Endocrine Flashcards
(114 cards)
1
Q
Endocrine system
A
the body’s communication system: achieves its role via hormones, chemicals that carry messages
2
Q
The endocrine system controls, regulates, or modulates….
A
the function or activity of all other bodily systems to maintain the body’s homeostasis, to adapt to changes, and to coordinate body’s complex processes
3
Q
The body relies on TWO communication systems to regulate bodily processes:
A
- The nervous system
2. the endocrine system
4
Q
functional unit of nervous system
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neuron
5
Q
functional unit of endocrine system
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gland cell
6
Q
chemical messenger of nervous system
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neurotransmitter
7
Q
chemical messenger of endocrine system
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hormone
8
Q
mode of transmission for nervous system
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action potentials
9
Q
mode of transmission for endocrine system
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circulation (blood)
10
Q
reaction time for endocrine system
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minutes to days
11
Q
reaction time for nervous system
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miliseconds to seconds
12
Q
the nervous system is….
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point to point, min to min, and rapid but short lived controls using neurotransmitters
13
Q
the endocrine system….
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broadcasting (blood vessels reaching every corner of the body), and slow, but sustained control using hormones
14
Q
hormones…
A
- chemical messengers from ductless glands
- a hormone may function as an autocrine, paracrine, or endocrine agent
15
Q
Autocrine
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a cell targets itself
16
Q
Paracrine
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they act on nearby cells
17
Q
Endocrine
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a cell targets a distance cell through the blood stream
18
Q
hormone effect
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is determined by the hormone’s binding and activating its specific receptors in the target cell
19
Q
hormones may be removed or cleared by
A
- metabolism and degradation
- binding their receptors in target cells
- excretion by the kidneys
20
Q
hydroPHILIC hormones
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- catecholamines
2. peptide hormones
21
Q
hydroPHOBIC hormones
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- thyroid hormones
- steroid hormones
- vitamin D
22
Q
HydroPHILIc hormones (catecholamines and peptide hormones)
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- almost all of hydrophilic hormones travel free of protein in the plasma
- hydrophilic hormones bind and activate specific trans-membrane (integral) receptor proteins
23
Q
CATECHOLAMINES
A
- made in the neurons and adrenal medulla
- synthesized via enzymatic reactions:
tyrosine -> DOPA -> DA -> NE -> Epi
- TYROSINE HYDROXYLASE for tyrosine to dopa is RATE LIMITING enzyme
- PNMT is required for the reaction of NE to Epi
- polar, circulate free in plasma, short half-life in plasma, and bind and activate membrane receptors (GPCRs)
24
Q
Catecholamines bind and activate..
A
- different GPCRs (alpha and beta adrenergic receptors) that activate different second messenger systems and can alter different cellular functions
25
Peptide hormones
```
GH: growth hormone
IGF: insulin like growth factor
FSH: follicle stimulating hormone
LH: luteinizing hormone
TSH: thyroid stimulating hormone
hCG: human chronic gondaotropin
```
26
Peptide/protein hormones
- chains of AMINO ACIDS
- Made via transcription (nucleus) then translation in ribosomes located in cytosol then further processing in ER and golgi and then are stored in secretory vesicle and secreted in response to stimuli
- circulate free in plasma (except GH, IGF circulate bound to proteins)
- short half life, ~minutes
27
Insulin is example for peptide hormone
insulin secreted along with C-peptide
- insulin is secreted in response to HIGH plasma glucose
- hyperglycemia is high risk for oral disease
