Endocrinology Flashcards
(86 cards)
1
Q
What type of cellular message is sent to other cells via the bloodstream?
A
Endocrine
2
Q
What type of cellular message is sent to other cells via the gastrointestinal tract?
A
Exocrine
3
Q
What type of cellular message is sent to other cells neurologically?
A
Neurocrine
4
Q
What type of cellular message is sent to other cells via the interstitial fluid?
A
Paracrine
5
Q
What are some characteristics of an amine?
A
- Very short half life
- Includes things like tryptophan, epinephrine, and melatonin
6
Q
What are some characteristics of a peptide?
A
- Generally an unbroken chain of AA of 50 or less
- HYDROPHILIC (H2O soluble) = doesn’t cross cell membranes easily
- Must first bind to membrane bound receptors
7
Q
What are some characteristics of a protein?
A
- Made of chains of AA (>50)
- Primary, secondary, and tertiary structures
8
Q
What are some characteristics of a glycoprotein?
A
- Conjugated proteins bound to carbs
- Solubility and half life are similar to protein hormones
9
Q
What are some characteristics of a steroid?
A
- Derived from a lipid (typically cholesterol)
- HYDROPHOBIC = must be transported into the blood bound to carrier proteins and can cross the cell
10
Q
What are some characteristics of a fatty acid?
A
- Small fatty acid derivatives of an arachidonic acid
- Rapidly degraded
- Effective only seconds
11
Q
Define metabolism
A
The sum of chemical processes that occur within a living organism to maintain life and includes both catabolism and anabolism
12
Q
What determines the extent to which hormones are capable of binding to receptors and eliciting their intended effects?
A
The rate of catabolism or anabolism
13
Q
How does alcohol consumption affect hormones metabolism?
A
- It appears to INC the degradation of testosterone
- Extended consumption may cause cirrhosis, which in turn causes less albumin and other binding proteins
14
Q
Many hormones are produced in the ___ ___ by a cascade of ___ reactions
A
Adrenal gland; enzymatic
15
Q
What are the two predominant organs for eliminating hormones?
A
Kidney and Liver
16
Q
What is the role of the liver in hormone elimination?
A
Tagging certain hormones for destruction or creation of different molecules
17
Q
How are steroid hormones eliminated?
A
By inactivating metabolic pathways and excretion in the urine or bile
18
Q
How are thyroid hormones eliminated?
A
They are inactivated by intracellular deiodinases
19
Q
How are catecholamines eliminated?
A
They are rapidly degraded within the blood circulation
20
Q
How are fatty acid derivatives eliminated?
A
They are rapidly inactivated by metabolism and typically active for a short period of time (seconds)
21
Q
What are the two forms in which hormones will circulate the bloodstream after they are released from the endocrine gland?
A
Free (unbound)
Protein bound
22
Q
T/F:
Free floating hormones are susceptible to degradation and metabolism
A
TRUE
23
Q
Hydrophilic = ____ soluble
A
Water
24
Q
Lipophilic = ___ soluble
A
Fat
25
T/F:
Water-soluble hormones are transported bound to a carrier protein
FALSE
FAT-soluble are transported bound to a carrier protein
26
What are Micelles?
Enclosed packages containing lipid-rich substances with hydrophilic outer layer and hydrophobic inner layer
27
What is the most common feedback mechanism in the body?
Negative feedback
28
What occurs during negative feedback?
The stimulus will feedback upstream to decrease the production of itself
29
What occurs during positive feedback?
Increases stimulus received until a distinct endpoint is achieved. Because this causes an increased production of stimuli, this pathway can go out of control
30
A disorder affecting a regulating endocrine gland is a ___ disorder
Secondary or tertiary
31
Disorders that affects the final endocrine gland that is regulated is a ___ disorder
Primary
32
List factors that can affect hormone levels
- Emotional stress
- Time of day
- Menstrual cycle
- Menopase
- Food intake/diet
- Drugs
33
What are the three distinct parts of the pituitary?
- Anterior pituitary
- Intermediate lobe
- Posterior pituitary
34
What is the function of the posterior pituitary?
Storage and release of oxytocin and AVP (formerly known as ADH)
35
The anterior pituitary received 90-90% of its blood supply and many hypothalamic factors via the ___-___ ___ ___
Hypothalamic-hypophyseal portal system
36
T/F:
Pituitary function can be detected between the 6th and 8th week of gestation
FALSE
Can be detected between the 7th and 9th week of gestation
37
What are lactotrophs ?
Prolactin secreting cells
38
What are somatotrophs?
Growth hormone (GH) secreting cells
39
What are thyrotrophs?
Thyroid stimulating hormone (TSH) secreting cells
40
What are corticotrophs?
Adrenocorticotropin hormone (ACTH) secreting cells
41
What are gonadotrophs?
Luteinizing hormone (LH) and follicle stimulating hormone (FSH) secreting cells
42
T/F:
All anterior pituitary hormones are secreted in a pulsatile fashion
TRUE
43
What are the best examples of pituitary pulsatility?
