Ch 80, 81, 82 Flashcards
(265 cards)
1
Q
What are 3 different ways of sexual differentiation?
A
genetic sex, gonadal sex, phenotypic sex.
2
Q
What is genetic sex?
A
male- XY, Female- XX
3
Q
What is gonadal sex?
A
Males- testies. Females- ovaries.
4
Q
What is phenotypic sex?
A
Determined by action of hormones produced by gonads during fetal life.
5
Q
What will the paramesonephric duct become in females?
A
Fallopian tubes, uterus and part of vagina.
6
Q
In males what will the mesonephric ducts become?
A
Connections between testis and prostate: epididymis, vas deferens, semial vesicles.
7
Q
What leads to the development of female genital tract and genitalia?
A
Lack of testosterone and MIS (which are produced by the fetal testies).
8
Q
In females high levels of androgens before external genitals have differentiated can result in what?
A
Male phenotype or malformation.
9
Q
Where is GnRH synthesized at?
A
In the hypothalamus.
10
Q
How will the hypothalamus release GnRH?
A
In vesicles from the median eminence in a pulsatile fashion through the hypothalamohypophyseal portal blood.
11
Q
GnRH reaches the anterior pituitary gland and binds to what?
A
membrane receptors on gonadotrophs.
12
Q
How is synthesis and secretion of GnRH regulated?
A
By feedback control from gonadal hormones.
13
Q
Besides gonadal hormones how will the synthesis and secretion of GnRH regulated?
A
stress, pheromones, light/dark cycles.
14
Q
What is the general functions of the gondaotrophes (LH & FSH)?
A
Promote gametogenesis, and gonadal hormone secretion.
15
Q
LH and FSH are active in who males or females?
A
Both.
16
Q
What happens to levels of LH and FSH in a fetus and why?
A
We get a spike of these hormones so there are more gonadal hormones secreted to help with development.
17
Q
What are levels of LH and FSH like in childhood?
A
Low with no spikes.
18
Q
What are levels of LH and FSH like during puberty?
A
They gradually increase.
19
Q
What are levels of LH and FSH like during the adult reproductive period?
A
Females- rises and falls monthly. Males- levels off.
20
Q
What is Senescence?
A
Growing old or aging. The period after the adult reproductive period.
21
Q
What are levels of LH and FSH like during senescence?
A
Females- rises fast and then levels off. Males gradually rises
22
Q
During gestation GnRH is secreted when?
A
Week 4.
23
Q
Secretion of GnRH starts during week 4 of gestation and remains low until when?
A
Puberty.
24
Q
During gestation secretion of FSH and LH begins when?
A
Week 10-12.
25
Secretion of FSH and LH begins during week 10-12 of gestation and remains low until when?
Puberty.
26
What levels are higher in childhood FSH or LH?
FSH.
27
What is puberty?
Transition from non-reproductive to reproductive state.
28
Puberty is an essential event due to what?
Pulsatile secretion of GnRH.
29
During puberty what level is higher LH or FSH?
LH.
30
During puberty plasma levels in females increase with what?
Estrogen and inhibin.
31
During puberty plasma levels in males increase with what?
Testosterone and inhibin.
32
Responsiveness of target cells to gonadal hormones that increase at puberty leads to what?
Secondary sex characteristics.
33
The ovaries produce what during puberty?
Estradiol.
34
What is menarche?
Onset of menstrual cycles.
35
When will female growth spurts be at?
between 11-14 years old.
36
During male puberty what cells will proliferate?
Leydig cells.
37
What are the 3 major functions of the male reproduction?
1. Regulation and synthesis and secretion of hormones. 2. speratomgenesis. 3. Sexual act.
38
What are the 2 jobs of the testes?
Produce sperm, and secrete hormones.
39
What hormone will the testes mainly secrete?
Testosterone.
40
What are the 2 compartment of the testes and what cells are found in the compartments?
1. Connective tissue interstitium- leydig cells. 2. Seminiferous tubules- sertoli cells.
41
The Leydig cells found in the connective tissue intersitium of the testes do what?
They are the primary endocrine area.
42
What cells produce sperm?
Sertoli cells.
43
What is inner male genitalia?
The prostate.
44
How many lobes does the prostate have?
Five.
45
What will the prostate produce?
A thin alkaline milky fluid.
