Repro Test 2 Review
1. What is the start of puberty dependent on? It requests what to mature and to support what?
2. Puberty is required for what production? Does it differ between male and female? What things influence it?
3. What sign in females means puberty has begun? (definition) 4. What sign in females/definition means they are sexually mature?
5. What two things impact development of the hypothalamic GnRH neurons in the female?
6. What is the first definition of puberty in males?
7. What is the second definition of puberty in males?
8. What is the third definition of puberty in males?
9. What is the surge center responsible for? Tonic?
10. What is the structure that connects the hypothalamus with the AP? 11. What prevents reproductive sexual maturation in the body?
12. What causes females to have an active surge center and not males? All hypothalamus’s start off as a? We also discuss several other topics like What happened to the anasazi?
13. What does LH need from the surge center? After puberty, how does this differ in males and females?
14. What type of feedback is occurring when estrogen feedback is low? High? What does high estrogen cause?
15. What is the limiting factor of the maturation of the hypothalamus?
16. What does GnRH do with age in the male and female? Therefore, puberty is a ___ process.
17. In the female, what happens during maturation of the hypothalamus? 18. What is the fundamental requirement for puberty?
20. Explain maturation of the hypothalamus in males.
21. Explain maturation of the hypothalamus in females.
22. Label sequence chart of maturation of hypothalamus in females
23. Before puberty there is low ____ and ____ secretion. __ pulse frequency is also low. Low ____ from the ovaries and no ____ on _____ GnRH center. With age, _____ rises, ____/___ rises, ______ ________ rises, ___ feedback estrogen rises and _____ rises. An ____ surge causes ovulation.
24. What has the least amount of estrogen receptors tonic center or surge center?
25. What is the function of glands? Name three and what they secrete. 26. Is the ovary a gland? Don't forget about the age old question of What is ir theory?
27. Name the three major things that effect hypothalamus maturation.
28. When it comes to genetics, what two things effect the onset of hypothalamus maturation? What type is typically more delayed and give an example.
29. When it comes to nutrition, what about it is what triggers/controls when puberty will/ can occur?
30. If you have extra nutritional characteristics like fat what does it do to puberty onset? Restricted amounts?
31. Explain the metabolic signals that occur in puberty. Review flow chart page 8 of slides.
32. What two things affect the hypothalamus control of GnRH secretion? Moment to moment regulation of GnRH only occurs when what is available? If you want to learn more check out What types of religious specialists have anthropologists classified?
33. What is leptin? What are they from?
34. When it comes to metabolic signals in puberty, what two things are involved in it and what are they directed by?
35. Leptin concentration is directly related to what?
36. What are the two leptin receptors?
37. What is leptin possible associated with? It has an association with what two other things as well?
38. Why do we interfere to modify age at onset of puberty?
39. What can we do to modify age at onset of puberty?
40. What are two environmental cues that will cause hypothalamus maturation?
41. What two sensory neurons notify the hypothalamus of these environmental factors?
42. Optic and olfactory cues translate stimuli to hypothalamus and tell it to do what? What types of feedback can it cause and what will each feedback cause?
43. Explain the difference between spring born ewes and fall born ewes when it comes to onset of puberty.
44. Season of birth is present in ____ but not ____. What effect does it have on a Bitch? Queen?
45. What is the social cue of puberty in animals?
46. What are pheromones?
47. Explain how the vomeronasal organ works. Don't forget about the age old question of What is the slope factor?
48. In swines, what is the social cue that stimulates the onset of puberty?
49. When swines are in large groups what effect does this have on puberty? Small groups? Male exposure?
50. Heifers with high growth rate compared to moderate have a more accelerated or delayed onset of puberty? What about moderate with a bull? High with a bull?
51. What is spermatogenesis?
52. What is spermiogenesis?
53. What is spermiation?
54. What three endocrine requirements must be met before spermatozoa can be produced?
55. Explain endocrine regulation for spermatogenesis starting with GnRH. 56. Explain why LH pulses are important and what occurs because of it. 57. What is secreted at the peak of LH secretions?