- insulin and C-peptide levels would be low by hyperglycemic insulin deficiency
28
Peptide hormones bind to SPECIFIC trans-membrane receptor proteins and change cellular functions of their target cells
1. Glucagon-R, GHRH-R, Adrenergic-R bind to GCPR (only one with 2nd messengers)
2. IGF-R, Insulin-R bind to tyrosine kinase receptors
3. GH-R, Leptin-R, PRL-R bind to JAK STAT receptors
29
Catecholamines
- synthesized through enzymatic reactions from tyrosine
- stored in secretory vesicles
- secreted in response to sectretagogue
- bind and activate G-protein coupled receptors
30
Protein hormones
- synthesized through transcription-translation
- stored in secretory vesicles
- secreted in response to secretagogue
- binding and activating transmembrane receptors
31
HydroPHOBIC hormones (thyroid hormones, steroid hormones, vitamin D)
- made on demand/not stored
| - circulate protein bound in plasma
32
Thyroid hormones, T3 & T4
- secreted by the thyroid gland
- made by enzymatic reactions from tyrosine, requires iodine ingestion
- in plasma, hydrophobic T3 & T4 bind liver produced proteins (thyroxine-binding globulin, albumin) -> long half life in plasma
- in target cells, free T3 & T4 bind to intracellular thyroid hormone receptors (T3R) and alter transcription
- in liver, thyroid hormones are modified -> become hydrophilic and excreted
33
STEROID HORMONES
- Secreted by : ADRENAL GLANDS (aldosterone, cortisol), OVARIES (progesterone, estradiol), and TESTES (testosterone)
- made from cholesterol via enzymatic reactions
- rate limiting step is: P450 scc (P450 side chain cleavage enzyme) in the mitochondria
- upon synthesis hydrophobic steriod diffuse out of the plasma
34
C27 COMPOUNDS
CHOLESTEROL (PRECURSOR)
35
C21 COMPOUNDS
- MINERALOCORTICOIDS (E.G. ALDOSTERONE)
- GLUCOCORTICOIDS (E.G. CORTISOL)
- PROGESTINS (E.G. PROGESTERONE)
36
C19 COMPOUNDS
ANDROGENS (E.G. TESTOSTERONE)
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C18 COMPOUNDS
ESTROGENS (E.G. ESTRADIOL)
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1,25-(OH)2-VITAMIN D (calcitriol)
- supply of precursor vitamin D
diest: vitamin D2 or vitamin D3
de novo synthesis in skin from UV
- 2 step activation:
LIVER (vit-D -> 25-(OH) vit-D (biologically inactive)
KIDNEYS with 1-hydroxylase
25-(OH) vit D -> 1,25-(OH)2 vit-D (biologically active calcitriol)
39
MITOSIS
- 1 diploid parent cell (2n) creates 2 diploid daughter cells (2n)!
- cellular process used by somatic (non germ) cells during duplication
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MEIOSIS
- 1 diploid parent cell (2n) creates 4 haploid daughter cells!
- cellular process used by germ cells for gametogenesis
- meiosis comprised of MEIOSIS 1 during which homologous chromosomes are separated and MEIOSIS during which sister chromatids are separated
41
Genetic sex determination
1. genetic sex is determined by genetic inheritance of two chromosomes known as the sex chromosome X and one Y.
2. males possess one X and one Y
3. females possess two X
42
Males: testes:
1. epididymis
2. vas deferens
3. seminal vesicle
4. scrotum
5. prostate
6. penis
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Female: ovaries
1. fallopian tube
2. uterus
3. upper vagina
4. labia
5. clitoris
6. lower vagina
7. cervix
44
Every embryo (XX or Xy) is bi-potential with:
- bipotential gonads
- mullerian ducts
- wolffian ducts
- bi potential urogenital
45
bi-potential gonads
may become female ovaries or male testes
46
mullerian ducts
can develop into FEMALE internal genitalia
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wolffian ducts
can develop into MALE internal genitalia
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bi-potential urogenital
may become female or male external genitalia and urethra
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The default pathway for an 46, XX embryo during 4 to 12 weeks
1. bipotential gonads differentiate into ovaries
2. mullerian dicts differentiate into FEMALE internal genitalia
3. WOLFFIAN ducts REGRESS
4. Bipotential urogential sinus differentiate into female external genitalia and urethra
50
An 46, XY embryo develop male primary sex characteristics during 4 to 12 weeks
1. about 4 weeks: the SRY (sex determining region on the Y chromosome) gene is ON !!!
