Principles of Endocrinology and the Central Endocrine Glands
Which of the following is correctly defined? A) Synergism is when the actions of several hormones are complementary and their combined effect is greater than their separate effects. B) Permissiveness is when one hormone causes the loss of another hormone's receptors. C) Antagonism is when one hormone must be present in adequate amounts for the full exertion of another hormone's effect. D) "Unintentional" Abnormalities happen when a target cell receptor deliberately altered due to physiological control mechanisms.
A) This is the correct answer. B and C are false, since the definitions are switched. D is false because unintentional abnormalities happen when there is a lack of hormone receptors. INTENTIONAL abnormalities happen when a target cell receptor deliberately altered due to physiological control mechanisms.
Which of the following statements regarding control of hormone secretion is correct A) Output of a system counteracts a change in input in order to maintain plasma concentration of hormone at a given level B) A sudden increase in hormonal output in response to a stimulus is referred to as diurnal (circadian) rhythms C) Diurnal (circadian) rhythms are entrained to internal cues D) Hormone secretion is mainly controlled through positive feedback.
A) This is the correct answer. B is false; this is the definition of Neuroendocrine Reflexes. C is false; circadian rhythms are entrained to EXTERNAL cues. D is false; hormone secretion is mainly controlled through NEGATIVE feedback.
Which of the statements about Vasopressin is correct? A) As a response to hypovolemia, vasopressin secretion increases leading to an increase in blood pressure. B) When someone eats a meal low in sodium osmolarity decreases and vasopressin secretion increases to increase water retention. C) V2 is a vasopressin receptor found in vascular and GI smooth muscle, and it has a pressor effect. D) V1 is a vasopressin receptor found in renal collecting duct, and it has an antidiuretic effect.
A) This is the correct answer. Hypovolemia is a condition where the liquid portion of the blood is very low. Vasopressin secretion increases as a response, and water retention is enhanced. B is false since vasopressin secretion increases at high osmolarity (high solutes concentration) which leads to enhancement of water retention. In options C and D, V1 and V2 are switched.
Which of the following statements is FALSE A) Steroid hormones constitute the majority of hormones in our body, and they are secreted by adrenal cortex and gonads. B) Amine hormones are derived from the amino acid tyrosine, and they are secreted by thyroid and adrenal medulla C) Peptide hormones are made of specific amino acids arranged in a chain of varying lengths. D) Steroids and thyroid hormones are lipophilic (hydrophobic)
A) This statement is false. It is true that steroid hormones are secreted by adrenal cortex and gonads, however steroid hormones DO NOT constitute majority of hormones. Peptides constitute majority of hormones.
Which of the following hormones is NOT secreted by the anterior pituitary? A) Thyroid stimulating hormone (TSH) B) Prolacting-releasing hormone C) Growth hormone D) Follicle-stimulating hormone
B) Is the correct answer. Prolacting-releasing hormone is a hypophysiotrpoic hormone that stimulates the release of prolactin from the anterior pituitary.
Hyperplasia is A) An increase in protein synthesis B) A decrease apoptosis C) A decrease cell division D) A decrease the number of cells
B) This is the correct answer. Hyperplasia is an increase in the number of cells. It is an increase in cell division, and a decrease in apoptosis (programmed cell death). Hypertrophy is an increase in size of cells as well as protein synthesis.
Which of the following statements is true? A) Hypersecretion of GH in adults results in rapid growth in height and soft tissues without distortion of body proportions B) Gigantism results from hyperscretion of GH in children C) Acromegaly results from hyperscretion of GH in children D) Hyposecretion of GH in adults leads to acromegaly
B) This is the correct answer. Hyperscretion of GH in children results in rapid growth in height and soft tissues without distortion of body proportions, which is called gigantism. A is false since it falsely describes hypersecretion of GH in adults. C is false since acromegaly results from hypersecretion of GH in adults. D is false since it falsely describes acromegaly in adults as a result of HYPOsecretion of GH.
All of the following statements about the Endocrine System are true EXCEPT A) The endocrine system's ductless glands are scattered throughout the body B) It constitutes a system in an "anatomical" sense C) One endocrine gland may produce many hormones D) The endocrine system controls activities that require duration rather than speed.
B) This is the correct answer. The statement in B is false because the Endocrine System constitutes a system in a "functional" sense, which means glands are related in that they behave in a similar way, but they are not connected anatomically. (slide 3 Introduction)
All of the following statements are correct EXCEPT A) The hypothalamus coordinates the physiologic responses of organs that maintain homeostasis. B) The anterior pituitary is connected by a neural pathway, whereas the posterior pituitary is connected by the hypothalamic-hypophyseal portal. C) Oxytocin and vasopressin are synthesized in ER as pre-prohormones D) Oxytocin ad vasopressin are made in the hypothalamus and are stored in the posterior pituitary
B) This is the correct answer. The statement is false since the anterior pituitary is connected by the hypothalamic-hypophyseal portal (it is more of a glandular tissue) whereas the posterior pituitary is connected by a neural pathway (more of a neuron tissue).
A tropic hormone is BEST described as A) A longer-distance chemical mediator that is secreted by an endocrine gland into the blood to be transported to target cells. B) A hormone that stimulates and maintains target tissues C) A hormone that is influenced by many hormones D) Usually secreted by the neurohypophysis
B) This is the correct choice. While A is true, it defines a hormone in general, not a tropic hormone. C is false; a tropic hormone is the one that influences other hormones. D is false since in humans it is the adenohypophysis (anterior pituitary) that secrets tropic hormones.
