Endocrine System Flashcards
1
Q
function of endocrine system
A
change the metabolic activity of cells
2
Q
neuroendocrine link
A
when the brain generates a nervous impulse and sends the impulse to an endocrine gland to activate it to start secreting
3
Q
exocrine glands
A
secreted into a duct; does not produce hormones
produces a substance (like sweat)
4
Q
endocrine glands
A
ductless, hormone-producing, and vascular (so hormones enter bloodstream)
5
Q
T/F some glands are both endocrine and exocrine
A
true- for example, the pancreas
6
Q
hormone
A
long-distance chemical messengers
produced in one part of body, affect somewhere else
7
Q
autocrine
A
chemical messenger that affects the same cells that produce it
“self regulator”
8
Q
paracrine
A
chemical messenger that affects neighboring cells to where it was produced
local effect
9
Q
pheromone
A
chemical messenger secreted by one individual that changes activity of another individually
generally a sexual attractant (humans release as sweat)
10
Q
types of hormones
A
amino acid based
steroid
11
Q
most hormones are which type?
A
amino acid based
12
Q
amino acid based hormones
A
water-soluble
transported by plasma in bloodstream; cannot cross plasma membrane
interact with receptor on outside of cell
found everywhere steroid hormones are not
13
Q
other names for amino acid based hormones
A
peptide/protein/nonsteroid
14
Q
steroid hormones
A
fat-soluble
cannot be transported by plasma alone; attaches to another molecule
can cross cell’s plasma membrane; attach to receptor inside of cell
found in adrenal cortex and gonads
15
Q
where are steroid hormones found?
A
adrenal cortex
gonads (ovaries and testes)
16
Q
steroid hormones find receptors ____ of cell
A
inside
17
Q
amino acid based hormones find receptors ____ of cell
A
outside
18
Q
eicosanoid
A
biologically active lipid that functions more like a paracrine than a hormone
local signaling molecule
2 classes: prostaglandins and leukotrines
19
Q
2 classes of eicosanoids
A
prostaglandins and leukotrines
20
Q
leukotrienes
A
class of eicosanoid that promotes inflammation
21
Q
target cells
A
cells with receptors for certain hormones; can have receptors for 1 or > 1 hormone
22
Q
hormone actions
A
open or close ion channels stimulate protein synthesis activate or deactivate enzymes promote secretion stimulate mitosis
23
Q
steroid action (process)
A
- hormone diffuses through plasma membrane
- hormone binds with (specific) intracellular receptor
- activated complex binds to receptor protein on DNA
- transcription (production of mRNA) initiated
- mRNA translated
- protein produced
24
Q
function of steroids
A
produce new proteins
25
which type of hormone uses direct activation?
steroid
26
mechanisms of amino acid based hormone action
Cyclic AMP mechanism
| PIP-Calcium mechanism
27
which type of hormone involves G proteins and secondary messengers for activation?
Amino Acid Based
28
cyclic AMP mechanisms uses how many secondary messengers?
1
29
PIP-Calcium mechanism uses how many secondary messengers?
2
30
cyclic AMP mechanism (process)
1. hormone binds to (external) membrane receptor
2. modified receptor binds with G protein
3. G protein is activated
4. Activated G protein activates adenylate cyclase
5. Adenylate cyclase generates cAMP from ATP
6. cAMP stimulates protein kinase reactions (activating proteins that already exist within the cell)
7. proteins are phosphorylated
8. phosphodiesterase degrades/shuts down cAMP
31
which type of hormone mechanism activates proteins that already exist within the cell?
cyclic AMP
32
PIP-Calcium mechanism (process)
1. hormone binds to (external) membrane receptor
2. modified receptor binds with G protein
3. G protein is activated
4. activated G protein activates phospholipase
5. phospholipase splits PIP2 into DAG and IP3
6. DAG activates protein kinases
7. IP3 triggers release of calcium from endoplasmic reticulum
8. Calcium acts as additional secondary messenger
33
secondary messenger(s) in cAMP mechanism
cAMP
34
secondary messenger(s) in PIP-Calcium mechanism
DAG and Calcium
35
factors that affect hormone action
- hormone level in bloodstream
- number of receptors in/on target cells
- receptor affinity
36
receptor affinity
how easily receptor binds to hormone; incr affinity --> incr. effect of hormone
37
permissiveness
1 hormone functions better when a 2nd hormone is present
| Even though 2nd hormone has a different function
38
synergism
2 hormones work better together
| they both have the same function
39
antagonism
2 hormones have opposite effects
| work in opposition to help fine tune things in body
40
downregulation
continued stress causes decreased # of receptors
| body stops trying/relaxes in response to continued stress
41
upregulation
continued stress causes increased number of receptors
| body is adapting to continued stress
42
modes of endocrine gland stimulation
```
humoral
neural
hormonal
overriden by nervous system
inhibited by negative feedback
```
43
humoral regulation
change of concentration of something in blood causes gland stimulation
humor=fluid
44
neural regulation
neural stimulation directly contacts gland
45
hormonal regulation
1 hormone causes production of a different hormone
46
neurohypophysis
posterior pituitary gland
47
adenohypophysis
anterior pituitary gland
48
posterior pituitary gland
made of neural tissue
| stores/regulates hormones (BUT CANNOT PRODUCE)
49
anterior pituitary gland
made of glandular tissue
can produce hormones
originated from oral cavity
50
hormones secreted by posterior pituitary gland
oxytocin; ADH (antidiuretic hormone)
51
hormones secreted by anterior pituitary gland
```
GH (growth hormone)
TSH (thyroid stimulating hormone)
ACTH (adenocorticotropic hormone)
Gonadotropins- FSH and LH
Prolactin (PRL)
```
52
where are neurohypophysal hormones produced?
hypothalamus
53
by what mechanism are neurohypophysal hormones produced?
PIP-Calcium mechanism
54
where are adenohypophysal hormones produced?
anterior pituitary gland
55
what kinds of hormones are adenohypophysal hormones
Amino Acid Based
56
function of oxytocin
stimulates smooth muscle contraction; involved in childbirth, milk ejection, orgasm, and nurturing
57
what is the "cuddle hormone"?
oxytocin
58
how is oxytocin involved with childbirth?
1. fetus grows and stretches uterus
2. uterus sends stretch signal to brain
3. brain sends signal to pituitary to secrete oxytocin
4. oxytocin causes contraction
59
what functions is oxytocin involved with
```
childbirth
milk ejection
orgasm/arousal
nurturing
amnesiac (so you forget pain of childbirth)
```
60
function of antidiuretic hormone (ADH)
regulates water balance and prevents urine formation
61
how does ADH regulate water balance?
targets kidneys to resorb H2O, instead of excreting
62
why do we pee more when were drunk?
Alcohol suppresses ADH
63
what triggers ADH secretion?
when blood is too thick; not enough H2O in blood
64
general process of tropic hormones
hypothalamus produces "releaser hormone"
releaser activates special cells in anterior pituitary (these cells have word 'trop' in it)
negative feedback mechanism
65
what do tropic hormones do?
cause production of a different hormone
| their target cells are another endocrine organ
66
pro-opiomelanocortin (POMC)
gives rise to a hormone
opiate (feel good)
activates melanocytes
can activate adrenal cortex
67
functions of growth hormone
stimulates: cell growth/division, protein synthesis, fat metabolism, glucose conservation
68
Where is GH most active? Why?
in muscles and bones; because of an increased number of receptors
69
how does GH stimulate glucose conservation?
changes concentration of glucose in cell to keep it inside
70
conditions of growth hormone
pituitary dwarfism
giantism
acromegaly
71
pituitary dwarfism
too little GH in a child
72
giantism
too much GH in a child
73
acromegaly
too much GH in an adult
74
growth hormone (GH) process
1. hypothalamus secretes GHRH (growth hormone releasing hormone)
2. GHRH activates somatotropin cells of anterior pituitary to begin GH synthesis
3. GH has both direct and indirect effects on tissues
4. circulating GH triggers production of GHIH (growth hormone inhibiting hormone)
5. production of GH stops
75
direct GH effects on tissues
increase blood levels of fatty acids
decrease glucose uptake and metabolism
encourages breakdown and release of glucose from glycogen in the liver
76
how does GH increase blood levels of fatty acids?
it pulls fat from fat stores, making it available to new cells
77
diabetogenic effect
direct action of GH encouraging breakdown and release of glucose from glycogen in liver
78
indirect actions of GH
operate through IGF (Insulin-like growth factors)
stimulates uptake of Amino Acids from blood into cellular proteins
stimulates uptake of sulfur into matrix of cartilage
79
somatomedins
insulin-like growth factors
| produced by GH in liver
80
how does GH stimulate cell and skeletal growth indirectly?
by stimulating uptake of Amino acids into cellular proteins and sulfur into matrix of cartilage
81
another name for TSH
thyrotropin
82
thyroid-stimulating hormone (TSH) function
stimulates development and secretion from the thyroid gland
83
process of TSH
1. hypothalamus secretes TRH (thyrotropin releasing hormone)
2. TRH causes thyrotrope cells of anterior pituitary to produce TSH
3. increased levels of TSH inhibit both pituitary gland and hypothalamus (also stimulate production of GHIH)
84
what stimulates production of GHIH?
circulating GH and/or increased levels of TSH
85
what does GHIH inhibit?
