| Question | Answer |
| 1. Which cells produce T3 and T4.
2. Which cells produce calcitonin.
3. Which cells secrete parathyroid hormone? | 1. Follicular cells of the thyroid
2. Parafollicular (C cells) of the thyroid
3. Chief cells of the parathyroid |
| What are the 3 thyroid binding proteins? | 1. thyroid binding globulin
2. Transthyretin (prealbumin)
3. Albumin |
| Low total T₄ but normal TSH and free T₄ usually signifies... | deficiency in TH-binding proteins |
| Folicular cells secrete __ into the colloid space. Iodine is added to __ amino acid residues. | 1. thyroglobulin
2. tyrosine |
| 1. Enzyme that adds iodine to thyroglobulin
2. Peripheral tissues contain __ that convert T₄ into T₃ by removing iodine from tyrosine residues. | 1. thyroid peroxidase
2. Deiodinases |
| 1. How does estrogen effect thyroid binding globulin?
2. How does this effect bound T₄, free T₄, and total T₄? | 1. estrogen increases TBG synthesis
2. T4 temporarily decreases as more in bound to TBG. TSH levels increase until T₄ returns to equilibrium. Bound T₄ will be elevated above normal as will total T₄ but free T₄ will not be elevated. |
| 1. A preprohormone is synthesized in the __.
2. After cleavage of signal peptides, the prohormone is transported to the __. | 1. rough endoplasmic reticulum
2. golgi |
| 1. Thyroglobulin is released into the colloid space through the process of ___.
2. Iodide is transported into the follicular cell by __. | 1. exocytosis
2. sodium-iodide symporter NIS |
| Function of vitamin D | 1. ↑ gut absorption of dietary Calcium & phosphate
2. ↑ bone resorption of calcium |
| In vitamin D metabolism which metabolite is produced in the liver? Which is produced in the kidney? | 1. 25OH vitamin D in liver
2. 1,25(OH)₂ vitamin D in the kidney |
| Function of calcitonin | ↓ bone resorption of calcium |
| Which endorine hormones act through receptor associated tyrosine kinase (JAK/STAT) pathway? | GH, prolactin |
| Which enzyme is responsible for the second hydroxylation of vitamin D in the kidney? | 1α-hydroxylase |
| 1. What effect do sex steroid hormones have on bone?
2. What effect do glucocorticoids have on bone? | 1. ↓ bone resorption
2. bone resorption |
| 1. GH stimulates the production of IGF1 mainly in the __.
2. What negatively feeds back to inhibit GH release? | 1. liver
2. GH and IGF1 |
| What are the effects of GH on blood sugar in the:
1. acute phase
2. chronic phase | 1. proinsulin - stimulates glucose and amino acid transport
2. anti-insulin - increased blood glucose, insulin resistance |
| What is the effect of the following hormones on growth?
1. thyroid hormone
2. glucocorticoids
3. sex steroids
4. insulin | 1. ↑ growth
2. inhibit growth
3. ↑ growth but closes epiphyseal plate
4. ↑ growth of fetus |
| 1. Primary hypoadrenalism is usually due to..
2. Secondary hypoadrenalism is due to. | 1. decreased cortisol from autoimmune destruction of the adrenal cortex
2. decreased cortisol from ACTH deficiency |
| What is the cause of hyperpigmentation in primary adrenal insufficiency? | excess MSH and ACTH production from POMC precursor |
| 1. Which endocrine hormones are derivatives of tyrosine?
2. Carrier proteins that transport posterior pituitary hormones in circulation | 1. thyroid hormones
2. neurophysins |
| What part of the adrenal cortex are the following secreted
1. aldosterone
2. cortisol
3. androgens | GFR
1. glomerulosa
2. fasciculata
3. reticularis |
| 1. Where is ADH synthesized?
