Processes of Conception (exam 1) Flashcards

1
Q

Spermatogenesis

A

the meiotic process by which male gametes are produces

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2
Q

Oogenesis

A

the process by which female gametes are produced

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3
Q

Meiosis occurs when

A

the germ cell divides and decreases their chromosomal numbers by 1/2 and are called gametes or zygotes

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4
Q

In the mitosis stage

A

the 23 chromosomes of the ovum unite with the 23 of the sperm making 46 chromosomes (germ cell)

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5
Q

smallest cell in the male body

A

sperm

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6
Q

production of sperm begins

A

at puberty in response to testosterone

  • predictable amount of sperm production from early teens to advanced age (not cyclic)
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7
Q

important factor in production of adequate numbers of sperm

A

temperature (Dartos muscle)

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8
Q

sperm are transported in secretions from the

A

seminal vesicles and the prostate gland (seminal fluid)

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9
Q

pH of seminal fluid

A

Alkaline -> helps to neutralize the normally acidic female vagina in an attempt to assure viability of the sperm until it can fertilize an ovum

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10
Q

largest single cell in the body

A

Ovum

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11
Q

lifespan of sperm after ejaculation

A

48-72 hours

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12
Q

of sperm per normal ejaculation

A

200-500 million

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13
Q

average sperm travel time to egg

A

4-6 hours, but can be as little as 5 minutes

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14
Q

motion that transports sperm

A

flagellated, whip like motion

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15
Q

oocytes form by

A

12 weeks gestation

  • females have a lifetime supply of oocytes at birth
  • born with the amount of eggs they will ever have
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16
Q

amount of eggs that mature in a lifetime

A

400-500

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17
Q

hypothalamic-pituitary-ovarian axis

A

hypothalamus exerts control through release and inhibiting factors

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18
Q

ovarian cycle

A

maturation and ovulation of primary ova follicle is cyclic

  • ovulation occurs 14 +/- 2 days before the next menstrual period
  • 1 ovum matures each month with supportive cells
  • increase in estrogen increases motility of the Fallopian tubes and fimbriae (cilia)
  • captures the ovum and propels it to the uterine cavity

*An ovum cannot move by itself

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19
Q

conception

A

sperm meets egg (fertilization) in the outer 1st 1/3 of the fallopian tube

Females 22XX
Males 22Xy
- 23 chromosomes = 22 pairs are autosomes (traits in the body), leaving 2 chromosomes to determine the sex

Zygote (2 cells) begins descent through FT to uterus

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20
Q

prep for conception

A

Hyaluronidase -> path through cells for sperm to reach ovum

One sperm penetrates the ovum

Membrane of the ovum changes -> prevents entry of other sperms

Capacitation also occurs

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21
Q

Blastocyst

A

Inner layer of cells
undifferentiated embryonic cell

Secretes HCG to make sure that the corpus luteum remains viable

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22
Q

capacitation

A

removes the protective coating from the heads of the sperm - cannot penetrate the ovum

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23
Q

Corpus Luteum

A

secretes estrogen and progesterone first 2-3 months of pregnancy

main source of estrogen and progesterone until the 3rd month of pregnancy -> placenta takes over

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24
Q

First weeks of human development:

A

Follicular development in the ovary, ovulation, fertilization, and transport of early embryo down uterine tube and into uterus, where implantation occurs

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25
Q

mitotic cellular replication (cleavage) occurs as

A

baby (zygote) is propelled toward uterus

26
Q

morula

A

16 cells (3rd day)

27
Q

trophoblast

A

outer layer of cells

outer layers are chorionic villi implants 6-7 days after fertilization

28
Q

Implantation

A

Blastocyst implanted at the top of the uterine wall 6-8 days after ovulation

Trophoblast (outer layer) develops projections -> chorionic villi
- Chorionic villi extend into endometrium and tap maternal blood supply for O2 and nutrients

Endometrium is now call the decidua

Decidua basassi (beneath the blastocyst)

29
Q

Inhibition of Implantaion

A
  • IUD initiates foreign body response
  • Interferes with both fertilization and implantation

Progesterone changes cervical mucus and endometrium to mature the uterine lining for implantation

Progestin prevents pregnancy

IUD may cause substances to accumulate in uterus and interfere with implantation

30
Q

Ovum

A

conception to day 14

this period encompasses cellular replication -> zygote to blastocyst formation and differentiation into 3 primary germ layers of cells

31
Q

Embryo

A

day 15 to eight weeks

organs are forming
greatest vulnerability

the embryonic stage is the most critical time in the development of the organ systems and the external features

32
Q

fetus

A

eight weeks to birth

33
Q

ectoderm

A

trophoblast (outer layer) develops into the placenta, integument, neural tissue, and glands

34
Q

mesoderm

A

forms muscles, bones, connective tissue, circulatory system, and GU system

35
Q

endoderm

A

forms digestive, respiratory, and parts of the gu system

36
Q

teratogen

A

Environmental substances or exposures that result in functional or structural disability

Developing areas with rapid cell division are the most vulnerable to malformation by environmental teratogens