GH and TSH
86
function of adenocorticotropic hormone (ACTH)
stimulates adrenal cortex to release corticosteroid hormones (especially glucocorticoids)
87
class of hormone produced most in response to ACTH
glucocorticoids
88
process of ACTH
1. hypothalamus secretes CRH (corticotropin releasing hormone)
2. CRH stimulates corticotrope cells to release ACTH
3. increased levels of glucocorticoids stop CRH
4. ACTH secretion stops
89
stimuli for release of CRH (--> production of ACTH)
fever, hypoglycemia, and stressors
90
function of gonadotropins
regulate functions of gonads
91
function of FSH
stimulate gamete production
92
function of LH
promotes production of gonadal hormones
93
which gonadotropin is tropic?
LH
94
process of gonadotropins
1. at puberty, hypothalamus secretes GnRH
2. GnRH stimulates gonadotrope cells to secrete gonadotropins
3. gonadotropins cause gonads to mature and begin producing hormones
4. increased levels of gonad hormones suppress FSH and LH
95
male FSH function
stimulates sperm production
96
male LH function
stimulates interstitial cells of testes to produce testosterone
97
female FSH function
stimulates ova production
98
female LH function
triggers ovulation and promotes synthesis of ovarian hormones (mostly estrogen, some progesterone)
99
gonadotropin that causes maturation of follicles in an ovary
FSH and LH! (both)
100
function of prolactin (PRL)
stimulates milk production by breasts
101
what makes PRL different than the other adenohypophysal hormones?
it is controlled by an inhibitor (PIH) rather than a releaser
102
why dont men produce PRL?
their estrogen levels never get high enough to suppress PIH
103
PRL process in Cycling (nonpregnant) women
1. high estrogen levels stimulate releaser PRL
2. estrogen stimulates lactotropes to secrete PRL by suppressing PIH production
3. PRL production tried fur to ovarian hormone cycling
4. low estrogen levels stimulates production of PIH from hypothalamus
5. PRL production stops
104
T/F: PRL can cause breast tenderness in non pregnant women
true- may cause breast tenderness but no milk!
105
why is production of PRL so short?
because ovarian hormone cycling (estrogen levels going up and down)
106
PRL process in Pregnant women
1. high estrogen levels stimulate release of PRL
2. estrogen stimulates lactotropes to secrete PRL by suppressing PIH production
3. PRL triggered near end of pregnancy, when estrogen levels get v high
4. suckling from baby maintains PRL production
5. lack of suckling and return to normal hormonal cycles leads to PIH production
107
thyroid
2 lobes wrapping around the front of trachea connected by isthmus
produce thyroid hormone and calcitonin
108
largest pure endocrine gland
thyroid
109
histological composition of thyroid
contains follicles made of epithelial cells
| contains parafollicular cells
110
2 separate hormones of thyroid hormone
T3 and T4
111
everywhere has receptors for thyroid hormone except...
```
brain
testes
thyroid
spleen
uterus
```
112
major hormone for metabolic activity
thyroid hormone
113
calorigenic effect
thyroid hormone increases basal metabolic rate and heat production
114
functions of thyroid hormone
increases metabolic rate and heat production
maintains bp
regulates tissue growth and development (esp skeletal, nervous, and reproductive)
115
how does thyroid hormone maintain blood pressure
increases number of adrenergic receptors on surface of blood vessels
promotes vasoconstriction --> causes increase in blood pressure
116
______ and ______ combine in ____ to make thyroid hormone
thyroglobulin; iodine; colloid
117
Feedback of Thyroid Hormone
Increased levels of T4 inhibit TSH productiom (decreased levels would stimulate)
Increase in body energy needs stimulate release of TRH
Levels of iodine, sex hormones, and glucocorticoids affect thyroid hormone production
118
Diurnal Cycle
Thyroid can store hormone (2-3 mo supply)
TSH peaks before sleep and remains high at night
Produced TH stored in extracellular colloid
Sleep deprivation leads to underproduction of thyroid hormone
119
What hormone regulates Calcium in youth?
Calcitonin
120
Follicle cells of thyroid produce:
Thryoglobulin —> thyroid hormone
121
Parafolicular cells of thyroid produce:
Calcitonin
122
Another name for parafollicular cells
C cells
123
Function of calcitonin
Lowers blood Ca levels (by taking Ca from blood to cells)
| Involved in skeleton growth and reformation
124
When is calcitonin most important?
