ENDOCRINOLOGY Flashcards

1
Q

Network of ductless glands that secrete hormones directly into the blood
Considered to be the regulatory system of the body
Regulated by means of control of hormone synthesis rather than by degradation

A

Endocrine System

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2
Q

Chemical signals produced by specilized cells, secreted into the blood stream and carried to a target tissues

A

Hormones

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3
Q

An increased in the product results to elevation of the activity of the system and the production rate
Ex: Gonadal, Thyroidal and Adrenocortical hormone

A

Positive Feedback System

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4
Q

An increased in the product results to decreased activity of the system and the production rate
Ex: Leutenizing Hormone

A

Negative Feedback system

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5
Q

Secreted in one location and release into blood circulation; binds to specific receptor to elicit physiological response

A

Endocrine

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6
Q

Secreted in endocrine cells and released into interstitial space; binds to specific receptor in adjacent cell and affects its dunction

A

Paracrine

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7
Q

Secreted in endocrine cells and released into interstitial space; binds to specific receptor in adjacent cell and affects its function

A

Paracrine Hormones

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8
Q

Secreted in edocrine cells and sometimes released into interstitial space; binds to specific receptor on cell of origin resulting to self-regulation of its function

A

Autocrine

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9
Q

Secreted in endocrine cells and remains in relation to plasma membrane; acts on immediately adjacent cell by direct cell-to-cell contact

A

Juxtacrine Hormone

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10
Q

Secreted in endocrine cells and remained as well as function inside the synthesis of origin

A

Intracrine hormone

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11
Q

Secreted in endocrine cells and released into lumen of gut; affects their function

A

Exocrine Hormone

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12
Q

Secreted in neurons and released into extracellular space; binds to receptor in nearby cell and affects its funciton

A

Neurocrine Hormone

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13
Q

Synthesized and stored within the cell in the form of secretory granules and are cleaved as needed
Cannot cross the cell membrane due to their large molecular size and thus; produce their effects on the outer surface of the cell

A

Peptides and Proteins

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14
Q

Follicle-Stimulating Hormone
HCG
Thyroid Stimulating Hormone
Erythropoietin

A

Glycoprotein

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15
Q

ACTH
ADH
GH
Angiotensin
Calcitonin
Cholecystokinin
Gastrin
Glucagon
Insulin
Melanocyte-Stimulating Hormone
Oxytocin
PTH
Prolactin
Somatostatin

A

Polypeptide

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16
Q

Lipid molecules that have cholesterol as a common precurosi
Produced by adrenal glands, ovaries, testes and placenta
Water insoluble (hydrophobic) and circulate bound to a carrier protein

A

Steroids

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17
Q

Derived from an amino acid & they are intermediary between steroid and protein hormones
Ex: Epinephrine, Norepinephrine, Triiodothyronine, Thyroxine

A

Amines

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18
Q

Portion of the brain located in the walls and floor of the third ventricle
Link between the nervous system and the endocrine system

A

Hypothalamus

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19
Q

Hormone
TRH
Gn-RH
GH-IH
GH-RH
PIF

A

Hormones produced in the Hypothalamus

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20
Q

Attached to the midbrain
Secretes melatonin that decreases the pigmentation of the skin
Secretions are controlled by nerve stimuli

A

Pineal Gland

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21
Q

“Master Gland”
Located in a small cavity in the sphenoid bone of the skull called the sella turcica or Turkish saddle
Connected by the infundibular stalk to the median eminence of the hypothalamus
All pituitary hormones have circadian rhythms

A

Pituitary Gland
Hypophysis

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22
Q

“True Endocrine Gland”
Regulates the released and production of hormones
Hormones are either peptides or glycoproteins

A

Adenohypophysis
Anterior Pituitary Gland

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23
Q

Secrete growth hormone

Immunochemical Test

A

Somatotrophs

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24
Q

Secrete prolactin

Immunochemical Test

A

Lactotrophs
Mammotrophs

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25
Q

Secrete TSH

Immunochemical Test

A

Thyrotrophs

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26
Q

Secrete Proopiomelandcortin produce ACTH, B-endorphin, & B-lipotropin

Immunochemical Test

A

Corticotrophs

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27
Q

Secrete LH & FSH

Immunochemical Test

A

Gonadotrophs

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28
Q

Most abundant of all pituitary hormones
Major stimulus: Deep sleep
Secretion is erratic and occurts in short burst

A

Growth Hormone (GH) Somatotropin

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29
Q

Reference Value:

A

(< 7 ng/mL)

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30
Q

Most common cause of GH deficiency in children
Children with pituitary dwarfism, normal proportions are retained and show no intellectual abnormalities

