Endocrine System Flashcards

1
Q

What are the major differences between the endocrine and nervous system?

A

the endocrine system;
- transmits ligands
- exhibits longer reaction times
- has longer lasting effects

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2
Q

What are the types of circulating hormones?

A
  • steroids
  • biogenic amines
  • proteins
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3
Q

What are local hormones?

A

signaling molecules that don’t circulate in blood

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4
Q

what are Eicosanoids?

A

a type of local hormone formed from fatty acids within phospholipid bilayer of membrane

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5
Q

What are the effects of eicosanoids?

A
  • autocrine stimulation: effects on the same cell where messenger was formed
  • paracrine stimulation:
    effects on neighboring cells
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6
Q

What are the advantages of lipid soluble hormones using carrier molecules?

A
  • do not dissolve readily in blood
  • carriers are water soluble proteins made by liver
  • carriers protect hormones from early destruction
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7
Q

True or false, only lipid soluble hormones use carrier molecules

A

false, some water soluble hormones use carrier proteins to prolong their life

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8
Q

What two factors determine the concentration of a hormone?

A

how fast it is synthesized and eliminated

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9
Q

How does hormone elimination occur?

A

occurs in multiple ways:
- enzymatic degradation in liver cells
- removal from blood via kidney excretion or target cell uptake

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10
Q

What is a hormone’s half life?

A

time necessary to reduce a hormone’s concentration to half of its original level

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11
Q

How does the half life of water soluble hormones compare to that of steroid hormones?

A
  • water soluble hormones generally have a short half life
  • steroid hormones generally have a long half life
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12
Q

What allows for lipid soluble hormones to diffuse across target cell membrane

A

they are small, nonpolar, and lipophillic

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13
Q

what happens once a lipid soluble hormone enters its target cell

A
  • binds to receptor and forms hormone-receptor complex
  • complex binds to a hormone response element of DNA
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14
Q

Why can’t water soluble hormones diffuse through membrane?

A

they are polar

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15
Q

where are water soluble hormone receptors

A

on cell membrane

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16
Q

Describe the signal transduction pathway of a water soluble hormone

A
  1. hormone is first messenger and binds to receptor
  2. binding actives a G protein
  3. G protein activation causes activation of a membrane enzyme
  4. activated enzyme catalyzes the formation of a second messenger
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17
Q

What are the actions of water soluble hormones?

A
  • enzymes can be activated or inhibited
  • growth can be stimulated
  • cellular secretions can be released
  • membrane permeability can be changed
  • muscles can be contracted or relaxed
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18
Q

what are the advantages of a signal transduction pathway?

A
  • signal is amplified at each enzymatic step
  • there are many places to regulate pathway activities
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19
Q

What determines the target cells response to a particular hormone?

A
  • number of hormone receptors
  • interactions among other hormone actions
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20
Q

What structure is the pituitary gland attached to and how so?

A

connected to hypothalamus by infundibulum

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21
Q

How do the size and tissue of each part of the pituitary compare?

A
  • posterior pituitary is smaller, neural part
  • anterior pituitary is large, glandular part
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22
Q

What are the components of the posterior pituitary?

A

composed of pars nervosa(lobe) and infundibulum

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23
Q

What are the three sections of the anterior pituitary?

A
  • pars distalis: large anterior rounded portion
  • pars tuberalis: thin wrapping around infundibulum
  • pars intermedia: scant region between other two
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24
Q

the posterior pituitary is the storage and release site for which hormones?

A

oxytocin and antidiuretic hormone (both are made in hypothalamus)

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25
Q

What is the relationship between the hypothalamus and the anterior pituitary?

A

the hypothalamus stimulates anterior pituitary to release its hormones by secreting regulatory hormones

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26
Q

what are the two types of regulatory proteins secreted by the hypothalamus

A
  1. releasing hormones: increase secretion of anterior p hormones
  2. inhibiting hormones: decrease secretion of anterior p hormones
27
Q

What are the hormones released by the anterior pituitary gland?

A
  • thyroid stimulating hormone (TSH)
  • prolactin
  • adrenocorticotropic hormone (ACTH)
  • follicle-stimulating hormone and leutenizing hormone (FSH and LH)
  • growth hormone (GH)
28
Q

What are the functions of growth hormone?

A
  • stimulation of linear growth at epiphyseal plate
  • hypertrophy of muscle
  • release of nutrients from storage into blood
29
Q

what hormone stimulates the releases of GH?

