EX 2; Endocrinology Flashcards Preview

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Flashcards in EX 2; Endocrinology Deck (86):
1

What is the main route of communication in the endocrine system

chemical signals (hormones) released into blood

2

What are two factors affecting onset and duration of signal effects

the response can be delayed; time for the blood to travel
the duration is prolonged; some hormones stay in blood

3

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

endocrine glands

4

The endocrine glands for an organ system without what

physical links; hormone connection

5

What are the three steps in hormone travel

release
in the blood
reaching the target

6

The specificity of target cells is due to what

receptors on the target cells

7

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

gland

8

Most hormones are made of this structure

peptides

9

True or False
Only very small peptides are hormones

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

10

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

glycosylations

11

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

where it is released; the blood or a synapse

12

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

preprohormone
contains lots of aa's and gets folded

13

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

prohormone

14

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

hormones

15

What two things are released from the vesicles

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

16

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

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

17

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

gonads
outer adrenal cortex
placenta
some brain cells

18

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

cholesterol

19

Some cholesterol needed for the membrane is produced via which method

de novo synthesis

20

Most cholesterol is derived from what

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

21

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

steridogenic cells

22

These determines which stereoid is produced

enzymes

23

Steroid hormone synthesis is typical stimulated by what

peptide hormones from other glands

24

This frees cholesterol from stores

cholesterol esterases; PKA phosphorylates cholesterol esterases to free cholesterol

25

This protein facilitates intracellular transport of cholesterol (to mitochondria)

steroid acute regulatory protein (StAR)

26

Steroids are not stored why?

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

27

What three things regulate steroids

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

28

Most steroid biosynthesis enzymatic reactions are what

uni-directional

29

What are the five different molecules along the steroid biosynthesis pathway

cholesterol --> progestagens --> corticosteroids or androgens --> estrogens

30

Amine hormones are all derived from which amino acid

tyrosine

31

What are the two hormones that are synthesized in the thyroid

thriiodothyronine (T3)
thyroxine (T4)

32

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

solubility and receptors

33

Catecholamines are synthesized in which two areas

adrenal gland
hypothalamus

34

What are three examples of catecholamines

norepinephrine
epinephrine
dopamine

35

catecholamines are common what

neurotransmitters

36

Catecholamines are similar to what in respect to solubility and receptors

peptide-like

37

What is the 4t class of hormones

eicosanoids

38

Lipids are derived from what

arachindonic acid

39

Most hormones are secreted in which way

in short burst; timing based on upstream signals

40

Secretion of GH and cortisol is what type of pattern

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

41

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

plasma concentration of a nutrient
neuronal control
hormone control

42

This type of hormone dissolves in the blood

hydrophilic hormones

43

This type of protein requires a carrier protein

lipophilic hormones

44

The use of these will affect hormone availability

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

45

Metabolism and excretion of hormones does what to the signal

inactivates it

46

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

liver and kidney

47

True or False
Some hormone degradation occurs in the blood

True

48

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

catecholmines and peptides

49

These hormones are protected via attachment of carrier proteins from degradation

steroids

50

Circulating concentrations are a function of what

synthesis va removal or clearance

51

Receptors for hydrophilic hormones are where

on the cell surface or in plasma membrane

52

Receptor activation triggers what

a signal transduction pathway; activates the 2nd messenger system

53

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

ionotropic responses

54

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

metabotropic responses

55

A response involving ions and phosphorylation is what type of response

rapid response

56

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

delayed response

57

Receptors for lipophilic hormones are located where

intracellular and/or nuclear

58

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

receptor + ligand

59

Where is the location of the hypothalamus and pituitary gland

hypothalamus is on the floor of the diencephalon
pituitary gland lies just below the hypothalamus in the sella turcica

60

What are the three components of the pituitary gland

anterior = adenohypophysis
posterior = neurohypophysis
infundibulum connecting the two structures

61

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

anteriorhypophysis

62

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

neurohypophysis; posterior

63

The hormones are synthesized where

in the neuronal cell bodies in the supraoptic and paraventicular nuclei

64

hormones are released in response to what

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

65

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

oxytocin; labor

66

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

vasopressin (ADH)

67

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

adenohypophysis

68

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

hypothalamic neurons

69

Axon terminals lie where

in the median eminence

70

Hypothalamic hormones are transported in the in the blood within what

the portal vessels to the anterior pituitary

71

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

anterior pituitary

72

Hypophysiotropic or releasing hormones are typically named for what

the pituitary hormones they regulate; both stimulatory and inhibitory

73

Hypophysiotropic hormones all do what

regulate the release of hormones from the anterior pituitary

74

What are 6 of the 8 hormones the anterior pituitary secretes

FSH
LH
GH
thyrotropin
prolactin
ACTH

75

This is a precursor polypeptide synthesized in corticotrophs

pro-opiomenalocortin (POMC)

76

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

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

77

True or False
hypophysiotropic hormones are often found elsewhere in the nervous system

True

78

True or False
Hypophysiotropic hormones are all peptides

False; they are not all peptides

79

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

neuroendocrine system

80

The hypothalamus + pituitary + target = what

an axis

81

The complexicity of the neuroendocrine system provides what two thins

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

82

The release of the hypophysiotropic horses is controlled by what

neural signals; both stimulatory and inhibitory inputs
involving specific neural pathways

83

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

loop feedbacks

84

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

long-loop negative feedback

85

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

short-loop negative feedback

86

Feedback mechanisms return hormone concentrations to what

normal; i.e maintain homeostasis