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88 Cards in this Set
- Front
- Back
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How many sperm each day?
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200 million
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How many sperm/ ejaculate?
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40-500 million
avg. 180 million |
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How many sperm make it to the uterus? the oviduct? the egg?
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<1,000,000 make it to the uterus
100-1000 reach oviduct 20-200 reach egg |
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Fertility Index:
# sperm/ml? % able to swim? % normal shape and size? |
20 million sperm/ml
40% able to swim 60% normal shape/size |
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Sperm size?
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40-250 micrometers
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Seminal plasma:
secreted by? components? purpose? |
secreted by accessory glands
prostaglandin+citric acid + bicarbonates+ fructose +zinc +ATP --> maintenance maturation and transport of sperm |
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Where does fertilization of ovum by sperm occur?
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ampullary-isthmic junction
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Sperm transport in Oviduct:
Estrogen purpose? Progesterone purpose? |
Estrogen = increase cilia #
Progesterone = increase cilia beating and egg transport |
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Oviduct: Ridges vs. Recesses?
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Sperm travel in recesses
Ova travel along ridges cilia in recesses beat towards ovary --> move sperm cilia in ridges beat toward uterus --> move egg |
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Sperm Capacitation =
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during journey through female tract, sperm matures:
gains the ability to fertilize eggs increases tail movements |
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Fertilization:
7 steps |
1. Sperm passage through cumulus oophorus
2. Sperm passage through zona pellucida 3. Sperm attachment to egg plasma membrane 4. Sperm penetration of egg 5. Cortical reaction 6. Completion of 2nd meiotic division of egg 7. Formation/fusion of sperm and egg pronuclei |
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Cumulus oophorus
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layer of loosely packed follicle surround ovum
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Hyaluronidase
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As sperm enters cumulus oophorus, this enzyme dissolves the cementing material b/wn cells (hyaluronic acid) and allows sperm to reach the zona pellucida
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Zona pellucida
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extracellular matrix
composed of three glycoproteins |
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Acrosomal reaction
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hydrolytic enzymes released from acrosome degrade zona pellucida and create a tunnel for sperm to move through
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What happens when sperm penetrates the egg?
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Calcium ions are released into egg cytoplasm which triggers egg activation and completion of 2nd stage of meiosis in egg
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Cortical Reaction =
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sperm penetrates egg --> cortical granules --> enzymes debilitate ZP3 and 2 --> prevents attachment of additional sperms --> prevents polyspermy
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Egg activation
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1. Cortical reaction
2. Completion of meiosis 2 3. increase egg metabolism 4. synthesis of protein, RNA and DNA |
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2 haploid genomes merge and form a........?
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diploid zygote --> divides mitotically --> two celled preembryo --> 2 identical daughter cells (blastomeres)
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How many mitochondria come from sperm? what happens to them? Where do the rest of mitochondria come from?
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100 mitochondria from sperm
disappear soon after fertilization all other mitochondria from mothers |
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Preembryo which weeks?
Embryo which weeks? Fetus which weeks? |
Preembryo = Wk 1-2
Embryo = Wk 3-8 Fetus = Wk 9-birth |
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Biological Age
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avg time is 38 wks from fertilization/conception to birth
divided into 3 trimesters |
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Gestational Age
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avg 40 wks
"duration since day 1 of last menstrual period" ~ 2 weeks longer than duration since conception |
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Onset of pregnancy =
Bio Def? Clinical Med? General Public? |
Bio = conception
Clinical Med= 2 weeks BEFORE conception Gen Pub = (1-2 days after missed period) 2 weeks AFTER conception |
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Human chorionic gonadotropin is produced by what?