58. What four things do successful testis require?
59. For four things are required for production of normal number of fertile spermatozoa?
60. Label endocrine system of the male
61. Review diagram on page 205 of book
62. Label cell in testes
63. Sertoli cells are ___ dependent. It transfers testosterone to _____ (role unclear) Negative feedback on ______. Inhibin blocks ___.
64. Name the four general functions/goals of spermatogenesis. 65. Where does spermatogenesis occur?
66. What are the three phases of spermatogenesis?
67. Explain the proliferation phase (basal compartment).
68. Explain the mitosis.
69. Explain the meiosis phase.
70. Explain the differentiation phase.
71. What is the purpose of intercellular bridges?
72. What is the tight junction?
73. What is interstitial space?
74. Review flow diagram in notebook.
75. Explain the Golgi phase of differentiation
76. What is an acrosome?
77. Explain the Cap phase of differentiation.
78. What is acrosome reaction?
79. Explain the acrosomal phase of differentiation.
80. Explain maturation phase of differentiation.
81. Review structure of sperm tail pics in slides
82. What are the three reproductive behavior stages?
83. In males, what are the three precopulatory behaviors and explain each 84. In males, what is the copulatory act and how is it learned
85. In males, during copulatory behavior, what is emission? Intromission? Ejaculation?
86. In males, what are three parts of the post copulatory stage
87. Review male and female reproductive behavior charts. Just know basics of what each animal does and differences
88. In females, what are the three reproductive behaviors and explain each
89. Explain what impact the central nervous system has on sexual behavior. What reflex system does this relate too?
90. Explain pheromones in females
91. Explain how female pheromones initiate male behavior 92. Explain pheromones in males
93. What is vocalization? Give female and male examples.
94. Visual signals in females? Males? Give example for male 95. Males role in tactile stimulation. One example
96. Name the penile erection requirements
97. Review penile erection figure on page 238 of book
98. What is penile erection?
99. What is erotogenic stimuli?
100. What controls penile vascular muscle tone? (goes with erotogenic stimuli) 101. Review basic steps in erectile process diagram on page 239 of book 102. Explain vascular and biochemical control of erection
103. What is a flaccid penis?
104. What is NANC? What must be present for an erection?
105. What is occurring vascularly and biochemically in an erect penis? 106. What is the role of Viagra?
107. Copulatory behavior for males involves what three things and explain each. 108. Explain the process of emission starting from sensory stimulation 109. Explain the process of ejaculation
110. Give the sequence of fluid fractions in these 5 species: Ram & bull, Stallion, Boar and Dog
111. Explain the first stage coitus in dog copulation
112. Explain “the turn” in dog copulation
113. Explain the second stage coitus in dog copulation
115. What is the refractory period? What factors determine its length? 116. What is satiation?
117. What is exhaustion?
118. What are two ways that reproductive behavior can be enhanced? 119. What is the Coolidge effect?
120. What is sexual stimulation and what is its purpose?
121. What is sexual preparation, what is its purpose, and what are three approaches?
122. What is false mounting? Restraint? What does doing both result in?
123. For sit of semen deposition in natural mating, what animals are in the cranial vagina? Cervix? Cervical lumen of uterus?
124. For site of semen deposition in AI, where is it deposited in the mare, cow, and sheep? Sow? Dogs and cats?
125. What are two ways that sperm are lost from the female tract? 126. Explain phagocytes by neutrophils in the female vagina and uterus 127. What is the function of the cervix during fertilization?
128. In the cow, what are the two types of mucus secreted in the cervix and their roles
129. Cervix may be a filter that eliminates what?
130. What is the result of rapid transport?
131. What is the transport stage?
132. What must be present for tone to occur?
133. Explain capacitation
134. Explain how sperm bind to the zona pellucida
135. Label sperm head
136. Explain the acrosomal reaction
137. During the acrosomal reaction, what enzymes allow sperm to digest zona? Explain what how they do it. What happens in acrosomal reaction after that?
