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62 Cards in this Set
- Front
- Back
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Where do the ova and the sperm rendezvous?
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In the oviduct
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Sperm leave the epididymus and enter where to be stored/transported?
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Vas deferentia
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How many sperm are produced each day?
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200 million
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What two structures produce seminal plasma?
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Secretions of the male accessory glands(prostate and seminal vesicle)
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Where do the sperm and seminal plasma mix?
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The ejaculatory duct
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What is the purpose of seminal plasma?
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Contributes to maintenance, maturation, and transport of sperm
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What is in seminal plasma?
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-ATP
-Bicarbonates -Carnitine -Citric and ascorbic acid -Fructose -Glycerylphosphocholine -Prostaglandins (for sperm motility) -Zinc - - |
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What is role of prostaglandin in seminal fluid?
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Prostaglandins contract smooth muscles in the vasa deferentia, thus aiding sperm passage during ejaculation
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How much sperm in a single ejaculation?
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40-500 million with an average of 180 million
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What percentage of ejaculated sperm are structurally or biochemically abnormal and are not capable of fertilization?
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30%
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How much has sperm count decreased by over the past 50 years? (% per year)
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1% a year
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What are some characteristics of human semen?
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Creamy texture with gray to yellow color
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What is the average volume of human semen after 3 days of abstinence?
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2.5-3.5 ml
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What are the minimum qualifications for male fertility? sperm/ml? % able to swim? % normal shape and size?
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• ≥ 20 million sperm/ml
• ≥ 40% being able to swim • ≥ 60% are normal shape and size |
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What is the size of an average sperm in micro meters?
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40-250 micro meters long
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What are the different structures of a sperm?
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• Sperm head
• Neck • Midpiece: contains mitochondria which produces energy for tail movement • Tail |
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What is the elongated haploid nucleus of the sperm head surrounded by?
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A nuclear membrane
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On the sperm head, what is the acrosome and what is it's role?
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• Acrosome: membrane bound vesicle external to nucleus that fits over the head of the sperm like a cap
• Acrosome is full of enzymes important in the penetration of the ovum |
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What is the flagellum made of and how is the tail configured?
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Made of midpiece and tail and is configured in a "9+2" arrangement of microtubules
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What is the purpose of the flagellum?
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Provides propulsive force, allowing for locomotion of the sperm cell and penetration of the ovum
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Trace the path of a sperm to the oviduct ampullary-istmic junction.
(Uterus, Cervix, Vagina, Uterotubal junction, oviductal isthmus, ovidcut ampullary-istmic junction) |
• Vagina
• Cervix • Uterus • Uterotubal junction • Oviduct isthmus • Oviduct ampullary-isthmic junction which is most common site of fertilization |
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Of the 40-500 million sperm from a single ejaculate, how many make it to the uterus? How many make it to the oviduct? How many make it to the egg?
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• < 1,000,000 make it to the uterus
• 100 - 1000 reach the oviduct • 20 - 200 reach the egg |
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Can sperm "smell" the egg?
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Yes
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What does the semen increase the vaginal pH to and why?
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pH 7.2 to increase sperm motility
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What is semen coagulation?
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about one minute after deposition into the vagina, the semen becomes thicker which may prevent sperm loss from vagina
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What is semen liquefaction?
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about 20 minutes after deposition into vagina, semen again liquefies which enables sperm to swim faster toward cervix
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What is a female orgasm?
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• Female orgasm includes vaginal wall muscular contractions that produce pressure in vagina that is greater than in uterus which creates a pressure gradient that facilitates sperm movement through cervix
• Female orgasm can also cause the cervical os to dilate which allows the sperm to pass through more easily |
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What is the cervical canal lined by?
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Folds and crypts with tiny cervical fibers
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During the menstrual cycle, is the mucus thick and are the fibers densely packed?
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Yes
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Shortly before ovulation, estrogen levels rise, what does this cause the mucus to do?
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Mucus becomes more liquid and the gaps between the fibers become wider
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What do cervical fibers do to aid sperm movement through the cervix?
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Cervical fibers may vibrate in rhythm with sperm tail beat frequency
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How do sperm climb up the uterine wall? What mechanism of the uterus plays a more important role in transporting the sperm up the uterus? How?
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By beating their tails, however, uterine muscle contractions and cilia movement play a more important role in facilitating sperm transport up the uterine wall
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What hormone is released from the posterior pituitary when the cervix is stimulated by the penis during coitus?