2. Where is oxytocin synthesized? | 1. supraoptic nucleus
2. paraventricular nucleus |
| What increases growth hormone secretion? | 1. sleep
2. stress
3. arginine (high protein meal)
4. hypoglycemia |
| What are the two hormones that decrease growth hormone release? | 1. somatostatin
2. somatomedins (IGF) |
| Where are somatomedins produced? | the somatomedin IGF is produced in the liver after growth hormone binding |
| Which hormone is produced by the following pancreatic cell types:
1. α
2. β
3. δ | 1. insulin
2. glucagon
3. somatostatin |
| Where are the following glucose transporters located:
1. GLUT1
2. GLUT2
3. GLUT4 | 1. RBCs, brain
2. β islet, liver, small intestine
3. (insulin responsive) adipose tissue, muscle, |
| Which enzymes does insulin stimulate for:
1. glycolysis
2. liver synthesis of fatty acids
3. release of fatty acids from VLDL
4. storage of glucose as glycogen | 1. glucokinase, PFK-2, PDH
2. acetyl CoA carboxylase
3. lipoprotein lipase
4. glycogen synthase |
| How does glucose trigger insulin release? | 1. glucose enters liver cells through GLUT-2 transporter and undergoes glycolysis
2. ATP ↑ in cell and K + channels close
3. cell depolarizes and calcium channels open
4. Exocytosis of insulin |
| How does glucagon affect:
1. blood glucose
2. fatty acid level
3. urea production | 1. ↑ glycogenolysis and gluconeogenesis
2. ↑ lipolysis
3. amino acids used for gluconeogenesis and resulting amino groups incorporated into urea |
| 1. Inhibits prolactin release
2. Hormones that increases prolactin release
3. Which hormone does prolactin inhibit | 1. dopamine
2. TRH, estrogen
3. GnRH |
| 1. How does cortisol increase blood pressure?
2. How does PTH effect phosphate? | 1. upregulates α1 receptors on arterioles
2. ↓ kidney reabsorption of phosphate |
| What 3 ways does PTH increase calcium? | 1. ↑ bone resorption
2. ↑ kidney reabsorption
3. ↑ vitamin D production → ↑ GI absorption |
| What is the mechanism of vitamin D activation by PTH? | PTH stimulates kidney 1α-hydroxylase |
| What is the mechanism of bone resorption by PTH? | PTH ↑ production of macrophage colony-stimulating factor and RANK-L in osteoblasts which stimulate osteoclasts |
| 1. How does PTH effect calcium and phosphate
2. How does vitamin D effect calcium and phosphate? | 1. ↑ calcium reabsorption, ↓ phosphate reabsorption
2. ↑ both calcium and phosphate reabsorption |
| Which endocrine hormones act through IP₃ (Gαq)? | GOAT
1. GnRH
2. Oxytocin
3. ADH (V1 receptor)
4. TRH |
| Which hormone binds a nuclear steroid receptor? | T₃/T₄ |
| Which hormones bind cytosolic steroid receptors? | VET CAP
1. vitamin D
2. estrogen
3. testosterone
4. cortisol
5. aldosterone
6. progesterone |
| Hormones that act through cAMP | FLAT CHAMP
1. FSH
2. LH
3. ACTH
4. TSH
5. CRH
6. hCG
7. ADH (V2 receptor)
8. MSH
9. PTH |
| Hormones that act through intrinsic tyrosine kinase (MAP kinase pathway) | insulin, IGF1, PDGF |
| By which mechanism do thyroid hormones effect:
1. cardiac output
2. basal metabolic rate | 1. ↑ β1 receptors in hear
2. ↑ Na+/K+ ATPase activity |
| 1. What is calcitriol?