A

Idiopathic Growth Hormone Deficiency

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31
Q

Most common etiology in adult-onset GH deficiency

A

Pituitary Adenoma

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32
Q

Due to Overproduction of GH

A

Acromegaly

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33
Q

Patient preparation for Growth Hormone measurement

A

Rest 30 minutes before blood collection

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34
Q

Screening Test for measurement of GH
Result: Elevated Serum GH

A

Physical Activity Test
Exercise test

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35
Q

Confirmatory test:
GOLD STANDARD for measurement of GH

A

Insulin Tolerance Test

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36
Q

2nd Confirmatory Test for GH
It is a 24-hour or nighttime monitoring of GH
Confirmed GH deficiency: Failure of GH to rise >5ng/mL in adults & >10ng/mL in children

A

Arginine Stimulation Test

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37
Q

Screening test for detection of Acromegaly

A

Insulin-like Growth Factor 1 (IGF-1)

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38
Q

Confirmatory test for the detection of Acromegaly
Blood is collected every after 30 minutes for 2 hours
Fasting sample is required

A

Glucose Suppression Test

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39
Q

Important markers in diagnosing fertility and menstrual cycle disorders
Present in the blood of both male and female at all ages

A

Gonadotropins
FSH & LH

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40
Q

Aids in spermatogenesis in male (Sertoli cells)
Aids in follicular growth in female

A

Follicle-Stimulating Hormone

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41
Q

Helps Leydig cells to produce testosterone and is necessary for ovulation and final follicular growth in female

A

Luteinizing Hormone

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42
Q

Acts on Thecal cells to cause the synthesis of androgens, estrogens and progesterone

A

Luteinizing Hormone

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43
Q

Elevation of FSH is a clue in the diagnosis of

A

Premature menopause

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44
Q

Also known as Thyrotropin
Main stimulus for the uptake of iodide by the thyroid gland
Acts to increase the number & size of follicular cells; stimulates thyroid hormone synthesis

A

Thyroid Stimulating Hormone (TSH)

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45
Q

Single-chain peptide without disulfide bonds
Produced in response to low serum cortisol, regulator of adrenal androgen synthesis

A

Adrenocorticotrophic Hormone (ACTH)

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46
Q

Deficiency of ACTH will lead to atrophy of the _____

A

Zona Glomerulosa
Zona Reticularis

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47
Q

Highest levels of ACTH is between

A

6:00 - 8:00

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48
Q

Lowest level of ACTH is between

A

6:00 pm - 11:00 pm

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49
Q

ACTH is increased in:

A

Addison’s Disease
Ectopic Tumors
Protein-rich meals

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50
Q

Best time to collect specimen for ACTH

A

8:00 am - 10:00 am

51
Q

Pituitary lactogenic hormone; Stress hormone; Direct effector hormone
Functions in the initiation and maintenance of lactation
Acts in conjunction with estrogen & progesterone to promote breast tissue development

A

Prolactin

52
Q

Major inhibitor of Prolactin:

A

Dopamine

53
Q

Highest levels of prolactin during:

A

4:00 am - 8:00 am
8:00 pm - 10:00 pm

54
Q

Reference Value of Prolactin

A

Male: 1-20 ng/mL
Female: 1-25 ng/mL

55
Q

Capable of releasing the hormones: Oxytocin & Vasopressin but not capable of producing it
Release is in response to serum osmolality and by suckling

A

Neurohypophysis
Posterior Pituitary Gland

56
Q

Secreted in association with a carrier protein
Stimulates contractions of the gravid uterus at term “Fergusson Reflex”
Released in response to neural stimulation of receptors in birth canal & uterus, and of touch receptors in breast

A

Oxytocin

57
Q

Nonapeptide that acts on the distal convoluted and collecting tubules of the kidneys
Maintains Osmotic homeostatis by regulating Water balance
Decreases production of Urine by promoting reabsorption of water by the renal tubules
Increases blood pressure
Promotes Factor VII release from hepatocytes & factor VIII

A

Anti-Diuretic Hormone
Arginine Vasopressin (AVP)

58
Q

Reference Value of Vasopressin/ ADH

A

0.5 - 2 pg/uL

59
Q

Principal regulator of ADH secretion

A

Increased plasma osmolality

60
Q

Deficiency of ADH; Results in severe Polyuria (>3L of urine/day)

A

Diabetes insipidus

61
Q

Clinical picture of Diabetes insipidus

A
  1. Normoglycemia
  2. Polyuria with low specific gravity
  3. Polydipsia
  4. Polyphagia
62
Q

Deficiency of ADH with normal ADH receptor
Due to failure of the pituitary gland to secrete ADH
Large volume of urine excreted (3-20L/day)