138. Explain fertilization of the oocyte
139. What is the cortical reaction and what does it prevent.
140. What is polyspermy?
141. What is decondensation of the sperm nucleus?
142. What is superfecundation?
Repro Test 2 Review Answers
1. Hypothalamus production of GnRH. Requests hypothalamus to mature to support oogenesis and spermatogenesis.
2. Gamete (testes, ovaries) production. Yes, response to E2. Genetics, environment, nutrition, season, social cues
3. First ovulation occurs (with or without estrus) and is at threshold body size 4. Able to support a pregnancy
5. Development of a threshold body size and exposure to certain environmental cues
6. Behavioral traits first expressed (mounting and erection, precedes sexual maturity)
7. First ejaculation. Coordination of nerves, muscles, seminal fluids. Substantially precedes ability to produce enough sperm for fertilization
8. Ejaculate contains threshold spermatozoa for fertilization 9. GnRH spikes, Basal GnRH secretions
10. PPP- primary portal plexus
12. Protein (alpha-fetoprotein) in female that is bound to estradiol, prevents estradiol from being able to enter the brain. In males they do not have that protein and it enters the brain creating testosterone which turns into estrogen/estradiol in the brain and causes the surge not to develop. “Female”
13. Secretion from the surge center to peak and induce ovulation. After puberty in males it stays a basal GnRH secretion with small LH spikes due to an undeveloped surge center than in the female causes GnRH secretion and large LH spikes which is what induces ovulation.
14. Negative. Positive. Makes hypothalamus secrete GnRH.
15. Ability of the hypothalamus to secrete enough GnRH (limiter of prepubertal animals) to induce LH spike.
16. Increase gradually. Gradual
17. Prepubertal pituitary and ovaries respond to exogenous GnRH, the mechanics (neurons) which switch from negative to positive feedback, are already in place when this occurs
18. Secretion of GnRH at appropriate frequencies and quantities to stimulate gonadotrophins release by pituitary
20. GnRH secreting neurons loose sensitivity to blocking estrogen so both estrogen and testosterone levels rise to inhibit GnRH secretion and enhance puberty
21. Low estrogen and negative feedback GnRH secretions switch to positive when estrogen levels increase in the body. Hypothalamic sensitivity to negative feedback by testosterone and estradiol decreases
23. Estrogen, GnRH. LH. Estrogen, feedback, tonic. Estrogen, LH/FSH, follicle development, positive, GnRH. LH.
24. Tonic center
25. Secrete hormones. Hypothalamus- Oxytocin & GnRH, Pituitary- FSH/LH, Gonads- Male-Sertoli and Leydig, Female- theca and granulosa
26. No, it’s a tissue
27. Genetics, nutrition, environmental cues
28. Age of puberty in male and female in various species; Influence of breed on age at puberty. Bos Indicus- cow
29. Body size of male/female, development of muscle, bone, fat/degree of fatness
30. Enhances puberty; delays puberty
31. GnRH neurons secrete GnRH which is regulated by Kisspeptin neurons. These are in contact with neurons that say how much glucose there is, fat, and leptin in the blood which then sends signals to the hypothalamus saying if body is or is not ready to start puberty
32. Glucose, free fatty acids. Glucose and fatty acids in the blood
33. Hormonal peptide, tells how much adipose tissue (fat) is in the blood stream. Adipocytes
34. Glucose and fatty acids; GnRH sensitive neurons positive LH release. Directed by level of nutrition
35. Amount of body fat (remember cow example wit increasing feed, increase puberty onset)
36. Anterior Pituitary and Hypothalamus
37. High LH secretion; fatness and onset of puberty
38. Higher production rates, produce more milk
39. Change the diet, select genetically advanced animals, and use sunlight/light to “trick” animal into thinking it is a different time of the year (spring)
40. Season of birth and social cues
41. Optic and olfactory sensory neurons
42. Start GnRH secretion. Positive feedback for puberty to start or negative feedback which will reduce GnRH secretion
43. Spring born ewes only have a 6 month long period before they start puberty due to the sunlight cue(long photoperiods) which stimulates it to start (reach in fall). Fall born ewes have to wait 6 months after being born until they reach spring then 6 months after that they will begin puberty due to the same cue.
