5.1 Intro To Endocrine Flashcards
(91 cards)
0
Q
Functions of endocrine system
A
- Regulates multiple organs
- Maintains growth and reproductive needs
- Respond to fluctuations within the internal environment
1
Q
Study of processes involved in the regulation and integration of cells and organ systems by hormones
A
Endocrinology
2
Q
Endocrine glands of the brain
A
Hypothalamus gland and pineal gland
3
Q
Transitory endocrine gland
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Placenta
4
Q
Type of communication where the cell recognizes itself as the target cell
A
Autocrine
5
Q
Signaling molecule is received by a neighboring cell (type of communication)
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Paracrine
6
Q
Characteristics of neuron doctrine communication
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- Secreted by neuron
- Travels via blood
- Acts on distant target cells
7
Q
Mode of travel for endocrine communication
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Via blood
8
Q
Precursor of secretory peptides
A
Prehormone/preprohormone
9
Q
What happens to secretory hormones after its synthesis
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Stored in secretory vesicles
10
Q
At what terminal of nascent peptides can signal peptides be found
A
N-terminal
11
Q
Where are the receptors of hydrophilic peptides found
A
Membrane-bound/surface of cell membrane
12
Q
Signals from hydrophilic peptides are amplified by
A
Second messengers
13
Q
Water-soluble hydrophilic peptides can enter the circulatory system (T/F)
A
True
14
Q
Peptide hormones are biologically active and are free to interact with receptor of target cell when in what form
A
Free form
15
Q
What condition of free hormones will result to the release of hormones from transport protein?
A
Decreased levels of free hormones
16
Q
Extends the half-life of hormones
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Bound hormones
17
Q
The only 2 peptide hormones that work in bound form
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Growth hormone and IGF-1
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Q
Onset and duration of peptide hormone
A
Fast onset and short-time duration
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Q
Number of amino acids for it to be considered a protein
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Greater than 100 amino acids
Peptide if less than 100 amino acids
20
Q
Peptide hormone: Rough ER
Steroid hormone: __________
A
Smooth ER
21
Q
Steroid hormones are stored in secretory vesicles (T/F)
A
False - peptide hormone not steroid
22
Q
Peptide hormone: water soluble
Steroid hormone:
A
Lipid soluble/hydrophobic
23
Q
Peptide hormones are degraded by
A
Peptidases
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Site of steroid hormone receptors
Intracellular (cytoplasm or nucleus)
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Steroid hormones with cytoplasmic receptors
Adenocorticosteroids, glucocorticoids, mineralocorticoids
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Location of Vitamin D and sex steroid hormone receptors
Inside nucleus
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Effect of steroid hormones
Increase or decrease transcription of regulatory proteins by modulating gene expression
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Precursor of steroid hormone
Cholesterol
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Steroid hormones have no storage, thus, must be synthesized after stimulus is received. How does the body compensate for this
Large stores of cholesterol esters in cytoplasm vacuoles are available for steroid synthesis
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Amino acid derivatives
Tyrosine or tryptophan
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Amino acids can function either as a peptide or a steroid (T/F)
True
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Ioidothyronine, a steroid-like amine, is synthesized in
Thyroid gland
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Ioidothyronine derivative
Tyrosine
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Half-life of T3 and T4
T3- 18 days
| T4- 7 days
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Thyroid hormone is a steroid-like amine. How is it similar to steroid hormones
1. Intracellular receptor (nucleus)
2. Acts as a transcription factor
3. Protein bound
4. Slow onset and long duration
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Primary hormones produced by endocrine system
Catecholamines
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Catecholamines are synthesized by
Adrenal medulla and neurons
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Catecholamines are copackaged with
ATP, Calcium, Chromogranins (proteins)
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After Catecholamines are synthesized, the final product is stored in
Chromaffin granules
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Catecholamines are secreted in response to
Sympathetic stimulation
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Catecholamines only circulate when bound to albumin (T/F)
False - circulate either unbound or loosely bound to albumin
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Half-life of Catecholamines
1-2 minutes
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Catecholamines are peptide-like amines. How are they similar to peptide hormones
1. Do not cross cell membrane
2. Membrane-bound receptors
3. Make use of second messengers
4. Stored in vesicles
5. Plasma form is unbound
6. Fast onset and fast/short duration
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Cells and receptors exhibit specificity (T/F)
False- only receptors exhibit specificity. Cells may have receptor for different hormones
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What are the cell membrane receptors
GPCR, Catalytic, Cytokine
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How many domains does GPCR have? Describe each
3 - extracellular (ligands bind), transmembrane (7 subunits), intracellular (G-protein bind)
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When inactivated, alpha subunit remains dissociated from beta-gamma subunit (T/F)
False- alpha reforms with beta-gamma when inactivated
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Peptide hormones that bind Receptor Tyrosine Kinase
Insulin
IGF-1
NGF
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Peptide hormones that bind to Cytokine receptors
Prolactin
GH
Erythropoietin
Leptin
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In the mechanism of GPCR, GTP binds to which heterotrimer subunit?