- SRY causes bipotential gonads to become testes (testes secrete 2 hormones: Mullerian inhibiting hormone MIH and testosterone T)
MIH causes regression of mullerian ducts, T causes WOLLFIAN DUCTS to be male internal gentalia
2. about 8 weeks: T is converted to DHT in urogential sinus: DHT causes bipotential urogential sinus to become external genitalia and prostate along with urethra
3. 3rd trimester birth: T causes testes to decend into scrotum
51
Some hormones are transported in plasma bound proteins. These proteins function to increase:
the half life of hormones in plasma
b/c: the binding globulin (from the liver) that is associated with hydrophobic hormone increase the half-life of the hormone by decreasing destruction and clearance of the hormone
52
when a decrease in sensitivity to thyroid hormones (TH) occurs in the absence of changes in the number of available TH receptors,
an increased concentration of TH is required to elicit the half maximal response
53
Thyroid hormone (TH) itself has no effect on release of fatty acids from adipose cells. In the absence of TH, epinephrine (E) stimulates release of small amount of fatty acids from adipose cells. In the presence of TH, epinephrine would cause a more substantial release of fatty acids because:
TH increases beta-receptors in adipose cells
54
The precursor for cortisol is _______ which is enzymatically derived from _______. Cortisol is secreted by the ________ when stimulated by the hormone ________ from the anterior pituitary.
1. progesterone
2. cholesterol
3. adrenal cortex
4. ACTH
55
the posterior pituitary is a tissue composed of __________ that secretes ADH or oxytocin into the _______ when stimulated by ______ generated in the hypothalamus
1. axons/terminals
2. general circulation
3. action potentials
56
Which of the following hormones has the slowest metabolic clearance rate (longest half life)?
thyroxine
- hydrophobic hormones (thyroid and steroid hormones) have the longest half lives in the plasma, slowest clearance rate
57
Hypertrophy of the adrenal cortex could result from the following
1. excessively rapid clearance of cortisol from the circulation
2. a tumor of the pituitary gland that secretes excessive amounts of ACTH
3. inactivation of enzymes that are required to synthesize corticosteroids
4. excessively rapid clearance of cortisol from the circulation and a tumor of the pituitary gland that secretes excessive amounts of ACTH
58
a subject consuming a diet deficient in iodine is likely to have
low plasma thyroxine, high plasma TSH, goiter
59
a blood clot that blocked the hypothalamic-pituitary portal system would cause a decrease in
ACTH secretion and atrophy of the adrenal cortex
60
which of the following does NOT produce hormones that affect long-bone growth?
Uterus
Graafian follicles - estrogen
zona fasciculate - cortisol
anterior pituitary gland - GH
61
A subject with type II diabetes would have elevated plasma:
All of the above
- glucose
- fatty acids
- amino acids
b/c: Type II diabetes = insulin insensitivity, insulin does not function normally, almost like fasting period with high levels of glucose (less glucose uptake and increase gluconeogenesis), fatty acid from increased lipolysis, amino acids from increase protolysis
62
Which of the following does not produce hormones that by themselves or together stimulate lipolysis within adipocytes?
UTERUS
```
Zona fasciculata - cortisol
pancreatic alpha cells - glucagon
andrenal medulla - epinephrine
anterior pituitary gland - GH
These four hormones that counteract insulin's metabolic effects their plasma leveks increase during fasting
```
63
Which of the following statements do BEST characterize intermediate metabolism in an individual who has NOT eaten for two days?
Lipolysis in adpiocytes is an important energy source for non-CNS cells
Fasting for more than 2 days...
glycogen storage is just for one day worth of energy requirement for a person
proteins are spared until later
brain does not take up fatty acids due to the fact fatty acids cannot cross blood brain barrier
glucagon sitmulates lipolysis
lipolysis is the main source for fatty acids-used by NON-CNS cells, there will be ketones which are converted from fatty acids by the liver are also used by non cns cells
64
Pubertal growth spurt in male requires the enzyme_______ that converts testosterone to estradiol
Aromatase
65
Bilateral ovariectomy (removal of both ovaries) during the luteal phase in a woman would result in:
elevated LH levels, compared to those observed during the luteal phase prior to the surgery
66
Fertilization normally occurs in the
fallopian tube
67
Which of the following is responsible for the generation of the midcycle LH surge?
Estradiol from the dominant follicle
68
Inhibin inibits secretion of
FSH only from the anterior pituitary
69
According to the two cell mechanism of follicular estradiol synthesis
theca cells synthesize testosterone which granulosa cells convert to estradiol
70
The dominant follicle
produces copious amount of 17beta-estradiol
- the dominant follicle is the mature, graafian follicle that is formed at the midpoint of the follicular phase. It is the follicular structure that contains the prophase I primary oocyte and secretes a copious amount of estrogen.
