Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Metabolic Endocrinology > Introduction > Flashcards

Introduction Flashcards

1
Q

Classical definition of ‘hormone’

How is this different from the modern definition?

A

chemical messenger released by 1 type of cell -> carried in bloodstream to act on specific target cells

Modern definition also includes factors made/used locally (without entering bloodstream)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why is an endocrine system essential in multicellular organisms?

A

allows for communication between cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are 3 basic functions in the body that require the endocrine system?

A
  1. differentiation (development from egg to adult)
  2. homeostasis (maintain environment for cells to live)
  3. reproduction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The human body is composed of (number)____ cells, coordinated by the networking of ____ ____ ____.

A

10^14

protein encoding genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

the 3 layers of signaling networks:

A
  1. within cells
  2. between groups of cells (tissues)
  3. between tissues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the advantage of having a complex control network in genes/body systems?

A

acts as BUFFER against mutation; even if one gene pathway knocked out, can still reach ‘output’ through other pathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Earliest sign of complex animal life:

A

550-590 million yrs ago (pre-cambrian period)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

True/False: all hormones are extremely specific for 1 type of target cell

A

False; some can target multiple cell types, but response can vary depending on cell type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

hormones are generated by ______, and recognized by: ______, which contributes to an ______ response.

A

hormone-producing cells
target/recipient cells

integrated response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the meaning of ‘integrated response?’

A

cells exposed to many signals -> summation of signals (positive/negative) => total response to ALL signals combined

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the 2 main control systems of the body? Compare them.

A

nervous system (DIRECT connection, fast, immediate response/changes)

endocrine system (chemical message to remote areas, slower, ADAPTIVE changes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the types of signalling molecules? What is their role? (5)

A

Endocrine: go into blood vessels -> distant cells
Paracrine: act on nearby cells
Autocrine: act on self/identical neighbors
Neuroendocrine: from axon terminal -> bloodstream
Neurotransmitter: from axon terminal -> adjacent neuron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

True/False: the amount of hormone used as a signal in blood is usually in mg/mL

A

False: VERY low, usually ng/ml or pg/ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

True/False: hormones are HIGHLY SPECIFIC

A

True: one hormone -> one receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are some examples of molecule types that can act as hormones?

A 
peptides (3 - >180aa)
modified AA
cholesterol-based (steroids)
synth from FA
gases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Example of a gas hormone:

A

Nitric oxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Example of hormone type synthesized from fatty acids:

A

prostaglandins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how does a hormone signal trigger an effect? describe the general steps that occur

A 
bind to receptor protein
conformation change
activate signal cascade
activate target genes/proteins
trigger cellular response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

examples of potential cell responses:

A

altered metabolism (alter enzyme action)
altered gene expression (alter gene regulatory protein)
alter cell shape/movement (alter cytoskeletal protein)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what happens in a cell with NO SIGNALING?

A

programmed death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where are hormone-synthesizing cells found? (2)

A

In clusters (Major endocrine glands)

interspersed in organs as single cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

The 3 chemical classes of hormones:

A
  1. lipids (steroids, eicosanoids)
  2. proteins (short polypeptides, large proteins)
  3. AA derivatives
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Steroid hormones are derivatives of ____. What are their chemical properties?

A

cholesterol

large molecules with hydrocarbon ring, HYDROPHOBIC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Where does cholesterol come from, and where is it found in the body?

A 
de novo (synth) or from diet
in cell membranes or lipoproteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Cholesterol can be processed into what products? (3)

A

vitamin D
bile acid (digestion)
steroid hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are 2 types of hormones that are steroid hormones

A

sex hormones

adrenal steroids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

all cholesterol derivatives can be recognized by the ___ ____

A

sterol ring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How is testosterone coverted to estradiol?

A

AROMATASE enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Why can hormones with very similar chemical compositions have very different effects?

A

slight changes in chemical structure can cause large structural changes -> affect receptor fit and action

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What steroids are produced in the adrenals? What is their function?

A

mineralocorticoids (mineral homeostasis)

glucocorticoids (glucose metabolism, immune function)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What steroids are produced in the gonads?

A

estrogens
progestins/progestagens
androgens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are eicosanoids? what does it include?

A

Lipid hormones derived from 20C fatty acid (arachidonic acid)

Includes: prostaglandins, thromboxanes, leukotrienes, prostacyclins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

True/False: Arachidonic acid is an EFA in the diet

A

False, can produce from phospholipids or diacylglycerol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What are the roles of prostaglandins? (2)

A

inflammatory reaction

reproduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

How are prostaglandins (PGH2) produced from Arachidonic acid?

