Endocrine Flashcards

1
Q

endocrinology

A
  • study of hormones
  • chem that go thruought the body
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2
Q

hormones are responsible for what?

A
  • long term ongoing fxns of the body
  • metabolism (thyroid)
  • regulation of the internal environment as a homeostasis
  • reproduction
  • growth
  • development
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3
Q

hormones act in 3 basic ways

A
  • (1) Rates of enzymatic reactions (speeds up rxn)
  • (2) Transport of ions or molecules across cell membranes
  • (3) Gene expression and protein synthesis (Ex: growth hormone)
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4
Q

cellular mechanism of action for hormones

A
  • depends on binding to target cell receptors
  • initiates biochemical responses
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5
Q

hormone action must be terminated

A
  • half-life indicates length of activity
  • measure how long molecules can degrade
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6
Q

most hormones are what

A
  • peptides or proteins
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7
Q

peptide hormone synthesis, storage, and release

A

– Preprohormone is a large, inactive precursor
– Prohormone is processed to smaller form but still inactive
– Active hormone stored in vesicle; requires signal to be released

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8
Q

transported in the blood and half-life of peptide hormones

A
  • relatively short half-life
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9
Q

cellular mechanism of action of peptide hormones

A

– Bind surface membrane receptors
– Cellular response through signal transduction system

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10
Q

steroids hormones are derived from cholesterol

A
  • Made only in a few organs
    – Adrenal cortex of adrenal gland and gonads
  • Steroid hormone synthesis and release
    – Made as needed, not stored
  • Transport in the blood and half-life of steroid hormones
    – Bind carrier proteins in blood
    – Longer half-life (example: cortisol = 69-90 minutes in blood)
  • Cellular mechanism of action of steroid hormones
    – Cytoplasmic or nuclear receptors stimulate genomic effects
    – Cell membrane receptors stimulate nongenomic repsonses
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11
Q

some hormones are derived from single amino acid

A
  • Derived from tryptophan
    – Melatonin from pineal gland
  • Derived from tyrosine
    – Single tyrosine give rise to catecholamines
    ▪ Epinephrine, norepinephrine, and dopamine
    ▪ Behave like peptide hormones
    – Two tyrosine molecules give rise to thyroid hormones
    ▪ Behave like steroid hormones
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12
Q

stimulating hormones come from what?

A

anterior pituitary gland

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13
Q

inhibiting or releasing comes from what?

A

hypothalamus

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14
Q

anterior pituitary gland hormones

A
  • thyroid stimulating hormones (TSH)
  • luitenizing hormone (LH)
  • follicle stimulating hormone (FSH)
  • growth hormone (GH)
  • prolactin (lactation)
  • ACTH = adrenocortical tropic hormone (gets released when you’re stressed. goes to adrenocortex to release cortisol)
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15
Q

primary, secondary, teritary

A
  • primary: think actual gland itself
  • secondary: think pituitary gland
  • tertiary: think hypothalamus
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16
Q

posterior pituitary gland

A
  • anti-diuretic (vasopressin)
  • oxytocin (milk outlet and stimulates pos feedback loop in birthing)
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17
Q

reflex pathways have similar components

A

– Stimulus, sensor, input signal, integration, output signal, one or more targets, & response

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18
Q

the endocrine cell is the sensor in simple endocrine reflexes

A
  • parathyroid hormone (PTH)
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19
Q

many endocrine reflexes involve the what?

A

nervous system

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20
Q

neurohormones are secreted into the blood by what?

A

neurons

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21
Q

the posterior pituitary stores and releases two neurohormones

A

– Neural tissue
– Stores hormones produced in the hypothalamus
– When hypothalamus is stimulated, posterior pituitary secretes two
neurohormones: vasopressin (antidiuretic hormone (ADH) and oxytocin

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22
Q

the anterior pituitary secretes six hormones

A

– Epithelial origin, thus true endocrine gland
– Trophic hormones stimulate secretion of other hormones
– Prolactin (PRL), thyrotropin (TSH), adrenocorticotropin (ACTH), growth hormone (GH), follicle-stimulating hormone (FSH), and luteinizing hormone (LH)
– Regulated by hypothalamic hormones
▪ Somatostatin (SS) = growth hormone-inhibiting hormone

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23
Q

portal systems

A
  • encapsulation of veins
  • consists of two sets of capillaries connected in series by a vein
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24
Q

hypothalamic-hypophyseal (pituitary) portal system

A

– Hypothalamic neurons produce trophic hormones
– Released into 1st capillary bed in portal system to anterior pituitary
– Anterior pituitary endocrine cells produce trophic hormones
– Released into 2nd capillary bed in portal system to target tissues

