Repro Flashcards
1
Q
GnRH
A
Gonadotropin releasing hormone
2
Q
GnIH
A
Gonadotropin inhibiting hormone
3
Q
PIH
A
Prolactin-inhibiting hormone
4
Q
Pulsatile release
A
hormones are released every few hours, not constantly
5
Q
The attainment of puberty is controlled by ________ and ______
A
gene expression and repression
6
Q
The castration of a male will result in ______ levels of LH/FSH
A
increased
7
Q
Why does castration lead to increased LH/FSH levels in the male?
A
No negative feedback
- no testosterone = no neg. feedback to hypothalamus
- no inhibin = no neg. feedback to anterior pituitary
8
Q
Castrated bull
A
steer
9
Q
castrated horse
A
gelding
10
Q
castrated sheep
A
wether
11
Q
castrated pig
A
barrow
12
Q
castrated goat
A
wether
13
Q
When is the hypthalamo-hypophyseal-gondal axis established?
A
at puberty
14
Q
There are two specialized centers of the hypothalamus that are related to sexual differentiation and imprinting of the brain.
A
tonic center
surge center
15
Q
The female hypothalamus has both the ___ and _____ centers; while the male hypothalamus only has ______
A
tonic and surge; tonic
16
Q
GnRH is synthesized as a _______ protein
A
precursor
92 aa
17
Q
GnRH is cleaved to ______ and ______
A
- GnRH
- GAP - 56 aa-assoc protein
18
Q
GAP function?
A
inhibits prolactin secretion
19
Q
Why can GnRH not be measured in the blood?
A
degraded by proteolysis a few minutes after its release
20
Q
How do we know GnRH is released in a pulsatile manner?
A
B/c we can measure LH release, which is stimulated by GnRH release
21
Q
If the pulses of GnRH are too frequent, how does this affect LH release?
A
decreases LH release d/t desensitization of GnRH receptors
22
Q
Where is the GnRH pulse generator located?
A
arcuate nucleus of the mediobasal hypothalamus
23
Q
What controls the frequency and amplitude of the GnRH pulse?
A
spontaneous activity of pulse generator
24
Q
Stimulation of GnRH Secretion (3)
A
- low levels of sex steroids (androgens and estrogens)
- high levels of estrogens at certain threshold
- catecholamines
25
High levels of estrogens at certain threshold stimulate GnRH secretion by acting on _____ centers
surge
26
Inhibition of GnRH Secretion (4)
- Progesterone and Androgens (high levels)
- Corticotropin releasing hormone (CRH) and opioids
- autocrine regulation of GnRH production
- GnIH
27
In mammals, synthesis and secretion of GnIH is stimulated by _________
estradiol
28
Where is GnIH secreted?
neurons in hypothalamus and septal area
29
How does GnIH work in mammals? (2)
Release into:
- hypthalamic region containing GnRH neurons to inhibit GnRH release directly
- median eminence = from here it reaches pars distalis to inhibit gonadotropin release
30
Physiological Effects of GnRH (4)
- stimulates synthesis and release of LH
- stimulates synthesis and release of FSH
- regulates turnover of its own receptors on gonadotrophs
- GnRH present in the pre-optic region is involved in mating behavior
31
Clinical Stimulation of Reproductive Function using GnRH
- synchronization of cattle
| - initiation of ovulation
32
Clinical Inhibition of Reproductive Function using GnRH
- fertility control in pets and wildlife
| - polycystic ovarian disease
33
Hourly injection of GnRH stimulates production of gonadotropins which _______ reproductive process
stimulates
34
Frequent administration of GnRH (long term use) results in ________ of gonadotropin production
inhibition
35
Follicle Stimulating Hormone (FSH) and Lutenizing Hormone (LH) are __________
gonadotropins
36
T/F: The alpha subunit is identical in LH, FSH, Thyroid stimulating hormone (TSH), and human chorionic gonadotroping (hCG)
True
37
The _____ subunit of gonadotropins has specificity.
beta
38
Half-life of LH?
10 minutes
39
Physiological Effects of LH - Females (Direct Effects)
- ovulation
- theca cells = testosterone production
- corpus lutem = develpment and progesterone production
40
Physiological Effects of LH - Females (Indirect Effects)
- estrogen production
| - maintenance of pregnancy -progesterone
41
Physiological Effects of LH - Males (Direct Effects)
- Leydig cells
| - Steroid hormone production
42
Physiological Effects of LH - Males (Indirect Effects)
- spermatogenesis
- male reproductive tract
- accessory sex glands
43
________ is a protein of 46-50 aa in length that is synthesized in osteoblasts
Osteocalcin
44
Osteocalcin stimulates the production of _______, independent of LH pathway
testosterone
45
FSH production is under the control of _____
GnRH
46
What is the half-life of FSH?
40 hours
47
FSH is ______ glycosylated as compared to LH
heavily
48
In mares, FSH goes by this name
PMSG = pregnant mare serum gonadotropin
49
Physiological Effects of FSH - Females
- follicle development, growth, and maturation
- estradiol synthesis during follicular phase
- superovulation
50
What is superovulation?
development of more than the usual number of mature follicles
51
Physiological Effects of FSH - Males
- Sertoli cells = synthesis of 3 things
- initiation/re-initiation of spermatogenesis
- spermiation
52
What is synthesized by Sertoli cells that have been stimulated by FSH?
- ABP = antigen binding protein
- inhibin
- estradiol
53
T/F: The feedback regulation of LH is less complex than FSH.
True
54
Half-life of prolactin
10 minutes
55
Effect of Prolactin is on an _______ organ - hence why it does not have a feedback response like other things.
EXOCRINE
56
Physiological Effects of Prolactin in Females
- mammary gland development and milk production
- non-lactational aspects = maintenance of CL in rodents, dogs, and skunks
- social behavior
57
How does prolactin affect mammary gland development and milk production?
- induces lobuloalveolar growth
| - stimulates lactogenesis after parturition
58
Two other things prolactin works in relation with for mammary gland development and milk production?
insulin and cortisol
59
What is a non-lactational aspect of prolactin?
maintenance of CL in rodents, dogs, and skunks
60
What social behaviors are related to prolactin?
- nest building
| - retrieval of scattered offspring
61
Negative Regulation of Prolactin Secretion
- dopamine
| - GnRH Associated Protein (GAP)
62
Positive Regulation of Prolactin Secretion
- PRH
- TRH
- GnRH
- VIP
- Estrogen
- Spinal Reflex (stimulation of teats)
63
Physiological Effects of Oxytocin - Females (4)
- stimulation of milk ejection (myoepithelial cells)
- stimulation of uterine smooth muscle contraction
- establishment of meternal behavior
- induction of PGF2-alpha synthesis in uterus (species dependent effect)
64
Physiological Effects of Oxytocin - Male (2)
- facilitation of sperm transport
| - acts on myoid peritubular cells = for sperm transport in teh seminiferous tubules
65
Positive regulation of Oxytocin
- tactile stimulation
| - sex steroid hormones
66
How does Tactile Stimulation have a positive regulation on oxytocin?
stimulation of teat sends neurosignal to the hypothalamus to release oxytocin from post. pituitary
67
How do sex steroid hormones have a positive regulation on oxytocin?
At parturition - burst of oxytocin is triggered by decline in plasma progesterone levels, and cervical and vaginal stimulation by the fetus
68
What is the affect of acute stress on oxytocin?
stress triggers the release of catecholamines by adrenal glands. Catecholamines inhibit oxytocin release
69
Steroid hormones are ________ derivatives
cholesterol
70
How does cholesterol get in the body? (2)
- synthesized by liver
| - absorbed from the diet
71
Where are steroid hormones produced?
mainly in gonads and adrenal glands
72
Cholesterol being made into pregnenolone by desmolase is the ___________
rate-limiting step
73
T/F: Newly synthesized hormones are stored in the cells until they are needed
FALSE!!!!!!
Steroid hormones are rapidly secreted and not stored in the cells
74
Steroid hormones have ________ solubility in aqueous solutions. Why?
limited; they are lipophilic
75
At the target tissue, an ______ exists between bound and free steroid hormone.
equilibrium
76
_______ converts testosterone to estradiol
aromatase
77
_________ converts testosterone to dihydrotestosterone
5-alpha reductase
78
How do human males have estradiol in their bodies?
d/t expression of aromatase in adipose tissue
79
Number of carbons in testosterone?
19
80
Number of carbons in estrogen?
18
81
Number of carbons in progesterone?
21
82
Environmental factors that can affect reproducion
- Rainfall = food
- Temperature = summer vs. winter
- Photoperiod = long day vs. short day
83
what are pheromones?
chemicals that allow communication among animals through the vomeronasal organ
84
Maintenance of the CL in rodents, dogs, and skunks is d/t what?
Prolactin
85
When does oogenesis occur?
In pre-natal stages (during fetal development)
86
The ovaries of the newborn will only have primordial follicles. Follicles are arrested in the ___________ stage
dictytate
87
What does dictyate mean?
a stage in the development of oocytes which are arrested at the same stage of meiotic prophase
88
In the ______ phase of growth and differentiation, only oogenesis occurs.
prenatal
89
Folliculogenesis occurs during the ________ phase
prepubertal
90
Folliculogenesis and oogenesis both occur during the _________ phase
pubertal
91
What initiates transition from primordial to primary follicles? (positive impact) (5)
- kit ligand (KL)
- leukaemia inhibitory factor (LIF)
- bone morphogenic proteins (BMP)
- keratinocyte growth factor (KGF)
- basic fibroblast growth factor (bFGF)
92
What inhibits the transition from primordial to primary follicles?
Anti-mullerian hormone (AMH)
93
Do all follicles become Graafian follicles?
No
94
What is generally the initiation for follicular atresia?
lack of support signal
95
More than ________% of follicles and oocytes degenerate during germ cell development
60
96
________ follicles constitute the higher proportion of follicles that undergo atresia
Antral
97
__________ estrous cycles are required for a follicle to go from primordial to Graafian
10
98
What are the 2 patterns of follicular development?
- dominant, ovulatory-size follicles develop through the estrous cycle
- dominant, ovulatory-size follicles develop only during follicular phase
99
Which species have ovulatory-size follicles developing throughout the estrous cycle?
- cattle
- sheep
- horse
100
Which species have ovulatory-size follicles developing only during the foliicular phase?
- primates
- pigs
- rats
101
cAMP is transferred from the follicular granulosa cells to the ooctye. How does the levels of cAMP affect the oocyte maturation?
- high levels of cAMP = inhibits oocyte maturation
| - low levels of cAMP = stimulate oocyte maturation
102
Does the 1st meiotic division split equally?
No - the 1st polar body that is released in this split has little cytoplasm
103
In what stage is a secondary oocyte arrested until fertilization?
M II stage
104
__________ production increases within the follicle in teh pre-ovulatory phase and is highest at the time of LH/FSH surge
estrogen
105
Low levels of ______ have positive feedback on FSH and LH secretion in females
estrogen
106
High levels of _____________ (at certain thresholds) has positive feedback on LH secretion (LH surge)
estradiol
107
VERY high levels of estradiol have __________ feedback on FSH and LH secretion
negative
108
____________ required for ovum maturation
estrogen
109
In some species (cow and sheep), _____________ is luteolytic
estradiol
110
____________ causes growth and development of oviducts for gamete transport
estrogen
111
This substance can
- increase cervical mucus secretion
- increase oxytocin receptor numbers in the endometrium
- increase prostaglandin synthesis at term
- cause duct and stromal tissue growth and development in the mammary glands
ESTROGEN!
112
4 characteristics of small luteal cells
- have LH-receptors
- are highly stimulated by LH
- make little basal progesterone
- have few receptors for PGF2-alpha
113
4 characteristics of large luteal cells
- NOT responsive to LH
- produce progesterone spontaneously
- have tonically active PKA (protein kinase A)
- have more receptors for PGF2-alpha
114
What hormone inhibits uterine contraction, causes development of mammary glands during pregnancy, and stimulates development of uterine secretory glands?
Progesterone
115
This hormone prevents estrus
Progesterone
116
Progesterone acts primarily at the hypothalamus and ____________ LH/FSH secretion
inhibits
117
At the end of ____________, levels of progesterone __________, which has a positive feedback on FSH and LH.
diestrus; decrease
118
Female site of gametogenesis
ovaries
119
site of fertilization and cleavage?
oviducts
120
site of fetus development
uterus
121
How is the female internal reproductive tract suspended from the dorsolateral body wall?
broadligament
122
How many parts are there to the broad ligament? What are they?
3
- mesovarium = to the ovary
- mesosalpinx = to the uterine tube
- mesometrium = to the uterus
123
What is a bipartite uterus?
the 2 uterine horns fuse together before opening into cervix
124
What is a bicornuate uterus?
the 2 uterine horns openly separately into the cervix
125
Perimetrium
- outermost later
| - continuous with ligament
126
Myometrium
-outer longitudinal muscle layer
blood vessels
-inner circular layer
127
Endometrium
- simple epithelium consisting of simple columnar ciliated cells and secretory cells
- simple tubular glands
128
In cows and ewes, certain regions in the endometrium are highly vascular and lack glands. These areas have structures called ____________ that serve as attachment sites for ______________________.
caruncles; cotyledons of the embryo
129
Where is semen deposited in mares?
in the uterus
130
In most species, semen is deposited in the __________ or in the _________
anterior part of the vagina; cervix
131
T/F: The vagina has true glands
FALSE
132
What kind of epithelium lines the vagina?
stratified squamous epithelium
133
__________ is provided by cervical mucus and vestibular glands
vaginal lubrication
134
Vestibular glands in females are like ________ in males.
Cowper's glands
135
________________ is the common duct for reproductive and urinary systems
Vestibule
136
Describe winking in mares
Closing and opening of lower part of vulva - a sign for stallion that mare is ready for mating
137
Phases of the Estrous Cycle
- Estrus
- Metestrus
- Diestrus
- Proestrus
138
What is the longest phase of the estrus cycle?
diestrus
139
How many phases are in the estrous cycle for cats?
2 - estrus and interestrus
140
Proestrus
- begins with the regression of CL
- decrease in progesterone production
- extends to the start of next estrus phase
141
During proestrus phase, the follicles rapidly grow. Growing follicles produce low levels of what hormone?
estrogen
142
Estrogen released from the growing follicles promotes what? (4)
- growth
- vascularity
- edema of the endometrium
- cornification of vaginal epithelium
143
The vascularity of the endometrium reaches its peak about _________ after the end of estrus
1 day
144
_____________ induce cervical relaxation and dilation, as well as increase cervical mucus secretion
Estrogen
145
What induces behavioral symptoms of the approaching estrus phase as the proestrus phase ends?
increased plasma estradiol levels
146
When might a female animal have a silent estrus?
- 1st ovulation during puberty
- 1st post-partum ovulation
- 1st ovulation after beginning of the breeding season
147
When does ovulation occur in the cow?
10-12 hours after the end of estrus
148
When does ovulation occur in the ewe?
mid-late estrus
149
When does ovulation occur in the sow?
mid-estrus
150
When does ovulation occur in the mare?
1-2 days before the end of estrus
151
What species has the longest estrus phase?
mare
152
Animals that ovulate at every estrus are called ____________
spontaneous ovulators
153
Animals that ovulate only if mating occurs are called _____________
induced or reflex ovulators
154
Examples of induced or reflex ovulators
cat, rabbit
155
Most species have estrus phases that last several hours. Which species is it common for the estrus phase to last 4-8 days?
Horses
156
In the _____ phase, the ruptured follicles are transformed into CL.
metestrus
157
In the cow and doe, ovulation occurs during ____________
metestrus
158
T/F: The dog DOES NOT have a metestrus phase
True
159
Diestrus Phase (2)
- fully functional CL
| - increase in plasma progesterone levels
160
In the pig, the CL also produces ______________
relaxin
161
During the ________ phase, the uterus is prepared for implantation and pregnancy
diestrus
162
If pregnancy does not ensure, the CL regress and stop synthesizing ______________
progesterone
163
Hormone that stimulates growth and development of oviducts for gamete transport?
Progesterone
164
stimulates proliferation and secretory activity of E. glands?
Progesterone
165
Inhibits myometrial contractions?
Progesterone
166
Decreases estrogen receptors in the uterus?
Progesterone
167
Increaes cervical mucus consistency and maintains functional closure of the cervix?
Progesterone
168
________________ inhibits estrogen-induced vaginal cornification
Progesterone
169
Cycle only once in a year?
monoestrous
170
Cycle throughout the year?
polyestrous
171
Cycle only during breeding season?
seasonally polyestrous
172
Termination of the CL by a luteolytic agent, ______, of uterine origin
PGF2-alpha
173
MECHANISM of transport of PGF2-alpha from uterus to ovary
Ovarian artery is in close contact with uterine vein
PGF2-alpha diffuses from uterine vein to the ovarian artery
174
Which species has systemic transport of PGF2-alpha?
the horse
175
T/F: PGF2-alpha in not released in spikes during pregnancy
True
176
MECHANISM of Action of PGF2-alpha on CL
- causes dramatic decrease in blood flow (min)
- increases additional oxytocin release (min)
- causes decrease in progesterone production (h)
- complete regression of CL in 1-2 days, leaving corpus albicans
177
T/F: A persistent CL is defined as prolongation of the luteal phase beyond diestrus that lasts 1-5 months
True
178
Reasons for Persistent CL
1. failure of uterus to produce PGF2-alpha
2. Two reasons in horses
- inadequate production of PGF2-alpha by uterus
- occurrence of diestrus ovulation around day 14 when PGF2-alpha is normally releasead
179
Two reasons for persistent CL in horses
- inadequate production of PGF2-alpha
| - occurrence of diestrus ovulation around day 14 when PGF2-alpha is normally released
