endocrine testing Flashcards

1
Q

describe endocrine glands

A

they are ductless glands who secrete hormones into the blood for systemic circulation

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2
Q

endocrine glands are controlled by

A

feedback loops

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3
Q

example of an exocrine gland

A

salivary glands

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4
Q

what types of stimulus are a part of endocrine gland regulation

A

Humoral, neural and hormonal

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5
Q

humeral stimulus example

A

when there is a low concentration of Calcium in the capillary blood the parathyroid glans respond but secrete PTH which increases blood calcium

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6
Q

what is a humoral stimulus

A

hormone release causes by alter level of certain critical ions of nutrients

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7
Q

what is a neural stimulus

A

hormone release caused by a neural input

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8
Q

neural stimulus example

A

action potentials in preganglionic sympathetic fibers to the adrenal medulla and then the adrenal medulla responses by secreting epinephrine and norepinephrine

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9
Q

what is a hormonal stimulus

A

hormone release cause by another hormone

a tropic hormone

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10
Q

hormonal stimulus

A

hormones from hypothalamus causes the APG to secrete hormones that stimulate other endocrine glands to secrete hormones as a response

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11
Q

which hormones is responsible for regulating body ttemp

A

TRH

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12
Q

how do hormone circulate

A

both free and bound to plasma proteins
Binding helps to increase the half-life of the hormone in the circulation
Hormones bound to transport proteins serve as reservoirs, replenishing the concentration of free hormones when they are bound to target tissue receptors or cleared from the circulation

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13
Q

levels of ______-______ ______ are subject to hormone regulation and can vary with age disease Staes and certain drug therapies

A

plasma-binding proteins

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14
Q

plasma-binding proteins examples

A

CBG (cortisol binding globulin), SHBG (sex hormone binding globulin) and TBG (thyroid binding globulin)

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15
Q

free hormones generally represent the

A

fraction available for binding to the receptors, or the active hormone

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16
Q

free hormones dictate

A

the magnitude of feedback inhibition that that controls hormone relase

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17
Q

free hormone is also the fraction

A

that is cleared from the circulation

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18
Q

Would you just order a TSH test in the clinic

A

no you would prefer to order the TSH AND free T3/T4 because a free hormone test is ideal for current health status (clinical states, hormone excess and deficiency)

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19
Q

shorter half life in hormones

A

Certain hormones are secreted in a more pulsatile/episodic manner and have shorter half lives
This leads to the need to measure hormones at particular times of the day or to rely on 24 hour collection methods

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20
Q

using circadian rhythms of hormones help us

A

determine when to order that the hormone levels are checked

for instance we should order ACTH and Cortisol levels in the morning because they are the highest around 6 am

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21
Q

hormone secretion rates

A

The secretion rates of many (not all) hormones rhythmically fluctuate up and down as a function of time

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22
Q

basal sectarian of hormones

A

Basal secretion of most hormones is not a continuous process but rather has a pulsatile nature