A 
cyclooxygenase enzyme (COX) /PGH2 synthase
(cyclic pathway)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How are Prostaglandins related to thromboxanes and prostacyclins?

A

common precursor (PGH2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How are leukotrienes produced?

A

arachidonic acid -> lipoxygenase enzyme (linear pathway)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What type of signal (according to function) would eicosanoids be classified as?

A

paracrine (act locally)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

True/False: eicosanoids can have far-reaching effects on the body due to efficient transportation through the blood

A

False: only act on cells close to their formation site

rapidly degraded

40
Q

What determines what type of eicosanoid PGH2 will be converted to?

A

Cell type (diff cells will convert it to diff things)

41
Q

_____hormones are short-chain peptide protein hormones. Give 4 examples:

A 
Neurohormones
GnRH
Oxytocin
TRH
ADH
42
Q

True/False: mutations in AA sequence in peptide protein hormones can have major effects

A

True: short sequences, so can cause dramatic changes

43
Q

What are characteristics of large protein hormones?

A

linear chain
subunits linked by S-S bonds
specific 3D structure (for linking with receptor)

44
Q

examples of large protein hormones:

A

insulin

GH

45
Q

What 2 types of hormones are AA metabolite hormones? What are they made from?

A

Thyroid hormones
Adrenal medulla hormones

made from Tyrosine

46
Q

What are the thyroid hormones?

A

thyroxine (T4)

Triiodothyronine (T3)

47
Q

What are the adrenal medulla hormones?

What is their alternative function?

A

epinephrine
norepinephrine
dopamine

also used as neurotransmitters

48
Q

General composition of endocrine glands:

A

parenchyma (cell mass) - made of secretory cells

blood vessels - highly vascularized

no ducts

49
Q

Are all endocrine glands permanent?

A

many are (pituitary, adrenal, pancreas, etc)

but some are transient (ovarian follicle, corpus luteum)

50
Q

What types of cells can make hormones?

A

specialized secretory cells (1 cell -> 1 hormone)

neurons

51
Q

where can hormone-producing neurons be found in the body?

A

hypothalamus
posterior pituitary
adrenal medulla

52
Q

process of hormone synthesis for protein hormones:

A
  1. transcription
  2. translation
  3. phys/chem modification (cleave chain to make peptides; interact/link subunits; form 3D structure)
53
Q

An inactive molecule that must be modified to become an active hormone is known as a _______

A

preprohormone

54
Q

What is a ‘signal peptide’ and what is its role in hormone synthesis?

A

signal peptide = lipophilic leader sequence -> allow peptide to cross ER into cisternal space before cleaved off (further modified & packaged for export)

55
Q

What are some examples of peptide phys/chem modifications?

A

S-S bridges, glycosylation, cleavage

56
Q

peptide prehormones are sometimes packaged into vesicles along with a ______

A

activating peptidase

57
Q

Can peptide hormones be stored?

A

Yes; stored in GRANULES (secretory vessels) in cytoplasm

58
Q

How are stored peptide hormones secreted?

A

stimulate -> change Ca permeability (open Ca channels)

granule brought to surface by cytoskeleton microtubule/microfilament ->

59
Q

How are steroid hormones synthesized?

A

cholesterol taken from lipid droplets in cytosol
side chain cleaved by mitochondria (become prenenolone)
modified in ER

60
Q

Can steroids be stored?

A

no (immediate egression from cell)

61
Q

How are peptide/protein hormones transported in blood?

A

can circulate in free state

62
Q

How are hydrophobic hormones transported in blood?

A

requires specific carrier protein (usually binding proteins or globulins)

63
Q

What is the significance of a hormone binding protein?

A

protects from degradation in liver (act as buffer)
solubilize in blood
remains inactive while bound

64
Q

What is the difference in half-life of small peptide vs large protein vs hydrophobic hormones?

A

small peptide; very short half-life (quick degraded by enzymes)

proteins: longer half life
hydrophobic: longest half life (protected by carrier)

65
Q

What are the 3 main controls for synthesis and secretion of hormones?

A
  1. neural input (brain, hypothalamus)
  2. hormone stimulation/inhibition (releasing/inhibitory factors; feedback)
  3. metabolic status (stress, blood concentrations)
66
Q

What are positive and negative feedback?

A

positive: resulting hormone production -> feedback and promote MORE hormone production
negative: resulting hormone production -> feedback to STOP hormone production

67
Q

Lack of GH will lead to:

A 
Dwarfism (children)
muscle atrophy (adult)
68
Q

Adrenal gland deficiency results in lack of ___ and ____, known as ____ disease.

A

cortisol, aldosterone

Addison’s disease

69
Q

What causes the freckling seen in Addison’s disease?