46
What is an out-pocketing of the vas deferens?
The semial vesicles.
47
What % of semen is from the semial vesicles?
70%.
48
What is the semen like that is secreted from the seminal vesicles?
Energy for sperm because it is rich in fructose, citric acid and prostaglandins.
49
What are the male hormones secreted by the testes called?
Androgens.
50
What is the major Androgen?
Testosterone.
51
Leydig cells make up what % of testes mass?
20%.
52
Testoternone and FSH leads to what?
Spermatogenesis.
53
What % of andorgens come from leydig cells and where else can they come from?
95% from leydig cells and 5% can come from adrenals.
54
Androgens are what type of compounds?
Steroid.
55
How is dihydrotestosterone synthesized?
From testosterone in some target tissues.
56
What is androstenedione?
a precursor of testosterone with 1/10th the activity.
57
Testosterone is released on a diurinal pattern and is high when and low when?
High- morning . Low-night.
58
What will testosterone levels be like as a fetus and why?
High to masculinize the external genitalia.
59
What happens to testosterone levels after birth?
They are low until puberty when they start to ramp up and then they level off as an adult and then start to decline around age 60.
60
What causes testosterone levels to drop off around 60 years of age?
The leydig cells lose responisveness to LH.
61
What are the results of testosterone levels droping off at age 60?
Loss of libido, but spermatogenesis still occurs.
62
What is an androgen?
A male sex hormone.
63
What % of androgens circulate in blood bound to proteins?
97-98 percent.
64
Since most of the androgens are bound to proteins in the blood how long will they last before they are transferred to target tissues or degraded?
30 minutes to several hours.
65
What is the major protein that the androgens will bind to?
Sex hormone-binding globulin, and some to albumin.
66
2-3 % of testosterone in the blood is unbound and is active and will be converted to what in target tissues by what?
Converted to dihydrotestosterone by 5-alpha reductase.
67
Excess testosterone is exreted how?
Through liver via bile or kidneys via urine.
68
What part of target cells will testosterone bind to?
Cytoplasmic receptors since it is a steroid hormone and can pass through the cell membrane.
69
Once testosterone binds to receptors in the cytoplasm of target tissues what happens?
Testosterone will then enter the nucleus and affects DNA-RNA transcription, translation and protein production.
70
Where will testosterone stimulate production of proteins?
Almost everywhere in the body.
71
What will the proteins do that were made by testosterone stimulation?
These proteins are then responsible for various actions of the androgens like primary and secondary sex characteristics.
72
Many target tissues of testosterone have enzymes that convert it to active metabolites. What will aromatase and 5 alpha-reductase convert testosterone into?
Aromatase- E2 (estradiol). 5-alpha reductase- dihydrotestoterone.
73
In utero what week will testosterone and metabolites start to be produced?
Week 7.
74
In utero what will stimulate the secretion of testosterone and metabolites?
hCG from the placenta.
75
What will stimulate the descent of the testis?
hCG that will increase the fetal secretion of testosterone and metabolites.
76
Testosteron is responsible for what during puberty?
Development of primary and secondary sex characteristics.
77
What will testosterone do to muscles during puberty?
Increase size by 50% at puberty.
78
What will make a males voice get deeper during puberty?
Tesosterone secretion that enlarges the larynx and thickens the vocal cord.
79
What will promote the secretion of male genital tract (prostate and seminal vesicles)?
Testosterone and metabolites.
80
What effects on the skin will testosterone and the metabolites have?
Increases thickness of skin over entire body.
81
What will testosterone do to the BMR?
Increase it up to 15%.
82
FSH most directly controls what?
Spermatogenesis.
83
In early fetal life the fetal gonadotropins transform primordial germ cells into what?
Speratogonia.
84
What type of receptors do spermatogonia have and what activates them at puberty?
They have FSH receptors and are stimulated by FSH.
85
What will testosteron do to inhibin?
Stimulate secretion in a minor role.
86
Sertoli cells envelop spermatogonia and then the spermatogonia does what?
Enlarges to become primary spermatocyte.
87
What happens to primary spermatocytes?
They undergo meiotic division to become secondary spermatocytes with 46 chromosomes.
88
What happens to secondary spermatocytes?
They divided and become spermatid with 23 chromosomes.
89
What will spermatid become?
Spermatazoa.
