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BIO 241 [Exam #2] > Chapter 11 - The Endocrine System > Flashcards

Chapter 11 - The Endocrine System Flashcards

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1
Q

Name the three functions of the endocrine system:

A
  • growth
  • reproduction
  • metabolism
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2
Q

What makes up the endocrine system?

A
  • endocrine glands
  • hormones
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3
Q

What are endocrine glands?

A

ductless glands that produce, store, and/or release hormones directly into the blood

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4
Q

What are hormones?

A

chemical messengers of the endocrine system that are carried to target cells that have receptors for those specific hormones

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5
Q

List the three classes of hormones based on their chemical structure.

What are they made of?

A
  • amine hormones: derived from AA; short (tyrosine and tryptophan)
  • peptide (protein-based) hormones: several AA long
  • steroid hormones: derived from cholesterol
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6
Q

What are examples of amine hormones?

Lipid or water soluble, or both?

A
  • norepinephrine and epinephrine - from tyrosine
  • serotonin - from tryptophan
  • Both: lipid OR water soluble
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7
Q

What are examples of peptide (protein-based) hormones?

Lipid or water soluble, or both?

A

I Get Oxy, Lets Feel Ghood

Insulin, Glucagon, Oxytocin, LH, FSH, GH

Water soluble only (hydrophilic/polar)

LH and FSH are glycoproteins; sugar bound to protien

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8
Q

Which hormones are glycoproteins?

What category based on chemical structure do they belong to?

A

LH and FSH

Peptide hormones

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9
Q

What are examples of steroid hormones?

Lipid or water soluble, or both?

A

TEA CT

testosterone, estrogen, aldosterone, cortisol, thyroid hormone

  • lipid soluble only (hydrophobic/ nonpolar)
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10
Q

Compare a polar hormone with a nonpolar hormone in terms of solubility

A

polar: hydrophilic and water soluble

nonpolar: hydrophobic and water-insoluble (lipophilic)

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11
Q

Compare a polar hormone with a nonpolar hormone in terms of where their receptors are found on target cells

A

polar hormone: receptor on cell surface because charged/polar substances cannot pass through the CM

nonpolar hormone: receptor found on inside target cell because they can enter the target cell directly

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12
Q

Define the anterior pituitary (location and function)

Name the hormones found here

A

hangs from base of brain

produces, stores, and secretes 6 hormones

FLAT PiG

FSH, LH, ACTH, TSH, PRL, hGH

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13
Q

Function of the hGH? (human growth hormone)

What endocrine gland does it belong to?

A

to grow: bone, muscle, adipose tissue

anterior pituitary

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14
Q

Function of the TSH? (thyroid stimulating hormone)

What endocrine gland does it belong to?

A

secretes hormones by thyroid gland

anterior pituitary

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15
Q

Function of the ACTH? (adrenocorticotropic hormone)

What endocrine gland does it belong to?

A

secretes hormones by adrenal cortex

anterior pituitary

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16
Q

Function of the PRL? (prolactin)

What endocrine gland does it belong to?

A

produces milk (in mammary glands)

anterior pituitary

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17
Q

Function of the FSH? (follicle stimulating hormone)

What endocrine gland does it belong to?

A

maturation of sperm and ovarian follicle and ovum (egg)

anterior pituitary

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18
Q

Function of the LH? (luteinizing hormone)

What endocrine gland does it belong to?

A

secretes testosterone and causes ovulation (releases ovum)

anterior pituitary

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19
Q

The posterior pituitary gland does not produce its hormones, it only stores and secretes it. Where are the hormones found in the posterior pituitary produced?

A

hypothalamus

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20
Q

Define the posterior pituitary (location and function)

Name the hormones found here

A

behind anterior pituitary and stores and secretes 2 hormones

DOES NOT PRODUCE HORMONES

ADH,OT

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21
Q

Function of ADH (anti-diuretic hormone)

What endocrine gland does it belong to?

