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MCAT - biology > mechanisms of hormone action > Flashcards

mechanisms of hormone action Flashcards

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1
Q

hormones can be _________, _________, or ________ derivatives

A

peptide
steroids
amino acids

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2
Q

examples of peptide hormones?

A

ADH
insulin

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3
Q

peptide hormones are all derived from larger ___________ that are cleaved during postranslational modification

A

polypeptides

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4
Q

T / F - peptide hormones are charged

A

true

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5
Q

the peptide hormone is considered the, ____________ it binds to the receptor and triggers the transmission of a second signal known as __________

A

first messenger
second messenger

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6
Q

examples of hormone amplification?

A
  1. one hormone molecule may bind to multiple receptors
  2. each receptor may activate multiple enzymes
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7
Q

common second messengers?

A
  1. cAMP
  2. IP3
  3. calcium
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8
Q

the effects of peptide hormones are usually (rapid / slow) and (long / short) lived

A

rapid
short lived

*due to second messenger cascades

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9
Q

T / F - peptide hormones are genrally water insoluable

A

false, they are water soluable

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10
Q

T / F - peptide hormones can travel through the blood stream

A

true

*do not require carriers

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11
Q

steroid hormones are derived from _____________

A

cholesterol

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12
Q

steroid hormones are primarily produced by the ___________ and __________

A

gonads
adrenal cortex

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13
Q

T / F - because steroid hormones are derived from nonpolar molecules, they can easily cross the membrane

A

true

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14
Q

upon binding to the receptor, the steroid hormone-receptor complex undergoes conformation changes, the receptor can then bind directly to ________ in either increasing / decreasing _____________ of particular genes

A

DNA
transcription

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15
Q

______________ is a conformational chnage that pair two receptor hormone complexes

A

dimerization

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16
Q

the effects of steroid hormones are usually (rapid / slow) and (long / short) lived

A

slow
long lived

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17
Q

why are steroid hormone effects longer lasting?

A

they participate in gene regulation, causing alterations in the amount of mRNA and protein present in a cell

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18
Q

T / F - steroid hormones are not water soluable

A

true

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19
Q

how are steroid carried through the blood stream?

A

carrier proteins

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20
Q

examples of steroid hormones carrier proteins?

A

sex hormone binding globulin
albumin

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21
Q

examples of amino acid derivative hormones?

A

epinephrine
norepinephrine
triiodothyronine
thyroxine

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22
Q

thyroid hormones are derived from __________

A

tyrosine

*addition of 7 iodine atoms

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23
Q

____________ hormones are secreted and then act directly on the target tissue

A

direct

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24
Q

example of a direct hormone?

A

insulin

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25
Q

__________ hormones require an intermediary to act on the tissue

A

tropic

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26
Q

example of tropic hormones?

A

GnRH stimulates FSH and LH

LH stimulates gonads for testosterone production

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27
Q

where do tropic hormones usually originate from?

A

brain
anterior pituitary gland

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28
Q

examples of endocrine glands?

A

pineal gland
adrenal gland
gonads
pancreas
parathyroid
thyroid
hypothalamus

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29
Q

what organs serve partial endocrine roles?

A

kidneys
heart
GI glands
thymus

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30
Q

____________ is the bridge between the nervous and endocrine systems

A

hypothalamus

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31
Q

by regulating the pituitary gland through __________ hormones, the hypothalamus is capable of having organism wide effects

A

tropic

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32
Q

where is the hypothalamus located?

A

forebrain

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33
Q

hypothalamus controls the pituitary gland through __________ release of hormones

A

paracrine

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34
Q

what is the purpose of the suprachiasmatic nucleus in the hypothalamus?

A

receive light input from the retinae and helps control sleep-wake cycles

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35
Q

what doesthe hypothalamus control?

A

retinae light input
sleep-wake cycles
increases in blood osmolarity
regulate appetite / satiety

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36
Q

______________ is a blood vessel system that directly connects the hypothalamus with the anterior pituitary gland

A

hypophyseal portal system

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37
Q

hypothalamus tropic hormone:
GnRH

anterior pituitary hormone response:
?

A

FSH
LH

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38
Q

hypothalamus tropic hormone:
GHRH

anterior pituitary hormone response:
?

A

GH

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39
Q

hypothalamus tropic hormone:
TRH

anterior pituitary hormone response:
?

A

TSH

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40
Q

hypothalamus tropic hormone:
CRF

anterior pituitary hormone response:
?

A

ACTH

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41
Q

what happens when PIF is released from the hypothalamus?

A

PIF = prolactin inhibiting factor

decrease in prolactin secretion

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42
Q

____________ inhibits the hypothalamus and anterior pituitary from releasing CRF and ACTH

A

cortisol

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43
Q

what types of hormones are released by the posterior pituitary gland?