44. Rams, bulls. Minimal seasonal effect on puberty. Increased photoperiod (more light) hastens onset of puberty
45. Olfactory recognition of pheromones in urine (rat, ewe, sow, and possibly cow)
46. Chemical compounds secreted by body, are volatile and detected by olfactory system of same species
47. It is on the roof of the mouth, its two dots that have fluid inside of them that travel to the nasal cavity to send signals to the brain
48. Dictated by number of gilts in a pen and exposure to intact males
49. Normal puberty onset. Delayed puberty onset. Accelerated puberty onset, can be physical or non-physical interaction, large and small groups
50. More accelerated. Even more accelerated than high growth without bull. Most accelerated
51. A process involving sequential mitotic and meiotic divisions and concludes after differentiation of spherical spermatids into highly specialized spermatozoa
52. Final product of meiosis (spermatid). Remodels sperm
53. New sperm leave Sertoli cells
54. Adequate secretion of GnRH from hypothalamus; FSH and LH secretion from the anterior lobe of the pituitary; Secretion of gonadal steroids (testosterone, estradiol)
55. GnRH is discharged from hypothalamus in intermittent episodes and target the Anterior pituitary. This causes discharge of LH which only occur 4-8times every 24 hours. LH secretions are high but short lived. Unlike the discharge of FSH which last longer due to constant secretion of inhibin and longer half-life. FSH targets Sertoli cells for production of inhibin and other hormones for spermatogenesis. LH targets the Leydig cells that synthesize progesterone and convert it to testosterone. The testosterone is then converted to estrogen by Sertoli cells.
56. LH pulses are related with GnRH pulses. Is important for normal testicular function. It prevents sustained concentrations of LH which would cause the Leydig cells to become refractory (unresponsive). If Leydig cell secretion is stopped and not coming periodically, severe down regulation of GnRH and LH feedback system occurs, and soon testosterone will run out, they will be infertile and spermatogenesis stops
58. Pulsatile GnRH secretion (4-6hours), High concentrations of testosterone in seminiferous tubules, low concentrations of testosterone in systemic blood, adequate LH receptors in Leydig cells
59. Endocrine regulation of testis, mitotic divisions of spermatogonia, meiotic divisions resulting in haploid spermatids, morphologic transformation of spermatids
60. Endocrine system of male
61. 205 review
63. FSH. Estradiol. Hypothalamus. FSH
64. Continual gamete supply vis stem cell renewal, provide genetic diversity, provide billions of sperm daily to maximize production, provide an immunologically privileged site so germ cells are not destroyed by immune system
65. Seminiferous tubules
66. Proliferation phase, meiotic phase, differentiation phase
67. All mitotic divisions of spermatogonia. A-spermatogonia undergo mitotic divisions which generate a large number of B-spermatogonia. An important part in this is the stem cell renewal which is where there is loss of intracellular bridges. Some type B cells continue on to meiosis but some also are replacements of the A1 spermatogonia. DIPLOID cells
68. 1 maternal and 1 paternal chromosome in the cell. They then duplicate and divide into two daughter cells
69. Start off as diploid cells. The cells undergo meiosis 1 which replicate the DNA through crossing over and homologous pairing which produce secondary spermatocytes. No two cells are alike! They then undergo meiosis 2 which produces HAPLOID (1N) spermatids
70. No further cell division take place. Transforms spermatids to spermatozoon (single sperm) which contains a head (nuclear material), flagellum with midpiece (mitochondrial helix) and principal piece. Has four phases: Golgi, Cap, Acrosomal, Maturation
71. To connect spermatogonia, spermatocytes or spermatids by intercellular bridges so the cytoplasm of an entire cohort is interconnected
72. Between Sertoli cells- blood testis barrier. If you destroy them, the male becomes infertile
73. Leydig cells, lymph, macrophages, blood vessels
74. Review notebook
75. Initial stage of acrosomal formation. Spermatids contain a golgi apparatus which is the intracellular packaging system in all secretory cells and gives rise to the acrosome. First, proacrosomic vesicles are formed and they fuse together to create a larger vesicle called acrosomic vesicle. Centrioles develop the tail out of
microtubules. The proximal centriole is the attachment point of the nucleus to the flagellum. The distal centriole creates the central portion (tail) or axoneme.