37
Q

inner membranes that surround the baby

A

amniotic sac

38
Q

fluid within the sac and around the baby

A

Amniotic fluid

  • Source of oral fluid for fetus
  • Repository for wastes (urine and meconium)
  • Assists in lung development
  • Volume = 800-1200 mL (fetal urine contributes to volume)
  • Transparent yellow liquid
  • Characteristic odor but should not be malodorous
39
Q

meconium

A

First stool
- Green, tarry, sticky

  • Released into AF when baby is stressed or distressed

Source of concern at delivery if AF is meconium stained -> meconium aspiration (if it’s their first breath, it could be fatal - think breathing in syrup)

40
Q

Oligohydramnios

A

< 300 mL AF

Associated with fetal kidney obstruction or renal agenesis

(oli = too little)

41
Q

Polyhydramnios

A

> 2000 mL AF

Associated with esophageal atresia and with severe CNS anomalies

(poly = too much)

42
Q

“water break”

A

amniotic fluid made up of sterile baby urine

  • amniotic fluid completely replaces itself every 3 hours, even after ROM
43
Q

baby “practice breathing”

A

the cord gives baby oxygen, but they do “practice breathing” which includes breathing/swallowing amniotic fluid

  • fluid is secreted by the respiratory and GI tracts of the fetus (replacing the fluid back into the amniotic sac)
44
Q

Functions of Amniotic Fluid

A
  • Protects fetus from mechanical injury & infection
  • Maintains stable thermal environment
  • Helps in fluid and electrolyte homeostasis
  • Allows freedom of movement for baby

Amount of fluid increases weekly

45
Q

Properties of Amniotic Fluid

A
  • Slightly alkaline

Contains: albumin, urea, uric acid, creatinine, lecithin, sphingomyelin, bilirubin, fructose, fat, leukocytes, proteins, epithelial cells, enzymes, lanugo hair

Lecithin & Sphingomyelin

  • a major component of Surfactant
  • L:S ratio 2:1 indicates fetal lung maturity

*Turns nitrazine paper BLUE
(urine is acidic and turns it red/yellow)

46
Q

ROM nursing action

A

Always check the fetal monitor for decelerations in FHR

47
Q

Placenta

A
Provides nutrients (O2) and removes waste (CO2)
(transfers O2 & CO2 through intervillous spaces)

Metabolizes drugs and other substances

Produces hormones estrogen/progesterone for maintenance of pregnancy

Flat, disc shaped
- when hCG is release it produces as the placenta and begins to grow

Highly vascular, operates as a lung
- Metabolic function are respiration, nutrition, excretion (esp. drugs), and storage

48
Q

Intervillous spaces

A

Large spaces separating chorionic villi in the placenta

Blood enters the intervillous spaces from uterine arteries that penetrate the basal part of the placenta

  • Oxygenated blood transported to fetus through the umbilical vein
  • Oxygen depleted blood leaves the fetus -> chorionic villi by umbilical vein
49
Q

umbilical arteries

A

Deoxygenated blood leaves the fetus through UA and enters the placenta, where it is oxygenated

50
Q

umbilical vein

A

oxygenated blood leaves the placenta through the umbilical vein, which enters the fetus via the umbilical cord

51
Q

endometrial artery

A

CO2, deoxygenated blood

52
Q

endometrial vein

A

returns oxygenated blood to fetus

53
Q

placenta has (veins, arteries)

A

2 arteries and 1 vein

  • vein carries oxygenated to the embryo
  • artery carries deoxygenated from the embryo
    (opposite in fetus than adult and switches when the cord is cut)

approximately 1% of umbilical cords have one artery and one vein (sometimes associated with congenital malformations)

54
Q

Wharton’s jelly (connective tissue)

A

cushions vessels from compression

55
Q

battledore placenta

A

when the cord is located toward the edge

usually centrally located

56
Q

dirty duncan

A

placental side next to uterine wall

57
Q

shiny shultz

A

placental side nearest to the baby that holds the amniotic fluid

58
Q

stimulates uterine development to provide environment for baby

A

estrogen (go go go)

59
Q

relaxes uterine muscle to prevent spontaneous abortion

A

progesterone
- slows down for pregnancy
“Pro-Life”

60
Q

Factors that Affect Placental Perfusion

A

Decreased blood flow r/t maternal position

  • Vena Cava Syndrome (mother in recumbent position) -> cuts off O2 and nutrition to baby
  • Heavy uterus presses on aorta and vena cava -> cuts off circulation to brain and to the uterine arteries that perfuse the placenta (often occurs during vaginal exam)

Blood pressure changes - increased or decreased (HTN or blood loss) = vasoconstriction -> perfusion limited -> blood supply to baby decreased

Vasoconstrictor drugs (includes nicotine)

Mom being dizzy and faint (baby suffocating)

61
Q

Umbilical Cord

A

Connects fetus and placenta

Arises from center of fetal side of placenta

Contains 1 large vein and 2 arteries

Arteries carry deoxygenated blood and waste from fetus

Vein carries oxygenated blood and provides O2 and nutrients to fetus

Vein & arteries surrounded by Wharton’s jelly

62
Q

Function of the Umbilical Cord

A

Transport of O2 and nutrients from mom to baby and waste back to maternal blood

Permits free movement for baby within the membranes

Complication:

  • knotted and cut off circulation to baby
  • may be caught between baby head and ischial spine during birth or ROM -> fetal hypoxia