2. How many phosphate groups are attached to it? | 1. hormonally active vitamin D
2. 3 hydroxyl groups |
| What 3 components compose serum calcium? | 1. albumin bound calcium
2. phosphorus bound calcium
3. free, ionized calcium |
| What is the physiological cause of tetany seen with hypocalcemia? | lower threshold potential of nerve causes partial depolarization |
| How does glucagon effect insulin levels? | 1. glucagon promotes release of somatostatin → ↓ insulin (and glucagon) secretion
2. glucagon binds pancreatic β-cell → ↑cAMP → insulin secretion |
| How does insulin effect glucagon levels? | insulin directly inhibits glucagon release |
| Why is insulin levels higher after oral glucose than IV glucose? | incretins (e.g. GLP-1) are released from the intestines following oral glucose and they stimulate β-cell insulin secretion |
| How does insulin deficiency lead to an increase in ketones? | without insulin, lipolysis is increased producing increased ketoacids |
| Why does growth hormone excess lead to hyperglycemia? | Growth hormone actions:
1. ↑ gluconeogenesis
2. ↓ glucose uptake into insulin sensitive tissues |
| 1. The activity of which adrenal enzyme is increased by ACTH?
2. The activity of which adrenal enzyme is increased by angiotensin II? | 1. Desmolase (converts cholesterol to pregnenolone)
2. Aldosterone synthase |
| Why does ↑ GH lead to gigantism while ↑ adrenal androgens do not when both promote bone growth? | androgens aromatized to estrogens which lead to premature epiphyseal plate closure leading to short stature while GH → ↑ IGF which does not |
| How do anabolic steroids effect total T4, free T4 and TSH levels? | anabolic steroids divert poteins (plasma proteins) into building muscle. thyroid binding globulin is low
1. ↓ total T4
2. normal free T4
3. normal TSH |
| Drainage of the:
1. Left adrenal
2. Right adrenal | 1. left adrenal → left adrenal vein → left renal vein → IVC
2. right adrenal → right adrenal vein → IVC |
| Embryologic origin of:
1. adrenal cortex
2. adrenal medulla
3. posterior pituitary
4. anterior pituitary | 1. mesoderm
2. neural crest
3. neuroectoderm
4. oral ectoderm (Rathke's pouch) |
| Which hormones share a common α subunit to LH? | TSH, LH, FSH, hCG |
| 1. What causes somatostatin secretion from the hypothalamus?
2. Common cause of death from acromegaly or gigantism? | 1. somatomedin (IGF) from liver as a feedback mechanism for Growth Hormone regulation
2. cardiomegaly; GH causes IGF release from liver, IGF increases organ size |
| How does pulsative GnRH vs non-pulsatile GnRH effect pituitary secretion of LH and FSH? | 1. pulsatile stimulates pituitary secretion
2. nonpulsatile inhibits secretions |
| Which hormone:
1. ↑ breast milk production
2. ejection of milk from breast | 1. prolactin
2. oxytocin |
| T4 vs T3
1. longer half life
2. created in peripheral tissues
3. negative feedback on TRH | 1. T4
2. T3
3. T3 |
| 1. Number one cause of cushing syndrome
2. What is cushing's disease
3. What is the most likely cause of ectopic ACTH secretion? | 1. exogeneous steroids
2. ACTH secreting pituitary adenoma
3. small-cell lung cancer |
| How is epinephrine level effected by cortisol? | cortisol sytimulates the enzyme PNMT which converts norepinephrine to epinephrine leading to increase epi levels |
| How do thyroid hormones effect:
1. protein synthesis
2. lipid store levels
3. cholesterol levels
4. plasma glucose levels | 1. ↑
2. ↓ through lipolysis
3. ↓ through lipolysis
4. ↑ through gluconeogenesis and glycogenolysis |
| 1. How do sleep, stress and glucose levels effect GH secretion?
2. Which amino acid increased GH secretion? | 1. sleep, stress and hypoglycemia ↑ GH secretion
2. Arginine |
| How does cortisol effect:
1. Blood pressure
2. Bone
3. immune function
4. Glucose levels | 1. maintains blood pressure
2. ↓ bone formation
3. ↓ immune function
4. ↑ gluconeogenesis and lipolysis |
| PTH vs vitamin D in calcium increase:
1. acts on gut
2. acts on bone
3. acts on kidney | 1. vitamin D
2. PTH
3. PTH |
