18.2 Endocrine System Flashcards

1
Q

4 Mechanisms of intercellular communication

A

direct, paracrine, endocrine, synaptic

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2
Q

Both nervous & endocrine systems regulated mainly by what type of feedback?

A

negative feedback

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3
Q

3 classes of hormones

A
  1. amino acid derivatives
  2. peptide hormones
  3. lipid derivatives
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4
Q

amino acid derivatives synthesized from

A

tyrosine and tryptophan

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5
Q

hormones synthesized from tyrosine

A

thyroid hormones

catecholamines: E, NE, & dopamine

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6
Q

hormones synthesized from tryptophan

A

melatonin

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7
Q

groups of peptide hormones

A
  1. glycoproteins (>200 amino acids long)

2. short polypeptides, small proteins

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8
Q

classes of lipid derivatives

A
  1. eicosanoids

2. steroid hormones

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9
Q

eicosanoids

A

signalling molecules derived from arachadonic acid..strong paracrine effects.. leukotrienes, prostaglandins, thromboxanes, prostacyclins

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10
Q

steroid hormones

A

derived from cholesterol.. released by reproductive organs (androgens, estrogens, progestins), cortex of adrenal glands (corticosteroids), and kidneys (calcitrol)

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11
Q

which hormones are likely to attach to transport proteins in the bloodstream?

A

thyroid hormones and steroid hormones

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12
Q

glycoproteins

A

> 200 amino acids long.. ex: TSH, LH, FSH

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13
Q

short chain polypeptides/small proteins

A

-includes all hormones secreted by hypothalamus, heart, thymus, digestive tract, pancreas, and posterior pituitary gland.
ADH, OXT (each 9 amino acids long)
GH (191 amino acids), PRL (198 amino acids)

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14
Q

Hormones with receptors in plasma membranes

A

extracellular: catecholamines, peptide hormones
intracellular: eicosanoids

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15
Q

first messenger

A

hormone

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16
Q

second messengers

A
  1. cAMP
  2. cGMP
  3. Calcium ions
17
Q

down regulation

A

presence of hormone decreases number of receptors

18
Q

up-regulation

A

absence of a hormone triggers increase in receptors.

19
Q

G protein

A

enzyme complex coupled to a membrane receptor..binds to GTP

20
Q

G protein & cAMP

A
  • g protein activates adenylate cyclase, which converts ATP to cAMP, which functions as a second messenger to activate a kinase, leading to phosphorylation
  • g protein stimulates PDE, inhibiting adenylate cyclase activity
21
Q

phosphodiesterase (PDE)

A

inactivates cAMP

22
Q

G proteins and Calcium ions

A

g protein activates phospholipase C (PLC), which triggers a cascade:

  • production of diacylglycerol (DAG) and inositol triphosphate (IP3)
  • IP3 triggers release of Ca2+ from intracellular reserves
  • DAG and Ca2+ activate Protein Kinase C (PKC), which opens channels to extracellular Ca2+
  • Ca2+ serve as messengers with calmodulin (protein)
23
Q

hormones with intracellular receptors

A

Steroid hormones diffuse through membrane (receptors in cytoplasm or nucleus), Thyroid hormones transported across membrane (receptors at mitochondria increase ATP production, nucleus)

24
Q

endocrine reflexes can be triggered by:

A
  1. humoral stimuli
  2. hormonal stimuli
  3. neural stimuli
25
Q

endocrine reflexes are usually controlled by what type of feedback?

A

negative feedback

26
Q

simple endocrine reflexes control the hormone secretion of which organs/tissues?

A

heart, pancreas, parathyroid glands, and digestive tract.

27
Q

regulatory hormones of the hypothalamus control..

A

endocrine cells of anterior pituitary

28
Q

hormones secreted by anterior pituitary control..

A

endocrine cells in thyroid, adrenal cortex, and reproductive organs

29
Q

hypothalamus exerts direct neural control over..

A

endocrine cells of adrenal medullae