EX 2; Endocrinology Flashcards

1
Q

What is the main route of communication in the endocrine system

A

chemical signals (hormones) released into blood

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2
Q

What are two factors affecting onset and duration of signal effects

A

the response can be delayed; time for the blood to travel

the duration is prolonged; some hormones stay in blood

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3
Q

This part of the endocrine system releases hormones directly into the blood of ECF

A

endocrine glands

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4
Q

The endocrine glands for an organ system without what

A

physical links; hormone connection

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5
Q

What are the three steps in hormone travel

A

release
in the blood
reaching the target

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6
Q

The specificity of target cells is due to what

A

receptors on the target cells

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7
Q

This is any organ or tissue that secretes something; ducts (exocrine)

A

gland

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8
Q

Most hormones are made of this structure

A

peptides

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9
Q

True or False

Only very small peptides are hormones

A

False; thy can vary in size, from small to very larg

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10
Q

These are sugar residues attached to backbone, helping to protect the hormone from degradation, and to enhance specificity

A

glycosylations

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11
Q

Some peptide hormones function as neurotransmitters, what is the main difference between them

A

where it is released; the blood or a synapse

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12
Q

This is the first thing synthesized in peptide hormone synthesis it comes off of ribosomes

A

preprohormone

contains lots of aa’s and gets folded

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13
Q

This step in peptide hormone synthesis is to the RER, then off to golgi, then to secretary vesicles

A

prohormone

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14
Q

Cleavage of he pro-part (aa’s) of a pro-hormone, leads to this, that is stored in vesicles

A

hormones

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15
Q

What two things are released from the vesicles

A

pro fragments and hormones

the pro-hormone is cleaved to the pro fragments and hormone in the secretory vesicles

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16
Q

What three things are important in the packaging and storing of peptide hormones

A

allows a cell to store until its needed
helps regulate cell itself
prevents degradation

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17
Q

What are some of the glandular source of lipid hormones (steroids)

A

gonads
outer adrenal cortex
placenta
some brain cells

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18
Q

All steroids are derived from what by a series of enzymatic reactions

A

cholesterol

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19
Q

Some cholesterol needed for the membrane is produced via which method

A

de novo synthesis

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20
Q

Most cholesterol is derived from what

A

low density lipoproteins; LDL is up-taken by a cell via LDL receptor to an endosome where it is broken down to a cholesterol ester

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21
Q

This type of cell stores cholesterol esters; looks like an adipocyte

A

steridogenic cells

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22
Q

These determines which stereoid is produced

A

enzymes

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23
Q

Steroid hormone synthesis is typical stimulated by what

A

peptide hormones from other glands

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24
Q

This frees cholesterol from stores

A

cholesterol esterases; PKA phosphorylates cholesterol esterases to free cholesterol

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25
Q

This protein facilitates intracellular transport of cholesterol (to mitochondria)

A

steroid acute regulatory protein (StAR)

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26
Q

Steroids are not stored why?

A

they are lipid soluble; they will diffuse out of the membrane to intracellular fluid

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27
Q

What three things regulate steroids

A

enzymes
regulate peptide hormone stimulating steroidogenesis
increases cell division of steroid producing cells

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28
Q

Most steroid biosynthesis enzymatic reactions are what

A

uni-directional

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29
Q

What are the five different molecules along the steroid biosynthesis pathway

A

cholesterol –> progestagens –> corticosteroids or androgens –> estrogens

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30
Q

Amine hormones are all derived from which amino acid

A

tyrosine

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31
Q

What are the two hormones that are synthesized in the thyroid

A

thriiodothyronine (T3)

thyroxine (T4)

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32
Q

Thyroid hormones are steroid-like with respect to what two things

A

solubility and receptors

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33
Q

Catecholamines are synthesized in which two areas

A

adrenal gland

hypothalamus

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34
Q

What are three examples of catecholamines

A

norepinephrine
epinephrine
dopamine

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35
Q

catecholamines are common what

A

neurotransmitters

36
Q

Catecholamines are similar to what in respect to solubility and receptors

A

peptide-like

37
Q

What is the 4t class of hormones

A

eicosanoids

38
Q

Lipids are derived from what

A

arachindonic acid

39
Q

Most hormones are secreted in which way

A

in short burst; timing based on upstream signals

40
Q

Secretion of GH and cortisol is what type of pattern

A

circadian

GH secretion high when sleeping and cortisol is high during the day

41
Q

What are the three factors that hormone secretion may be controlled by

A

plasma concentration of a nutrient
neuronal control
hormone control

42
Q

This type of hormone dissolves in the blood

A

hydrophilic hormones

43
Q

This type of protein requires a carrier protein

A

lipophilic hormones

44
Q

The use of these will affect hormone availability

A

carriers; only free hormones can react, therefore it must be released by the carrier protein