90
How long will the development from spermatogonia to spermatozoa take?
70 days.
91
How much sperm is produced each day by a male?
70-100 million.
92
Where and how long will it take sperm to mature?
2 weeks in the epididymis.
93
The number of sperm produced is directly related to what?
Number of sertoli cells.
94
What role will GH have in spermatogenesis?
Controls metabolic function of testis and aids in division of spermatogonia.
95
Semen is made of what % of fluids from where?
vas deferens-10%. Prostate- 30%. Seminal vesicles-60%.
96
What is the average pH of semen?
around 7.5
97
What will decrease viscosity of semen to increase motility?
Fibrinolysin from prostate gland.
98
What makes up the head of a sperm?
Condensed nucleus a thick cap (acrosome) filled with proteolytic enzymes to aid in fertilization.
99
What is the flagellum of sperm for?
Back and forth movement creating motility.
100
Sperm can be stored in the vas deferens of the testes for how long?
Up to 1 month.
101
How long can sperm live for in female?
24-48 hours.
102
Sperm can be frozen for how long?
Years.
103
Each month females develop an ova in the ovaries that goes where when?
Midcycle expulsion of this single ovum from ovary into ABDOMINAL CAVITY.
104
When will GnRH be released from the Hypothalamus?
pulses every 90 minutes in males and females.
105
How will GnRH secretions change during the monthly cycle?
It will not.
106
In females when will the anterior pituitary gland start to secrete FSH and LH?
At puberty.
107
What are granulosa cells?
Cells that provide norishment for ovum.
108
What will granulosa cells secrete?
Oocyte inhibiting factor
109
What will oocyte inhibiting factor do?
Keep ovum in primordial state until stimulated by FSH at puberty.
110
What type of receptors do granulosa cells have?
LH and FSH.
111
GnRH is secreted when during fetal development?
Midgestation and drop off before birth.
112
When will plasma levels of estradiol increase?
During puberty.
113
Increased estradiol causes what?
Growth and development of the female reproductive tract.
114
What is the first sign of secondary sec characteristics in females?
Budding breasts.
115
How long after increased estradiol causing growth and development of the female reproductive tract until menarche?
about 2 years.
116
What happens to estrogen levels in adulthood?
High and cyclic and correlate with the menstrual cycle.
117
What causes menopause?
Burn out of the ovaries when few follicles remain to be stimulated by FSH and LH.
118
What happens to secretion of estradiol during menopause?
Ovarian secretion virtually ceases.
119
What happens to Plasma levels of FSH and LH during menopause?
The levels rise due since there is no estrogen and progesterone to provide negative feedback of FSH and LH secretion.
120
FSH caused what to happen in the ovaries?
Growth of 6-12 ovum into primary follicles.
121
Further growth of primary follicles is caused by what?
Estrogen.
122
Granulosa cells are more sensitive to what?
FSH.
123
Only 1 follicle matures each month and is called what?
Mature follicle.
124
Ovulation depends on what?
A surge of LH.
125
When will ovulation occur?
14 days after 1st day of menses.
126
When will there be a surge of LH?
2 days before ovulation.
127
When will the surge of LH peak?
16 hours before ovulation.
128
LH converts granulosa and theca cells to what after ovulation?
Progesterone
129
When will estrogen and progesterone be secreted?
Estrogen days 0-14. Progesterone- 14-28.
130
When an ovum is ovulated it is surrounded by what?
Thosands of granulosa cells called the corona radiata.
131
After ovulation the remaining follicular cells do what?
They become lutein cells.
132
What causes the remaining follicular cells to become lutein cells?
LH.
133
What do lutein cells do?
They enlarge and fill with luteinization.
134
What are lutein cells with luteinization called?
Corpus luteum.
135
What cells produce progesterone?
Granulosa cells.
136
Theca cells produce what?
Androgens (testosterone).
137
What happens to the androgens produced by theca cells?
Most is converted by granulosa cells to female hormones.
138
What is Mittelschmertz?
Pain in the middle of the ovulation cycle.
139
What happens after ovulation to body temperature?
Basal body temperature rises.
140
When will the corpus luteum involute with no pregnancy and why?
12 days after ovulation due to low FSH and LH..
141
What are corpus luteums called after they involute?
Corpus albicans.
142
What happens to corpus luteums during pregnancy?
