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Question 1
Incorrect
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The TSH receptor produces its effects in the thyrocyte via:
Your Answer: Opening of voltage-gated iodine channels in the thyrocyte membrane
Correct 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 2
Correct
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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: 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 3
Incorrect
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Which of the following forms one of the characteristic and functional cells making up the anterior pituitary gland?
Your Answer: Rathke cell
Correct Answer: Corticotrope
Explanation:The anterior pituitary, also known as adenohypophysis or pars anterior contains the following types of cells: – acidophil cells: somatotroph cells, which produce growth hormone; and lactotrophs, which produce prolactin- basophil cells: corticotropes, which produce adrenocorticotropic hormone; thyrotropes, which produce thyroid stimulating hormone; and – gonadotrophs, which produce luteinizing hormone and follicle stimulating hormone.
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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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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 5
Incorrect
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Which of the following features is least commonly seen in Gitelman’s syndrome?
Your Answer: Metabolic alkalosis
Correct 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 6
Correct
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The onset of puberty is triggered by
Your Answer: Increase in pulsatile GNRH secretion from hypothalamus
Explanation:The onset of puberty is associated with high GNRH pulsing, which precedes the rise in sex hormones. Brain tumours which increase GNRH output may also lead to premature puberty. The cause of the GNRH rise is unknown.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 7
Incorrect
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Physiological effects of T3 on the heart include all the following except:
Your Answer: Increased proportion of α-myosin heavy chain in the atria
Correct Answer: Increased expression of β-myosin heavy chain gene
Explanation:Tri-iodothyronine, also known as T3, is a hormone which can affect almost every system in the human body. In the heart, it increases the number of β1-adrenergic receptors, enhances the response to circulating catecholamines, increases the proportion of α-myosin heavy chains in the atria, and increases the expression of serca pump gene.
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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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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: 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 9
Correct
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Which cells secrete insulin?
Your Answer: B cells of the pancreatic islets
Explanation:Insulin is synthesised and stored by the B cells of the pancreatic islets (70% of islet cells), glucagon is synthesised and stored in the A cells (20%) and somatostatin is synthesised and stored in the D cells (10%).
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 10
Incorrect
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Which of the flowing plasma proteins has the greatest affinity for T4?
Your Answer: Thyroglobulin
Correct Answer: Thyroxin-binding globulin
Explanation:There are three principal plasma thyroid hormone-binding proteins, thyroxine-binding globulin (TBG), transthyretin (TTR), and albumin. TBG is synthesized in the liver and due to its relatively high affinity for iodothyronines, binds and carries approximately 70–75% of circulating T4 and T3.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 11
Correct
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Where does one find the thyroid receptors?
Your 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 12
Incorrect
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Where does the anterior pituitary receive most of its blood supply?
Your Answer: Medial mammillary nucleus
Correct Answer: Portal hypophysial vessels
Explanation:The anterior pituitary receives its arterial supply from the superior hypophyseal artery, which is a branch of the internal carotid that forms a capillary around the hypothalamus; thus forming the hypothalamo-hypophysial portal system.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 13
Incorrect
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In which of the following are the enzymatic mechanisms for producing aldosterone found?
Your Answer: Paraganglia cells
Correct Answer: Zona glomerulosa
Explanation:The zona glomerulosa is the outermost layer of the adrenal gland. In it, aldosterone is secreted as a response to an increase in potassium levels, decreased blood flow, or renin. This secretion is regulated by the renin-angiotensin system.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 14
Incorrect
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Calcium is transported over the brush border in the gut, via which transporter / channel?
Your Answer: Calcium / Na+ exchanger
Correct 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 15
Incorrect
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Which of the following biochemical profiles is seen in a normal 65 year old female? (in comparison to a normal 24 yr. old female)
Your Answer: Decreased FSH, LH; decreased oestrogen, progesterone
Correct Answer: Increased FSH, LH; decreased oestrogen, progesterone
Explanation:During menopause, a woman’s number of ovarian follicles becomes depleted; as a result, oestrogen and progesterone levels drop, and LH and FSH levels increase. One of the criteria to diagnose menopause is the absence of menstrual period for a year, along with a serum FSH level increased to 30 mIU/ml or higher. LH also rises with the onset of menopause.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 16
Incorrect
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The apical enzyme responsible for the oxidation and reaction of iodide with thyroglobulin is:
Your Answer: Iodotyrosine deiodinase
Correct 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 17
Correct
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In a newly diagnosed acromegaly patient, which of the following would you not expect to find?
