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Phg 204 > Endocrinology1 > Flashcards

Endocrinology1 Flashcards

1
Q

Endocrinology is concerned with the study of the biosynthesis, storage, chemistry, and physiological function of hormones and with the cells of the endocrine glands and tissues that secrete them.
T/F

A

T

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2
Q

The endocrine system is composed of a numerous (duct or ductless?) glands in different parts of the body, that secrete hormones directly into the ____ rather than into a ____ system.

A

ductless

blood

duct

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3
Q

Endocrine system is an anatomically and functionally connected system.
T/F

A

F

Just functionally

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4
Q

endocrine glands can talk to one another

T/F

A

T

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5
Q

one hormone may have several effects on different target organs

T/F

A

T

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6
Q

one target organ can’t be affected by more than one hormone.

T/F

A

F

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7
Q

The target cell/organ
-if the target cell does not have a receptor for the signaling molecule, it can still respond to the signal under some conditions
T/F

A

F

It can’t

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8
Q

Paracrines

  • local chemical messengers that exert their effects only on neighboring cells
  • they are not transported in any quantity through the blood stream.
  • E.g. histamine (involve in inflammatory response,causing localized vasodilatation)

(B)Autocrine
-in which a cell secretes substances that affect the function of the same cell by binding to the cell surface receptors.

(C)Neurotransmitters

  • are very localized signaling molecules
  • acting only across the space of the synapse, neuromuscular junction, or neuroeffector junction.

(D)Neuroendocrine
-in which neurons secrete substances (neurohormones) that reach the circulating blood and influence the function of cells at another location in the body

(E) Endocrine

  • in which glands or specialized cells release into the circulating blood chemicals that influence the function of cells at another location in the body.
  • They are the true long-range chemical messengers, secreted by the ductless glands.

Amines

  • such as norepinephrine, epinephrine, and dopamine, are derived from single amino acids, in this case tyrosine.
  • Thyroid hormones such as 3,5,3’-triiodothyronine (T3) and 3,5,3’,5’-tetraiodothyronine (thyroxine, T4) make up a subset of this class because they derive from the combination of two iodinated tyrosine amino acid residues.
  • thyroid hormones
  • stored in the protein thyroglobulin
  • Hormone secretion occurs when the amines are split from thyroglobulin and the free hormones are then released into the blood stream.
  • In the blood, most of the thyroid hormone combines with plasma proteins, which slowly releases the hormones to the target tissues.
  • Act via the same mechanism as steroid hormones.
  • Solubility:Thyroid hormones-lipophilic
A

Vc

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9
Q

Paracrines

  • local chemical messengers that exert their effects only on ____ cells
  • E.g. _____
A

neighboring

histamine

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10
Q

Paracrines are transported in only a little quantity through the blood stream.
T/F

A

F

In no quantity

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11
Q

Histamine is involved in ______ response,causing localized _____

A

inflammatory

vasodilatation

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12
Q

Autocrine

-in which a cell secretes substances that affect the function of ____ cell by binding to the cell surface receptors.

A

the same

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13
Q

Neurotransmitters are slightly localized signaling molecules

T/F

A

F

Very localized

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14
Q

Neuroendocrine
-in which ____ secrete substances (_____) that reach the circulating blood and influence the function of cells at another location in the body

A

neurons

neurohormones

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15
Q

Amines

-such as norepinephrine, epinephrine, and dopamine, are derived from _____ amino acids, in this case _______.

A

Single

tyrosine

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16
Q

Thyroid hormones such as ____-triiodothyronine (T3) and ____-tetraiodothyronine (thyroxine, T4) make up a subset of this class because they derive from the combination of __ iodinated ____ amino acid residues.

A

3,5,3’

3,5,3’,5’

two ; tyrosine

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17
Q

thyroid hormones

  • stored in the protein ____
  • Hormone secretion occurs when the ____ are split from ____ and the free hormones are then released into the blood stream.
A

thyroglobulin

amines

thyroglobulin

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18
Q

In the blood, most of the thyroid hormone combines with ____ , which slowly releases the hormones to the ___.

A

plasma proteins

target tissue

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19
Q

Thyroid hormones Act via the same mechanism as steroid hormones.
T/F

A

T

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20
Q

Thyroid hormones are lipophobic

T/F

A

F

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21
Q

Catecholamines

-Epinephrine and norepinephrine are formed in the ____, which normally secretes about four times more ____ than ____

A

adrenal medulla

epinephrine than norepinephrine.

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22
Q

Catecholamines are taken up into preformed vesicles and stored until secreted.
T/F

A

T

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23
Q

Similar to the ____ hormones, catecholamines are released from adrenal medullary cells by ____.

