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Physiology of Reproduction > Exam 2 > Flashcards

Exam 2 Flashcards

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1
Q

What do estrous and menstrual cycles provide females with?

A

Repeated opportunities to become pregnant

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2
Q

When does the estrous cycle begin?

A

After puberty

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3
Q

What is the estrous cycle?

A

A series of predictable reproductive events beginning at estrus and ending at the subsequent estrus

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4
Q

What is anestrus?

A

A period of ceased cyclicity

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5
Q

What are some causes of anestrus? (6)

A 
Pregnancy
Lactation
Season
Poor nutrition 
Stress
Pathology
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6
Q

What is estrus? (2)

A

A noun

time of sexual receptivity, “heat”

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7
Q

Is estrous a noun or adjective?

A

Adjective

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8
Q

What does it mean if an animal is polyestrus?

A

Uniform distribution of estrous cycles throughout the entire year

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9
Q

What animals are polyestrus? (4)

A

Cattle
Swine
Cats
Rodents

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10
Q

What does it mean if an animal is seasonally polyestrus?

A

They display clusters of estrous cycles that occur during certain times of the year

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11
Q

What animal(s) are short-day breeders?

A

Sheep and goats

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12
Q

What animal(s) are long-day breeders?

A

Mare

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13
Q

What does it mean if an animal is monoestrus?

A

They have one cycle per year

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14
Q

What animals are monoestrus? (4)

A

Dog
Wolf
Fox
Bear

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15
Q

What are the phases of the estrous cycle?

A

Follicular

Luteal

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16
Q

What is the follicular phase?

A

Period from regression of CL to ovulation

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17
Q

What is the dominant structure in the follicular phase? Hormone?

A

Follicles

Estrogen

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18
Q

What is the luteal phase?

A

Period from ovulation to CL regression

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19
Q

What is the dominant structure in the luteal phase? Hormone?

A

Corpus luteum

Progesterone

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20
Q

How much of the cycle is in the luteal phase?

A

80%

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21
Q

What are the stages of the estrous cycle?

A

Proestrus
Estrus
Metestrus
Diestrus

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22
Q

What is the main event of proestrus?

A

Formation of ovulatory follicles and estradiol secretion

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23
Q

How long does proestrus last?

A

From CL regression to estrus

2 to 5 days

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24
Q

What does LH and FSH cause in proestrus?

A

Transition from progesterone dominance to estradiol dominance

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25
What is the main event of estrus?
Sexual receptivity and peak estradiol secretion
26
What is the dominant hormone of estrus?
Estradiol
27
How long is estrus?
Ranges from hours to days
28
What is the main event of metestrus?
CL formation and the beginning of progesterone secretion
29
When does metestrus occur?
From ovulation to the formation of CL
30
What are the levels of E2 and P4 like during metestrus?
Low
31
How long is metestrus?
2 to 5 days
32
What is the main event of diestrus?
Sustained luteal secretion of progesterone
33
How long does diestrus last?
10 to 14 days
34
What is the shortest stage of the estrous cycle?
Estrus
35
What is the longest stage of the estrous cycle?
Diestrus
36
What is the reproductive classification of a cow?
Polyestrus
37
What is the mean length of estrous in a cow?
21 days
38
What is the mean length of estrus in a cow?
15 hours
39
What is the time from onset of estrus to ovulation in a cow?
24-32 hours
40
What is the time from LH surge to ovulation in a cow?
28 hours
41
What is the reproductive classification of a ewe?
Seasonally polyestrus (short day breeders)
42
What is the mean length of estrous in a ewe?
17 days
43
What is the mean length of estrus in a ewe?
30 hours
44
What is the time from onset of estrus to ovulation in a ewe?
24-30 hours
45
What is the time from LH surge to ovulation in a ewe?
26 hours
46
What is the reproductive classification of a mare?
Seasonally polyestrus (long day breeders)
47
What is the mean length of estrous in a mare?
21 days
48
What is the mean length of estrus in a mare?
7 days
49
What is the time from onset of estrus to ovulation in a mare?
5 days
50
What is the time from LH surge to ovulation in a mare?
2 days
51
What is the reproductive classification of a sow?
Polyestrus
52
What is the mean length of estrous in a sow?
21 days
53
What is the mean length of estrus in a sow?
50 hours
54
What is the time from onset of estrus to ovulation in a sow?
36-44 hours
55
What is the time from LH surge to ovulation in a sow?
40 hours
56
What are the stages of estrous in a dog?
Anestrus Proestrus Estrus Diestrus
57
What is superfecundation?
Multiple oocytes ovulated over time, so multiple sires are possible
58
What are the stages of estrous in a cat?
``` Proestrus Estrus Postestrus Diestrus Anestrus ```
59
What is an induced ovulator?
Copulation is required for induction of LH surge
60
What is postestrus?
Occurs when copulation/ovulation did not occur
61
What does anestrus result from?
Insufficient GnRH release
62
When does anestrus occur?
During pregnancy and after parturition until uterus involution occurs
63
What is silent ovulation?
The first ovulation after anestrus is not accompanied by estrus behavior
64
Why is there no estrus behavior after the first ovulation?
The first CL produces P4 to increase estrogen sensitivity. When the second ovulation produces E2,behavioral estrus is present
65
How does photoperiod affect reproduction?
When light hits the retina, the secretion of melatonin is inhibited, so short day breeders have an increase of GnRH (cyclicity) and long day breeders have a decrease of GnRH (anestrus)
66
What is lactation anestrus?
Controlled by suckling. 2 or fewer promotes the return of cyclicly and more than 2 causes anestrus
67
What is menses?
Sloughing of the endometrium to the exterior
68
What are the phases of the menstrual cycle?
Proliferative phase | Secretory phase
69
What is the proliferative phase?
Menses occurs and the endometrium begins to thicken
70
What is the secretory phase?
P4 increases which causes the endometrium to proliferate and thicken for embryo
71
Summarize the follicular phase. (4)
Initiated after luteolysis when P4 is reduced P4 no longer has a neg. feedback on hypothalamus, resulting in increased FSH and LH release Follicles develop and produce E2, which has a pos. feedback on hypothalamus Inhibin is released, which suppresses FSH
72
What are the 4 main events of the follicular phase?
Gonadotropin release from anterior pituitary Follicular preparation for ovulation Sexual receptivity Ovulation
73
What does the follicular phase consist of?
Proestrus and estrus
74
What is the hypothalamic nuclei?
Anatomically discrete regions formed by clusters of nerve cell bodies
75
What are the 4 processes in follicular dynamics?
Recruitment Selection Dominance Atresia
76
What is atresia?
Irreversible degenerative process
77
What percentage of follicles of through atresia?
90%
78
What are follicular waves?
Due to growth in the presence of P4, therefore, will not ovulate and instead go through atresia
79
What does FSH do for follicles?
Follicle recruitment
80
What does LH do for follicles?
Follicle development
81
What does estrogen do? (6)
``` Increased blood flow Genital swelling Leukocytosis Increased mucosal secretion Initiation of uterine gland growth Elevated myometrial tone ```
82
What are the steps to estrogen synthesis? (5)
1. LH binds to LH receptors on theca interna 2. Causes cholesterol to be converted to testosterone 3. Testosterone diffuses out of theca interna and into granulosal cells 4. FSH binds to FSH receptors on granulosal cells 5. Causes testosterone to be converted to E2
83
What does ovulation result from?
A cascade of events that begins with an LH surge
84
What is hyperemia?
Increased blood flow to ovary and dominant follicle
85
Read through ovulation in chapter 8 notes. Summarize as if needing to write an essay
Read through ovulation in chapter 8 notes. Summarize as if needing to write an essay
86
What are the 4 phases of oocyte maturation?
Mitotic division of primordial germ cells Nuclear arrest Cytoplasmic growth Resumption of meiosis
87
When does mitotic division occur?
Prenatally
88
What does the last mitotic division result in?
Meiotic prophase, which then arrests
89
What brings the oocyte out of dormancy?
Stimulation from the gonadotropins after puberty
90
What forms during the formation of zona pellucida? What do they allow?
Junctional complexes | Communication between oocyte and granulosal cells
91
What mediates oocyte growth?
Granulosal cells
92
What is the zona synthesized from?
Mucopolysaccharide material from the oocyte
93
What initiates meiosis?
LH surge
94
How is the first polar body formed? When?
Chromosomes line up and separate and form first polar body | Just before ovulation
95
How is the second polar body produced? When?
Second meiotic division | After fertilization
96
What estrous phases is the luteal phase made up of?
Metestrus and diestrus
97
When does the corpus hemorrhagicum appear?
After follicular rupture during ovulation
98
When is the corpus hemorrhagicum observed?
From ovulation until day 1 to 13 of estrous cycle
99
What happens as luteal tissue increases?
Bloody appearance clears and corpus luteum forms
100
What is luteinization?
Process whereby cells of ovulatory follicles are transformed into luteal tissue
101
What is the corpus luteum controlled by?
LH
102
What are thecal cells considered?
Small luteal cells
103
What are granulosal cells considered?
Large luteal cells
104
How long does the CL increase in size?
About midway through luteal phase
105
What are large and small luteal cells classified as?
Steroidogenic (produce steroids)
106
What do only large cells consist of?
Secretory granules that secrete oxytocin and relaxin
107
Do large cells increase in size or number?
Size
108
Do small cells increase in size or number?
Number
109
What are the target organs of progesterone?
Hypothalamus Uterus Mammary gland
110
What does P4 stimulate?
Secretion from endometrium
111
What does P4 inhibit?
Motility from muscular myometrium
112
What does progesterone require?
Basal LH
113
What is P4 formed from?
Cholesterol
114
What does P4 prevent?
Preovulatory follicles Production of E2 Behavioral estrus Preovulatory surge of GnRH and LH
115
What is luteolysis?
Disintegration of the CL
116
When does luteolysis begin?
After trigger of PGF2α from uterus
117
What transports PGF2α to the ovary?
Vascular countercurrent exchange mechanism
118
Explain process of PGF2α to ovary
PGF2α released into uterine vein and diffuses into ovarian artery. The artery caries it to the ovary
119
Why does the vascular countercurrent exchange mechanism exist?
Because PGF2α has a short half-life
120
When do pulses of PGF2α begin?
During the second half of the luteal phase
121
How is the CL regressed? (3)
PGF2α causes vasoconstriction, which decreases blood flow to CL PGF2α causes breakdown of capillaries PGF2α bonds to large luteal cells and causes them to die
122
What are the prerequisites to sperm production? (3)
Adequate secretion of GnRH from hypothalamus FSH and LH secretion from anterior pituitary Secretion of testosterone and estrogen
123
What are leydig cells analogous to?
Theca internal cells in follicles
124
What kind of receptors do leydig cells have?
LH
125
What happens when LH binds to leydig cells?
P4 is produced which is converted to testosterone
126
How is LH released?
In pulses, 4 to 8 per day lasting 10 to 20 minutes
127
When exposed to a lot of LH, what do leydig cells have? Why?
A refractory period because LH has a negative feedback on its own receptors
128
Since testosterone has a negative feedback on GnRH, how must it be released? Why?
In pulses so that GnRH secretion does not get shut off, which would prevent spermatogenesis
129
What are sertoli cells analogous to?
Granulosal cells in follicles
130
What do sertoli cells do?
Convert testosterone to estradiol
131
What increase the function of sertoli cells?
FSH
132
What is spermatogenesis?
All cellular transformations dealing with developing germ cells
133
Where does spermatogenesis occur?
Seminiferous tubules
134
What are the 3 phases of spermatogenesis?
Proliferation phase Meiotic phase Differentiation phase
135
What is the main event of the proliferation phase?
All mitotic divisions and the replacement of stem cells
136
What is the main event of the meiotic phase?
Primary and secondary spermatocytes are formed | DNA replication and crossing over occurs
137
What is the result of the meiotic phase?
Haploid spermatids
138
What is the main event of the differentiation phase?
Undifferentiated spherical spermatid transforms into a typical shaped differentiates spermatozoa
139
Do cell divisions occur in the differentiation phase?
No
140
What does sperm consist of?
Head containing nuclear material Flagellum Principal piece
141
What is mitosis?
The cell divisions occurring in which the daughter cell nucleus receives the full set of chromosomes
142
What is meiosis?
The cell divisions occurring in developing germ cells in which the daughter cell nucleus receives half the number of chromosomes found in somatic cells
143
What are the 4 phases of the differentiation phase?
Golgi Cap Acrosomal Maturation
144
What is the main event of the golgi phase?
Acrosomic formation
145
What is the main event of the cap phase?
Acrosomic vesicle spreading over the nucleus
146
What is the main event of the acrosomal phase?
Nuclear and cytoplasmic growth
147
How much of the anterior nucleus does the acrosome cover?
2/3
148
What is the main event of the maturation phase?
Final assembly that forms spermatozoan
149
What does the head of sperm consist of?
Nucleus Acrosome Post-nuclear cap
150
What does the tail of the sperm consist of?
Middle piece Principal piece Terminal piece
151
What is spermiation?
Release of sperm from sertoli cells into lumen of seminiferous tubule
152
What is spermiation analogous to?
Ovulation
153
What is an acrosome?
Membrane-Bound lysosome that contains hydrolytic enzymes
154
What are enzymes require for?
Penetration of oocyte
155
What is an acrosome reaction?
A series of events that releases enzymes that digest zona pellucida
156
What is the sperm tail?
A self-powered flagellum
157
What is the sperm tail composed of?
Capitulum Middle piece Principle piece Terminal piece
158
How do males produce gametes?
Continuously and uniformly
159
Do seasonal breeders make gametes uniformly?
No
160
How many stages are in the cycle of the seminiferous epithelium?
8
161
How long does it take to get through the 8 stages of the cycle of the seminiferous epithelium in the bull?
13.5 days
162
How long is the process from spermatogonia to the formation of fully differentiated in a bull?
61 days
163
What is a spermatogenic wave?
The wave of spermiation along the tubule
164
How can you make estimations about sperm production?
Total number of sperm ejaculated in an ariticfical vagina with daily ejaculation for 2-3 weeks Testicular size
165
In a stallion and boar, what is used to estimate sperm production?
Scrotal width or length
166
In a bull and ram, what is used to estimate sperm production?
Scrotal circumference
167
What is fertility determined by? (5)
Sperm producing ability Viability of spermatozoa Number of morphologically abnormal spermatozoa that he ejaculates Number of functionally normal sperm that he ejaculates Ability for intromission and ejaculation
168
In order to perform fertilization, what must the sperm be like?
Alive and highly motile
169
What is motility?
Ability of sperm to swim progressively forward
170
What is the most commonly used assessment of viability?
Motility
171
How is motility expressed?
As a percentage of sperm that are swimming within a given environment
172
How many sperm are produced per second?
200,000
173
What is the normal percentage to have abnormal sperm?
5-15%
174
At what percentage of abnormal sperm is there reduced fertility?
More than 20%
175
What are 2 assessments made on sperm?
Motility and morphology
176
What are other things that could be wrong with sperm?
Abnormal nuclear composition Abnormal biochemical composition Surface protein deficiency Faulty response to female reproductive tract
177
What are the stages of male reproductive behavior?
Precopulatory Copulatory Postcopulatory
178
What happens during the precopulatory stage? (5)
``` Search for sexual partner Courtship Sexual arousal Erection Penile protrusion ```
179
What happens during the copulatory stage? (3)
Mounting Intromission Ejaculation
180
What happens during the postcopulatory stage? (3)
Dismount Refractory period Memory
181
What are 3 functions in the female for reproductive behavior?
Attractivity Proceptivity Receptivity
182
What happens during attractivity? What can help with this? (4)
Behaviors and other signals to attract males | Pheromones, vocalization, increased physical activity, and posture changes
183
What happens during proceptivity? What can help with this? (2)
Behaviors towards males that stimulate the male to copulate | Head butting and mounting the male
184
What happens during receptivity? What can help with this? (2)
Behaviors allowing males to copulate and ensure insemination Immobility and mating stance (lordosis)
185
Once a mate has been found, what courtship behaviors begin? (7)
``` Sniffing of he vulva Female urinate in presence of male Flehmen behavior Chin resting Circling Increased phonation Lordosis signals to the male that she is receptive ```
186
What animals are short copulators?
Bull, ram, buck, and tom
187
What animals are sustained copulators?
Boar, dog, and camelids
188
What kind of copulators are horses?
Intermediate
189
What is the refractory period?
The period of time during which a second copulation will not occur
190
When does sexual differentiation occur?
During embryogenesis when the brain is either feminized or not
191
What α-fetoprotein do?
Binds to estradiol and prevents it from crossing blood-brain barrier
192
What is reproductive behavior controlled by?
Central nervous system
193
What are the 3 sources of stimulation?
Auditory Visual Tactile
194
What are auditory sources?
Vocalization, particularly in long-range scenarios
195
What are visual sources? What do they do?
Sexual posturing | Increases time to ejaculation and concentration of sperm in semen
196
What are tactic sources?
Biting on the neck and withers, chin resting
197
In the female, where are pheromones?
In vaginal and urinary secretions
198
Where do boars produce a pheromone?
Saliva
199
What is the vomeronasal organ?
An accessory olfactory organ located past opening in roof of the mouth for flehman behavior
200
What is ejaculation?
Reflex expulsion of semen
201
What is ejaculation a result of?
Sensory stimulation from the glans penis , which causes a series of coordinated muscular contractions
202
What are important muscles involved with ejaculation?
Urethras Ischiocavernosus Bulbospongiosus
203
What does the release of oxytocin from the posterior pituitary do for ejaculation?
Causes contraction of smooth muscle around tail of epididymis and ductus deferens which transports sperm from tail to pelvic urethra
204
What does stimulation cause for ejaculation?
Nerve impulses to be transmitted to spinal cord, which activate nerves that trigger contractions of muscles, pushing semen into urethra
205
Why do some species exhibit homosexual like behavior? (2)
To signal to the male that female is in estrus | We have selected animals that show strong estrous behavior
206
What is most often used to collect semen?
Artificial vagina
207
What is electroejaculation?
Electrical stimulation of the accessory sex glands and pelvic urethra, which causes ejaculation
208
What are the 6 steps of fertilization?
1. Sperm must transverse the cervix 2. Be transported through the uterus to the oviduct 3. Undergo capacitation 4. Bind to the oocyte 5. Undergo acromsome reaction 6. Penetrate the zona pellucida and fuse with the oocyte plasma membrane where the sperm enters the oocyte cytoplasm and its nucleus decondenses
209
When has a successful fertilization take place?
When the male pronucleus is formed
210
What animals ejaculate into the vagina? (6)
``` Cow Sheep Rabbit Primates Dog Cat ```
211
What do pigs ejaculate into?
Cervix
212
Where do horses and camelids ejaculate into?
Cervical lumen where much of it goes into uterine body
213
What is the stallion's ejaculate like?
Bursts. The first few are highly concentrated with sperm
214
What is the boar's ejaculate like?
Large volume
215
What does estradiol cause the immune system to do?
Neutrophils to accumulate in the vagina and uterine mucosa
216
What do neutrophils do?
Attack foreign materials, including sperm
217
What happens 6-12 hours after the introduction of sperm?
There is a large migration of neutrophils from uterine mucosa into uterine lumen
218
What are the 2 phases of sperm transport?
Rapid transport phase | Sustained transport phase
219
What is the rapid transport phase?
Sperm reach oviduct a few minutes after copulation, but the sperm are not fertile
220
What is the sustained transport phase?
Sperm are transported to oviducts in a trickle-like effect from reservoirs in the tract
221
What assists with sperm transport? (2)
Contraction of muscularis and seminal fluids
222
What stimulates contractions?
Estradiol
223
What increases sperm concentration?
Prostaglandins in semen
224
What are the 2 types of mucus produced in the cervix of a cow?
Sialomucin | Sulfomucin
225
What is sialomucin?
A mucus of low viscosity produced by cells in the basal areas of the crypts
226
What is sulfomucin?
A mucus of high viscosity produced in the apical portions of the epithelium covering the tips of the cervical folds
227
What happens to sperm that swim into sulfomucin?
They get stuck and get flushed out
228
What happens to sperm the swim into sialomucin?
They swim through
229
What triggers capacitation?
The female reproductive tract
230
What does capacitation involve?
Stripping of the various proteins that cover the sperm
231
As sperm moves into the oviduct, what happens?
They become hyperactive
232
What happens to the motility of sperm as they move to the oviduct?
The switch from swimming in a straight line to a frenzied circular motion
233
What is the primary zona binding region responsible for?
Adherence
234
What is the second binding site?
Acrosome reaction promoting ligand
235
What is the acrosomal reaction?
An orderly fusion the spermatozoa plasma membrane and the outer acrosomal membrane
236
What is the purpose of the acrosomal reaction? (2)
Reaction enables sperm to penetrate the zona pellucida | Exposes the equatorial segment so that it can fuse with the plasma membrane of the oocyte
237
When does the acrosomal reaction begin?
When plasma membrane of sperm forms multiple fusion sites with the outer acrosomal membrane of the sperm which forms vesicles
238
What happens in the acrosomal reaction after vesicles form?
The acrosomal contents are dispersed and the sperm nucleus is left with the inner acrosomal membrane surrounding it
239
What does the acrosomal reaction release?
Enzymes that allow sperm to digest its way through the zona pellucida
240
What is acrosin?
An enzyme that hydrolyzes zona proteins and enhances sperm's ability to bind
241
What is proacrosin?
The inactive form of acrosin with a strong affinity for the zona
242
What is the penetration of zona assisted by?
Flagellar action
243
What is the cortical reaction?
A reaction that occurs which creates a zona block so that more sperm cannot penetrate
244
What is polyspermy?
When more than one sperm penetrate
245
What is the vitelline block?
A reduction in the oocyte plasm membrane's ability to fuse with additional sperm and prevents polyspermy
246
What happens to the sperm nucleus after fertilization?
It decondenses
247
What does the sperm nucleus become after fertilization?
Male pronucleus
248
What is the fertile life-span of sperm in reptiles?
5 years
249
What is the fertile life-span of sperm in dogs?
9-11 days
250
What is the fertile life-span of sperm in camelids?
4-5 days
251
What is the fertile life-span of sperm in a cow?
1.5-2 days
252
What is the fertile life-span of sperm in a mare?
4-5 days
253
What is the fertile life-span of sperm in a woman?
5-6 days
254
What is the average percent that pregnancy will occur when copulation occurs within 2 days of ovulation?
33%
255
What is the cascade of events in fertilization? (8)
``` Hyperactive motility Binding to zona pellucida Acrosomal reaction Penetration of zona pellucida Sperm-oocyte membrane fusion Sperm engulfed Decondensation of sperm nucleus Formation of male pronucleus ```

Physiology of Reproduction (3 decks)

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