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23
Q

circhoral

A

episodic release of about an hour

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24
Q

ultradian

A

episodic release long than and hours but less than 24 hours

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25
circadian
episodic release approximately every 24 hours | e.g release of ACTH and Cortisol to wake up
26
diurnal
episodic activity expressed at defined periods of the day
27
primary disease-- endocrine dysfunction
involves the organs the produce the hormone
28
secondary endocrine dysfunction
related to the pituitary gland which produces trophic hormones
29
primary disease-- endocrine dysfunction example
primary hypothyroidism results from an underactive thyroid gland and ↓ T4
30
secondary disease-- endocrine dysfunction example
secondary hypothyroidism is due to an underactive anterior pituitary which secondarily ↓ thyroid function owing to ↓ TSH and subsequent ↓ T4
31
Tertiary Disease -- endocrine dysfunction example
tertiary hypothyroidism due to ↓ release of TRH which ↓ TSH which ↓ synthesis of T4
32
Tertiary Disease -- endocrine dysfunction
hypothalamic problems
33
Endocrine Hypofunction
diminished production and secretion of hormones
34
primary deficiency disorders
Hashimoto’s thyroiditis Addison’s disease Type 1 DM the endocrines trophic (stimulating) hormone is actually elevated due to it normal feedback responses Hashimoto’s thyroiditis -the thyroid gland is under active and T4 is not being produced in regular amounts so it is unable to perform properly in the negative feedback loop and therefore more and more TSH is produced
35
Secondary Deficiency Disorder
Secondary hypothyroidism Secondary adrenal insufficiency occurs when the trophic hormone for the target organ is deficient, and it therefore can not properly perform it's function can develop to primary hypopituitarism Under active anterior pituitary results in ↓ TSH which results in ↓ thyroid hormones
36
Tertiary Deficiency Disorder
Occurs one step higher than secondary problems Hypothalamic problem Impaired function of the hypothalamus results in ↓ TRH which ↓ TSH which ↓ thyroid hormones
37
Types of Endocrine Hyperfunction
As with deficiency syndromes, endocrine excess may occur in primary, secondary, or tertiary forms.
38
primary endocrine hyperfuncion examples
Parathyroid adenoma and graves
39
secondary endocrine hyperfuncion examples
Anterior pituitary adenoma resulting in acromegaly Anterior pituitary adenoma resulting in hyperthyroidism
40
Parathyroid adenoma
causes an increase in PTH production
41
Graves disease
antibodies binding to TSH receptors causing ↑ thyroid hormone production
42
primary function of endocrine testing
identify the hormone(s) that are being over- or under-produced, to determine which gland(s) are involved, and to determine the cause of the hormone imbalance. This may involve measuring hormone levels and their metabolites in the blood and/or urine tests are a "snapshot" of what is occurring within a dynamic system
43
Stimulation test to assess
hypofunctioning (hormone deficiency)
44
Suppression test to assess
hyperfunctioning (hormone excess)
45
Sources for Testing Endocrine Function
blood, urine (urine sample or 24 hour urine), imaging and tissue
46
how are tissues gather for endocrine testing
obtained by biopsy
47
blood sources for Testing Endocrine Function-- capillary puncture
finger stick glucose
48
Sources for Testing Endocrine Function- venipuncture
blood obtained directly from the vein | used for the majority of test run on blood
49
Sources for Testing Endocrine Function-- material stick
blood is obtained directly from the artery, typically used for blood gas analysis
50
glucose
The simple sugar (monosaccharide) that serves as the chief source of energy in the body. Glucose is the principal sugar the body makes. The body makes glucose from proteins, fats and, in largest part, carbohydrates. Glucose is carried to each cell through the bloodstream. Cells cannot use glucose without the help of insulin. Some cells such as brain cells have severely limited storage capacities for either glucose or ATP, therefore the blood must maintain a fairly constant supply of glucose.
51
insulin
pancreatic hormone which works to lower the blood glucose levels
52
glucagon
Pancreatic hormone which works to raise blood glucose levels (works opposite to insulin)
53
Fatty Acids (FA) / Free Fatty Acids (FFA)
Source of fuel that is the product of fat breakdown
54
Triglycerides (TG)
Fatty acids packaged for future use
55
amino Acids (AA)
Source of fuel that is the product of protein breakdown
56
Glycogen
Long term storage molecule of glucose which is stored and synthesized mainly in the liver and muscles
57
Lypolysis
Breakdown of triglycerides to fatty acids and further degradation which leads to production of ketones and energy