The placenta hCG causes the Corpus luteum to persist for 2-4 months.
143
Once the corpus luteum involutes what causes menstruation?
The Corpus luteum is no longer secreting inhibin, estrogen, and progesterone which are inhibiting the secretion of FSH and LH and once LH and FSH secretions increase again this will start a new cycle.
144
What is the most important estrogen?
Estradiol aka E2.
145
What is the most important progestin?
Progesterone.
146
What are the general functions of estrogens?
Promote growth and development of genital tract and secondary sex characteristics.
147
What are the general functions of Progestines?
Prepare the uterus for pregnancy and breast for lactation.
148
What type of receptors will Estrogens and progestins use and why?
Intracellular receptors because they are steroid hormones.
149
How will estrogens and progestins work together?
They complement or enhance each others actions.
150
Can estrogens and progestins antagonize each others actions?
Yes.
151
From what are estrogens and progestins derived?
Cholesterol.
152
What is the Follicular phase?
Progesterone and testosterone are synthesized 1st and before being secreted they are converted to estrogen by granulosa cells.
153
What is the Luteal phase?
Too much progesterone is secreted to be completely converted to estrogen so serum levels rise.
154
Synthesis of progesterone and estrogen is a function of what 3 cells in ovum?
Theca, granulosa, and corpus luteum.
155
What converts testosterone into estrogen?
Aromatase.
156
Will males have aromatase?
No.
157
98% of estrogen and progesterone circulate bound to what proteins?
Albumin and SHBG.
158
How tightly are the proteins boudn to estrogen and progesterone?
Loose so the hormones are easily and rapidly relesed into tissues.
159
How long will it take for estrogen and progesterone to be released into the tissues?
30 minutes.
160
Where is the primary and secondary sites for degradation of ovarian steroids?
Primary- Liver into bile. Secondary- Kidneys for urine secretion.
161
What else will the liver do to Estradiol?
Converts it to E1 and E3.
162
How active is E3?
almost inactive.
163
Most estrogen comes from \_\_\_A\_\_\_ and small amounts come from \_\_\_B\_\_\_, except in pregnancy where large amounts come from \_\_\_C\_\_\_\_.
A- Ovary. B-adrenal cortex. C-Placenta.
164
E2 is the most potent estrogen, but E1 comes from where and is how potent?
1/12 as potent as E2 and comes from peripheral conversion of adrenal/ovarian testosterone.
165
E3 is how potent and comes from where?
1/80 as potent as E2 and comes via oxidation of E1 and E2 in the liver.
166
What will estrogen do to the ovaries during puberty?
Promote follucular growth (granulosa cells).
167
What will estrogen do to the uterus during puberty?
Stimulate growth and proliferation of endometrium with its glands and spiral arteries.
168
What will estrogen do to the vagina during puberty?
Creates stratified epithelium that is resistant to trauma and infection, and reduces the pH.
169
What will estrogne do to the fallopian tubes?
Promotes growth of glandular and ciliated epithelial cells, promotes ciliary action.
170
What is required for growth and maintenance of external female genitalia?
Estrogen.
171
What will estrogen do to breasts?
Promotes growth of the ducts and deposition of adipose.
172
What will estrogen do to cervical mucus?
make it thinner, copius, elastic and less acidic.
173
Will estrogen have a general catabolic or anabolic activity?
Anabolic.
174
What type of anabolic activity will estrogen cause?
Increse of cell metabolism and BMR, and deposition of subcutaneous fat.
175
What type of effect will estrogen have on skeletal growth?
Inhibit osteoclastic activity and stimulate bone growth.
176
What leads to osteoporosis post menapause?
almost no estrogen secretion and this increases the osteoclastic activity and decreases the bone matrix and deposition of calcium.
177
What will estrogen do to skin?
Increase the thickness.
178
What will estrogen do to the kidneys?
Cause sodium and therefore water to be retained.
179
What effects will estrogen have on the CNS?
Increased Libido, social behavior, mood.
180
Estrogen in excess causes what?
Severe cramps, severe nausea or edema during pregnancy or menses, enlarged uterus, fibrocystic breasts, menorrhagia.
181
What will estrogen deficiency cause?
scant menses, small uterus, small breasts, mid cycle spotting.
182
What are the 2 types of progesterone and what do they do?