Secretion of hormones that regulate gonadal function (LH and FSH)
44
T/F:
The nervous system will regulate the hypothalamic-pituitary hormone secretion at a constant rate throughout the day
FALSE
The hypothalmic-pituitary unit is cyclic in nature and will be regulated by the nervous system in response to external signals such as light/dark changes
45
T/F:
Hormones secreted from the anterior pituitary are larger and more complex than those from the hypothalamus
TRUE
These are either tropic (action specific for another endocrine gland) or are direct effectors (they act directly on peripheral tissues)
46
What are hypophysiotropic or hypothalamic hormones?
Hormones produced in the hypothalamus that have a direct effect on classic pituitary function
47
What hormones are produced in the anterior pituitary?
- GH
- TSH
- ACTH
- FSH
- LH
- PRL
48
What hormones are produced in the posterior pituitary?
- ADH
- OXT
49
What does it mean when a hormone is tropic?
Action is specific for another endocrine gland
50
What does it mean if a hormone is a direct effector?
They act directly on peripheral tissues
51
Action of TRH
Releases TSH and prolactin
52
Action of GnRH
Releases LH and FSH
53
Action of CRH
Releases ACTH
54
Action of GHRH
Releases GH
55
Action of somatostatin
Inhibits GH and TSH release
56
Action of dopamine
Inhibits prolactin release
57
Target gland of LH
Gonad (tropic)
58
Target gland of FSH
Gonad (tropic)
59
Target gland of TSH
Thyroid (tropic)
60
Target gland of ACTH
Adrenal (tropic)
61
Target gland of growth hormone
Multiple (direct effector)
62
Target gland of Prolactin
Breast (direct effector)
63
Growth Hormone
- Vital for normal growth
- Amphibolic = directly influences anabolic and catabolic processes
- Mediated by insulin-like growth factors (IGF), more specifically IGF-1
- Stimulates production of IGF-1 from liver
- Baseline measurements are helpful
64
Acromegaly is a result of what?
Pathological or autonomous GH excess, typically from the result of a GH releasing tumor
65
Prolactin
- Stress hormone with vital functions in relationship to reproduction
- Major mode of hypothalamic regulation is TONIC INHIBITION (versus other anterior pituitary hormones with intermittent stimulation)
- Inhibited by dopamine
66
Clinical representation of a prolactinoma is dependent on what?
Patient age, gender, and tumor size. Premenopausal women will present differently then men/postmenopausal women
67
Clinical evaluation of hyperprolactinemia include what?
- History and physical exam to exclude common, nonendocrine causes
- obtaining TSH and FT4 values to eliminate primary hypothyroidism as a cause
- If a pituitary tumor is suspected, anterior pituitary function assessment: ACTH/cortisol, LH, FSH
- MRI
68
Hyperprolactinemia is associated with what?
Renal failure, cirrhosis, hypothyroidism, trauma, inflammation, drugs, adrenal insufficiency, prolactinomas
69
Define hypopituitarism
Failure of either of pituitary or the hypothalamus resulting in loss of anterior pituitary function
70
The complete loss of anterior pituitary function is referred to as ___
Panhypopituitarism
71
The loss of a single hormone is referred to as ___ ___ ___
Monotropic hormone deficiency
72
What is the difference between primary and secondary failure of an endocrine gland
Primary: failure of gland accompanied by dramatic INC in circulating levels of corresponding pituitary tropic hormone
Secondary: Associated with low or normal levels of tropic hormone
73
List 10 causes of hypopituitarism
1. Pituitary tumors
2. Parapituitary/hypothalmic tumors
3. Trauma
4. Radiation therapy/surgery
5. Infarction
6. Infection
7. Infiltrative disease
8. Immunologic
9. Familial
10. Idiopathic
74
How do you treat panhypopituitarism?
Replacement therapy, thyroxine, glucocorticoids, gender-specific sex steroids
75
AVP and oxytocin are what type of hormones?
Posterior pituitary hormones
76
Where are AVP and oxytocin produced?
Supraoptic and paraventricular nuclei or hypothalamus and transported to neurohypophysis via axons in hypothalamoneurohypophyseal tract
77
What hormone plays a critical role in lactation, labor, and parturition?
Oxytocin
78
What type of feedback loop is for oxytocin secretion?
Positive feedback koop
79
Uterine contractions cause what in regards to oxytocin
Propagates oxytocin release, resulting in more contractions
80
What is the major action of Arginine vasopressin (AVP)
Regulate renal free water excretion
ALSO
Potent presser agent and effect blood clotting by promoting Factor VII release and Von Willebrand factor release
81
What regulates the release of vasopressin from the posterior pituitary?
Hypothalamic osmoreceptors and baroreceptors
82
T/F:
Osmoreceptors only detect significant changes
FALSE
Osmoreceptors are extremely sensitive to small changes
83
What do vascular baroreceptors respond to?
Fall in blood volume or blood pressure
84
___ - ___% fall in arterial blood pressure will trigger vasopressin release
5% - 10%
85
Diabetes insipidus is a consequence of what?
Vasopressin deficiency or resistance
86
Excess AVP leads to what?
Pathological retention of free water
