Question 1

Under normal physiological conditions, what process functions to maintain relatively constant levels of circulating hormones?&#10;A)circadian rhythm&#10;B)feedback control&#10;C)hypothalamic stimulation&#10;D)second messenger control

Accepted Answer

A unique feature of the endocrine system is its ability to regulate itself by providing negative or positive feedback stimuli to each gland that produces a secretory hormone.All hormone production comes under some form of feedback control.Under normal physiological conditions, the overall effect of the two parts of the feedback loops in the endocrine system is to maintain relatively constant levels of circulating hormones.

Question 2

What term refers to direct cell-to-cell communication elicited by growth factors that are anchored to each cell's membrane?&#10;A)autocrine factor&#10;B)paracrine factor&#10;C)juxtacrine factor&#10;D)intracrine factor

Accepted Answer

The term juxtacrine factor refers to direct cell-to-cell communication elicited by growth factors that are anchored to each cell's membrane.When the cells come into contact with each other, this membrane-bound growth factor directly influences its neighboring cell.

Question 3

Somatostatin exerts a negative influence on which of the following hormones?&#10;1)TSH&#10;2)glucagon&#10;3)GH&#10;4)testosterone&#10;A)1, 2, 3&#10;B)1, 2, 4&#10;C)1, 3, 4&#10;D)2, 3, 4

Accepted Answer

A hypothalamic peptide, somatostatin, exerts a negative influence on TSH, GH, and several other hormone secretions, including gastrointestinal and pancreatic hormones.Somatostatin inhibits virtually all endocrine secretions (including gastrin, insulin, glucagon, and secretin) of the gastrointestinal tract, pancreas, and gallbladder.Its primary role is to attenuate hypersecretion of these hormones in pathological states.

Question 4

An increased TSH and decreased T&#8324; provide laboratory evidence of which disease?&#10;A)primary hypothyroidism&#10;B)secondary hypothyroidism&#10;C)tertiary hypothyroidism&#10;D)quaternary hypothyroidism

Accepted Answer

Abnormalities of hormone secretion are usually defined in terms of the serum levels of the hormone (that is, high or low levels) and the endocrine gland directly demonstrating the abnormality.In addition, the disease is defined by whether the hormone abnormality is the result of the endocrine gland producing the hormone (primary disease), a disease of the pituitary gland controlling the primary gland (secondary disease), a disease of the hypothalamus controlling the pituitary (tertiary disease), or an inability of the hormone's target tissue to respond to the hormone (end-organ, or quaternary, disease).The low T₄ indicates hypothyroidism.The low T₄ stimulates the increased production of TSH through the negative feedback mechanism.The elevated TSH, however, is unable to increase T₄ levels.Thus the problem lies with the endocrine gland producing the hormone, the thyroid gland, and is identified as primary hypothyroidism.

Question 5

The most commonly utilized challenge test to assist in evaluating a potential growth hormone deficiency is the:&#10;A)insulin challenge test&#10;B)dexamethasone suppression test&#10;C)oral glucose tolerance test&#10;D)LH-RH challenge test

Accepted Answer

The diagnosis of hypothalamic and pituitary disease is sometimes difficult and usually requires some type of suppressing or stimulating (i.e., challenge) test.The most commonly performed challenge test for a growth hormone problem is the insulin challenge test.

Question 6

The posterior lobe of the pituitary is also known as the ______, and the anterior lobe of the pituitary is also known as the ______.The ______ is the lobe that releases trophic hormones.&#10;A)adenohypophysis, neurohypophysis, anterior&#10;B)neurohypophysis, adenohypophysis, anterior&#10;C)adenohypophysis, neurohypophysis, posterior&#10;D)neurohypophysis, adenohypophysis, posterior

Accepted Answer

The hypothalamus exerts control over pituitary function by both direct neurostimulation and neurosecretion.The hypothalamus directly innervates the posterior lobe of the pituitary, which is also known as the neurohypophysis.In contrast, the anterior lobe of the pituitary, which is also known as the adenohypophysis, responds to hypothalamus-derived neuropeptides which are released into the portal circulation of the brain.These hypothalamus-derived neuropeptides stimulate the adenohypophysis to release trophic hormones into the circulation.

Question 7

Which of the following are true of the second messenger signaling system?
1)This system requires the availability of energy in the form of ATP.
2)This system is utilized by steroid and peptide hormones.
3)An example of a second messenger is cyclic-AMP.

A)1, 2, 3
B)1, 2
C)2, 3
D)1, 3

Accepted Answer

The second messenger signaling system indeed requires ATP, as it is often used in the process of converting primary signals into secondary ones, such as the conversion of ATP to cyclic-AMP (cAMP). Steroid hormones, however, typically do not utilize second messenger systems; they usually pass directly through the cell membrane and act on intracellular receptors, contrasting with peptide hormones that often do use second messenger systems.