A

protein

exocytosis

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24
Q

catecholamines are hydrophilic

T/F

A

T

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25
Q

Peptide and protein

  • consist of ___ to more than ____ amino acid residues
  • can have molecular weights as large as _____.
A

three

200

30,000

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26
Q

TRH contains ___ amino acid

A

3

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27
Q

FSH contains ___ amino acid

A

200

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28
Q

Polypeptides with 100 or more amino acids are called ___, and those with fewer than 100 amino acids are referred to as ___.
-They are synthesized on the ___ of the different endocrine cells first as larger proteins that are not biologically active ( _____hormones) and are cleaved to form smaller ___hormones.

A

proteins

peptides

RER

pre­pro; pro

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29
Q

Prohormones are then transferred to the ___ for packaging into secretory vesicles stored within the cytoplasm or bound to the cell membrane until their secretion is needed.
-When needed, the secretory vesicles fuse with the cell membrane and the granular contents are extruded into the interstitial fluid or directly into the blood stream by ____.

A

Golgi apparatuses

exocytosis

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30
Q

The peptide hormones are _____ soluble, allowing them to enter the circulatory system easily and be carried to their target tissues.

A

water

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31
Q

Steroid

  • are converted from their parent compound, ____.
  • Mammalian steroid hormones can be grouped into five groups by the receptors to which they bind: glucocorticoids, mineralocorticoids, androgens, estrogens, and progestagens.
  • The chemical structure of steroid hormones is similar to ____.
A

cholesterol

cholesterol

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32
Q

Steroid hormones Are Stored.

T/F

A

F

They aren’t

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33
Q

Much of the cholesterol in steroid-producing cells comes from the ____

A

plasma

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34
Q

Steroids are ____ soluble so, once synthesized, they simply diffuse ____ and enter the _____ and then the _____

A

lipid

across the cell membrane

interstitial fluid

blood.

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35
Q

*Mechanism of steroids
-binding to ____ receptor 
-binding of hormone-receptor complex directly on target DNA 
-regulation of transcription of specific target genes 
-can induce production of specific proteins

A

intracellular

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36
Q

Factors affecting hormone concentrations
*neuroendocrine reflexes 
-stimulation of the nervous sytem affects hormone production or release 
-examples: stimulation of the ___ in cats and ___ causes release of ___ and subsequent ____ or _____ reflex

A

cervix

rabbits

LH

ovulation

milk ejection

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37
Q

circadian and circannual rhythms :


-temporal patterns of hormone release 
e.g. ____ rise in ADH 
e.g. pituitary hormones in seasonal breeding animals

A

nocturnal

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38
Q

Factors affecting hormone action:

  • Number of receptors and strength of binding
  • Presence of other hormones eg antagonists
  • Second messenger systems
A

T
T
T

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39
Q

Endocrine Disorders

(1) Hypersecretion
* primary : problem with ——- causes oversecretion
* secondary :______ causes target gland to overproduce the hormone in question

A

gland itself

overproduction of trophic hormone

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40
Q

Hyposecretion

  • primary:
  • _____ defect (e.g. lack of or mutated steroidogenic enzyme)
  • ____ deficiency (e.g. lack of iodine which is necessary for synthesis of thyroid hormones)
  • destruction of gland by___ or ___ (e.g. autoimmune destruction of pancreatic Beta cells which produce insulin)
  • secondary
  • _______ of trophic hormone

(3) Abnormal target cell responsiveness e.g. insulin resistance
- defect in _____
- disorder of _____ system

(4)Altered metabolism of hormone 
-example is effect of antibiotics on _____

A

genetic

dietary

disease or injury

underproduction

hormone receptors ; second messenger
oral contraceptives

41
Q

MECHANISMS OF ACTION OF HORMONES

  • The first step of a hormone’s action is to ___ to ______ at the ____ cell.
  • When the hormone combines with its receptor, it initiates cascades of reactions in the cell, with each stage becoming more powerfully activated so that even ___ concentrations of the hormone can have a ____ effect.
A

bind

specific receptors

target

small

Large

42
Q

Cells that lack receptors for the hormones do not respond.

T/F

A

T

43
Q

Receptors are usually highly specific for a single hormone and are located on the target cell membrane (___,___,_____hormones) or the target cell cytoplasm (different ____ hormones) or even the target cell nucleus (_____ hormones)

A

protein, peptide, and catecholamine

steroid

thyroid

44
Q

Some Hormones Change Membrane Permeability. E.g. as ____ and ______

A

epinephrine

norepinephrine

45
Q

Some Hormones Activate Genes by Binding with Intracellular Receptors. Several hormones, especially the ___ hormones and ____ hormones.

