(IEMR2)Hormones, Hormone Receptors and Mechanisms of Hormone Action Flashcards
(162 cards)
1
Q
Chemical transport take place through what general operations?(3-6 points)
A
Diffusion, Osmosis, faciliate transport, active transport, exocytosis, endocytosis and hormone transport in circulation
2
Q
A
3
Q
Most hormones are what type of macromolecule?
A
peptides or proteins
4
Q
What are the three general type of hormone structures?(3 points)
A
protein and peptide hormones, steroid hormones, and tyrosine derivatives
5
Q
What are examples of group of hormones in the group of tyrosine derivatives?(2 points)
A
**thyroid hormones **and catecholamines
6
Q
What are examples or hormones that are synthesized form modified tryptophan?(1-2 points)
A
Serotonin and melatonin
7
Q
Peptide hormones are synthesized in what general location?
A
they’re synthesized in the cell
8
Q
How are peptide hormones synthesized and released generally speaking?(7 points)
A
Peptides hormones are transcribed from mRNA, **translated **into a polypeptide. This process creates a preprohormone. The preprohormone is modified to turn into a prohormone. the prohormone is modified and turned into a hormone. The hormone is stored in granules for release later due to the fact that synthesis takes a long time. The exocytosis of the hormone is calcium depedent.
9
Q
What is longer, the synthesis of a peptide hormone or hte synthesis of a steroid hormone?
A
the synthesis of a peptide hormone
10
Q
What tends to be generally larger, peptide hormones or steroid hormones?
A
steroid hormones tend to be bigger than peptide hormones
11
Q
What has a longer half-life, peptide hormones or steroid hormones?
A
peptide hormones have a relatively shorter half-life than steroid hormones
12
Q
What group of hormones in the body have the longest half-life?
A
thyroid hormones
13
Q
What are examples of hormones that are produced by one gene, i.e., one gene producing one hormone?(1-2 points)
A
insulin and growth hormone
14
Q
insulin is produced by one gene, two genes are multiple genes?
A
one gene
15
Q
What gene is known to produce many hormones?
A
POMC
16
Q
What are examples of hormones produced by the POMC gene?(2-3 points)
A
MSH, ACTH and α-endorphin
17
Q
What are examples of hormones that are produced by two genes?(2-3 points)
A
FSH, LH and TSH
18
Q
LH is produced by one gene, two genes are multiple genes?
A
two genes
19
Q
TSH is produced by one gene, two genes are multiple genes?
A
two genes
20
Q
How do peptide hormones exit the cell after processing is complete?
A
Peptide hormones exit the cell via calcium dependent exocytosis
21
Q
What are the two general sources of cholesterol?(2 points)
A
Circulating LDL or synthesized from acetate
22
Q
What basic intracellular step is necessary for the synthesis of steroids from cholesterol?
A
mobilzation of cholesterol into the mitochondria
23
Q
How is cholesterol mobilized into the mitochondria for steroid hormone synthesis?
A
The StAR enzyme completes this step when it combines with cholesterol
24
Q
Where is the location of StAR?
A
inner-mitochondrial membrane
25
What is the action of the enzyme StAR?**(2 points)**
**Side chain cleavage** to form **pregnenolone**
26
What exits the mitochondria after the action of StAR takes place?
pregnolone
27
What enzymes assist with the movement of pregnolone outside of the mitochondria?
SER(enzymes associated with smooth membranes in the cytoplasm)
28
What is SER?
enzymes associated with smooth membranes in the cytoplasm
29
Does pregnenolone re-enter the mitochondria or is it used immediately for the synthesis of steroid hormones?
It may require re-entry into the mitochondria
30
Why does stroage of steroid hormones take place?
they don't
31
Is modification always necessary after secretion of steroid hormones?
yes, modification may be required
32
What are the three main classes of steroid hormones?**(3 points)**
mineralcorticoids, glucocorticoids and androgenstendione
33
What is the precursor and end substarte for the three main classes of steroids?**(3-6 points)**
**pregnenolone **goes through a series of steps to become **aldosterone**. **17-OH pregnenolone** goes through a series of reactions to become **cortisol**. **DHEA** goes through a series of reactions to become **androgenstendione**.
