Endocrine System I Flashcards

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1
Q

hormones

A
  • greek for “to excite”
  • chemical signaling molecules responsible for regulation
  • messenger of endocrine system -> allows cells to communicate with each other
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2
Q

what happens when hormones are secreted into body fluids?

A
  • usually secreted into blood
  • bind to target cells
  • all cells exposed, only those with correct receptor respond
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3
Q

receptors

A
  • large proteins or glycoproteins on surface of target cells
  • recognize and bind to specific hormones
  • responsible for specificity of endocrine system
  • continually synthesized and degraded
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4
Q

homeostatic control of hormone levels

A
  • hormone levels too low, receptor up-regulation

- hormone levels too high, receptor down-regulation

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5
Q

what are the 6 types of intercellular communication?

A
  1. Endocrine Signaling
  2. Paracrine Signaling
    3, Autocrine Signaling
  3. Synaptic Signaling
  4. Neuroendocrine Signaling
  5. Signaling by Pheromones

Elephants Play And Sleep Nicely on Sundays

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6
Q

endocrine signaling

A

endocrine cells secrete hormones into extracellular fluid

-diffuse into bloodstream -> travel around body -> attach to receptors on target cells

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7
Q

short distance signaling

A
  • cells produce and secrete LOCAL regulators
  • reach target cells by diffusion (not through bloodstream)
  • short distance, very quick
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8
Q

paracrine signaling

A

target cells NEAR secreting cells

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9
Q

autocrine signaling

A

target cells ARE secreting cells

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10
Q

synaptic signaling

A
  • neurons form synapses (junctions) with target cells
  • neurotransmitters: signaling molecules are produced by neurons that secrete neurohormones, which diffuse across synapse and bind to receptors on target cells
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11
Q

neuroendocrine signaling

A

-neurosecretory cells - specialized neurons that secrete neurohormones, which diffuse into bloodstream

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12
Q

signaling by pheromones

A

phermones are chemicals that are released into the external environments
-target other individuals of same species to: define territory, warn of predators, attract mates

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13
Q

what are the two classes of local regulators?

A
  1. modified fatty acids

2. gases

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14
Q

modified fatty acids

A
  • contain long hydrocarbon chains

- ex: Prostaglandins - regulate many processes

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15
Q

gases

A

-ex: Nitric Oxide (NO)
-Blood O2 rises -> blood vessel lining releases NO
[diffuses to surrounding muscle]
[activates enzymes, relaxes cells]
[vasodilation]

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16
Q

how does solubility affect the response pathway?

A
  • water-soluble hormones affect protein in cytoplasm of target cells (act faster, but short term effects
  • lipid-soluble hormones affect gene expression of target cells (act slower, but long term effects)
17
Q

water soluble hormones

A

-involves signal transduction (series of changes in cellular proteins that convert extracellular chemical signals into specific intracellular responses)

18
Q

pathway of water soluble hormones

A

hydrophilic (cannot pass through membrane)

  1. hormone secreted via exocytosis
  2. travels freely in bloodstream
  3. binds receptor on target cell membrane (often G-protein-coupled-receptor)
  4. G-protein binds and activates adenylyi cyclase
  5. adenylyl cyclase converts ATP to cyclic AMP (cAMP) - 2nd messenger
  6. cAMP activates protein kinase (enzyme)
    [many kinds of kinases - all act by adding phosphat to specific protein -> post - translational control]
  7. other proteins inhibited or activated -> response
19
Q

pathway for lipid soluble hormones

A

hydrophobic (cannot dissolve in blood, can cross CM)

  1. diffuses across endocrine cell membrane (CM)
  2. binds transport protein - soluble in blood
  3. diffuses across cell membrane into target cells
  4. binds receptor in cytoplasm -> hormone-receptor complex enter nucleus
  5. H-RC binds DNA (change in gene expression -> response)
20
Q

how may target cells differ?

A

receptor and response molecule

21
Q

epinephrine

A
  • rapid response by body in emergencies
  • triggers glycogen breakdown in liver
  • high blood flow in skeletal muscle
  • low blood flow in smooth muscle
  • can be due to different receptor or different intracellular proteins
22
Q

endocrine

A
  • release hormones into surrounding fluid -> bloodstream
  • ductless
  • can be isolated cells or pair of organs
  • function with NS to regulated metabolism, maintain HS
23
Q

exocrine

A
  • exocrine glands release materials into ducts (carry secreted substances to target area)
  • ex: sweat, mucus, digestive enzymes