A

steroid

thyroid

46
Q

Some Hormones activate (or occasionally inactivation) Intracellular Enzymes When They Combine with Their Receptors.e.g.
Insulin
T/F

A

T

47
Q

Insulin+receptor Leads to formation of an activated ____.This ____ promotes _____ of several different substances inside the cell.
OR
*Leads to formation of activated enzyme _____.This cyclase in turn catalyzes the formation of ____, called a second messenger because it is not the hormone itself that directly institutes the intracellular changes; instead, it is the ____ that serves as a second messenger to cause these effects.

A

Kinase
Kinase

phosphorylation

adenylyl cyclase

cAMP

cAMP

48
Q

STEROIDS

  • The steroid hormone enters the ____ of the cell, where it binds with a specific receptor protein.
  • The combined receptor protein-hormone then diffuses into or is transported into the ____.
  • The combination binds at specific points on the ____ strands in the chromosomes which activates formation of ____.
  • The mRNA diffuses into the ____, where it promotes the translation process at the ribosomes to form new proteins
A

cytoplasm

nucleus

DNA

messenger RNA

cytoplasm

49
Q

the measurement of hormones, their precursors, and their metabolic end products are done using the method of

______( ___ )

Or

_______ ( _____ )

A

radioimmunoassay; RIA

Enzyme-linked immunosorbent assay

50
Q

Feedback Systems
-Feedback systems are the primary means by which the endocrine system maintains a relatively constant rate of secretion
T/F

A

T

51
Q

Homeostasis is the general rule for the endocrine system

T/F

A

T

52
Q

Types of feedback
____ feedback
____ feedback

A

Negative

Positive

53
Q

Negative Feedback:
-It prevents Overactivity of Hormone Systems.
T/F

A

T

54
Q

testosterone feeds back on LH to increase LH release

T/F

A

F

Inhibits it

55
Q

_____ feedback occurs when homeostasis is not the goal

A

Positive

56
Q

the surge of luteinizing hormone (LH) that occurs as a result of the stimulatory effect of _____ on the _____ before ______.
-The secreted LH then acts on the _____ to stimulate additional secretion of _____, which in turn causes more secretion of LH.

  • Eventually, LH reaches an appropriate concentration, and typical negative feedback control of hormone secre­tion is then exerted.
  • the output of the system stimulates the input, which then stimulates more output, which stimulates more input, etc.
A

estrogen

anterior pituitary

ovulation

ovaries

estrogen

57
Q

Cyclical-variations:
-Super­imposed on the negative and positive feedback control of hormone secretion are ____ variations in hormone release influenced by seasonal changes, various stages of development and aging, the diurnal (daily) cycle, or sleep.

-E.g. secretion of growth hormone is markedly increased during the ____ period of sleep but is reduced during the ____ stages of sleep.

A

periodic

early

later

58
Q

The concentrations of hormones required to control most metabolic and endocrine functions are (small or large?)

A

Small

59
Q

Corpus Luteum produces which hormone (s)?

A

Estradiol and progesterone

60
Q

____ of the cervix causes the posterior pituitary to secrete ____ which In turn, stimulates ______ , which causes _______.

In this example, the explosive event is _______

A

Dilation

oxytocin

uterine contraction

further dilation of the cervix

parturition

61
Q

If more hormone is required to produce 50% of the maximal response, then there has been a ___ease in sensitivity of the target tissue. If less hormone is required, there has been an _____ease in sensitivity of the target tissue.

A

Decr

Incre

62
Q

Human growth hormone contains ___ amino acids in a straight-chain polypeptide with ___ internal disulfide bridges.

A

191

2

63
Q

The gene for growth hormone is a member of a family of genes for related peptides,_____ and ______.

A

prolactin

human placental lactogen

64
Q

Human growth hormone is structurally similar to prolactin
T/F

A

T

65
Q

Prolactin, a ___–amino acid straight-chain polypeptide with ___ disulfide bridges, has ____% homology with growth hormone.

A

198

3

75

66
Q

Human placental lactogen, a ____–amino acid straight-chain polypeptide with __ disulfide bridges, has ___% homology.

A

191

2

80

67
Q

Growth hormone is secreted in a _____ pattern, with bursts of secretion occurring approximately every ____ hours.

A

pulsatile

2

68
Q

The largest secretory burst of growth hormone occurs within __ of falling asleep (during sleep stages ___ and ____).