A

True Diabetes Insipidus
Neurogenic DI

63
Q

Characterized by having normal ADH but abnormal ADH receptor
Due to failure of the kidneys to respond to normal or elevated ADH levels

A

Nephrogenic Diabetes Insipidus

64
Q

Diagnostic Test for Diabetes Insipidus
Fasting: 10:00 pm onwards
After 8-12 hours without fluid intake, urine osmolality does not rise above 300 mOsm/kg

A

Overnight Water Deprivation Test
Concentration Test

65
Q

Overnight Water Deprivation Test
ADH: LOW
Kidneys rapidly acts to conserve water in response to Exogenous ADH administration

A

Neurogenic DI

66
Q

Overnight Water Deprivation Test
ADH: N/High
Administration of additional ADH has little or no effect on renal water reabsorption

A

Nephrogenic DI

67
Q

Refers to the sustained production of ADH in the absence of a known stimuli
Characterized by decreased urine volume, low plasma osmolality and normal or elevated urine sodium levels

A

Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)

68
Q

Also known as the butterfly-shaped gland
Consist of two lobes located in the lower part of the neck

A

Thyroid Gland

69
Q

Fundamental structural unit of the thyroid gland

A

Follicles

69
Q

Two types of cells in Thyroid Gland

A

Follicular cells (T3 & T4)
Parafollicular Cells (Calcitonin)

70
Q

Glycoprotein that acts as a preformed matrix containing tyrosyl groups
Stored in the follicular colloi of the thyroid gland

A

Thyroglobulin

71
Q

Most important element in the biosynthesis of thyroid hormone

A

Iodine

72
Q

Neuroendocrine system that regulates the production and secretion of thyroid hormones

A

Hypothalamic-Pituitary-Thyroid Axis (HPTA)

73
Q

Most active thyroid hormonal activity
75-80% is produced from the tissue deiodination of T4
Better indicator of recovery from hyperthyroidism as well as the recognition of recurrence of hyperthyroidism

A

Triiodothyronine
T3

74
Q

Reference Value for T3

A

Adult: 60-160 ug/dL
Child: 105-245 ng/dL

75
Q

Principal Secretory product
Major fraction of organic iodine in the circulation
Prohormone for T3 production
Amount of serum T4 is a good indicator of the thyroid secretory rate

A

Tetraiodothyronine
T4

76
Q

Transports majority of T3 (affinity for T3 is lower than T4)
Transports 70-75% of total T4

A

Thyroxine-Binding Globulin
TBG

77
Q

Transports 15-20% of total T4
T3 has NO affinity for prealbumin

A

Thyroxine-Binding Prealbumin (Transthyretin)

78
Q

Transports T3 and 10% of T4

A

Thyroxine-Binding Albumin

79
Q

Thyroid autoantibodies responsible for autoimmune thyroid disorders:

A
  1. Thyroperoxidase (TPO)
  2. Thyroglobulin
  3. TSH Receptor
80
Q

Autoantibody involved in Hashimoto’s disease

A

Thyroperoxidase

81
Q

Autoantibody involved in Grave’s disease

A

TSH Receptor

82
Q

Excess of circulating thyroid hormone

A

Hyperthyroidism

83
Q

Elevated T3 and T4
Decreased TSH

A

Primary hyperthyroidism

84
Q

Increased FT4 and TSH

A

Secondary Hyperthyroidism

85
Q

Signs and Symptoms:
1. Tachycardia
2. Tremors
3. Weight LOSS
4. HEAT intolerance
5. Emotional ability
6. Menstrual changes

A

Hyperthyroidism

86
Q

Group of syndromes caused by high levels of free thyroid hormone in the circulation

A

Thyrotoxicosis

87
Q

FT3 increased
FT4 Normal
TSH Low

A

T3 Thyrotoxicosis
Plummer’s Disease

88
Q

T3 Normal or Low
T4 Increased
TSH Low

A

T4 Thyrotoxicosis

89
Q

Most commonc cause of Thyrotoxicosis
Antibodies are produced that activate the TSH receptor
Occurs 6x more commonly in women
Features: Exophthalmos & pritibial myxedema

A

Graves’ Disease
Diffuse Toxic Goiter

90
Q

Thyroid turns into a wooy or stony hard mass

A

Riedel’s Thyroiditis

91
Q

Shows no clinical symptoms but
TSH Low
FT3 FT4 Normal

A

Subclinical Hyperthyroidism

92
Q

Associated with neck pain, low-grade fever and swings in thyroid function tests
Thyroidal peroxidase (TPO) antibodies are absent

A

De Quervain’s Thyroiditis
Subacute Granulomatous Thyroiditis

93
Q

Insufficient amounts of thyroid hormone are available to tissues
Treated with thyroid hormone replacement therapy