45
Q

Metabolism and excretion of hormones does what to the signal

A

inactivates it

46
Q

Which two organs are important in the metabolism and excretion of hormones

A

liver and kidney

47
Q

True or False

Some hormone degradation occurs in the blood

A

True

48
Q

These hormones and water soluble and can be activated by proteolytic degradation

A

catecholmines and peptides

49
Q

These hormones are protected via attachment of carrier proteins from degradation

A

steroids

50
Q

Circulating concentrations are a function of what

A

synthesis va removal or clearance

51
Q

Receptors for hydrophilic hormones are where

A

on the cell surface or in plasma membrane

52
Q

Receptor activation triggers what

A

a signal transduction pathway; activates the 2nd messenger system

53
Q

This response involves ions; opening the ion channels in plasma membrane or cell itself; rapid response

A

ionotropic responses

54
Q

This response is more delayed and involves metabolism within the cell; transport around the cell via secretory vesicles

A

metabotropic responses

55
Q

A response involving ions and phosphorylation is what type of response

A

rapid response

56
Q

A response involving the alteration of protein translation/transcription mechanism is what type of response

A

delayed response

57
Q

Receptors for lipophilic hormones are located where

A

intracellular and/or nuclear

58
Q

These two things form a DNA-binding protein that regulates transcription

A

receptor + ligand

59
Q

Where is the location of the hypothalamus and pituitary gland

A

hypothalamus is on the floor of the diencephalon

pituitary gland lies just below the hypothalamus in the sella turcica

60
Q

What are the three components of the pituitary gland

A

anterior = adenohypophysis
posterior = neurohypophysis
infundibulum connecting the two structures

61
Q

This part of the pituitary gland is derived from oral ectoderm; not neural

A

anteriorhypophysis

62
Q

This part of the pituitary gland is from the neural area; hypothalamus

A

neurohypophysis; posterior

63
Q

The hormones are synthesized where

A

in the neuronal cell bodies in the supraoptic and paraventicular nuclei

64
Q

hormones are released in response to what

A

an action potential; axon terminals are in the posterior pituitary; the hormones are released into capillaries of the systemic circulation

65
Q

This hormone from the posterior pituitary has actions on the smooth muscle

A

oxytocin; labor

66
Q

This hormone from the posterior pituitary has actions in the kidney and blood

A

vasopressin (ADH)

67
Q

This is NOT an extension of the hypothalamus, but it is regulated by hormones secreted by hypothalamic neurons

A

adenohypophysis

68
Q

This secretes hypophysiotropic (or releasing) hormones; stimulates ant. pituitary

A

hypothalamic neurons

69
Q

Axon terminals lie where

A

in the median eminence

70
Q

Hypothalamic hormones are transported in the in the blood within what

A

the portal vessels to the anterior pituitary

71
Q

This is composed of 5 different cell types that produce 6 primary hormones in response to different hypophysiotropic hormones

A

anterior pituitary

72
Q

Hypophysiotropic or releasing hormones are typically named for what

A

the pituitary hormones they regulate; both stimulatory and inhibitory

73
Q

Hypophysiotropic hormones all do what

A

regulate the release of hormones from the anterior pituitary

74
Q

What are 6 of the 8 hormones the anterior pituitary secretes

A
FSH
LH
GH
thyrotropin
prolactin
ACTH
75
Q

This is a precursor polypeptide synthesized in corticotrophs

A

pro-opiomenalocortin (POMC)

76
Q

POMC is cleaved to yield multiple peptides with varied actions and target tissues like what

A

ACTH
ɣ-MSH (melanocyte)
β-LPH (lipotropic)

77
Q

True or False

hypophysiotropic hormones are often found elsewhere in the nervous system

A

True

78
Q

True or False

Hypophysiotropic hormones are all peptides

A

False; they are not all peptides

79
Q

The hypo-thalmo-pituitary portion of the endocrine stem is often referred to as what

A

neuroendocrine system

80
Q

The hypothalamus + pituitary + target = what

A

an axis

81
Q

The complexicity of the neuroendocrine system provides what two thins

A

multiple control sites, and permits and amplification of the initial signal

82
Q

The release of the hypophysiotropic horses is controlled by what

A

neural signals; both stimulatory and inhibitory inputs

involving specific neural pathways

83
Q

Release of hypophysiotropic hormones is also controlled by feedback mechanisms like what

A

loop feedbacks

84
Q

This system is self-regulation by product/hormone of the ultimate target tissue

A

long-loop negative feedback

85
Q

This system occurs when the hormone from the 2nd gland in the axis affects the action of the 1st land

A

short-loop negative feedback

86
Q

Feedback mechanisms return hormone concentrations to what

A

normal; i.e maintain homeostasis