Alpha
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Peptide hormones that bind to receptor tyrosine kinase (RTK)
Insulin
IGF-1
NGF
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Peptide hormones that bind to Cytokine Receptor
Prolactin
GH
Erythropoietin
Leptin
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Effectors of adenylyl cyclase, Phospholipids C, Phospholipase A2
adenylyl cyclase - cAMP
Phospholipids C - DAG (activate protein kinase C) and and IP3 (open calcium channels)
Phospholipase A2 - eicosanoids (releases arachidonic acid)
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Catalytic receptors posses enzymatic activity on the cytoplasmic side (T/F)
True
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Ligand of guanylyl cyclase receptor
ANP
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Receptor of "Transforming Growth Factor beta (ligand)"
Serine/threonine kinase
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In Serine/Threonine Kinase Receptor, ligand binding to type II receptor leads to
Dimerization of type I and type II receptors (type II phosphorylates type I)
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Type I phosphorylates SMAD, which complexes with co-SMAD. What does this complex do
Act as a transcription factor
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In Tyrosine kinase receptor mechanism, ligand binding results to
Dimerization and autophosphorylation
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Effectors of tyrosine kinase
GRB2 and IRS1
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Receptor with a single membrane spanning domain
Cytokine Receptors/ Tyrosine Kinase Associated Receptors
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Cytokine receptors do not posses any catalytic activity instead they are associated with tyrosine kinases like JAK protein (T/F)
True
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Mechanism of Cytokine receptors
Ligand binding -> Dimerization then activation of JAK -> JAK phosphorylates STAT -> dimerize STAT dimer
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STAT dimer goes to the nucleus to act as
Transcription factor
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Intracellular receptors are peptide receptors (T/F)
False- steroid receptors not peptide
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Intracellular receptors function to modify protein synthesis through
Gene expression
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2 types of intracellular receptors and describe in terms of their bound state
1. Cytoplasmic receptor (bound receptor)
| 2. Nuclear receptor (unbound receptor)
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Intracellular receptors of glucocorticoids and mineralocorticoids
Cytoplasmic receptor
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Intracellular receptor of progestins, androgens, estrogens, and vitamin D
Nuclear receptor
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(T/F) Mechanism of cytoplasmic receptor:
Ligand binds in the cytoplasm -> dissociation of HSP -> ligand-receptor complex translocate to the nucleus -> complexes with HRE -> gene transcription is activated
True
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In nuclear receptors, how do steroids pass through the cytoplasmic membrane
Diffusion
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Steroid enters the nucleus through
Nuclear pore
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Response counteracts the stimulus, shutting off the response loop
Negative feedback
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Low levels of hormones: ______ production
| High levels of hormones: ______ production
Increase
| Decrease
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Negative feedback ensures stability by
Keeping a physiologic parameter within normal range
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Types of negative feedback loops
Response-driven feedback loop and endocrine axis-driven feedback loop
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Negative feedback has little to do with the physiologic response to the hormone (T/F)
True
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In positive feedback, the stimulus causes a _______ in response
Continuous increase
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Required to shut off positive feedback cycle
Outside force
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Causes the sequential series of release of hormones
HPT Axis
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In HPT Axis, what are the hormones involved
Anterior Pituitary Hormones only
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Which glands are involved in the HPT Axis and identify their hierarchy
```
Hypothalamus (1st tier)
Pituitary gland (2nd tier)
Peripheral endocrine gland (3rd tier)
```
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Type of hormone released by the following glands in HPT Axis:
Hypothalamus
Pituitary gland
Peripheral endocrine gland
Hypothalamus: releasing hormone
Pituitary gland: stimulating hormone
Peripheral endocrine gland: final hormone
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Negative feedback targets which glands in HPT Axis
Hypothalamus or pituitary gland
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Organs not directly controlled by anterior pituitary gland
Free-standing endocrine organs (ex. Parathyroid gland and endocrine pancreas)
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When does the parathyroid gland secrete hormones
When there is a decrease in ionized calcium
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Decrease in ionized calcium -> Parathyroid gland is stimulated -> secrete hormone-> PTH Hormone increase ______
Serum calcium back to normal
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Type of feedback loop wherein a change in substrate level causes negative feedback
Response-driven feedback
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Hypothalamic releasing hormones : ________
| ___________ : posterior pituitary
Anterior pituitary
| Nerve signals from hypothalamus
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Steroid-like amino acid derivatives (T3 and T4) are produced in
Cytoplasm