A

no cortisol/aldosterone -> no neg feedback to shut off ACTH -> pituitary keep making ACTH, co-secreted with MSH (melanocyte stimulating hormones) -> freckling

70
Q

Besides the problems due to lack of hormone, what other problems arise from defective enzymes in steroid synthesis?

A

accumulation of intermediates

71
Q

What is the most common endocrine disorder? What causes it? (2)

A

Diabetes mellitus

lack of insulin secretion from beta cells (from cells of Langerhans in pancreas); or from receptor defect (unresponsive)

72
Q

What determines ‘endocrine rhythms?’

A

endogenous mechanisms: from brain

entrained by external cues

73
Q

What are positive and negative feedback?

A

positive: resulting hormone production -> feedback and promote MORE hormone production
negative: resulting hormone production -> feedback to STOP hormone production

74
Q

Lack of GH will lead to:

A 
Dwarfism (children)
muscle atrophy (adult)
75
Q

Adrenal gland deficiency results in lack of ___ and ____, known as ____ disease.

A

cortisol, aldosterone

Addison’s disease

76
Q

What causes the freckling seen in Addison’s disease?

A

no cortisol/aldosterone -> no neg feedback to shut off ACTH -> pituitary keep making ACTH, co-secreted with MSH (melanocyte stimulating hormones) -> freckling

77
Q

Besides the problems due to lack of hormone, what other problems arise from defective enzymes in steroid synthesis?

A

accumulation of intermediates

78
Q

common techniques in endrocrinology: (9)

A 
ablation & replacement
bioassays
immunoassays
immunocytochemistry (ICC)
autoradiography
blot tests
in situ hybridization
 pharmacological techniques
genetic techniques
79
Q

What determines ‘endocrine rhythms?’

A

endogenous mechanisms: from brain

entrained by external cues

80
Q

the 24hr cycle of the body is known as: _____ ____

A

circadian rhythm

81
Q

What is RIA?

A

radioimmunoassay
use known amount of antibody & radiolabelled hormone

add increasing amounts of unlabelled hormone -> displaces labelled (comp. binding) -> construct standard curve

use curve to estimate hormone amount in test sample

82
Q

What is infradian rhythm?

A

28 day cycle (menstrual cycle)

83
Q

How do gonadotropin levels differ in adolescents and adults?

A

Puberty: released mainly at night
Adult: pulsatile rhythm

84
Q

Why is it important to consider hormone fluctuation rhythms?

A

need to take into account when measuring levels (‘normal’ level is different according to time in cycle or life stage)

85
Q

common techniques in endrocrinology: (9)

A 
ablation & replacement
bioassays
immunoassays
immunocytochemistry (ICC)
autoradiography
blot tests
in situ hybridization
 pharmacological techniques
genetic techniques
86
Q

Why are imaging studies useful in endocrinology?

A

MRI and CT can allow detection of tumours, visualization of glands

87
Q

how does the ‘rabbit test’ work?

A

hCG is made by placenta 8 days after fertilization

inject urine into rabbit (induced ovulator) -> hCG will trigger ovulation, form corpora lutea

Kill rabbit, look in ovaries for corpora lutea

88
Q

What is RIA?

A

radioimmunoassay
use known amount of antibody & radiolabelled hormone

add increasing amounts of unlabelled hormone -> displaces labelled (comp. binding) -> construct standard curve

use curve to estimate hormone amount in test sample

89
Q

What is EIA? How is it similar/different from RIA?

A

enzymoimmunoassay
also competitive binding assay (antibodies) but no radioactive tags; use color-change to indicate
ex: home preg test

90
Q

Where can samples be obtained from, for RIA or EIA tests?

A

blood or urine (depends on hormone)

91
Q

What is indirect measurement for hormone levels?

A

measure another compound that indicates level of hormone (ex: measure glucose instead of insulin)

92
Q

What are provocative/suppression tests? What is the advantage?

A

assess status by maximally stimulate/suppress hormone release, compare to healthy individuals

useful for hormones with natural fluctuation, less samples needed

93
Q

Why are imaging studies useful in endocrinology?

A

MRI and CT can allow detection of tumours, visualization of glands

94
Q

____ gene editing can help correct inborn endocrine diseases by _______

A

CRISPR/Cas9

collecting cells -> modifying in vitro to correct -> re-introducing in patient

95
Q

What are ‘mimetic designer cells?’ What is an example of how it is used to treat an endrocrine disease?

A

modifying cell pathways

treating diabetes: made synthetic circuit (coupled glycolysis-mediated Ca entry to gene for insulin production); made new glucose-sensitive pathway for insulin production

Metabolic Endocrinology (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions