Module 1 Flashcards
1
Q
What are the primary organs of the endocrine system?
A
- hypothalamus
- pituitary gland
- thyroid & parathyroid gland
- adrenal glands
- pancreas
- gonads
- placenta
2
Q
What does the endocrine system do?
A
- coordinate and integrate cellular activity throughout the body to maintain homeostasis
3
Q
How does the endocrine system produce an effect on the body?
A
- chemical messengers (hormones) use the circulatory pathways
4
Q
What are the functions of the endocrine system?
A
- homeostasis
- storage and utilization of energy
- regulation or growth, development, and reproduction
- response to environmental stimuli
5
Q
Compared to the nervous system, the endocrine system speed of response is _______ but has a _______ response time.
A
- slower
- prolonged
6
Q
T/F: Endocrine system response is more diffuse than the nervous system response.
A
- True
7
Q
What are the three general components of the endocrine system?
A
- endocrine glands
- target organs
- hormones
8
Q
What is a ductless gland that secretes hormones into blood?
A
- endocrine gland
9
Q
What is the organ that contains cells with receptors that have hormone specific receptors?
A
- target organ
10
Q
What are chemical messengers released by one cell and exert a biological action on a target cell?
A
- hormones
11
Q
Describe the action of a hormone
A
- a single hormone can facilitate multiple effects
OR - many hormones collectivly produce a single effect
12
Q
How is it possible for a single hormone to produce multiple effects?
A
- different receptor types
13
Q
Why does the body have the ability to create one effect with many hormones?
A
- protective mechanism
14
Q
What are the types of hormone signaling?
A
- endocrine
- paracrine
- autocrine
- intracrine
15
Q
Describe the MOA of endocrine signaling
A
- hormones travel through blood stream to reach distant target tissue
16
Q
Describe the MOA of paracrine signaling
A
- hormones release and act locally on the neighboring cells
17
Q
Describe the MOA of autocrine signaling
A
- hormone is released by a cell then acts on the same cell that released it
18
Q
Describe the MOA of intracrine signaling
A
- hormone produced in a cell and acts within the cell itself
19
Q
How are hormone secretions regulated?
A
- negative feedback
- positive feedback
20
Q
Which is more common, negative or positive feedback?
A
- negative
21
Q
Describe how negative feedback regulates hormone secretion
A
- hormone action directly or indirectly inhibits further release of that hormone
22
Q
Describe how positive feedback regulates hormone secretion
A
- hormone action directly of indirectly stimulates further release of that hormone
23
Q
What are the two types of negative feedback loops?
A
- short (one or two steps)
- long (many steps)
24
Q
What is a variation on the negative feedback loop?
A
- increasing levels of hormone stimulate the hormones inhibiting factor
25
How is a positive feedback loop terminated?
- outside stimulus
26
How are the types of hormones classified?
- derivative content
| - solubility
27
What are the derivative content types of hormone classifications?
- a.a.
- peptide/protein
- steroid
- fatty acid
28
What are the solubility types of hormone classifications?
- lipid soluble, water insoluble (lipophilic, hydrophobic)
| - water soluble, lipid insoluble (hydrophilic, lypophobic)
29
What types of hormones are lipophilic?
- steroid
| - thyroid
30
What is the precursor for all steroid hormones?
- cholesterol
31
How are lipophilic hormones circulated in the plasma?
- bound to a protein carrier
32
What types of hormones are hydrophilic?
- most
33
How are hydrophilic hormones circulated in the plasma?
- 'free'
34
Which has a shorter half life, lipophilic or hydrophilic hormones?
- hydrophilic
| - free and easily broken down
35
What are the cellular mechanisms of hormonal action?
- direct binding of hormone receptors
| - signal transduction
36
Where are hormone receptors located?
- cell membrane or within the cell
37
What do the number of receptors reflect?
- local or systemic conditions
38
What is up-regulation?
- [low hormone] will increase the number of receptors
39
What is the net result of up-regulation?
- increases sensitivity
40
What is down-regulation?
- [high hormone] will decrease the number of receptors
41
What is the net result of down-regulation?
- decreased sensitivitity
42
T/F: Receptor number is a fixed quantity
- False, dynamic & continuous turnover
43
Healthy receptors are adapting to make physiology _____ efficient while unhealthy receptors are making physiology _____ efficient.
- more
| - less
44
Define signal transduction
- process by which hormones are communicated into the cell
45
What are the two types of signal transduction hormones?
- primary
| - secondary
46
What is the type of signal transduction for lipophilic hormones?
- primary
47
What is the type of signals transduction for hydrophilic hormones?
- secondary
48
Define primary messenger as a type of signal transduction
- hormone itself enters the cell and mediates cell function
49
Define secondary messenger as a type of signal transduction
- messenger "link" between primary messenger and inside of the cell
50
How does a secondary messenger produce its action?
- hormone attaches to target receptor on cell membrane
| - receptor stimulates interior cascade to produce desired physiologic action
51
Why do hydrophilic hormones require a secondary messenger mechanism for signaling?
- water soluble hormone can't cross membrane
| - needs messenger to communicate to interior structures
52
What is the Hypothalamic-Pituitary Axis (HPA)?
- critical signaling pathway for the endocrine system
53
What are the two sections of the HPA?
- anterior pituitary
| - posterior pituitary
54
Describe the movement of hormones in the anterior pituitary
- hypothalamus releases "pituitary releasing hormones"
- releasing hormones descend via hypophyseal portal system
- releasing hormones either stimulate or inhibit release of pituitary hormone
55
What is the hypophyseal portal system?
- capillaries in hypothalamus communicate with pituitary capillaries before entering the venous system
56
Describe the movement of hormones in the posterior pituitary
- hypothalamic neurons produce hormones
| - released via hypothalamus neuron directly into post. pit and enter blood
57
What are the two posterior pituitary hormones?
- ADH
| - oxytocin
58
What is the function of the hypothalamus?
- 'links' CNS to endocrine system
59
Where is the hypothalamus located?
- diencephalon of CNS
60
What are the hormones that are released from the hypothalamus that control the ant. pit?
* The SUBmarine DA Prefers SOMe CRunchy Green growth hormone.
- TRH (thyrotropin releasing hormone)
- Substance-P
- DA
- PRF (prolactin releasing factor)
- Somatostatin (SRIF - somatotropin release-inhibiting factor)
- CRH (corticotropin releasing hormone)
- GnRH (gonadotropin releasing hormone)
- GHRH (growth hormone releasing hormone)
61
What is TRH and its action in the ant. pit?
- thyrotropin releasing hormone
| - stimulates release of TSH (thyroid stimulating hormone)
62
What is GnRH and its action in the ant. pit?
- gonadotropin releasing hormone
| - stimulates the release of LH (luteinizing hormone) and FHS (follicle stimulating hormone)
63
What is somatostatin and its action in the ant. pit?
- SRIF - somatotropin release-inhibiting factor
| - inhibits release of GH (somatotropin) and TSH
64
What is GHRH and its action in the ant. pit?
- growth hormone releasing hormone
| - stimulates the release of GH
65
What is CRH and its action in the ant. pit?
- corticotropin releasing hormone
| - stimulates release of ACTH (adrenocorticotropic hormone) and B-endorphin
66
What is substance-P's action in the ant. pit?
- inhibits synthesis/release of ACTH
| - stimulates release of GH, FSH, LH, and prolactin
67
What is DA's action in the ant. pit?
- inhibits synthesis/release of prolactin
68
What is PRF and its action in the ant. pit?
- prolactin releasing hormone
| - stimulates the release of prolactin
69
What is the hypophysis?
- pituitary gland
70
What is the adenohypophsis?
- anterior pituitary gland
71
What are the regions of the ant. pit?
- pars distalis
- pars tuberalis
- pars intermedia
72
What is the neurohypophysis?
- posterior pituitary gland
73
What is the function of the pituitary gland?
- regulates the activity of most endocrine glands in the body
- aka: the Master Gland
74
What are the bodily functions that the pituitary gland regulates?
- growth
- metabolism
- reproduction
- lactation
- fluid balance
- response to stress
75
What are the regions of the post. pit?
- median eminence
- infundibular stem of pit stem
- infundibular process
76
What is the function of oxytocin in females?
- stimulates milk ejection and uterine contraction
77
What can be used to induce labor?
- synthetic versions of oxytocin
78
What is the function of oxytocin in males?
- ? sperm motility
| - sexual activity
79
What is the target tissue of oxytocin?
- mammary gland
| - uterus during pregnancy
80
What are the stimuli for oxytocin release?
- distention of cervix
- breast stimulation
- positive emotional response
81
How is oxytocin release regulated?
- positive feedback
82
What are the stimuli for oxytocin inhibition?
- cessation of external stimulus
| - negative emotional stimuli
83
What can a deficiency of oxytocin result in?
- impaired nursing
84
What is the function of ADH?
- control osmolality/osmolarity of plasma
85
What does ADH lead to?
- increased blood volume
86
How does ADH increase blood volume?
- decrease osmolarity
| - increases BP
87
**What is the target tissue of ADH?**
- major: DCT & collecting duct of kidneys
| - minor: vascular smooth m.
88
What is the effect of ADH at the kidney?
- increases water reabsorption by increasing permeability of collecting ducts
89
What is the effect of ADH at the vascular smooth m.?
- mild vasoconstriction to increase BP
90
What is the stimulus for ADH release?
- increased plasma osmolarity (concentration)
- decreased blood volume (blood pressure)
- Angiotensin II, indirectly
91
**What is the primary control of ADH release?**
- increased plasma osmolarity; most sensitive to changes in [blood] levels
92
A 10% change in osmolarity leads to what?
- large ADH release
93
A 10% change in blood vol/ pressure leads to what?
- small ADH release
94
How does angiotensin II indirectly stimulate ADH release?
- renin-angiotensin system synergistically tries to increase blood vol/pressure
95
What does angiotensin II lead to?
- increased sensitivity of osmoreceptors in hypothalamus
| - stimulate thirst center in hypothalamus
96
What inhibits ADH release?
- decreased plasma osmolality
- increased blood vol/pressure
- ETOH & caffine
97
What are two clinical manifestations of ADH problems?
- diabetes insipidus (DI)
| - syndrome of inappropriate ADH secretion (SIADH)
98
What is DI?
- diabetes insipidus
| - too little of ineffective ADH
99
What are the types of DI?
- central
| - nephrogenic
100
Describe central DI
- decreased release of ADH from post pit
101
Describe nephrogenic DI
- inability of the kidneys to respond to ADH
102
What are the signs and symptoms of DI?
- polyuria
| - polydipsia
103
Define polyuria
- excessive urine volume (dilute production)
104
Define polydispia
- excessive thirst
105
Define SIADH
- syndrome of inappropriate ADH secretion
| - elevated ADH secretion results in excessive water reabsorption in kidney
106
**Describe the steps of SIADH**
- elevated ADH --> excessive H20 reabsorption in kidney --> hypervolemia --> hyponatremia & natiuresis
107
Define hypervolemia
- increase fluid volume which increases pressure
108
Define hyponatremia
- decreased Na in blood stream
109
Define natriuresis
- excessive Na secretion
110
What are the etiologies of SIADH?
- tumor
- head injuries or meningitis
- bronchogenic tumors
- DM
111
Describe the pars distalis
- forms most of the ant pit gland itself
112
Describe the pars tubularis
- thin layer that wraps around the anteriolateral aspect of infundibular stem
113
Describe the pars intermedia
- small layer between pars distalis and tubularis
| - disappears in adults
114
**What regulates the hormone released from the ant pit?**
- hypothalamic-hypophyseal portal system
115
What are the major hormones synthesized and released by the ant. pit?
- prolactin
- GH
- TSH
- LH
- FSH
- ACTH
- MSH ( melanocyte stimulating hormone)
116
**What is the function of prolactin?**
- breast development during puberty and pregnancy
- stimulates milk production after birth
- inhibits ovultion
117
**What is the target tissue of prolactin?**
- mammary glands during puberty, pregnancy, and while lactating
118
**What stimulates prolactin release?**
- puberty (breast development)
- pregnancy (breast/duct growth)
- lactation (milk production)
- sleep
- DA antagonist
119
When would a DA antagonist be used?
- induce lactation in adoption
120
**What inhibits prolactin release?**
- PIF
- DA agonist
- discontinuation of stimulus
121
How does PIF inhibit prolactin release?
- negative feedback: elevated prolactin stimulates hypothalamus to increase tonic release of DA
122
How is GH released?
- pulsing/cyclic & circadian rhythm pattern
123
When does GH release peak?
- adolescence
124
What is the function of GH?
- stimulates all tissue growth and maturation
125
What does GH work synergistically with?