A

oxytocin
ADH

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44
Q

_____________ stimulates uterine contractions during labor and milk letdown during lactation

A

oxytocin

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45
Q

___________ stimulates increased reabsorption of water in the colelcting ducts of the kidneys

A

ADH

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46
Q

what are the seven main hormones secreted by the anterior pituitary gland?

A

FLAT PEG

FSH
LH
ACTH
prolactin
endorphins
GH

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47
Q

___________ stimulates milk production in the mammary glands

A

prolactin

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48
Q

the release of ___________ from the hypothalamus decreases prolactin secretion

A

dopamine

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49
Q

what are the two reactions that must occur for milk ejection?

A
  1. oxytocin is released from the posterior pituitary gland, resulting in smooth muscle contractions of the breast
  2. hypothalamus stops releasing dopamine onto the antioer pituitary gland, which allows prolactin to be released
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50
Q

____________ decrease the perception of pain

A

enodorphins

51
Q

____________ promotes the growth of bone and muscle

A

growth hormone

52
Q

GH is stimulated by _____________ secreted by the hypothalamus

A

GHRH

53
Q

excess of GH in children? deficit of GH in children?

A

excess = gigantism
deficit = dwarfism

54
Q

when is ADH secreted?

A

low blood volume
increased blood osmolarity

*results in greater water retention = increased blood volume and higher blood pressure

55
Q

____________ is secreted during childbirth and allows for coordinated contraction of uterine smooth muscle

A

oxytocin

56
Q

the thyroid is controlled by TSH secreted from the ___________ pituitary gland

A

anterior

57
Q

what are the two major functions of the thyroid?

A
  1. setting basal metabolic rate
  2. promoting calcium homeostasis
58
Q

triiodothyronine (T3) and thyroxine (T4) are produced by the iodination of tyrosine in the _____________ cells of the thyroid

A

follicular cells

59
Q

increased amounts of T3 and T4 will lead to (increased / decreased) cellular respiration

A

increased

60
Q

a deficiency of iodine may result in ____________ in adults or ___________ in children

A

adults = hypothyroidism
children = cretinism

61
Q

an excess of thyroid hormone may result in _______________

A

hyperthyroidism

62
Q

sid effects of hypothyroidism? hyperthyroidism?

A

hypothyroidism:
lethargy
low body temp
slowed respiratory / heart rate
cold intolerance
weight gain

hyperthyroidism:
heighted activity level
high body temp
increased respiratory / heart rate
heat intolerance
weight loss

63
Q

what two types of cells are distinct within the thyroid tissue?

A
  1. follicular cells
  2. parafollicular cells (c cells)
64
Q

follicular cells produce ____________
c cells produce ___________

A

follicular = thyroid hormones
c cells = calcitonin

65
Q

what is the purpose of calcitonin?

A

decrease plasma calcium levels

66
Q

what are the three ways calcitonin decreases plasma calcium levels?

A
  1. increasing calcium excretion from the kidneys
  2. decreasing calcium absorption from the gut
  3. increasing storage of calcium in the bone
67
Q

what hormone is produced by the parathyroid?

A

PTH

68
Q

PTH serves as an antagonist hormone to ____________

A

calcitonin

69
Q

what is the purpose of PTH?

A

increase blood calcium levels
phosphorus homeostasis
activates vitamin D

70
Q

how does PTH increase blood calcium levels?

A
  1. decreases excretion of calcium by the kidneys
  2. increases absorption of calcium in the gut
  3. increases bone reabsorption (freeing up calcium)
71
Q

PTH activtes _______ which is required for the absorption of calcium and phosphate in the gut

A

vitamin D

72
Q

the adrenal coretx secretes _________

A

cortiocosteroids

73
Q

three types of cortiocosteroids?

A
  1. glucocorticoids
  2. mineralocorticoids
  3. cortical sex hormones
74
Q

____________ are steroid hormones that regulate glucose levels and protein metabolism

A

glucocorticoids

75
Q

how do glucocorticoids raise glucose levels?

A

increasing gluconeogenesis
decreasing protein synthesis

76
Q

two most common types of glucocorticoids?

A
  1. cortisol
  2. cortisone
77
Q

glucocorticoids release is under the control of ______________

A

ACTH

78
Q

hypothalamus release:
?

anterior pituitary gland release:
?

adrenal gland release:
glucocorticoids

A

hypothalamus = CRF
anterior pituitary gland = ACTH
adrenal gland = glucocorticoids

79
Q

_____________ are used in salt and water homeostasis

A

mineralocorticoids

80
Q

what is the most common mineralocorticoid?