During periods of ralid skeleton growth and reformation
Adolescence!
Basically stops after puberty
125
Calcitonin Action
Inhibits osteoclast activity
-Prevent Ca from being released into blood
Stimulates Ca uptake and deposition in bones, muscles, and other cells
126
Calcitonin feedback
Increased Ca levels stimulate C cell activity
(Humoral)
C cells stimulate production of calcitonin, which decreases blood Ca concentration
Decreased Ca levels inhibit C cell activity
127
C cells are involved with which hormone
Calcitonin
128
Chief cells are involved with which hormone
PTH
129
Parathyroid Gland
~4 glands embedded in posterior part of thyroid gland
| Produces PTH
130
Where are parathyroid glands located
Posterior pituitary
131
2 types of glandular cells of parathyroid
Oxyphil cells
| Chief cells
132
Oxyphil cells purpose
Unknown
133
Chief cells purpose
Produce PTH
134
Most important hormone for controlling blood calcium concentration?
PTH
135
PTH function
Increase blood calcium concentration
| Antagonist effect of calcitonin
136
Signsl for PTH production
Decreased blood Ca concentration
137
Parathyroid Hormone Action
Stimulates osteoclasts to release Ca (from bone) and phosphates into blood
Enhances reabsorption of Ca by kidneys (out of urine into bloodstream)
Increases absorption of Ca by small intestines
Promotes kidneys to cinvert Vitamin D into calcitrol (D3; active form of vitamin D)
138
Vitamin __ is needed to absorb Ca
Vitamin D
139
Adrenal glands
Paired (2) glands atop each kidney
Cortex, medulla, and capsule layers
All endocrine —> release hormones that react to and help resist stress
140
3 tyles of corticosteriods produced by adrenal glands
Mineralocorticoids
Glucocorticoids
Gonadocorticoids
141
Where are corticosteroids made?
Correx of adrenal glands
142
Tissue layers of adrenal glands (superficial to deep)
Zona glomerulosa
Zona fasciculata
Zona reticularis
143
Zona glomerulosa produces which corticosteroid?
Mineralocorticoids
144
Zona fasciculata produces which corticosteroid?
Glucocorticoids
145
Zona reticularis produces which corticosteroid?
Gonadocorticoids
146
Major hormone produced by mineralocorticoids
Aldosterone
147
Aldosterone function
```
Regulate electrolyte (mostly Na) concentration of extracellular fluids
Maintains Na and osmotic (H2O) balance in body
```
148
Aldosterone action
Stimulates Na reabsorption in distal parts of kidney tubules and from additional places where we lose electrolytes
Controls blood pressure and blood volume
149
How does aldosterone stimulate Na reabsorption in distal kidney tubules?
Pulls Na out of urine, puts it back into blood
150
4 Mechanisms of aldosterone secretion
Renin-Angiotensin Mechanism
Plasma concentration mechanism
ACTH Mechanism
Atrial Natriuretic Peptide (ANP)
151
Aldosterone feedback mechanism
```
Aldosterone secretion is stimulated by:
Increased K levels
Decreased Na levels
Decreased blood volume
Decreased blood pressure
(Humoral)
```
Aldosterone secretion is inhibited by: the opposite levels
152
Mechanism by which most aldosterone is secreted
Renin-angiotensin
153
Angiotensinogen
Inactive protein produced in liver, involved with aldosterone production
Breaks down RBCs
154
Renin-angiotensin mechanism of aldosterone secretion
1. Angiotensinogen triggers cells in kidney to produce renin
2. Renin converts angiotensinogen to its active form (angiotensin)
3. Angiotensin activates zona glomerulosa cells to produce aldosterone
155
Plasma concentration mechanism of aldosterone secretion
Triggered when Na concentration decreases
| Direct humoral mechanism
156
ACTH mechanism of aldosterone secretion
ACTH activates adrenal cortex and zona glomerulosa
| This causes production of glucocorticoids
157
ANP mechanism of aldosterone secretion
1. increased bp or increased blood volume causes heart to secrete ANP
2. ANP stops production of mineralocorticoids (stops absorbing Na)
Inhibits function of aldosterone
158
major hormone of glucocorticoids
cortisol
159
cortisol function
regulates energy metabolism of most body cells and resists stressors
160
effects of cortisol
increase in gluconeogenesis
assist in vasoconstriction
liberate fatty acids for energy
break down proteins into amino acids
161
action of cortisol
maintains (keeps high) blood sugar levels by gluconeogenesis
| maintains blood volume by preventing uptake of water by body cells
162
cortisol feedback process
1. CRH stimulated by stress
2. CRH (corticoreleasing hormone) promotes ACTH
3. ACTH activates zone fasciculate, then promotes cortisol
4. Cortisol inhibits both CRH and ACTH
163
major hormone of gonadotropins
DAGA (a weak androgen)
164
DAGA hormone
precursor to estrogen and testosterone
contributes to onset of puberty
provides sex drive in women
165
feedback of DAGA
technically there is no feedback mechanism!