A

controls water balance (causes H20 to be reabsorbed into blood)

increases blood pressure

posterior pituitary

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22
Q

Function of OT? (oxytocin)

What endocrine gland does it belong to?

A

uterine muscle contraction and milk release (letdown reflex)

posterior pituitary

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23
Q

Define the thyroid gland (location and function)

Name the hormones found here

A

below larynx, around trachea
involved in iodine uptake and produces 3 hormones

T4, T3, CT

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24
Q

In the thyroid gland, which are the true thyroid hormones

A

T4 and T3, NOT CT

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25
Q

Function of T4? (thyroxine)

What endocrine gland does it belong to?

A

inactive thyroid hormone

thyroid gland

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26
Q

Function of T3? (triiodothyronine)

What endocrine gland does it belong to?

A

active thyroid hormone

increases metabolic rate by breaking down glc to produce ATP

thyroid gland

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27
Q

Function of CT? (calcitonin)

What endocrine gland does it belong to?

A

bone formation and regulates (decrease) Ca2+ in blood

thyroid gland

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28
Q

Define the adrenal glands (location and function)

Name the hormones found here

A

located atop kidneys; divided into adrenal medulla and adrenal cortex

  • adrenal medulla: epinephrine and norepinephrine
  • adrenal cortex: aldosterone, cortisol
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29
Q

Define the adrenal medulla (location and function)

Name the hormones found here

A

middle portion of adrenal gland and functions in sympathetic NS

  • epinephrine
  • norepinephrine
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30
Q

Define the adrenal cortex (location and function)

Name the hormones found here

A

outer portion of adrenal gland and produces many steroid hormones when stimulated by ACTH

  • aldosterone
  • cortisol
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31
Q

Function of epinephrine and norepinephrine?

What endocrine gland does it belong to?

A

increase heart/breathing rate

adrenal medulla (of adrenal gland)

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32
Q

Function of aldosterone?

What endocrine gland does it belong to?

A

increases blood pressure

adrenal cortex (of adrenal gland)

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33
Q

Function of cortisol?

What endocrine gland does it belong to?

A

increases blood pressure and weakens immune activity

adrenal cortex (of adrenal gland)

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34
Q

What endocrine gland contains structures called the Islets of Langerhans?

A

pancreas

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35
Q

Define the pancreas (location and function)

Name the hormones found here

A

behind stomach on left side
functions as both an endocrine and exocrine gland

contains Islets of Langerhans that produce 2 hormones

  • insulin
  • glucagon
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36
Q

Function of insulin?

What endocrine gland does it belong to?

A

when stimulated by high glucose levels, secretes insulin to lower blood glucose (moves glc from blood into cells -> glycogen formation in liver and skeletal muscle)

pancreas

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37
Q

Function of glucagon?

What endocrine gland does it belong to?

A

when stimulated by low blood glucose levels, secretes glucagon to raise blood glucose (breaks down glycogen and releases glucose)

pancreas

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38
Q

What cells produce insulin and glucagon in the pancreas?

A

insulin - beta cells of Islets of Langerhans

glucagon - alpha cells in Islets of Langerhans

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39
Q

Insulin and glucagon can be described as having __________ effects

A

antagonistic

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40
Q

What hormones do the ovaries (endocrine gland) make?

A

estrogen
progesterone

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41
Q

What hormones do the testes (endocrine gland) make?

A

testosterone

42
Q

What are the islets of Langerhans and what do they secrete?

A

islands of endocrine cells

contain beta cells (secrete insulin) and alpha cells (secrete glucagon)

43
Q

In general terms, explain how insulin lowers blood glucose levels and how glucagon raises blood glucose levels

A

Insulin moves glucose from blood into cells to form glycogen in liver and skeletal muscle cells

Glucagon breaks down glycogen to release glucose into blood

44
Q

Some hormones, like epinephrine and norepinephrine, can also be neurotransmitters (NTs). What determines whether a hormone will act as a hormone vs a NT

A

depends which organ secretes them/binds to

ex: Epinephrine and norepinephrine can act as both NT and hormone.However, when they are released by a neuron then they’re acting as NT. However, when they are released by the adrenal medulla into the bloodstream, then they are acting as a hormone.