Oxytocin is A) A tropic hormone B) Secreted from the anterior pituitary C) Controlled by positive feedback D) Controlled by negative feedback
C) This is the correct answer, an example of this would be contractions/lactation. A is false since oxytocin is a neuropeptide hormone. B is false since it is secreted by the posterior pituitary.
Which of the following statements about Growth Hormone is true? A) GH stimulates GHRH B) GH release is inhibited by stomatotropin C) GH acts indirectly through stomatomedins D) IGF-1 promotes growth in tissues indirectly
C) This is the correct answer. A is false since Growth hormone-releasing hormone (GHRH) is the one that stimulates GH. B is false since GH release is inhibited by stomatoSTATIN (SST). Stomatotropin is another name for the Growth Hormone. D is false since IGF-1 is a stomatomedin that directly promotes growth in tissues.
Which of the following statements about hormone transport is true? A) Peptides are lipophilic. B) Steroids and Thyroid hormones are lipophilic, therefore they won't dissolve in microenvironments of the plasma at all. C) Only the small, unbound, freely dissolved fraction of "carried" hormone is biologically active. D) Albumin is a specific plasma protein carrier.
C) This is the correct answer. A is false; peptides and catecholamines are HYDROphilic (steroids and thyroid hormones are lipophilic). B is also flase; a small amount WILL dissolve in microenvironments of the plasma. D is false; Albumin is a non-specific protein carrier (sex hormone binding globulin and thyroxine binding globulin are specific protein carriers)
Hydrophilic hormones A) Include steroids and thyroid hormones B) Bind to receptors located inside the target cell C) Bind to receptors located on the plasma membrane surface of the target cell D) Are reversibly bound to and carried by plasma proteins
C) This is the correct answer. A is false; steroids and thyroid hormones are LIPOPHILIC hormones (Catecholamines and peptides are hydrophilic). B is false; since it describes hydrophobic (lipophilic) hormones. D is false; since hydrophilic hormones simply dissolve in plasma, and they do not require a plasma protein carrier.
Which of the following hormones required for growth is essential and permissive? A) Insulin B) Estrogen C) Thyroid Hormone D) Androgens
C) This is the correct answer. Growth is stunted in hypothyroid children, but hyperthyroidism does not cause excessive growth. A is false since insulin promotes protein synthesis. B is false since estrogen is not well understood and in fact large doses could decrease further body growth. D is false since it promotes protein synthesis.
Which of the following statements about endocrine control of growth is False? A) Growth is not synonymous with weight gain alone B) Growth is the net synthesis of proteins C) Growth is mainly influenced by genetic determination D) Rate of growth is not continuous.
C) This is the correct answer. Statement C is false since growth is mainly influenced by growth hormone (essential).
Which of the following factors decreases plasma concentration of free hormone? A) High secretion from gland B) High rate of metabolic activation C) High extent of plasma protein binding D) Low rate of metabolic inactivation and excretion
C) This is the correct answer. When there is a high extent of hormone-protein carrier binding, there will be very little amount of free hormone. Choices A, B, and D all increase the plasma concentration of free hormone.
Which of the following is correctly matched to its definition? A) Primary hyposecretion is when an endocrine gland secretes too much hormone due to an abnormality in that gland. B) Primary hyposecretion is when an endocrine gland is normal but secrets too little hormone due to a deficiency of its tropic hormone. C) Primary hypersecretion is when an endocrine gland secretes too little hormone due to an abnormality in that gland. D) Primary hyposecretion is when an endocrine gland secrets too little hormone due to an abnormality in that gland.
D) This is the correct answer. A and B are false false; primary hyposecretion is when an endocrine gland secrets too little hormone due to an abnormality in that gland. C is false; primary hypersecretion is when an endocrine gland secretes too much hormone due to an abnormality in that gland.
Which of the following statements about sex differences in growth is FALSE. A) Puberty occurs earlier in females B) Males are several inches taller than females because boys grow faster than girls at their peak rate. C) Males have a greater androgen-induced growth spurt D) Females have 2 more years of prepubertal growth before plates close.
D) This is the correct answer. The statement in D is false since it is males that have 2 more years of prepubertal growth before plates close. Females hit puberty before males, therefore females are usually several inches shorter than males.
Which of the following statements is correct? A) Ligand-gated ion-channels are slow. B) G-Protein-coupled receptors undergo a conformational change and therefore are considered to be slow. C) Nuclear protein receptors are located inside the cell, therefore they require a hydrophilic hormone. D) Receptor tyrosine kinase is slow.
D) This is the correct choice, a growth factor binding to receptor tyrosin kinase leads to phosphorylation which affects other proteins in the cell that change gene transcription, which is a slow process. A and B are false; ion channels and G-protein-coupled receptors are fast. C is also false; since the receptor is inside the cell, it requires a lipophilic hormone (slow).
Which of the following statements about the synthesis of hormones is FALSE A) Peptide hormones are synthesized and packaged in ER, modified in Golgi, stored in cytoplasm, and eventually released by exocytosis B) Steroid hormones are derived from cholesterol C) A small change in chemical structure can have a large impact on hormonal effect/function D) The enzymes that are directly involved in the synthesis of catecholamines and thyroid hormones are found in organelle compartments.
D) This statement is false, since these enzymes are NOT found in organelle compartments. Rather they are cytosolic.