A

aldosterone

81
Q

aldosterone affects ________ reabsorption in the disal convoluted tubule and collecting duct

A

sodium

82
Q

aldosterone decreases reabsorption of ________ and __________ ions, promoting their excretion in the urine

A

potassium
hydrogen

83
Q

aldosterone is primarily under the control of _____________

A

renin-angiotensin-aldosterone system

84
Q

decreased blood pressure cause _____________ cells to release renin

A

juxtaglomerular

85
Q

renin cleaves an inactive plasma protein, __________, it its active form, __________

A

angiotensinogen –> angiotensin I

86
Q

_____________ converts angiotensin I to angiotensin II

A

angiotensin-converting enzyme

87
Q

angiotensin II stimulates the adrenal cortex to secrete _____________

A

aldoesterone

88
Q

most common cortical sex hormones?

A

androgens
estrogens

89
Q

T / F - females are much more sensitive to disorders of cortical sex hormone production

A

true

*ovaries secrete smaller amounts of androgens

90
Q

main functions of the coticosteroids produced by the adrenal cortex?

A

3 S’s

  1. Salt = mineralocorticoids
  2. Sugar = glucocorticoids
  3. Sex = cortical sex hormones
91
Q

the adrenal (cortex / medulla) is a derivative of the nervous system

A

medulla

92
Q

what hormones does the adrenal medulla secrete?

A

catecholamines (epinephrine and norepinephrine)

93
Q

what effects does epinephrine have? norepinephrine?

A

epinephrine:
increase breakdown of glycogen to glucose
increased basal metabolic rate

both epinephrine / norepinephrine:
increase heart rate
brochi dilation
shunt blood flow to sympathetic systems
vasodilation of blood vessels

94
Q

cortisol = (long / short) term stress response

catecholamines = (long / short) term stress response

A

cortisol = long term (slow)
catecholamines = short term (fast)

95
Q

T / F - the pancreas has both endocrine and exocrine functions

A

true

96
Q

explain exocrine tissues

A

they secrete directly into ducts

97
Q

in the pancreas, endocrine clusters of hormone producing cells are grouped together into ______________

A

islets of langerhans

98
Q

the islets of langerhans contains what three types of cells?

A
  1. alpha
  2. beta
  3. delta
99
Q

what do the alpha, beta, and delta cells of the islets produce?

A

alpha = glucagon
beta = insulin
delta = somatostatin

100
Q

____________ is secreted during times of fasting

A

glucagon

101
Q

when glucose levels are low, glucagon increases glucose production by triggering _________, _________, and ________

A

glycogenolysis
gluconeogenesis
protein / fat degradation

102
Q

T / F - when blood glucose is high, glucagon release is inhibited

A

true

103
Q

___________ is secreted when blood glucose levels are high

A

insulin

104
Q

why is insulin secreted after eating?

A

blood glucose levels are high = eating

insulin induces muscle and liver cells to take up glucose and store it as glycogen

105
Q

insulin stimulates (anabolic / catabolic) process

A

anabolic

*such as fat and protein synthesis

105
Q

underproduction, insufficient secretion, or insensitivity to insulin results in _________________

A

diabetes
hyperglycemia

*high blood glucose

105
Q

excess insulin causes __________

A

hypoglycemia

*low blood glucose

106
Q

common symptoms of diabetes?

A
  1. polyuria = frequent urination
  2. polydipsia = increased thirst
107
Q

explain type 1 diabetes

A

autoimmune destruction of pancreas beta cells

low / absent insulin production

regular injections of insulin

108
Q

explain type 2 diabetes

A

partially inherited, partially due to environmental factors

receptor level resistance to the effects of insulin

109
Q

____________ is an inhibitor of both insulin and glucagon secretion

A

somatostatin

110
Q

high ________ and _______ concentrations stimulate somatostatin secretion

A

blood glucose
amino aids

111
Q

the testes secrete _________ in response to stimulation by ____________

A

testosterone
gonadotropins (LH and FSH)

112
Q

the ovaries secrete ________ and _________ in response to stimulation by ____________

A

estrogen and progesterone
gonadotropins (LH and FSH)

113
Q

where is the pineal gland located?

A

deep inside the brain

114
Q

what does the pineal gland secrete?

A

melatonin

115
Q

in the GI tract, where can endocrine tissue be found?

A

stomach
intestine

116
Q

types of hormones secretes by GI endocrine tissue?

A

secretin
gastrin
cholecystokinin

117
Q

kidneys release ____________ which increases water permeability in the collecting duct, and sodium / water reabsorption in the distal convoluted tubule and collecting duct

A

ADH

118
Q

kidneys produce ___________ which stimulates bone marrow to increase the production of erthrocytes

A

erythropoietin

119
Q

the heart releases __________ to help regulate salt and water balance

A

atrial natruiretic peptide (ANP)

120
Q

how is ANP secretion activated?

A

atria are stretched from excess blood volume

121
Q

what is the outcome of ANP release?

A

lowers blood volume and pressure

122
Q

the thymus releases _____________ which is important for proper t cell development and differentiation

A

thymosin

MCAT - biology (35 decks)

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