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25
what does the portal system connect?
- hypothalamus and anterior pituitary
26
what does the portal system ensure?
- small amount of concentrated hormone is directed to its target
27
growth hormone
* Promotes growth of the entire body by affecting: – Protein formation – Cell multiplication – Cell differentiation
28
physiological action of growth hormone
– Stimulate body growth – Stimulates secretions of insulin-like growth factor-1 – Stimulates lipolysis – Inhibits actions of insulin on carbohydrates and lipid metabolism
29
what is the most power lipid soluble hormone?
- growth hormone
30
antagonist for insulin
- glucagon
31
stimulations of growth hormone
* Decreased blood glucose * Decreased blood free fatty acids * Increased amino acids * Starvation or fasting, protein deficiency * Trauma, stress, and excitement * Exercise * Testosterone, estrogen * Deep sleep (stages II and IV) * Ghrelin (stimulates hunger/stomach releases it)
32
inhibits growth hormone
* Increased blood glucose * Increased blood free fatty acids * Aging * Obesity * Growth hormones (exogenous)
33
adrenocorticotrophic hormone controls what?
- the secretions of some adrenal hormones which affect metabolism of glucose, proteins, and fats
34
physiological actions of ACTH
– Stimulates production of glucocorticoids and androgens by the adrenal cortex – Maintains size of zona fasciculata and zona reticularis of cortex
35
ACTH releases 4 hormones (superficial to deep)
- aldosterone - cortisol - androgens - epinephrine
36
ACTH cortex
– Zona glomerulus: Aldosterone – Zona fasciculata: Cortisol – Zona reticularis: Androgens
37
ACTH medulla
- epinephrine
38
aldosterone
- uptakes sodium, kicks out acid, kicks out potassium * Regulates blood pressure by impacting the distal convoluted tubule of kidneys * Renin-Angiotension-Aldosterone System
39
renin
- detects BP in kidneys - if its too low = secrete angiotension 1 (liver) = turns into angiotension 2 (lung)
40
cortisol
* “Stress” hormone * Stimulates gluconeogenesis * Increases liver and plasma proteins – Muscle anabolism * Mobilization of fatty acids
41
androgens
* Several moderately active male sex hormones are continuously secreted by the adrenal cortex, especially during fetal life * Progesterone and estrogens (female sex hormones) are secreted within minute quantities.
42
epinephrine
* Neurohormone & neurotransmitter released in post ganglionic sympathetic fibers – Also secreted by adrenal medulla * Are post ganglionic sympathetic fibers of the autonomic nervous system part of the endocrine system? YES
43
thyroid stimulating hormone
* Controls the secretion rate of thyroxine (T4) and triiodothyronine (T3) by the thyroid gland – These hormones control the rate of most (if not all) intracellular chemical reactions in the body (i.e. METABOLISM) ▪ Functions of the two hormones are the same – T4 is more common ▪ 93% of metabolically active hormone ▪ iodine is required to formulate T4 – T3 is more potent ▪ T3 can produce more powerful physiological effects
44
prolactin
- promotes mammary gland development and milk production
45
follicle stimulating hormone and luteinizing hormone
* Controls growth of ovaries and testis * Control reproductive endocrinology activities
46
FSH
▪ Stimulates development of ovarian follicles ▪ Regulates spermatogenesis in the testis
47
LH
▪ Causes ovulation and formation of corpus luteum in the ovary ▪ Stimulates production of estrogen and progesterone by the ovary ▪ Stimulates testosterone production by the testis
48
antidiuretic hormone
* AKA vasopressin * Controls the rate of water excretion into the urine within the collecting ducts of the nephron – Thus helping the control of concentration of water in the body fluids
49
oxytocin
* Female Activity: Helps express milk from the glands of the breast to the nipples during suckling – Helps in delivery of the baby at the end of gestation * Male Activity ▪ Some research suggest it’s associated with male ejaculation and sexual desire in both sexes. ▪ Not enough research to make strong claim
50
hormones associated with the GI system
* Ghrelin – Released by the stomach – Stimulates hunger and appetite * Leptin – Released by adipose tissue – Stimulates “full” sensation
51
the pancrease secretes what?
- insulin and glucagon - beta cells: insulin (high BS stimulates insulin) - alpha cells: glucagon
52
the insulin to glucagon raio regulates metabolism
– In the fed state (eating), insulin dominates – In the fasting state, glucagon dominates
53
insulin
* Insulin (break down glucose) promotes anabolism – Insulin binds to tyrosine kinase receptors ▪ Activated – Insulin lowers plasma glucose ▪ 1. Insulin increases glucose transport into insulin-sensitive cells ▪ 2. Insulin enhances utilization and storage of glucose ▪ 3. Insulin promotes fat synthesis
54
glucagon
* Glucagon is dominant in the fasted state – Generally antagonist to insulin – Glucagon prevents hypoglycemia ▪ Liver is primary target ▪ Stimulates glycogenolysis and gluconeogenesis – Release stimulated by low blood glucose levels - increase sugar levels
55
parathyroid hormone
- released by parathyroid to increase blood calcium levels
56
calcitonin
- released by thyroid to decrease blood calcium levels - tones the bone - brings Ca+ into the bone
57
hematological modulated hormones
* Erythropoietin: detects all blood cells that go thru the kidney – Kidney releasing hormone to stimulating production of red blood cells * Atrial Natriuretic Peptide – Heart releasing hormone to lower blood pressure and control electrolyte homeostatis
58
long-loop negative feedback
– Peripheral endocrine gland produces hormone that suppresses secretion of anterior pituitary and hypothalamic trophic hormones – Most dominant feedback mechanism
59
short-loop negative feedback
– Pituitary hormone suppresses hypothalamic trophic hormone production – Secondary feedback mechanism
60
ultra-short-loop negative feedback loop
– Occurs in hypothalamus and pituitary – Autocrine or paracrine signals to regulate secretion
61
hormone interactions
* In synergism, the effect of interacting hormones is more than additive * A permissive hormone allows another hormone to exert its full effect – Permissiveness * Antagonistic hormones have opposing effects – One substance opposes the action of another – Competitive inhibitors vs. functional antagonists
62
down-regulation
- sensitivity issues – Decreased number of receptors in response to abnormally high hormone levels – Target cell is attempting to diminish its responsiveness to the excess hormone – Hyperinsulinemia
63
receptor and signal transduction
– Missing or nonfunctional receptors – Cells fail to respond or respond inappropriately to hormone signals
64
hormone evolution
* Evolutionary conservation of hormone function * Proteomics determines physiological role of hormones * Example: Calcitonin * Vestigial structures have lost functionality in humans – Example: Intermediate lobe of pituitary and melanocyte-stimulating hormone * Comparative endocrinology is the study of endocrinology in non-humans to reveal possible functionality in humans – Example: pineal gland and melatonin