A

growth hormone releasing hormone (GHRH)

30
Q

What cells does GH target?

A

hepatocytes which release insulin like growth factors (IGFs)

31
Q

What cells have GH receptor cells

A

all body cells have receptors for GH, IGF, or both

32
Q

How do GH and IGFs work?

A

cause adipose cells to release nutrients
- increases levels of glycerol and fatty acids in blood

33
Q

What is the thyroid gland composed of?

A

composed of microscopic follicles
- follicular and parafollicular cells

34
Q

What hormones do follicular cells produce?

A

thyroid hormone

35
Q

what hormone do parafollicular cells produce

A

calcitonin

36
Q

What is the difference between T3 and T4?

A
  • thyroid gland produces more T4 but T3 is more active form
  • most target cells convert T4 to T3
37
Q

What does thyroid hormone do?

A

increases metabolic rate and protein synthesis in targets, also fosters energy production

38
Q

describe the negative feedback loop for TH

A
  • Increases in TH cause decreases in its release
    o TH inhibits release of TRH from hypothalamus
    o TH inhibits release of TSH from anterior pituitary
    o TH causes release of growth hormone inhibiting hormone further inhibiting TSH release
39
Q

describe the anatomy of the adrenal medulla

A
  • forms inner core of each adrenal gland
  • red-brown color due to extensive blood vessels
  • releases epinephrine and norepinephrine with sympathetic stimulation
40
Q

describe the anatomy of the adrenal cortex

A
  • synthesizes over 25 corticosteroids
  • yellow color due to lipids within cells
  • 3 regions producing different steroid hormones
41
Q

From superficial to deep, list the three regions of the adrenal cortex

A
  • zona glomerulosa
  • zona fasciculata
  • zone reticularis
42
Q

What are the hormones of the adrenal cortex

A
  • mineralocorticoids: hormones that regulate electrolyte levels
  • glucocorticoids: hormones that regulate blood sugar
  • gonadocorticoids: sex hormones
43
Q

What is the function of cortisol

A

increase nutrient levels in blood

44
Q

what regulates the release of cortisol?

A

the hypothalamic-pituitary-adrenal axis

45
Q

Describe the process of how cortisol is released

A
  • stress, late stages of sleep, low cortisol levels stimulate hypothalamus to release CRH
  • CRH stimulates ant. pituitary to release ACTH ACTH stimulates adrenal cortex to release cortisol
  • cortisol travels through blood attached to carrier proteins
  • cortisol diffuses through target cell’s membrane & binds to intracellular receptor
  • cortisol causes target cell to increase blood nutrient levels
46
Q

what is corticosterone used a treatment for?

A

inflammation

47
Q

how does corticosterone treat inflammation?

A

it inhibits inflammatory agents and supresses immune system

48
Q

What causes Cushing syndrome?

A

excessive glucocorticoid

49
Q

what causes Addison disease?

A

form of adrenal insuffiency when adrenal glands fail

50
Q

What are the three stages of a stress response?

A
  • alarm reaction
  • stage of resistance
  • stage of exhaustion
51
Q

What endocrine organ also has exocrine functions

A

the pancreas

52
Q

What is the function of acini cells in the pancreas?

A

generate exocrine secretions for digestion

53
Q

What are pancreatic islets?

A

clusters of endocrine cells in pancreas

54
Q

what do alpha cells secrete?

A

glucagon

55
Q

what do beta cells secrete?

A

insulin

56
Q

What is the main function of the pancreatic hormones?

A

help maintain blood glucose

57
Q

What is the function of insulin

A

lowers blood glucose

58
Q

How does insulin lower blood glucose?

A
  • hepatocytes remove glucose from blood; store it as glycogen
  • adipose cell decrease fatty acid levels in blood
  • most body cells increase nutrient uptake in response to insulin
59
Q

What causes type 1 diabetes?

A

absent or diminished release of insulin by pancreas; requires daily insulin injections

60
Q

What causes type 2 diabetes?

A

decreased insulin release or insulin effectiveness usually due to obesity

61
Q

What is the effect of glucagon?

A

raises blood glucose

62
Q

How does glucagon raise blood glucose?

A

acts through membrane receptors and 2nd messenger causing body cells to release stored nutrients into blood

63
Q

What hormone does the pineal gland secrete?

A

melatonin

64
Q

What does the parathyroid gland do?

A

helps regulate blood calcium