45
Q

What mechanism can be used to regulate the amount of hormone released from an endocrine gland?

A

negative feedback

46
Q

True or False: A target cell can only respond to one hormone

A

False, target cells can usually respond to multiple hormones at the same time (have receptors for multiple hormones)

47
Q

hormones ______ the body and reaches the target cell which has ______ types of _______ receptors

A

circulate
two
hormone

48
Q

What are the two types of hormone receptors?

What type of hormones bind to these receptors?

A

surface receptors: polar hormones

intracellular receptors: non polar hormones

49
Q

Compare the location of surface receptors and intracellular receptors

A

surface receptors: found outside target cell

intracellular receptors: found inside target cell

50
Q

Generally describe how hormones work

A
  1. hormones are produced, stored, and secreted into bloodstream
  2. circulates body until reaches target cell with hormone receptors (surface/intracellular receptors)
  3. hormone binds to its receptor on/in target cell -> receptor activated
  4. intracellular pathways are induced -> target cell activity is changed through changes in enzyme activity/changes in gene activity
51
Q

What happens immediately after a hormone binds to its receptor and is activated?

A

intracellular pathways begin

52
Q

After intracellular pathways occur, in what ways is a target cell’s activity altered?

A

gene/enzyme activity can be altered

53
Q

Hormones are needed in _______ _____ amounts; are very _________

A

very small
potent (strong)

54
Q

Why do hormones usually affect other parts of the body?

A

are spread in the blood stream

55
Q

Hormones often have __________ effects, but effects are _______ _________

A

long-lasting
not immediate

56
Q

Define what a half-life is

A

how long it takes to break down a hormone by 50%

57
Q

Compare the half life of a NT to a hormone

A

NT have short half-life, while hormones have a longer half-life

58
Q

Some hormones have an effect on the cell that ______ it (ex: ______________ hormone)

A

secreted
autocrine
(cell targets itself)

59
Q

What are the different types of effects hormones can have on target cells?

A

synergistic effect
antagonistic effect
permissive effect

60
Q

Explain the synergistic effect (how it works). Provide examples

A

two hormones that have the SAME function, and their combined effect is greater than the sum of their individual efforts

ex: epinephrine and norepinephrine both have an affect on increasing heart rate; but together, their combined effect is greater than the sum of their individual efforts

61
Q

Epinephrine: increases heart rate by 10%

norepinephrine: increases heart rate by 20%

If both epinephrine affect the heart rate at the same time, does their combined effect increase heart rate by 30%?

A

No, they are synergistic and have the same function, so their combined effect will be much greater than 30% (maybe like 70% or smth)

62
Q

Explain the antagonistic effect (how it works). Provide examples

A

one hormone opposes/inhibits another hormone

ex: insulin and glucagon are both involved in the regulation of blood glucose levels, but both have opposite effects (one lowers blood glc, while the other increases blood glc)

another example: calcitonin and parathyroid (PTH) regulate blood Ca2+ levels, but one lowers blood Ca2+ and the other increases blood Ca2+

63
Q

Explain the permissive effect (how it works). Provide examples

A

one hormone permits/allows the other hormone to exert its full effect

ex: epinephrine (by itself) weakly stimulates lipolysis, but in the presence of T3, it increases the number of epinephrine receptors on target cell, so epinephrine has a greater effect

64
Q

Compare the priming effect and desensitization

A

priming (upregulation) effect: increases # of hormone receptors on target cell for same/different hormone

desensitization (down regulation) effect: decrease # of hormone receptors on target cell to prevent overstimulation due to lingering hormone

65
Q

The desensitization effect leads to a ________ response to a hormone after _____________ exposure

A

decreases
prolonged

(after prolonged hormone receptor -> decrease of hormone receptors -> decrease hormone reponse)

66
Q

What is the stimulus for the production of T4 and T3?