A

1hour

III

IV

69
Q

Factors stimulating Growth Hormone Secretion

______ glucose concentration

_______ free fatty acid concentration

__-Adrenergic agonists

A

Decreased

Decreased

β

70
Q

Factors affecting Growth Hormone Secretion

Pregnancy
Fasting or starvation 
Stage III and IV sleep 
Obesity 
Arginine
Senescence
A

Inhibits

Stimulate

Stimulate

Inhibits

Stimulate

Inhibits

71
Q

Factors affecting Growth Hormone Secretion

Hormones of puberty
Somatostatin
Exercise 
Somatomedins 
Growth hormone
Stress
A

Stimulate

Inhibits

Stimulate

Inhibits

Inhibits

Stimulate

72
Q

The highest rates of growth hormone secretion occur during ____, and the lowest rates occur in _____.

A

puberty

senescence

73
Q

GHRH stimulates growth hormone secretion by utilizing ______ as second messengers.

A

both cAMP and IP3/Ca2+

74
Q

Somatostatin is also secreted by the _____ and acts on the somatotrophs to inhibit _____ secretion.

A

hypothalamus

growth hormone

75
Q

Somatostatin inhibits growth hormone secretion by ____ the action of ____ on the somatotroph.

A

blocking

GHRH

76
Q

Somatostatin binds to its own membrane receptor, which is coupled to ____ by a G_ protein, inhibiting the generation of _____ and decreasing growth hormone secretion.

A

adenylyl cyclase

i

cAMP

77
Q

direct actions of growth hormone are mediated by _____ receptors.

Indirect actions of growth hormone are mediated through the production of ______ in the ____.

A

tyrosine kinase associated

somatomedins (or IGFs)

liver

78
Q

Some IGF receptors are similar to the insulin receptor, having ______ activity and exhibiting _____

A

intrinsic tyrosine kinase

Autophosphorylation

79
Q

growth hormone causes ____ease in blood insulin levels

A

Incr

80
Q

Growth hormone causes insulin resistance

T/F

A

T

81
Q

linear growth, protein synthesis and organ growth work of growth hormone is mainly carried out by ????

A

Somatomedins

82
Q

Growth hormone deficiency in children is treated with ________.

A

human growth hormone replacement

83
Q

Laron dwarfism, in which growth hormone levels are _____ and treatment with growth hormone is ______.

In these individuals, ______ are defective; thus growth hormone cannot cause production of ____ in target tissues.

A

elevated

ineffective

growth hormone receptors

IGFs

84
Q

Excess growth hormone Secretion after puberty cause insulin _____ and glucose _______

A

Resistance

Intolerance

85
Q

Conditions with excess secretion of growth hormone are treated with __________ (e.g., ______ )

A

somatostatin analogues

octreotide

86
Q

TRH is a stimulator of prolactin secretion

T/F

A

T

87
Q

Hypothyroidism causes ____prolactinaemia

A

Hyper

88
Q

Factors Affecting Prolactin Secretion

Dopamine antagonists
Sleep
Stress
Bromocriptine
Somatostatin 
Prolactin
A

Stimulates

Stimulates

Stimulates

Inhibits

Inhibits

Inhibits

89
Q

pregnancy does not have to occur for lactation to be possible

T/F

A

T

90
Q

Lactation occurs during pregnancy

T/F

A

F

91
Q

prolactin inhibits ovulation

T/F

A

T

92
Q

In males with high prolactin levels (e.g., due to a ______), there is a parallel (stimulatory or inhibitory?) effect on ____ secretion and ______, resulting in ______.

A

prolactinoma

inhibitory

GnRH

spermatogenesis

Infertility

93
Q

The major symptoms of excess prolactin secretion are _____ and _____

A

galactorrhea and infertility

94
Q

Factors Affecting Antidiuretic Hormone Secretion

Pain 
Nausea 
ANP
Hyperglycemia (change to hypo that stimulates)
Nicotine 
Ethanol 
α-Adrenergic agonists
Opiates
Antineoplastic drugs
A

Stimulates

Stimulates

Inhibits

Inhibits

Stimulates

Inhibits

Inhibits

Stimulates

Stimulates

95
Q

To increase water permeability, ADH uses V_ receptor

To contract vascular smooth muscle uses V_ receptor

A

2

1

96
Q

SIADH is treated with an ADH antagonist such as ______ or ______

A

demeclocycline

water restriction.

97
Q

Opiods stimulate oxytocin secretion

T/F

A

F

It inhibits

98
Q

Suckling is required for oxytocin secretion

T/F

A

F

It’s not

Phg 204 (9 decks)

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