76. Bed of lipids with digestive hydrolytic enzymes inside that digest a pat through the “jelly coat” of the oocyte
77. The acrosomic vesicle flattens and “caps” the nucleus. The primitive flagellum (tail) grows from distal centriole and projects towards lumen of seminiferous tubules. Acrosome membrane formed (outer and inner), Production of hydrolytic enzymes (acrosin, hyaluronidase, zona lysin, esterases, acid)
78. Exocytosis during fertilization, digest zona pellucida
79. Nuclear and cytoplasmic elongation. Acrosome covers 2/3 of nucleus and nucleus elongates. Manchette microtubules form and become the postnuclear cap which helps the tail form. Neck and annulus form (junction between midpiece and principle) and spermatids become embedded in Sertoli cells.
80. Mitochondria form a spiral assembly around the flagellum which creates the midpiece. Completion of all tail parts (mid-piece, principal piece, terminal piece). Spermatid is now a spermatozoon and covered with a plasma membrane. Finally, spermatozoa released from Sertoli cells into lumen of seminiferous tubules (called spermiation)
81. Review sperm structure
82. Precopulatory behavior, copulatory behavior, post copulatory behavior
83. Search for a sexual partner (look for female signals)- use olfactory, visual, auditory and tactile responses. Courtship behaviors- sniffing vulva and phonation (female urination), Flehmen response, Sight (main drive, leads to sexual arousal). Sexual Arousal- erection and penile protrusion (CNS control).
84. Learned by behavior. Mounting a female that shows lordosis (mating posture, stands to be mounted)
85. Seminal fluid and sperm movement into pelvic urethral. Entrance of penis into vagina. Expulsion of semen into female tract
86. Dismounting, refractory period (no further copulation), Memory (positive and negative experiences)
87. Male and female reproductive behavior charts
88. Attractivity- behaviors that attract male like posture, vocalization, pheromones, and searching for a male (high physical activity). Proceptivity- female behaviors that encourage male to copulate- posturing with male, homosexual behavior. Receptivity- copulation behavior of female- limited duration in female, species variation
89. Sensory cues come in from visual, olfactory, auditory, or tactile stimulants which send signals to the hypothalamus. The hypothalamus must be sensitized to respond to sensory signals. In the male testosterone is aromatized to estrogen in
brain and promotes reproductive behavior. Constant hormone supply, initiates repro behavior at any time. In the female, excessive estrogen only prior to estrus (receptiveness). It then goes to the midbrain “receiving zones” where it acts on neurons and speeds up impulses. It then goes to the medulla which initiates postural adaptation for lordosis and mounting. It then goes to the to the spinal cord which generates signals to the muscles for lordosis and mounting. Simple neural reflex.