Your Answer: Hypohidrosis
Explanation:Features of acromegaly may include:
- Soft tissue swelling visibly resulting in enlargement of the hands, feet, nose, lips and ears, and a general thickening of the skin
- Soft tissue swelling of internal organs, notably the heart with associated weakening of its muscularity, and the kidneys, vocal cords (resulting in a characteristic thick, deep voice and slowing of speech)
- Generalized expansion of the skull at the fontanelle, frontal bossing, prognathism with associated macroglossia (enlargement of the tongue) and teeth spacing.
- Hypertrichosis, hyperpigmentation and hyperhidrosis (not hypohidrosis) may occur in these patients as well as carpal tunnel syndrome and impotence.
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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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Which glucose transporter is responsible for the uptake of glucose in ß cells?
Your Answer: GLUT 2
Explanation:Glucose transporter 2, also known as GLUT2 is a transmembrane carrier protein which is not insulin dependent. It is found in the liver and the pancreatic islet ß cells, where it functions as the primary glucose transporter that allows the transfer of glucose between these organs and blood.
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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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What is the effect of vasopressin on the kidney?
Your Answer: Increase collecting duct permeability to water
Explanation:Vasopressin, also known as antidiuretic hormone or ADH, which increases water reabsorption in the kidney’s collecting ducts. It works by increasing water permeability in the collecting ducts and distal convoluted tubules. It induces the exocytosis of AQP-CD-laden vesicles, transferring water channels from intracellular vesicles to the apical plasma membrane, therefore allowing more water to be reabsorbed from the urine in the collecting ducts to the blood.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 20
Correct
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Which of the following is correctly paired?
Your 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 21
Incorrect
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Which cell secretes parathyroid hormone?
Your Answer: Parafollicular cells
Correct Answer: Chief cells
Explanation:Parathyroid chief cells, also known as parathyroid principal cells or parathyroid cells, are the most prevalent type of cell in the parathyroid gland and the only ones present at birth. They secrete parathyroid hormone (PTH).
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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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Select a factor which stimulates glucagon secretion.
Your Answer: Free fatty acids
Correct Answer: Protein meal
Explanation:Several studies have shown that glucagon levels are increased in individuals with a high protein diet. It is still debated, however, whether this type of diet affects insulin levels as well.
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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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The residual cleft of the intermediate lobe of the pituitary is lined by follicles resembling which human gland?
Your 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 24
Incorrect
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Phosphate absorption in the proximal tubules is via which transporting molecule?
Your Answer: K/Pi co transporter
Correct Answer: Na/Pi co transporter
Explanation:Sodium/phosphate cotransporters are located in the renal proximal tubular brush border, and are the key elements in proximal tubular phosphate reabsorption and phosphate homeostasis.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 25
Incorrect
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Pendrin is a Cl-/I- exchanger whose function is:
Your Answer: Uptake of iodide across the basolateral membrane into the thyrocyte
Correct 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 26
Incorrect
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The growth promoting protein anabolic effects of insulin are mediated by:
Your Answer: Igf-1
Correct Answer: Phosphatidylinositol 3-kinase
Explanation:Phosphatidylinositol 3-kinase or PI-3Ks are a group of enzymes which are involved in a number of different cellular functions. PI-3Ks interact with insulin and the insulin receptor substrate, regulating glucose uptake. They are an important element in the insulin signalling pathway.
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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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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 28
Correct
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Growth hormone deficiency causes?
Your Answer: Decreased epiphyseal growth
Explanation:Growth hormone deficiency is caused by conditions affecting the pituitary gland, such as tumours. Its effects depend on the age of the patient: in infancy and childhood, growth failure is most likely to occur. The epiphyseal plate is the area in long bones where growth occurs, and it is the area affected by growth hormone deficiency. Poor growth/shortness is the main symptom of GH deficiency in children, usually resulting in growth at about half the usual rate for age.
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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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Which of the following cells secrete glucagon?
Your Answer: A cells
Explanation:Glucagon counteracts hypoglycaemia and opposes insulin by promoting gluconeogenesis and glycogenolysis. It also decreases fatty acid synthesis in the liver and adipose tissue, and promotes lipolysis. It is secreted by the pancreatic islet α-cells. Its production is regulated by the insulin produced in β-cells.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 30
Incorrect
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What is the fat called that serves as a considerable source of heat in children?
Your Answer: White adipose tissue
Correct Answer: Brown adipose tissue
Explanation:Brown adipose tissue, also known as BAT or brown fat, coforms the adipose tissue along with white adipose tissue (WAT) or white fat. While WAT is responsible for energy-storage, BAT is involved in thermogenesis and energy expenditure. It is more prevalent in children than in adults, and its activation during adolescence is associated to less weight gain and adiposity. BAT produces heat by non-shivering thermogenesis.
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This question is part of the following fields:
- Endocrinology
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
