much growth hormone. In more than 95% of people the excess production is due to a benign tumour, known as a pituitary adenoma. The condition is not inherited.Complications:Severe headacheArthritis and carpal tunnel syndromeEnlarged heartLiver fibrosis and bile duct hyperplasiaHypertensionDiabetes mellitus (excess of GH leads to insulin resistance)Heart failureKidney failureColorectal cancerCompression of the optic chiasm leading to loss of vision in the outer visual fields (typically bitemporal hemianopia.)Increased palmar sweating and sebum production over the face (seborrhoea) are clinical indicators of active GH-producing pituitary tumours.hypertensiondiabetes (>10%)cardiomyopathycolorectal cancer
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 40
Incorrect
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Where does one find the thyroid receptors?
Your Answer: Cell membrane
Correct Answer: Cell nucleus
Explanation:Unlike many of the steroid receptors, inactive receptors for T3 are located in the nucleus. T4 is first converted into T3 within the cytoplasm of the cell, T3 then enters the nucleus and binds to its receptor. The hormone-receptor complex can now bind to DNA and activate specific genes.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 41
Correct
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Which one of the following is not part of the WHO diagnostic criteria for the metabolic syndrome?
Your Answer: High LDL
Explanation:The World Health Organization 1999 criteria require the presence of any one of diabetes mellitus, impaired glucose tolerance, impaired fasting glucose or insulin resistance, AND two of the following:
- Blood pressure: ≥ 140/90 mmHg
- Dyslipidaemia: triglycerides (TG): ≥ 1.695 mmol/L and high-density lipoprotein cholesterol (HDL-C) ≤ 0.9 mmol/L (male), ≤ 1.0 mmol/L (female)
- Central obesity: waist: hip ratio > 0.90 (male); > 0.85 (female), or body mass index > 30 kg/m2
- Microalbuminuria: urinary albumin excretion ratio ≥ 20 µg/min or albumin: creatinine ratio ≥ 30 mg/g
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 42
Correct
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Where does the pituitary gland lie?
Your Answer: In a pocket of the sphenoid bone at the base of the brain
Explanation:The pituitary lies in a small depression in the sphenoid bone, known as the sella turcica or Turkish saddle.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 43
Correct
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Which of the following values of bone mineral density measured by DEXA would signify osteopenia?
Your Answer: T score of -2.2
Explanation:DEXA T Scores:Normal T-score ≥ −1.0Osteopenia −2.5 < T-score < −1.0Osteoporosis T-score ≤ −2.5Severe osteoporosis T-score ≤ −2.5 with fragility fracture
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 44
Correct
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Which hormone is associated with the temperature surge in hot flushes?
Your Answer: LH
Explanation:Luteinizing hormone or LH is a hormone produced by the anterior pituitary gland. Studies have shown surges in LH levels during menopausal hot flushes, suggesting that a pulsatile release of LH is responsible for increased hypothalamic norepinephrine activity, causing the hot flushes.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 45
Incorrect
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Which of the following is correctly paired?
Your Answer: I cells : IgF – i
Correct Answer: F cells : pancreatic polypeptide
Explanation:Pancreatic polypeptide is secreted by F-cells, which represent the smallest proportion of islet cells in the pancreas. These cells establish the embryological origin of the pancreas. Pancreatic polypeptide regulates endocrine and exocrine activities by the pancreas.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 46
Incorrect
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The actions of dihydrotestosterone in male reproductive physiology include:
Your Answer: Increase in muscle mass at puberty
Correct Answer: Development of external genitalia in utero and at puberty
Explanation:Dihydrotestosterone mediates the differentiation of the urogenital sinus and genital tubercles, leading to the fusion of the urethral and labial folds; thus, it leads to the development of external genitalia in the male.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 47
Correct
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The TSH receptor produces its effects in the thyrocyte via:
Your Answer: G-protein coupled activation of adenylyl cyclise and phospholipase c
Explanation:The thyrotropin receptor, also known as TSH receptor, responds to the thyroid stimulating hormone or thyrotropin to stimulate production of T3 and T4. It is a G protein-coupled receptor which leads to stimulation of phospholipase C and adenylyl cyclase, mediated by Gq/11 and Gs.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 48
Correct
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Which one of the following leads to decreased prolactin levels?
Your Answer: Dopamine
Explanation:Dopamine has an important effect on the regulation of prolactin secretion. Dopamine binds to type-2 dopamine receptors of the lactotroph cells that are functionally linked to membrane channels and G proteins and suppresses the high secretory activity of the pituitary lactotrophs.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 49
Correct
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Which of the following hormones would stimulate secretion of TSH?
Your Answer: TRH
Explanation:Thyrotropin-releasing hormone, also known as TRH, thyrotropin-releasing factor, TRF is a hormone produced by the hypothalamus. It functions as a releasing hormone, promoting the production of thyroid-stimulating hormone or thyrotropin and prolactin.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 50
Incorrect
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What is the principle site of action of adrenocorticotrophic hormone (ACTH)?
Your Answer:
Correct Answer: Adrenal gland
Explanation:Adrenocorticotropic hormone, also known as ACTH or corticotropin, is a polypeptide tropic hormone. It is synthesized by the corticotropic cells of the anterior pituitary. It works by regulating the secretion of glucocorticoid hormones from the cortex cells in the adrenal gland. It binds to the melanocortin (MC) 2 receptors on the surface of the adrenal zona glomerulosa cells, producing cortisol.
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This question is part of the following fields:
- Endocrinology
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