90. Vaginal and urinary secretions that serve to attract male. Secretions different: estrus female vs no estrus
91. Flehman response for short range investigative behavior. Characterized by head elevation and lip curling. Detect less volatile pheromones by vomeronasal organ
92. Produces sex pheromones which attract female. Boars have preputial pouch secretions, saliva secreted by submaxillary gland (foamy saliva, must odor). Stimulate sows in estrus. Dogs identify females in estrus by olfactory discrimination. Detect odors in vaginal secretions, urine, milk, blood
93. Auditory stimulation for long range signals indication sexual readiness. Females- cows increase bellowing, sows grunt with estrus, queens yeow. Males- beef and dairy increase bellowing, elk bugling during breeding season
94. Sexual posturing. Observe others mating increases stimulation. Semen collection in bulls via AV, have a warm-up period and increases number of sperm in ejaculate
95. Invokes sexual and/or standing posturing by females. Biting neck
96. Elevated arterial blood inflow, contractions of ischiocavernosus muscle, dilation of corporal sinusoids, restricted venous outflow, elevated intrapenile pressure, relaxation of the retractor penis muscle
97. Review penile erection figure
98. Complex series of neural and vasomotor events that are stimulated by extrinsic external and erotogenic stimuli
99. Increases stimulation of nerves in behavior center of hypothalamus 100. Neurons synapse with parasympathetic and sympathetic efferent neurons 101. Review diagram on page 239
102. Two dorsal-lateral corpora cavernosa plus corpus spongiosum. Corpus sinusoids are supplied by helicine arteries and deep dorsal vein and superficial vein drain erectile tissue
103. Sinusoids flatten due to adrenergic neurons secreting norepinephrine that causes vasoconstriction. Blood flow to the cavernous tissue is low so no erection. No erection stimuli is present so NANC neurons do not fire (release nitric acid)
104. Nonadrengenic noncholinergic parasympathetic neurons. Nitric oxide
105. Erotogenic stimuli is present and the NANC neurons fire and release nitric oxide. This activates guanylate cyclase which converts GTP to cGMP and causes sinusoids to relax and cause erection (vasodilation). The cavernous sinusoids engorge with blood and intracorporal pressure increases. This compresses venules and prevents exit of blood.
106. Inhibits cGMP to GTP by blocking action of PDE. Prolongs cGMP effect for prolonged erection, must be in erotogenic state. (review flow diagram)
107. Mounting- positions male for intromission. Intromission- entrance into vagina. Emission- movement of seminal fluid and sperm into pelvic urethra, occurs prior to and during ejaculation, driven by neuroendocrine reflex. Ejaculation- reflex expulsion of sperm/seminal plasma from tract, response to sensory stimuli (pressure & temp) on glans penis.
108. Emission is triggered by optic, olfactory, tactile or auditory stimulation. These send signals to the afferent neurons and to the spinal cord. From there it sends signals to the brain and stimulates the nerves in the supraoptic and paraventricular nuclei which signal the release of oxytocin from the posterior pituitary which cause contractions of the smooth muscle in tail of epididymis and transports sperm to ejaculatory position.
109. Starts with intromission, then the pressure and temp stimulation on the glans penis sends a stimuli response to the afferent neurons which send signals to the spinal cord to initiate motor neuron response to the urethralis, bulbospongiosus and ischiocavernosus muscles to contract suddenly and powerfully. This causes expulsion of semen.
110. Ram & bull- 1 fraction. Stallion- 2 fractions, First- sperm rich (3-4jets), Last gel (3-4jets). Boar- 3 fractions, First- accessory fluid, gelatinous pellets, few sperm, Second- sperm rich, Third- gel portion. Dog- 3 fractions, First- pre sperm, prostate (first stage coitus), Second- sperm rich, Third- prostate fluid (second stage coitus) during tie thought to push sperm rich fraction in
111. Male mounts female, female hold tail to the side and penis is introduced by several thrusts (intromission). Lasts for 1-2min, first and second fractions of semen are ejaculated
112. Transition between first and second stage. Male dismounts and turns around will lifting one leg over the female. Now facing away.
113. Now facing away in “the tie”, third fraction of semen is deposited, may last 5- 45min. The tie is kept by bulbus glandis on penis which is engorged with blood and contractions of muscles near base of penis keep the blood there. Along with sphincter muscles of vagina. This pushes semen into the uterus, and tie should never be broken or may compromise fertility and cause injury
115. Period before next ejaculation. Part of satiation rather than exhaustion. Degree of sexual rest prior to copulation, age and species of male, degree of female novelty, and number of previous ejaculations.
116. Further stimuli will not cause immediate responsiveness or motivation. Restimulation may occur after refractory period
117. No further sexual behavior can be induced, even with sufficient stimulation 118. Introducing novel stimulus animals and changing stimulus settings
119. Restoration of mating behavior in sexually satiated males, when original female is replaced by novel female.
120. The presentation of a stimulus that will achieve mounting and ejaculation. To obtain ejaculation or mating in the shortest time possible so that manpower involved in managing the mating is minimized.