| ACTH stimulates production of DAGA, and there is no inhibition
166
hormones of adrenal medulla
epinephrine and norepinephrine (adrenaline)
167
norepinephrine
neurotransmitter in sympathetic nervous system released into bloodstream by adrenal medulla
168
chromatin cells
modified ganglionic sympathetic neurons in adrenal medulla
| they release norepinephrine and epinephrine
169
action of norepinephrine and epinephrine
stress promotes release of hormones by stimulating sympathetic nervous system
bgl, HR, and BP incr
blood vessels constrict
blood is diverted to brain, heart, skeletal muscles, and preganglionic sympathetic nerve endings in adrenal medulla (fight or flight)
170
exocrine functions of pancreas
secretes digestive enzymes into ducts
171
endocrine function of pancreas
produces hormones
172
histological composition of pancreas
acing cells
| pancreatic islets- alpha cells, beta cells
173
acinar cells
exocrine component of pancreas (most of pancreas)
| secretes digestive enzymes into duct
174
pancreatic islets/islets of langerhaans
endocrine part of pancreas
function to regulate blood glucose level
contain alpha cells and beta cells
produces insulin and glucagon
175
alpha cells of pancreatic islets
produce glucagon
176
beta cells of pancreatic islets
produce insulin
177
glucagon function
functions on liver to release glucose into blood --> raising bgl
thru breakdown of glycogen in liver
178
glucagon action
glycogenolysis: breaks down glycogen into glucose
gluconeogenesis: synthesizes glucose from lactic acid and noncarbohydrate molecules
releases glucose into blood
179
glucagon feedback
decreasing bgl and increasing AA levels stimulate alpha cells to produce glucagon (humoral control)
sympathetic stimulation medulla promotes glucagon release
somatostatin (GHIH) inhibits release of glucagon
180
insulin function
decreases bgl
| incr metabolism of fat and protein
181
insulin action
enhances membrane transport of glucose into cells
inhibits breakdown of glycogen --> glucose
inhibits gluconeogenesis
activates oxidation of glucose inside cells (promotes cells to convert glucose into ATP)
promotes glycogen formation
turns glucose into fat
182
insulin feedback
incr bgl, incr levels of fatty acids and AAs stimulates insulin production by activating beta cells
parasympathetic release of acetylcholine stimulates insulin release
hormonal influences (such as GH) also exist
183
hormones produced by gonads
testosterone, estrogen, and progesterone
184
testosterone functions
```
maturation and maintenance of male reproductive organs
secondary sex characteristics
sex drive
sperm production
increased aggression
```
185
male secondary sex characteristics
denser bones
deeper voice
more body hair
increased muscle mass
186
female sex hormones
estrogen and progesterone
187
progesterone
functions with estrogen to:
promote breast development
cause/regulate cyclic changes in uterine lining (menstrual cycle)
188
estrogen function
maturation of female reproductive organs (ovaries_
| secondary sex characteristics
189
female secondary sex characteristics
```
decr bone density
higher voice
decr muscle mass
decr body hair
fat deposition in hips/breasts
```
190
sex hormones feedback
regulated by gonadotropin (FSH and LH)
| negative feedback mechanism
191
pineal gland
located in epithalamus
| produces melatonin
192
pinealocytes
components of pineal gland that produce melatonin
193
melatonin
promotes drowsiness
inhibits sexual maturation (helps time puberty)
inhibited by sunlight
194
thymus
located in thorax
aka party hat of heart
decreases in size with age
195
hormones of thymus; what is their function?
thymoproteins, thymic factor, thymosins
| all linked to development of T lymphocytes (for immunity)
196
ANP
hormone produced by heart
| inhibits aldosterone; increases urine production
197
erythropoietin
hormone produced by kidneys
| stimulates RBC production
198
cholecalciferol
hormone produced by skin
| inactive form of vitamin D
199
hormones produced by placenta
estrogen, progesterone, and hCG
| influence embryo development
200
hCG
human chorionic gonadotropin
detected in pregnancy test
produced by placenta
201
leptin
hormone produced by adipose tissue
| increases energy expenditure; decreases appetitie
202
which endocrine glands does mesoderm lead to?
adrenal cortex and gonads
203
which endocrine glands does ectoderm lead to?
amino acid based hormones