1. Progesterone- most important progesterone. 2. 17-alpha-hydroxyprogesterone- same effects as progesterone.
183
In non pregnant females when will progesterone be secreted?
During last half of monthly cycle by corpus luteum.
184
In pregnant females when and from where will progesterone be secreted?
From the placenta in large amounts especially during the 4th month.
185
What effects will progesterone have on the endometrium?
Increases secretory changes to prepare uterus for implanation.
186
What effects will progesterone have on the uterus?
It will decrease contractions to prevent expulsion of implanted ovum.
187
What effects will progesterone have on the fallopian tubes?
Promotes secretion needed for nutrition of fertilized ovum as it travels through.
188
Will progesterone help maintain pregnancy or not?
It will help maintain a pregnancy.
189
What will progesterone do to basal temperature?
It will increase it by 0.3-0.5 degrees C.
190
What will progesterones effects of the CNS be?
Increased appetite, decreased wakefullness, increased sensitivity to carbon dioxide.
191
What happens with excess progesterone?
edema, bloating, headache, depression, weight gain, tiredness, hypertension with varicose veins.
192
What happens with progesterone deficiency?
Similar to anovulatory cycles, prolonged menses, heavy menses, severe cramps, luteal spotting.
193
What happens during days 1-13 of a 28 day ovarian cycle?
Follicular growth.
194
What happens on day 14 of a 28 day ovarian cycle?
Ovulation.
195
What happens during days 15-24 of a 28 day ovarina cycle?
Corpus luteum growth.
196
What happens during days 25-28 of a 28 day ovarian cycle?
Luteal degeneration.
197
What days of a 28 day ovarian cycle will menses occur on?
days 1-4.
198
When will the proliferative phase be?
Days 5-14.
199
What phase happens during days 15-28?
Secretory phase.
200
What is the average age of menarche in the US?
12.77 years.
201
How long will the average ovarian cycle be?
21-35 days.
202
How long will flow occur with menses?
3-5 days on average but up to 7 days.
203
How much flow will occur in a day?
Up to 80ml/day.
204
What will levels of FSH and LH look like during an ovarian cycle?
Low besides the midcycle spike of LH.
205
What will levels of progesterone and estrogen be like during an ovarian cycle?
Estrogen- Slowly builds up until before ovulation and then drops down and levels off relativley high. Progesterone- is very low until after ovulation when it spikes until the end of the ovarian cycle when it drops off again.
206
What will regulate the changes in endometrium, and secretion of FSH and LH?
Estrogen and progesterone.
207
Day 1 of an ovarian cycle marks what?
The 1st day of menses.
208
What hormone levels rise during day one and why?
FSH rises because estrogen and progesterone decrease and this induces follicular growth or the proliferative phase.
209
Once follicular growth has been induces what will stimulate the follicle to grow?
The theca cells secrete testosterone which is converted to E2 by aromatase and the E2 promotes follicular growth.
210
E2 will promote what else besides just follicular growth?
Growth of the uterine lining.
211
What happens as the follicles begin to mature?
They create lots of inhibin which is a negative feedback to the anterior pituitary gland and secretion of FSH.
212
What type of feedback in general will E2 have with the anterior pituitary gland?
Negative.
213
What happens midcycle with increasing E2 levels?
It has a positive feedback that stimulates the high LH and FSH (lower than LH) secretion.
214
What will the spike of LH and FSH (less than LH) do during the midcycle?
They lead to ovulation at day 14, and formation of a corpus luteum.
215
How long after ovulation will it take to develop a corpus luteum?
10-18 hours.
216
What will the corpus luteum do?
Increases secretion of progesterone and estrogen (less than progesterone).
217
What happens with progesterone and estrogen secretions during the luteal phase?
They send a high negative feedback inhibiting LH and FSH.
218
Where will negative feedback of corpus luteum secretions (estrogen, progesterone, and inhibin) go to?
Hypothalamus, and anterior pituitary gland.
219
How will hormonal contraceptives work?
They work on a negative feedback to anterior pituitary gland to inhibit FSH and LH preventing ovulation.
220
What other effects will hormonal contraceptives have?
Thickenes cervical mucus, and alters endometrial lining so implanation is unlikely.
221
Without implantation what happens 7-8 days post ovulation?
Regression of corpus luteum.
222
What % of ovulated ova make it from the abdominal cavity to the fallopian tubes?