121. Extending the period of sexual stimulation beyond what is needed for mounting and ejaculation. Its purpose is to prolong precopulatory stage of behavior and collect semen containing the greatest possible number of spermatozoa per ejaculation. False-mounting, restraint and both.
122. Deviating penis during a mount so that intromission can not occur. Prevents male from mounting even though he wants to. Results in the greatest improvement of spermatozoa output.
123. Cow, sheep, dog, cat. Rodents. Rodents: gel plug for vagina, prevents retrograde sperm loss. Pig- gel fraction, lowers retrograde sperm loss. Horse squirted through cervical lumen, gel fraction- lowers retrograde sperm loss
124. Transcervical. Intracervical. Intravaginal
125. Retrograde transport and phagocytosis by neutrophils
126. Female tract is under high estradiol influence during estrus and neutrophils are all in the mucosa of the vagina and uterus. Their job is to prevent microorganisms introduced during copulation from colonizing female tract. Unfortunally, it sees spermatozoa as foreign and they phagocytize or engulf spermatozoa. No real negative effect on fertility.
127. Barrier to spermatozoa (non-motile, abnormal, dead) transport and a reservoir for spermatozoa through mucus secretions.
128. Sialomucin- low viscosity, secreted by basal areas of cervical crypts. Creates “privileged pathways” for sperm to swim. Those that are not able to swim, are washed out by the sulfomucin- high viscosity, secreted by apical portion of cervical epithelium of crypts.
129. Non-motile spermatozoa
130. Elevated tone (level of contractions that repro tract has under estrogen) and motility of muscularis of the female tract. Usually non-viable and un-capacitated sperm
131. Sustained flow of viable sperm to oviduct in a “trickle like” effect from cervix to uterotubal junction. Sperm temporally “dock” in uterotubal junction (second reservoir) because it I the first region they encounter. Docking is important for sperm survival because it promotes viability.
132. Estradiol (female tract) and prostaglandins (semen)
133. Seminal plasma proteins on the sperm are stripped away by the female tract environment. Rate and location differs between species. Occurs during sperm transport of upper tract, fully capacitated in the oviduct and acquire hyperactive motility in ampulla which facilitates sperm-oocyte contact.
134. Zona pellucida has 3 glycoproteins (ZP1, ZP2, ZP3). ZP1 and ZP2 provide structural integrity of the zona. ZP3 has receptor like activity and binds to proteins on spermatozoal membrane, most important for fertilization. There are two binding regions, primary zona binding region and acrosomal reaction promoting ligand. The first binding site is responsible for adherence of sperm to zona. Second is when ARPL binds with ZP3 molecule and initiates acrosomal reaction
135. Sperm head
136. Is an orderly fusion of the spermatozoal plasma membrane and the outer acrosomal membrane. First vesiculation occurs which is when the plasma membrane forms multiple fusion sites with acrosomal membrane, two membranes fuse and form vesicles. After the reaction, the nuclear cap (acrosome) is open and fusion proteins are left on the outer layer.
137. Acrosin- hydrolyzes zona proteins and enhances the sperms ability to bind the zona. Proacrosin- inactive form of acrosin, aids in binding the spermatozoon to the zona as the acrosomal reaction proceeds. Flagellar action of tail moves sperm though zona, exposure of sperm equatorial segment occurs which fuses with oocyte plasma membrane and causes fertilization.
138. Spermatozoon enters perivitelline space and is engulfed by plasma membrane. This requires fusion of equatorial segment and oocyte plasma membrane by fusion proteins.
139. Granules on periphery of oocyte cytoplasm undergo exocytosis. Causes a zona block, where the zona undergoes biochemical changes so no further sperm can penetrate it. Also induces vitelline block, which prevents additional sperm binding to oocyte membrane. Prevents polyspermy.
140. Fertilization by more than one spermatozoon which results in embryo death
141. Reduction of disulfide cross links and nuclear material is released. Formation of male pronuceli occurs and syngamy occurs which is fusion of male and female pronuclei.
142. Female dog is mated by several males during estrus, the sperm from all males can fertilize oocyte and cause litters of different breeds.