34
What are two grouops of hormones that are modified tyrosine molecules?**(2 points****)**
**catecholamines** and **thyroid hormones**
35
Where are catecholamines stored?
secretory vesicles
36
Where are thyroid hormones stored?
colloid
37
What special about the storage of thyroid hormones?
they stored in colloids and they're formed as part of the thyroglobulin molecule
38
What specific group of hormones are water soluble?**(2 points)**
**most peptides and amines**
39
What large category of hormones are associated with proteins in plasma?
lipid soluble or hydrophobic hormones
40
Why do diabetics take insulin orally?
insulin doesn't work orally because they're going to be deactivated through the digestive process
41
What specific group of hormones have the longest half-life?
thyroid hormones
42
What is the relative half-life of peptides?
short
43
What is the relative half-life of catecholamines?
very short
44
What is the relatively half-life of steroids?
long
45
What is the initial event in hormone action?
binding of hormone to the receptor
46
The binding of the hormone to the receptor involves what properties of the interactions between the receptor and the hormone?**(2 points)**
The **receptor affinity** for the hormone it's binding and the **receptor specificity** for the hormone it is binding
47
What general type of molecules are the hormone receptors?
proteins
48
The binding site for the hormone on the reeptor is referred to as what?
the effector site or the hormone binding site(s)
49
Stress induces the release of what specific hormone?
cortisol
50
What provides specificity for hormone-cell interaction?
receptors
51
Where is the general location of hormone receptors?**(3 points)**
**cell wall, cytoplasm or nucleus**
52
Do cells possess receptors for all hormones?
no
53
Is it possible for a single hormone to have multiple receptors?
yes, i.e., CCK has a receptor on the pancreas an a receptor in the brain
54
The distribution of the hormone or the hormone receptor determines which cells respond?
distribution of the hormone receptor
55
Are hormone receptors limited to one cell type or are they distributed on most cells?
It can be one or the other depending on the hormone receptor
56
Binds and exerts biological effect similar ot hormone
agonist
57
binds and exhibits a supraphysiological response
superagonist
58
binds and produces a subphysiological response
partial agonist
59
Binds to receptor but does not activate it(no physiological response)
antagonist
60
Most cells in the body have receptors for what specfic hormone?
insulin
61
High specificity between hormone receptor and ligand is characterized by what?
homologous binding but not perfect
62
High affinity for hormone receptor and ligand is characterized by what?**(2 points)**
**adequate binding** at **low hormone concentrations**
63
Affinity for a partcicular hormone compared to affinity for another hormone determines what hormone receptor-ligand property?
specificity
64
Under normal circumstances, it is possbiel to gain a response from a hormone without the presence of a hormone receptor?
no
65
The structure and location of the receptor depends on what?
the structure of the hormone
66
Peptide/protein hormones have receptors located on what cellular/subcellualr structure?
cell surface
67
Steroid/lipid hormones have receptors located on what subcellular structure?**(2 points)**
cytoplasmic or nuclear receptors
68
When the hormone receptor has a high affinity for the hormone, the disassociation for the hormone and the hormone receptor should be slow or fast?
slow
69
Generally speaking, neurotranssmiters and their receptors have high afinity or low affinity? How is this compensated?
The afinity is low, therefore, a large amount of neurotransmitteres are released to elicit a response.
70
Hormone receptors that have affinity for their hormones, when the concentrations are abnormally high, what happens with the binding of that hormone?
The hormones may bind to "wrong" receptors despite the low affinity
71
The preference for a hormone receptor to bind to its respective hormone is referred to as what?
specificity
72
What is the number of hormone binding sites for protein hormones?
at least one
73
The binding between the protein hormones and their respective receptors are reversible or irreversible?
their reversible, non-covalent
74
What target tissue has a constant amount of receptor numbers?
none
75
What is a general example of homeospecific regulation of a hormone receptor?
the hormone regulated the amount of respecitve hormone receptor for it to bind
76
What is a general example of heterospecific hormone receptor regulation?
A hormone regulated the amount of available receptors for another hormone besdies itself
77
What is the up-regulation of a paricular receptor?
an increase in receptor number
78
What is the down-regulation of receptor number?
a decrease in receptor number
79
How does prolactin affect the PRL receptor in the liver?
Prolactin induces the appearance of PRl receptor in the liver, an example of positive feedback
80
How does the continuous exposure of insulin to lymphocytes affect the number of insulin receptors?
it decreases the nubmer of insulin receptors (negative feedback)
81
What is an example of homeospecific regulation of receptor number?**(2 points)**
**GnRH** downregulates or upregulated GnRH repcetors depending on **timing**
82
What is an example of hetrospecific regulation of receptor number?**(2 points)**
**TRH** stimulates the release of **TSH** which stimualtes the synthesis and secretion of **T3** and **T4** which can return and cause a **decrease of receptors for TRH**
83
Do glucocorticoids upreguate or downregulate TRH receptors?
up-regulate
84
What hormone always downregulates its receptors irrespective of tissue?
insulin
85
What is an example of a hormone that upregulates and downregulates it receptor depending on the location in the body?
Angiotensin II upregulates its own receptors in the adrenal but down-regulates receptors on certain smooth muscles
86
What are examples of ways that downregulation of receptors take place?**(2-5 points)**
inactivation of receptor molecules perhaps by phosphorylation. Inactivation of intracellular protein signaling molecules. Temporary sequestration of receptor inside cell. Destruction of receptors by lysosomal enzymes after internalization. Decreased production of new receptors.