98% of them.
223
Of the half a billion sperm inserted how many of them make it to the ovum?
A few thousand.
224
How long will it take for a fertilized ovum to travel to the uterus?
3-5 days.
225
What will help relax the smooth muscle of the fallopian tubes to help facilitate ovum transportation?
Progesterone.
226
When will implantation occur (days after ovulation)?
5-7 days.
227
What will trophoblast cells do?
Provide nutrition and aid in implantation and form fetal part of placenta.
228
Implantation depends on what levels of estrogen and progesterone?
Low estrogen and high progesterone.
229
What will the placenta secrete?
hCG, Estrogens, progesterone, hCS.
230
hCG secreted by the placenta chemically resembles what?
LH.
231
hCG is secreted by what and how long after implanation?
originally secreted by syncytiotrophoblast cells 2-3 days after implantation.
232
hCG will show up in urine how long after implantation and what is the use of this?
8-9 days after implantation and this is used as a pregnancy test.
233
What is the secretion of hCG like during pregnancy?
It reaches a maximum around weeks 10-12 when the corpus luteum stops secreting and the placenta takes over. Then the levels of hCG drop off from weeks 16-20 and remain low.
234
What is the function of hCG?
To inform the corpus luteum that a pregnancy has occurred and to prevent it frominvoluting until the placenta is ready.
235
Will the corpus luteum secrete hCG?
No the syncyitiotrophoblasts which will later become the placenta.
236
hCG directs the corpus luteum to secrete what?
Progesterone, estrogen, and inhibin.
237
The corpus luteum during pregnancy will do what 3 things?
1. Maintain uterine lining by inhibiting menstruation. 2. Promote endometrial growth and storage of nutrients. 3. Suppresses new follicular development.
238
hCG will do what to the maternal breasts?
Encourages development of alveoli.
239
What will hCG do to fetal gonads?
Males- it encourages the development of interstial cells and increases testoterone production for male genitalia growth. Females- nothing.
240
What is hCS?
a polypeptide hormone secreted by the placenta.
241
When will the placenta secrete hCS?
about week 5 of pregnancy.
242
How will secretion levels of hCS increase?
As the placenta increases.
243
hCS is secreted in what type of quantities?
Many times greater than other pregnancy hormones.
244
What will hCS do to breasts?
Partial development of breasts.
245
hCS is similar to what hormone?
GH but much weaker action on protein tissues.
246
What will hCS do to insulin?
decreases the bodies insulin sensitivity and decreased glucose utilization in mother making more glucose available to the fetus.
247
In early stages of pregancy progesterone is secreted by the corpus luteum and then after week 12 it is synthesized by what?
Syncytiotrophoblast of placenta.
248
During pregnancy how much more progesterone will be around?
10 fold increase.
249
Progesterone is produced from what?
Circulating maternal cholesterol.
250
What converts the cholesterol to progesterone?
The placenta.
251
What will progesterone do to the uterus during pregnancy?
Develops decidual cells important for nourishment, decreases contractions to avoid a spontaneous abortion.
252
Estrogen is produced where during pregnancy?
After the corpus luteum from the syncytiotrophoblast cells of the placenta.
253
What is needed to synthesize estrogen?
DHEA.
254
What is DHEA?
A weak androgen produced in maternal and fetal adernals.
255
Most DHEA comes from where?
Fetal adrenals.
256
DHEA is transported in the blood to the fetal liver and then to where?
Placenta.
257
What will the placenta do with DHEA?
Make E1, E2, and E3.
258
What is the general role of estrogen during pregnancy?
Enlargment fo uerus, breasts, external genitalia. RELAXATIN of pelvic ligaments.
259
What will supply food stuff for the fetus?
The placenta.
260
What will the placenta aid in?
diffusion of oxygen and removal of CO2.
261
When will the placenta secrete steroid hormones?
During the 2nd and 3rd trimesters.
262
What happens to the anterior pituitary gland during pregnancy?
It enlarges 50% increasing CRH, TRH, and prolcatin.
263
What happens to the thyroid gland with pregnancy?
It enlarges 50% increasing T4 productin.
264
Relaxin will be secreted by what?
Corpus luteum and then the placenta.
265
What will increase uterine contractions?
Oxytocin synthesized in the hypothalamus and secreted by the posterior pituitary gland.