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Oxytocin is released from the woman's posterior pituitary gland
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What does oxytocin do?
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Enhances force of rhythmic waves of uterine muscle contractions which help move sperm to the uterotubal junction
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What % of sperm go into the left and right oviducts?
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50/50
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On entrance of sperm into istmus of oviduct, does sperm tail beating increase or decrease?
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Decreases to wait for ovulation to occur
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What do the sperm do after ovulation occurs?
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• After ovulation, sperm move up to the ampullary-isthmic junction where it meets the
ovum that has traveled from the ovary through the oviductal infundibulum & ampulla • Fertilization of ovum by sperm usually occurs at the ampullary-isthmic junction (Fig 9-3) |
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What increases cilia number?
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Estrogens
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What increases cilia beating and egg transport?
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Progesterone
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Do oviductal cilia in the deep recesses beat toward the ovary or away from the ovary?
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Toward ovary to help move sperm
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Do oviductal cilia in the ridges beat toward or away the uterus?
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Toward to help move the egg and pre-embryo
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Where do the sperm and ova/pre-embryo travel? (Ridges or recesses)
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Sperm travel in recesses while ova and pre-embryo travels on the ridges.
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Are freshly ejaculated sperm capable of fertilization?
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No, sperm must undergo sperm capacitation
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What is sperm capacitation?
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during journey through female reproductive tract, the sperm matures and gains ability to
fertilize eggs and increases tail movements of sperm |
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How do eggs attract the sperm?
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Human sperm have at least 20 chemical receptor molecules on its head to detect the chemicals from the egg
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What must the sperm penetrate to fertilize an egg?
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• Sperm passage through cumulus oophorus
• Sperm passage through zona pellucida • Sperm attachment to egg plasma membrane • Cortical reaction • Completion of second meiotic division of egg • Formation/fusion of sperm and egg pronuclei |
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What is the cumulus oophrus?
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A layer of loosely packed follicle cells that surround the ovulated ovum
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What sperm enzyme dissolves the hyaluronic acid? What does this allow the sperm to do?
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Hyalouronidase: it dissolves the cementing material found between cells. This allows the sperm to reach the zona pellucida.
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What are the three glycoproteins in the zona pellucida?
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ZP1, ZP2, and ZP3
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What is the acrosomal reaction?
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Hydrolytic enzymes are released from acrosome which degrades the zona pellucida and creates a tunnel through which the sperm moves
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What triggers the sperm head to undergo the acrosomal reaction?
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Receptors on sperm plasma membrane attach to ZP3 to trigger the acrosomal reaction
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How does the sperm enter the perivitelline space?
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Inner acrosomal membrane of sperm has has egg binding proteins that attach to egg
cell membrane (Fig 9-5D) and enters in to the perivitelline space |
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What must happen for the sperm nucleus and centriole to enter the egg cytoplasm?
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The sperm cell membrane must fuse with the egg plasma membrane
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What do the egg and sperm pronuclei do in preparation of syngamy(sexual reproduction)?
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They migrate toward each other within the egg cytoplasm
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When sperm penetrates the egg, what ions are released into the egg cytoplasm?
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Calcium ions
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What does the sudden increase in calcium ions trigger?
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Triggers egg activation with cortical granule release and completion of the second meiotic division in egg before fertilization occurs
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What is the cortical reaction?
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• Once a sperm has penetrated an egg, a defense is mounted to prevent another sperm from penetrating the egg
• Cortical granules under the egg cell membrane release enzymes that debilitate ZP3 and ZP2 which prevents attachment of additional sperms which prevents polyspermy • This cortical reaction is the first step in a series of biochemical and physical changes known as egg activation |
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What is egg activation?
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• Cortical reaction
• Completion of 2nd stage of meiosis • Increase in egg metabolism • Synthesis of protein, RNA, and DNA |
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What happens soon after the sperm nucleus enters the egg?
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• Soon after sperm nucleus enters egg, its nuclear membrane breaks down
• Sperm DNA re-condenses as a result of exposure to egg cytoplasm • A new membrane is formed to enclose the sperm pronucleus |
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When the diploid zygote cell mitotically divides, what does the zygote produce?
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Two identical daugther cells called blastomeres
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How many mitochondria does each sperm bring into the egg?
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100
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What happens to the sperm mitochondria soon after fertilization?
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The mitochondria disappear, all of our mitochondria are inherited from our mothers
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