A

Hypothyroidism

94
Q

Signs & Symptoms:
1. Bradycardia
2. Weight GAIN
3. Coarsened skin
4. COLD intolerance
5. Mental Dullness

A

Hypothyroidism

95
Q

Primarily due to deficiency of elemental ioding
Caused by destruction or ablation of thyroid gland

A

Primary Hypothyroidism

96
Q

Most common cause of Primary Hypothyroidism
Characterized by a thyroid replaced by a nest of lymphoid tissue causing cell lysis and inflammatory reaction
TSH High
TPO Antibody POSITIVE

A

Hashimoto’s Disease

97
Q

Peculial nonpitting swelling of the skin
Skin becomes infiltrated by mucopolysaccharides

A

Myxedema

98
Q

Severe form of Primary Hypothyroidism

A

Myxedema Coma

99
Q

Due to pituitary destruction or pituitary adenoma
T3 T4 Low
TSH Low

A

Secondary Hypothyroidism

100
Q

Due to hypothalamic disease
T3 T4 low
TSH Low

A

Tertiary hypothyroidism

101
Q

Defect in the development or function of the fland

Screening: T4 Low
Confirmatory: TSH High

A

Congenital Hypothyroidism
Cretinism

102
Q

TSH Value <10mIU/L

A

No further test

103
Q

TSH value 10-12mIU/L

A

Repeat test in 2-6 weeks

104
Q

TSH >20mIU/L

A

For Endocrinologic evaluation to diagnose hypothyroidism

105
Q

T3 T4 Normal
TSH S. High

A

Subclinical Hypothyroidism

106
Q

Measures the relationship between TRH & TSH secretions
Used to differentiate euthyroid and hyperthyroid patients who had undetectable TSH levels

A

TRH Stimulation Test

107
Q

Most important thyroid function test
Best method for detecting clinically significvant thyroid dysfunction
Most clinically sensitive assay for the detection of primary thyroid disorders
Helps in early detection of hypothyroidism
Differentiates primary from secondary hypothyroidism

A

TSH Test

108
Q

Smallest endocrine gland in the body

A

Parathyroid Gland

109
Q

Most common cause of hypercalcemia
Due to presence of a functioning parathyroid adenoma
Accompanied with phosphaturia
Lab:
1. PTH High
2. Ionized Ca High
3. Ca in Urine High
4. Phosphate Low

A

Primary Hyperparathyroidism

110
Q

Develops in response to decrease serum calcium
Diffuse hyperplasia of all 4 glands
Patient develops severe bone disease

A

Secondary Hyperparathyroidism

111
Q

Occurs with Secondary hyperparathyroidism
Phosphate Normal to High

A

Tertiary Hyperparathyrodism

112
Q

Due to accidental injury to the parathyroid gland during surgery

A

Hypoparathyroidism

113
Q

Has pyramid-like shape located above the kidneys
Composed of distinct but conjoined glands, the outer adrenal cortex and inner adrenal medulla

A

Adrenal Gland

114
Q

Outer Region of the Adrenal gland secreting the Steroid hormone
Major site of steroid hormone production
Yellow

A

Adrenal Cortext

115
Q

3 Layers of Adrenal Cortex

A
  1. Zona glomerulosa - Mineralocorticoid
  2. Zona fasiculata - Glucocorticoid
  3. Zona reticularis - Androstenedione & Dehydroepiandrosterone
116
Q

Principal Glucocorticoid
Synthesis is regulated by ACTH
Mostly bound to glycoprotein, transcortin
Stimulates Gluconeogenesis

A

Cortisol

117
Q

Urinary Metabolite of Cortisol:

A
  1. 17-hydroxycorticosteroid
  2. 17-Ketogenic steroids
118
Q

Method to detect 17-hydroxycorticosteroid

A

Porter-Silber Method (Yellow)
Phenyl hydrazine in H2SO4 + Alcohol

119
Q

Method used to detect 17-Ketogenic Steroids

A

Method: Zimmermann Reaction (Reddish Purple)
Meta-Dinitrobenzene
Norymberski (Oxidation procedure)

120
Q

Excessive production of CORTISOL & ACTH, but decreased Aldosterone & renin

A

Hypercortisolism
Cushing’s Syndrome

121
Q

Due to decreased Cortisol production - 90% destruction of the adrenal cortex
Aldosterone deficiency
ACTH release
Disorder: Addison’s Disease

A

Primary Hypocorticolism
Primary Adrenal Insufficiency

122
Q

due to hypothalamic-pituitary insufficiency with loss of ACTH

A

Secondary Hypocorticolism

123
Q

205

A