71
The ovulated oocyte is meiotically arrested at
Metaphase II
72
Thyroid hormones increase metabolic activities by stimulating
the Na/K ATPase
73
The C18 compound from the ovaries
stimulates myometrial contractions
74
A polypeptide that is secreted from the posterior pituitary in response to suckling
Is made and released primarily by a neuron
75
When taken orally, which of the following hormone should have biological effects on their usual target tissues
Thyroxin
76
which of the following are found in the hypothalamus-pituitary portal vessel
DA and CRH
77
Activity of which of the following is elevated 1 hour post eating?
Glycogen synthase
78
the immune response to viral infections depends on the following
antigen presentation by class I MHC in infected cells, and cytokines
79
which of the follwoing statement about immunoglobulins?
their constant ends are antigen binding sites
80
An oposnin is a substance that _________. One example of an opsonin _________
1. creates a channel in bacteria
| 2. interferon-gamma
81
which of the following is not a characteristic of the innate immune system?
it is a specific response against microbial antigens
82
the secondary lymphoid organs are important because:
that is where clonal expansion of lymphocytes
83
the innate immune system relies on pattern recognition receptors to:
identify some non-specific microbial markers
84
type 1 interferons limit viral infections by:
inhibiting viral replication
85
one difference between lymphoctes and neutrophils is that
some lymphocytes re-enter the circulation
86
the development of immune tolerance includes a mechanism late fetal and early postnatal development called:
clonal deletion
87
the immeadiate hypersensittvity response is triggered by:
antigen binding to IgE on the surface of mast cells
88
the response of natural killer cells is non-specific, except in the case of:
antibody dependent cellular cytotoxicity
89
which of the following cells is not of lymphoid origin?
mast cells
90
which of the following is a shared characteristic of the innate and adaptive immune systems?
immunologic tolerance to avoid damage to normal tissues
91
the main difference between innate and adaptive immunity is:
all answers given are correct
- the specificity of the immune response
- development of immunological memory
- the timing of the immune response
92
A friend comes back from a month-long trip central Asia. two weeks later, he complains of chills, weakness, and loss appetite. A quick.....
it may be severe viral infection
93
Neutrophils are leukocytes that are important for the innate immune defenses. What would be a likely consequence of a congenital neutrophil deficiency?
higher risk of bacterial infections
94
Mice are resistant to typhoid fever, an infectious disease that can be quite deadly to humans. We
know that resistance to typhoid fever is due to the innate immune system. What is a likely
mechanism of resistance in mice?
The pattern-recognition receptors in mouse phagocytes.
95
How does complement kill microorganisms directly?
By producing the membrane attack complex.
96
What is a key difference between cytotoxic and NK cells?
Cytotoxic T cells are antigen-specific.
97
Which of the following is a stage of an adaptive immune response?
Specific cytotoxic responses.
98
Which of the following steps is important for the response of the adaptive immune system to viral
infections?
All the answers are incorrect.
- binding of type I interferon to cell membrane receptors
- antigens presentation by class I MHC to CD4+ cells
- activation and clonal expansion of natural killer cells
99
The process of antigen presentation by class I MHC involves:
interaction with antigen-specific T lymphocytes.
100
Which of the following statements about immunoglobulins is correct?
IgA is found in secretions.
101
The Center for Disease Control and Prevention recommends to get the flu shot no later than mid-
October. One reason for this is to:
achieve high levels of neutralizing antibodies.
102
this modified amino acid is an example of catecholamine
epinephrine
103
this hormone is carried plasma by liver produced binding globulin
thyroid hormone
104
this hormone's receptor is a transcription factor
cortisol
105
this hormone is synthesized by transcription translation processess
insulin
106
a patient with a lower sensitivity to insulin would require ______ insulin for the same response
more
107
receptors for all hromones are proteins
true
108
all diabetic patients suffer insluin deficiency
false
109
glucose is the main source of energy for peripheral tissues during fasting
false
110
triglycerides are broken down at adipocyte capillary beds during fasting
false
111
gluconeogensis is stimulated by insulin
false
112
glocuse effectively released from skeletal muscle during fasting
false
113
insulin causes GLUT4 translocation of to the plasma membrane in liver and skeletal muscle
false
114
the brain can only use glocuse for energy production
false