Where is it detected? |
hCG= produced by blastocyst and placenta of embryo
Detected in blood and urine |
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Preembryonic Sequence:
Day 0 Day 1 Day 3 |
0 = conception, zygote formation
1 = blastomere (2 cells) 3 = morula (8-32 cells) |
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Preembryonic Sequence:
Day 4 Day 5 Day 6 |
4= early blastocyst
5 = late blastocyst 6 = blastocyst attaches to endometrium |
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Preembryonic Sequence:
Day 7 Day 8 Day 9 Day 10 |
7= implantation begins
8 = amniotic cavity and embryonic disc form 9= uterine sinusoids develop 10 = implantation complete |
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Preembryonic Sequence:
Day 15 |
15= first missed period/positive pregnancy test
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How many days after fertilization does preembryo move to uterus?
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3-4 days after fertilization
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What is the single outer layer of the blastocyst called? surrounding fluid filled cavity?
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single outer layer = trophoblast
fluid filled cavity = blastoceol |
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How long does the blastocyst rest freely in the uterine cavity?
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2-3 days
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What does the uterus secrete 6 days after conception? what does this enzyme do?
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Secretes protease enzyme which dissolves the zona pellucida
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Progesterone, secreted by the corpus luteum primes the uterus and makes endometrium more vascular. It also stimulates the uterus to secrete this...
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Protease.
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What does protease do in the uterus?
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dissolves z.p. surrounding the blastocyst. When it is completely dissolved the inner mass of cells in the blastocyst attaches to the uterine wall and penetrates the endometrium
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Synctiotrophoblast
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= outer layer of trophoblast
secretes protease sinusoids w/ maternal blood form w/in it |
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By the end of week 2, early embryonic development starts and the cell mass becomes a........
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bilaminar embryonic disc
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What are the two layers of the embryonic disc? What are their functions?
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Hypoblast --> development of extraembryonic membranes
Epiblast--> ectoderm, medoderm, and endoderm layer |
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What do the three layers of the epiblast (of the embryonic disc) form into?
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Ectoderm = NS, epidermis of skin
Mesoderm= skeleton, vertebrae, muscles, heart, circ sys, kidneys, gonads Endoderm= digestive tube, liver, gall bladder, pancreas, respiratory tube |
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What are the 3 extraembryonic membranes that are formed from the inner cell mass?
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1. Yolk sac
2. Allantois 3. Amnion |
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What extraembryonic membrane is formed from the cytotrophoblast?
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Chorion = important component of placenta
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What is the purpose of amniotic fluid?
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protects fetus against mechanical shock and provides water
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At what rate is amniotic fluid secreted and absorbed?
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max rate = 300-600 ml
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How much amniotic fluid is there at 8 weeks? 20 weeks? 38 weeks? 40 weeks?
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8) 5-10 ml
20) 250 ml 38) 1000-1500ml 40) 500-1000ml |
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What is the function of the placenta?
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delivers O2, glucose, growth factors etc. TO fetus.
eliminates CO2 and other waste products FROM fetus |
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How much of the uterine wall does the placenta cover at week 4?
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20%
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How much of U wall does placenta cover at week 20 and how much does it weigh?
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50% of wall, weighs 200g (fetus = 500g)
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How much does the placenta weigh at week 40? how much blood is passing through it
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weighs = 700 g, 285 liters of blood
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What is the diameter and length of the umbilical cord at birth?
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diameter = .3 to 1 inches
length = 20 -22 inches |
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Dizygotic twins have how many placentas, chorions and amnions?
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2placentas, 2chorions, 2 amnions,
unless implant close together, then may have 1 placenta and fused chorions |
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Monozygotic twins have how many placentas, chorions, and amnions?
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1 placenta , 1 chorion , 2 amnionic sacs
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What are the major developments during WEEK 3 of embryonic development?
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trilaminar disc --> sausage shape
Neural tube develops |
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What are the major developments during WEEK 4 of embryonic development?
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C shape
Eyes begin to form on head, inner ear, tiny arm and leg buds Heart forms and begins beating. |
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What are the major developments during WEEK 5 of embryonic development?
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Rapid brain growth
Hands become paddle shaped |
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What are the major developments during WEEK 6 of embryonic development?