- IGF-1 (insulin-like growth factor)
126
**What is the function of GH working with IGF-1?**
- promotes growth of tissues and regulates metabolism to facilitate growth
127
**What is the target tissue of GH with direct effect?**
- liver
- muscle
- adipose
128
**What is the target tissue of GH with indirect effect?**
- liver
129
**What is the target tissue of IGF-1?**
- bone
- cartilage
- visceral organs
130
What is the action of GH in the liver and what type?
- IGF synthesis
- protein/a.a. synthesis
- anabolic
131
What is the action of GH in the adipose tissue and what type?
- increase lipolysis
- decrease glucose uptake (mobilize/maintain glucose for blood stream)
- metabolic
132
What is the action of GH in the muscle and what type?
- increase a.a. uptake/protein synthesis
- decrease glucose uptake (mobilize/maintain glucose for blood stream)
- metabolic
133
What is the action of IGF-1?
- mediates cell growth in most tissues of the body
134
What is IGF-1's action in the cartilage?
- stimulates cartilage matrix growth/balance
| - increase/maintain tissue growth
135
What is IGF-1's action in the bone?
- facilitate osteoblast/osteoclastic activity
136
What is IGF-2's effect on tissue growth?
- inhibitory (antagonistic)
137
How are GH and IGF-1 working on metabolic actions?
- GH direct
| - IGF-1 indirect
138
What are the metabolic actions of GH/IGF-1?
- protein metabolism
- carbohydrate metabolism
- fat metabolism
139
How does GH/IGF-1 affect protein metabolism?
- stimulates a.a. uptake/synthesis
| - stimulates protein anabolism in tissues
140
How does GH/IGF-1 affect CHO metabolism?
- assists in maintaining blood glucose levels
- impairs glucose uptake (opposite insulin)
- stimulates liver glycogenolysis
141
How does GH/IGF-1 affect fat metabolism?
- increases lipolysis
| - decrease glucose uptake into fat cell
142
What balances the actions of IGF-1?
- IGF-2
143
Describe the feedback of IGF-1
- inhibits GH release from pit
| - stimulates somatostatin (GH inhibiting factor) from hypothalamus
144
What stimulates GH release from ant. pit?
- GHRH from hypothalamus
- puberty (elevated sex hormones)
- dietary protein
- hypoglycemia
- stage 4 deep sleep
- exercise
145
How do dietary proteins stimulate GH release?
- increased ingestion of a.a. provide building blocks for growth
146
What inhibits GH release from ant. pit?
- somatostatin
- glucocorticoids
- hyperglycemia
- neg. feedback loops
147
What are two examples of glucocorticoids that will affect GH release?
- Cushing's syndrome of excessive cortisol
| - steroid therapy in children
148
Describe the negative feedback loops on GH release
- elevated GH inhibits GH
- elevated IGF-1 inhibits GH and stimulates somatostatin
- excessive androgens
149
What are the hormones that influence growth?
- GH
- thyroid hormones
- gonadal steroid hormones
- insulin
- cortisol
150
What are clinical pathologies of insufficient GH?
- dwarfism
151
What are clinical pathologies of excessive GH?
- gigantism
| - acromegaly
152
Which clinical pathology of GH occurs before the epiphyseal plates close? after? both?
- before: dwarfism
- after: acromegaly
- both: gigantism
153
Which clinical patholology of GH affects the long and flat bones?
- gigantism
154
Which clinical pathology of GH affects the irregular bones?
- acromegaly
155
What type of changes can long-term excessive GH cause?
- orthopedic
- i.e. arthopathy, neuopathy, cardiomyopathy/HTN, respiratory disease, CHO intolerance/diabetes, increased risk of malignancy, DECREASED lifespan
156
What is the function of TSH?
- stimulates synthesis and release of thyroid hormones (T3 & T4)
157
What are the gonatdotropin hormones?
- LH
| - FSH
158
What is the function of LH in females?
- stimulates ovulation
- formulation of corpus luteum
- synthesis of estrogen and progesterone in ovary
159
What is the function of LH in males?
- stimulates synthesis and secretion of testosterone
160
What is the function of FSH in females?
- stimulates the growth of ovarian follicles and estrogen secretion
161
What is the function of FSH in males?
- stimulates sperm maturation in testicles
162
What is the function of ACTH?
- stimulates synthesis and secretion of adrenal cortical hormones
163
What is the function of MSH?
- stimulates melanin synthesis/release from melanocytes