58
pancreas main function
is to make digestive enzymes but it does make a small amount of insulin and glucagon from pancreatic islet Beta cells
59
Pancreatic islets (Islets of Langerhans) comprise
comprise 2% of pancreas and produce insulin and glucagon
60
Insulin secreted by beta cell
Secreted during and after meal when glucose and amino acid blood levels are rising Stimulates cells to ABSORB these nutrients lowering blood glucose levels Promotes synthesis glycogen, fat, and protein Suppresses use of already stored fuels facilitates glucose in
61
_____, ____, _____, and _____ absorb glucose without insulin, but other tissues require insulin
Brain, liver, kidneys and RBCs
62
Insufficiency or inaction in insulin or beta cells is the cause of
diabetes mellitus
63
Glucagon-made by alpha cells liver
Released between meals when blood glucose concentration is falling In liver, stimulates gluconeogenesis, glycogenolysis, and the release of glucose into the circulation raising blood glucose level
64
Glucagon-made by alpha cells adipose tissue
Released between meals when blood glucose concentration is falling In adipose tissue, stimulates fat catabolism and release of free fatty acids
65
glucagon and amino acids
released in response to rising amino acid levels in blood, promotes amino acid absorption, and provides cells with raw material for gluconeogenesis
66
Gluconeogenesis
formation of glucose from everything BUT carbs
67
eating
eat, increases blood sugar, pancreatic beta cells release insulin, liver concerts glucose into glycogen and cells uptake glucose, blood sugar is regulated
68
starving
decrease in blood sugar, pancreatic alpha cells release glucagon, liver converts glycogen into glucose (glycogenolysis, gluconeogenesis, glucose released into bloodstream), blood sugar is normalized
69
blood sugar test are done when patents are
fasting | Blood glucose > 180 causes excess glucose to spill into urine (glucosuria)
70
hyperglycemia
elevated blood sugar | greater than 100 mg/dl
71
hypoglycemia
low blood sugar, less than 70 mg/dl
72
Glucose in urine increases
its osmotic pressure resulting in loss of water and electrolytes (polyuria) osmosis follows glucose into urine (dehydration) may cause bed wetting in younger patients
73
polydipsia
water loss increases thirst
74
polyphagia
cells aren’t getting nutrients so you crave food (insulin drives amino acids into cells so w/o it u become nutrient deficient) (catabolic state causes wt loss in DM1 juvenile)
75
Blood glucose should be evaluated based on
Serum glucose levels must be evaluated according to the time of day they are performed and whether the patient has been fasting no calories for at least 8 hours
76
Hemoglobin A1c
Hemoglobin A1c binds strongly to glucose called (hemoglobin glycosylation) Blood test that represents the amount of glycosylated hemoglobin – the average blood sugar level for the 120 (RBC live 3 months) day period before the test Reflects degree of hyperglycemia of the preceding 3 months Advantageous because it is not affected by short-term variations in glucose Used to diagnose and monitor DM
77
the higher the hbA1c then
the darker the test stains
78
Pre-Diabetes
Pre-Diabetes "Impaired fasting Glucose" "impaired glucose Tolerance" = b/w normal and overt “obvious” DM May be Asymptomatic but still at risk of Atherosclerosis (b/c blood flow is slowed from glucose and glucose causes inflammation which leads to fat deposits in arteries)
79
pre diabetes criteria
100 to 126 mg/dl on the FBG test, 140-199 mg/dl on the OGTT Hemoglobin A1c between 5.7 – 6.4%
80
Oral Glucose Tolerance Test
2 hours after 75g glucose in water
81
Diabetes Mellitus – ADA Screening
Testing should be considered in all adults who are overweight (BMI ≥25 kg/m2) and have additional risk factors* In the absence of criteria (risk factors), testing for diabetes should begin at age 45 years If results are normal, testing should be repeated at least at 3-year intervals, with consideration of more frequent testing depending on initial results (e.g., those with prediabetes should be tested yearly), and risk status
82
Screen for Complications of DM, Urinalysis
Certain components of the dipstick U/A can be used to assess/screen for complications related to DM
83
Glucosuria
kidney can't reabsorb the filtered glucose Glycosuria occurs when the filtered load of glucose exceeds the ability of the tubule to reabsorb it – with the most common etiology being uncontrolled diabetes mellitus
84
ketones
Ketones, products of fat metabolism, normally are not found in the urine. A positive result (ketonuria) is associated with diabetic ketoacidosis
85
protein
The reagent on most dipstick tests is sensitive to albumin. A significant amount of albumin in the urine (proteinuria) in a diabetic patient indicates renal disease (nephropathy