A

low body temperature

(because producing T4 increases metabolic rate, which releases energy in form of heat)

67
Q

“Draw” the hormone pathway that involved homeostasis of body temperature

A

stimulus: low body temp

hypothalamus -> TRH -> anterior pituitary -> TSH -> thryroid gland -> T4 and T3 (TH)

*if too hot, negative feedback will inhibit TRH (by hypothalamus) and TSH (by anterior pituitary) production

68
Q

Water-soluble hormones must bind to…

A

water-soluble hormone receptors located on the surface of target cell

69
Q

Water-soluble hormones are AKA?

A

polar/charged/hydrophilic hormones

70
Q

Explain how negative feedback is involved in thermoregulation

A

producing too much heat (making too much T4 into T3), will signal negative feedback to stop the production/release of TRH by the hypothalamus or stop the production/release of TSH by the anterior pituitary (end product inhibition)

71
Q

What category/type of hormone binds to extracellular/cell surface receptors? Why is the receptor located on the cell surface?

A

water-soluble (polar/charged/hydrophilic) hormones

located on the cell surface because they cannot pass through cell membrane

72
Q

What category/type of hormone binds to intracellular receptors? Why is the receptor located inside the cell?

A

lipid-soluble (nonpolar/uncharged/hydrophobic) hormones

because they can pass through the cell membrane (cannot stay in extracellular environment bc they are hydrophobic)

73
Q

Compare the end result from water-soluble hormones from lipid-soluble hormones

A

water-soluble hormones: changes enzyme activity (target cell physiology altered too)

lipid soluble: ↑ or ↓ in production of protein coded by genes (DNA)

74
Q

List the 2 pathways water-soluble hormones use to deliver their message to the cell interior. Which hormone is capable of activating these 2 pathways?

A

adenylate cyclase - cAMP pathway: glucagon, epinephrine, LH

phospholipase c - Ca2+ pathway:
ADH, angiotensin, TSH

75
Q

Describe how the adenylate cyclase – cAMP pathway works. What is the function/action of
active protein kinase?

A

water-soluble hormone binds receptor on cell surface → Gprotein’s alpha subunit dissociates → activates Adenylate cyclase → ATP converted to cAMP → cAMP activated PK → active PK phosphorylates enzymes (proteins) to deactivate or activate them.

76
Q

Who acts as the second messenger in the adenylate cyclase - cAMP pathways? Why do we need these?

A

cAMP

need second messenger because water-soluble hormones can’t cross the cell membrane to deliver its message (to nucleus?)

77
Q

Who acts as the second messenger in the phospholipase c - ca2+ pathways? Why do we need these?

A

IP3 or Ca2+

need second messenger because water-soluble hormones can’t cross the cell membrane to deliver its message (to nucleus?)

78
Q

Describe how the phospholipase C – Ca++ pathway works. What happens to the Ca++ that gets
released into the cytoplasm (what does it bind to)?

A

water-soluble binds to receptors on cell surface → Gprotein’s alpha subunit dissociates → activates Phospholipase C → IP3 and DAG → IP3 binds to IP3 receptor on ER/SR → Ca++ released from ER/SR → activates Calmodulin-Ca++ → activates PK → active PK phosphorylates enzymes to deactivate or activate them

Ca2+ binds to inactive calmodulin to form Ca2+ calmodulin

79
Q

True/False: calmodulin is an active compound

A

False, is active when bound to Ca2+ to make Ca2+ calmodulin

80
Q

What is glycogenolysis, in which cell(s) does it take place, what 2 hormones promote glycogenolysis, and what is the end product of glycogenolysis?

A

Glycogenolysis: the process of breaking down glycogen into glucose

Liver cells + Skeletal Muscle Cells

Glucagon and Epinephrine

Glucose

81
Q

List the 2 epinephrine receptors present on the liver cell

A

beta-adrenergic receptor (adenylate cyclase - cAMP)

alpha-adrenergic receptor (phospholipase C - Ca2+)

82
Q

Regarding the binding of epinephrine to 2 distinct receptors, explain how the adenylate cyclase
and phospholipase pathways work, and the product formed by BOTH pathways that starts the
common pathway.