Question 8

Which of the following statements are true of steroid hormones?
1)They interact with their target cells by binding to specific receptors located in both the intracellular cytoplasmic and nuclear fractions of the cells.
2)They enter the cell primarily through diffusion.
3)Transport proteins are necessary to carry steroids from the organ of synthesis, through the blood stream, to their site of action.
4)They utilize the second messenger signaling system.

A)1, 2, 3
B)1, 2, 4
C)1, 3, 4
D)2, 3, 4

Accepted Answer

The transport and actions of steroid hormones are based on the high lipid solubility and low water solubility characteristics of these substances.Because of their low water solubility, transport proteins are necessary to carry steroids from the organ of synthesis, through the highly polar nature of the blood stream, to their site of action.Once at the site of action, steroids enter the cell primarily through diffusion, bind to the receptor molecule, and produce a conformational change in the receptor structure.These intracellular receptors are located in both the cytoplasmic and nuclear fractions of the cells.

Question 9

An elevated serum insulin-like growth factor 1 (IGF-1) is useful in the diagnosis of which disease?&#10;A)Cushing's syndrome&#10;B)diabetes&#10;C)acromegaly&#10;D)pituitary adenoma

Accepted Answer

A growth hormone excess is associated with acromegaly.The major effect of growth hormone is to induce the synthesis of an insulin-like growth factor (IGF-1) by the liver.In patients with acromegaly, IGF-1 levels are raised to a greater extent than those of growth hormone itself.The recent availability of commercial immunoassays for IGF-1 has allowed for the routine measurement of this circulating growth factor for the diagnosis and management of patients with acromegaly.

Question 10

Trophic hormones are produced by the ______, and releasing factors are produced by the ______.&#10;A)hypothalamus, pituitary&#10;B)pituitary, hypothalamus&#10;C)specific endocrine glands, hypothalamus&#10;D)specific endocrine glands, pituitary

Accepted Answer

The hypothalamus produces releasing factors, and the pituitary produces trophic hormones.The hypothalamus senses the need and level of circulating hormone.When the level drops too low or the need is sensed, the hypothalamus will increase the production of releasing factors, which pass directly to the pituitary to stimulate hormone synthesis and secretion of trophic hormones.Trophic hormones are those hormones that affect growth, nutrition, and function of other endocrine glands.

Question 11

Which of the following best describes a hormone?&#10;A)a chemical produced in one part of the body that acts in a distant part of the body&#10;B)a chemical produced in one part of the body that acts in close proximity to its production&#10;C)a chemical produced whose action may be either close or distant to the site of production&#10;D)a chemical that must enter the blood stream to be transported to its site of action

Accepted Answer

The answer of Which of the following best describes a...

Question 12

What hormone has the following characteristics?
Source - anterior pituitary
Target organ - ovary/testis
Circulating level - 5 to 25 mIU/mL
Biological effect - corpus luteum, ovary, Leydig cells, testis

A)prolactin
B)ACTH
C)FSH
D)LH

Accepted Answer

The answer of What hormone has the following characteristics?&#10;Source -...

Question 13

Which test(s) is/are used to determine if hypothalamic or pituitary dysfunction are the cause of hypogonadal disease and hypergonadal disease?&#10;A)FSH&#10;B)LH&#10;C)prolactin&#10;D)both a and b

Accepted Answer

The answer of Which test(s) is/are used to determine if...

Question 14

An elevated serum cortisol and an elevated serum cortisol following a low-dose and a high-dose dexamethasone suppression test provide laboratory evidence of which clinical situation?&#10;A)Cushing's disease&#10;B)Cushing's syndrome&#10;C)ectopic ACTH-producing tumor&#10;D)pituitary adenoma

Accepted Answer

The answer of An elevated serum cortisol and an elevated...

Question 15

Which of the following laboratory tests is most useful in distinguishing between hypothalamic and pituitary causes of thyroid dysfunction?&#10;A)TRH stimulation test&#10;B)TSH&#10;C)T&#8324;&#10;D)T&#8323;

Accepted Answer

The answer of Which of the following laboratory tests is...

Question 16

Which of the following forms of thyroxine would be the least available to tissue receptors?&#10;A)thyroxine free in the circulation&#10;B)thyroxine bound to albumin in the circulation&#10;C)thyroxine bound to prealbumin in the circulation&#10;D)thyroxine bound to thyroxine-binding globulin in the circulation

Accepted Answer

The answer of Which of the following forms of thyroxine...

Question 17

Which of the following is/are limitations to the measurement of ACTH in the laboratory?&#10;A)short half-life of ACTH&#10;B)stringent specimen collection requirements&#10;C)need for immediate storage of the specimen at -20&#176;C&#10;D)all of the above

Accepted Answer

The answer of Which of the following is/are limitations to...

Question 18

The laboratory measurement of bioavailable testosterone includes measurement of:&#10;A)testosterone bound to circulating sex hormone-binding globulin (SHBG)&#10;B)testosterone that is free in the circulation&#10;C)testosterone that is bound to albumin in the circulation&#10;D)both b and c

Accepted Answer

The answer of The laboratory measurement of bioavailable testosterone includes...

Deck 48: General Endocrinology