87
How does up-regulation occur?**(2-3 points)**
increased synthesis of receptors, increased synthesis of intracellular signaling molecules and increased availability of receptors at hte cell surface
88
Why change receptor number?(2-3 points)
Prevents over-stimulation, prevent organ burn-out and allows for orderly sequencing of various hormonal secretions
89
Must all hormone receptors be occupid by hormone receptor to elicit a response?
no, all of the receptors don't have to be occupid to elicit a response
90
The receptor number influences what?
it influences the hormonal response
91
What is the typical percentage of receptors that must be occupid by hormones to be sufficient for maximal biological response?
1%
92
What is the reason for spare receptors?
Maintain a stable sensitivity to low levels of hormone
93
Are spare receptors biologically active?
yes
94
Epinephrine and glucagon both stimulate what in liver cells?
glycogenolysis
95
Epinephrine and glucagon act via what common second messenger?
cAMP
96
What common receptor does epineprine and glucagon bind at the liver?
they don't have a common receptor, each hormone has its own receptor
97
Hormone response depends on what?**(3-6 points)**
**receptor number, hormone concentration, duration of exposure, time between exposures, intracellular conditions, synergestic/antagonistic hormones**
98
The duration of exposure for the hormone to the hormone receptor is influenced by what?**(2-3 points)**
rate of hormone secretion, half-life of the hormone and clearance of the hormone
99
receptor desensitization
100
What is the difference between responsivity and sensitivity?
101
Does changes in responsivity result in changes of ED50?
no
102
Does changes in sensitivity result in changes in ED50?
no
103
Changes in responsivity happens as a result of what being changed?**(2-3 points)**
**More/few receptors, changes in the rate-limiting step of the receptor pathway and more/less tissue,cells**
104
Does responsivity result in a change in the maximal response?
yes
105
Does sensitivity change the maximal response?
no
106
Changes in sensitivity occurs as a result of what?**(1-2 point)**
changes in affinity and changes in hormone receptor number when you have submaximal concentration of hormone is present
107
108
What are the four classes of membrane boud receptors?
receptors that are enzymes or are enzymes linked, receptors that form channels, g-protein couples receptors and receptors with unknown mechanisms
109
Most peptide hormone receptors are coupled to what?
G-proteins
110
What are the different type of G-proteins coupled to membrane receptors?**(2 points)**
stimulatory and inhibitory
111
When a hormone binds to a Gα receptor, what are the general steps that take place with the second messengers?**(6 points)**
**Phopholipase C is activated** which **hydrolyrzes** phosphoinositol 4,5 bisphosphate into **IP3 and DAG**. IP3 diffuses to intracellular calcium stors and **indcues the relase of calcium** by bind to calcium channel-linked IP3 receptors. **DAG is lipophilic** and remains in the plasma membrane and activats **protein kinase C**.
112
Physiological communication takes place via what major systems in the body?**(3 points)**
hormonal, neural and immune
113
Negative or positive feedback reuglation can take place via what general substances?**(2 points)**
Hormones or the substrates in the respective pathways
114
What are general examples of neural regulation?**(2-3 points)**
hypothalamo-neurohypophyseal system, adrenal medulla, hypothalamoadrenohypophyseal end organ axis
115
What are four examples of hormonal regulation?
negative(positive) feedback reuglation, chronotropic regulation, neural regulation and stress
116
What are examples of chronotropic regulation?**(3-7 points)**
oscillating, pulsatile, circadian/diurnal, sleep-wae, menstrual, seasonal and developmental
117
What are the types of neural hormonal regulation?**(2 points)**
direct or indirect
118
The hypothalamo-adenophypophyseal end organ axis is an example of direct neural hormonal control or indirect neural hormonal control?
indirect
119
The hypothalamo-neurohypophyseal system is an example of direct neural hormonal control or indirect neural hormonal control?
direct
120
What are examples of direct neural hormonal control?**(1-2 points)**
The synthesis of ADH or oxytocin with storage and release from the poserior pituitary initiating affects in the renal tubules or the reproductive system. The actions at the adrenal medulla are also under direct neural hormonal control.
121
What is an example of indirect neural hormonal regulation?
The hypothalamus influencing the anterior pitutiary to release a hormone to affect a particular target tissue
122
What are the types of substrate regulation?
indirect and direct
123
What are examples of direct substarte control?**(2 points)**
The release or PTH or calcitonin in response to calcium levels. PTH is release to increase calcium levels while calcitonin is release to decrease calcium levels. Also, the release of insulin, glucagon and somatostatin in response to glucose levels. Insulin is relased to decrease glucose levels and glucagon is release to increase glucose levels. Somatosatin inhibits the action of both.
124
What is an example of indirect substrate control?