A

Adenylate cyclase uses cAMP to activate PK. Phospholipase pathway uses Calmodulin-Ca++ to activate PK.

83
Q

What 2 compounds can activate protein kinase?

A

cAMP and Calmodulin-Ca++

84
Q

True/False: phosphorylated enzymes are always active

A

false, they can be either inactive or active

85
Q

In glycogenolysis, what 2 enzymes does active protein kinase phosphorylate? Do these two enzymes both become active when phosphorylated?

A

phosphorylase kinase ⓟ (active when phosphorylated)

glycogen synthase (inactive when phosphorylated)

86
Q

What chemical reaction is catalyzed by active glycogen synthase? Is active glycogen synthase
phosphorylated or dephosphorylated?

A

Active glycogen synthase converts glucose into glycogen

Active glycogen synthase is dephosphorylated

87
Q

In glycogenolysis, after active PK phosphorylates phosphorylase kinase into the active form, what happens after?

A

PK (active) -> phosphorylase kinase (active) -> glycogen phosphorylase (active) -> converts glycogen into glucose

88
Q

Name all the enzymes involved in the converged pathway

A
  • protein kinase
  • glycogen synthase
  • phosphorylase kinase
  • glycogen phosphorylase
89
Q

Name 2 specific locations within the cell where you can find lipid soluble hormone receptors

A

cytoplasm and nucleus

90
Q

Because lipid-soluble hormones are hydrophobic, how are they carried to the target cell?

A

carried by a carrier protein through the blood to target cell

carrier protein does NOT enter target cell

91
Q

What happens to the hormone-receptor (HR) complex if it is found in the target cell’s cytoplasm?

A

The HR complex must get translocated into the nucleus.

92
Q

Where in the target cell does the HR complex ultimately need to be, and describe what it does once it arrives there.

A

Nucleus

Once inside the nucleus, the HR complex binds to a half-site of HRE to form a homodimer or heterodimer -> transcription into mRNA and translation to synthesize protein

93
Q

What is the relationship between the promoter, hormone response element (HRE), and a half site?

A

promoters contain HRE which has 2 half-sites

94
Q

What is a dimer, and compare a homodimer vs. a heterodimer

A

A dimer includes 2 half-sites of an HRE bound to 2 HR complexes.

if the 2 HR complexes are the same = homodimer

if different = heterodimer.

95
Q

TRUE or FALSE: If only 1 half-site is occupied by a HR complex, the lipid soluble hormone will have an effect on the target cell

A

False. Both half-sites need to be occupied by HR complexes to have an effect

96
Q

Which of the two thyroid hormones crosses the cell membrane, and which one crosses the nuclear membrane?

A

T4 crosses the cell membrane and T3 crosses the nuclear membrane.

97
Q

Where in the target cell does T4 get converted in T3?

A

cytoplasm (but needs to move to nucleus)

98
Q

Where in the target cell are T3 receptors located? How does that compare to other lipid soluble hormone receptors?

A

located in the nucleus bound to DNA

other hormone receptors are usually in the cytoplasm, therefore, they need to be translocated into the nucleus

99
Q

Compare the location formation of the HR complex of a standard lipid-soluble hormone to the HR complex of a thryoid hormone (TH)

A

standard: HR complex formed in cytoplasm (bc receptors found there)

TH: HR complex formed in nucleus (bc T3 receptors found there)

100
Q

For thryoid hormones, the HRE on the DNA has two half sites, one for _______ receptor and one for a _________ receptor

A

T3 receptor
9-cis-retinoic acid receptor (RXR)

101
Q

Describe the other HR complex that forms a dimer with the thyroid hormone-
thyroid hormone receptor complex on the HRE.

A

9 cis retinoic acid and its 9-cis-retinoic acid receptor (RXR) occupy the other half-site on the HRE

BIO 241 [Exam #2] (3 decks)

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