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Eyes pigmented
Exterior ears Leg buds become paddle shaped Hand rays --> position of digits |
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What are the major developments during WEEK 7 of embryonic development?
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Toe Rays --> position of digits
Rapid development of gut tube Tail diminished |
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What are the major developments during WEEK 8 of embryonic development?
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Eyelids grow and meet each other --> closed
Fingers and toes seen, thin webbing still Tail disappeared Brain, spinal cord, and peripheral nerves |
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What are the major developments during WEEK 9 to birth of embryonic development?
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Organ systems established
Period of rapid growth |
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When does the tail disapper?
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Week 8
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When does the heart start beating?
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Week 4
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When does the embryo begin to look human?
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Week 8
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When can the fetal heart rate be heard w/ stethoscope?
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Week 12
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When can the mom feel fetus moving?
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Month 4-5
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What is the skin covered with by the end of month 6?
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verniz caseosa = protective layer of fatty secretions
lanugo = down hair |
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What happens during months 7,8,9 of the fetal period?
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fetus adds layers of fat, loses wrinkled appearance, lungs mature
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How much urine/day is produced by fetal kidneys during fetal period?
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450 ml/day
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What is the function of the ductus arteriosis?
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allows fetal blood to by pass the lungs
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What is the function of the ductus venosus?
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shunts blood around the liver
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What is the function of the foramen ovale?
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allows blood to go from the right atrium to the left atrium
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What percentage of preembryos/embryos die w/in the first 3 weeks of life?
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50%
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What percent of confirmed pregnancies miscarry?
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15-20%
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What percentage of spontaneously aborted fetuses are accounted for by chromosomal abnormalities?
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42%
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Teratogens and mutagens such as mercury, lead, alcohol, and tobacco have main effects during which weeks?
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4th through 7th week of gestation
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Multiple serum marker test?
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from maternal blood
hCG, alpha-fetoprotein, estriol levels estimate likelihood of downsyndrome |
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What is an Amniocentesis and when is it performed?
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b/wn 14th and 16th week of pregnancy
cells and amniotic fluid evaluated for chromosomal abnormalities |
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What is chorionic villus sampling and when is it performed?
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Performed 8th-10th week
Needle through vagina cervix, into uterine cavity Chorionic cells removed from placenta and analyzed |
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What percentage of induced abortions in the USA are in the 1st trimester?
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87%
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What are four things that the placenta secretes?
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1. Progesterone
2. Hormones similar to ones produced by the pituitary gland 3. Human placental lactogen (hPL) 4. Relaxin |
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What is the function of hPL?
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helps prime mammary glands for milk production
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What is the function of Relaxin?
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Relaxes connective tissue connecting pubic bones (pubic symphysis)
Prepares cervix to soften and dilate |
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What is the fetal ejection reflex?
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stimulation of oxytocin release by mechanical stimulation of uterus, cervis, or vagina --> further uterine contractions
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What three things can cause a baby to be delivered EARLIER?
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1. if it is Male
2. shorter follicular phases/menstrual cycles 3. excercise through pregnancy |
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What is cervical effacement?
Initiation of effacement? Progression of effacement? |
=thinning of normally thick cervical walls and retraction of cervix upwards
Initiation = cervical mucus plug dislodged and small amt of blood Progression = amniotic sac weakend, may break and release amniotic fluid |
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What is the Deciduoma response?
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cells of uterine stroma multiply rapidy form cap over blastocyst
Implantation is complete |
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Acrosomal reaction occurs as sperm penetrates?
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Zona pellucida
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Sperm head releases hyaluronic acid as it penetrates?
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Cumulus oophorus
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The cortical reaction is initiated when sperm penetrates?
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Egg plasma membrane
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Which is NOT a characteristic of preeclampsia in pregnant women?
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High blood sugar
(Edeam, high blood pressure, and proteinuria ARE characteristics) |