Sodium influences the release of aldodster indirectly by conveying a decrease supply of sodium at the mecula densa stimulating the renin-angiotensin system which results in the conversion of angiotensinogen to angiotensin I which is converted to angiotensin II in the liver. Angiotensin II stimulates the production of aldosterone at the zona glomerulosa which vasoconstricts the blood vessels resulting in an increase in blood pressure.
125
What is the reason for short loops and long loops when studying negative feedback loops in the endocrine system?
126
What are teh two major categories of endocrine dysfunction?
hypofunction or hyperfunction
127
How are endocrine dysfunction pathologies categorized in either hypofunction disease states or hyperfunction disease states?**(4 points)**
primary, secondary, autoimmune or receptor abnormalities
128
A primary endocrine dysfunction usually has some type of pathology at the endocrine disorder in question or an organ outside of the endocrine organ in question?
There is usually a problem with the endocrine organ in question.
129
A secondary endocrine dysfunction has a problem with the endocrine organ in question or an endocrine organ/target organ besides the endocrine organ in question?
There is usually a problem with the target organ/endocrine organ outside of the endocrine organ in question
130
131
132
Transient autoimmunity is usually in response to what genearl circumstance?
infection
133
Chronic autoimmunity is usually a result of what?
a pathological consequence
134
What autoimmune disorder occurs in Graves disease and how does this affect hormone production?
Antibodies stimulate the production of TSH in Grave's disease
135
What type of autoimmune disorder occurs in Hashimoto's thyroiditis?
Antibody produced in teh body target enzymes within the thyroid cell which results in the destruction of thyroid cells.
136
What is an example of antibody-mediated disease?
Graves disease
137
What is an example of a T-cell mediated disease?
Hashimoto's thyroiditis
138
What is an example of an immune complex mediated diseae?
Systemic Lupus erythematosus
139
If a pregnant woman is affected with Graves disease, is it possible for the child to manifest symptoms related to thyroiditis?
Yes, the IgG antibodies can cross the placenta
140
What is the pathophysiology of a patient affected with Hashimoto's thyroiditis?
Autoreactive T cells produce cytokines that recruit cytotoxic T cells and macrophages to destroy follicular T cells. Paradoxcially, this can initlaly result in hyperthyroidism due to the fact that the linkage between the storage of the thyroid horones, in the colloid, and the follicular cells, there will be an initla increase of thyroid hormones beucase the thyroid hormones will leak out.
141
The pathology of immune complex disease is characterized by what?
the production of autoantibodies that circulate the bloodstream. A major pathology as the result of these complexes is the deposition of these complexes in small areas of the body like the glomeruli in the kidneys or joints spaces resulting in kidney failure and joint pain.
142
What gender is more likely to have autoimmunity disorder?
female
143
What are possible triggers of autoimmunity?**(2-4 points)**
Release of sequestered antigens as a result of truama, infections, neoantigens and shared/cross-reactive antigens
144
What are the two categories that autoimmunity can affect the body?
systemic and organ specific
145
What are examples of organ specfic autoimmuity diseases in the endocrine sysetm?**(4 points)**
**Hashimoto's thyroiditis, addison's disease, Graves disease and insulin dependent diabetes mellitus **
146
What are exampels of systemic autoimmune disorders?**(3 points)**
**Rheumatoid arthritis, scleroderma and systemic lupus erythrematosus**
147
What are hte general types of polyglandular disorders?
Type I, type II and type III
148
Excessive hormone production is usually caused by what general type of pathology?
neoplasia
149
Medullary Carcionma tumor in the thyroid gland produces what hormone in excess?
calcitonin
150
Polyglandular disease is usually the consequence of what genearl type of pathology?
autoimmune disorders
151
What is the type of polyglandular disorder: Type I, II or III: usuallly diabetes or thyroid disease and Addison's disease, sometimes ovarian failure and non-endocrine autoimmune disease
type II
152
What is the type of polyglandular disease: onset in early childhood (skin infection) associated with hypoparathyroidism and Addisons's, often gonadal failure
type I
153
What is the type of polyglandular disease: thyroid and autoimmune disease and at least two other autoimmune disease, but NOT Addison's disease
type III
154
Does polyglandular diseases reuslt from neoplastic issues or autoimmunity issues?
autoimmunity
155
What are examples of autoimmune disease that affected the thyroid gland?**(2 points)**
hashimoto's and graves
156
What is an example of an autoimmune diseae that affects that adrenal gland?
addison's disease
157
What is an example of an autoimmune disease that affects the pancreas?
insulin dependent diabetes mellitus
158
What is an example of an autoimmune disease that affects the parathyroid gland?
hypoparathyroid
159
What is an example of an autoimmune disease that affects the pituitary gland?
hypophysitis
160
What is an example of an autoimmune disease that affects the ovaries?
oophoritis
161
What is an example of an autoimmune disease that affects the testes?
orchitis
162
