MCN LESSON 1

Question 1

from ovulation to fertilization

Answer 1

Ovum

Question 2

rom fertilization to implantation

Answer 2

Zygote

Question 3

from implantation to 5-8 weeks

Answer 3

Embryo -

Question 4

from 5-8 weeks until term

Answer 4

> Fetus

Question 5

developing embryo and placental structures throughout pregnancy

Answer 5

> Conceptus

Question 6

earliest age at which fetuses survive if they are born; is generally accepted as 24 weeks or at the point a fetus weighs more than 500-600g.

Answer 6

Age of Viability

Question 7

> first 3 weeks, starting from fertilization

Answer 7

Pre-embryonic Stage

Question 8

aka CONCEPTION and IMPREGNATION
union of an ovum and a spermatozoon
occurs in the outer third of the fallopian tube (ampullar portion)
only one ova matures each month and is released (ovulation) and if fertilization does not occur within 24-48 hours, it atrophies and becomes nonfunctional
spermatozoon’s functional life is about 48-72 hours
Fertilization is successful in about 72 hours (48 hours before ovulation, 24 hours after)
Mucopolysaccharide Fluid = Zona Pellucida & Corona Radiata {covers the ovum so as to protect it from injury (will develop into placenta,

Answer 8

Fertilization

Question 9

3 weeks through 8 weeks

Answer 9

Embryonic Stage

Question 10

Factors affecting Fertilization

Answer 10

matured egg and spermatozoa
able to reach the ovum
able to penetrate the zona pellucida + corona pellucida

Question 11

contact between the growing structure and the uterine endometrium 8-10 days after fertilization

Answer 11

Implantation

Question 12

(cluster of cells formed by the ovum as it travels from the fallopian tube) - immediately burrows deeply into the endometrium and establishes an effective communication network with the blood system of the endometrium (inner lining of the uterus)

Answer 12

blastocyst

Question 13

once implanted, zygote becomes ______

Answer 13

embryo

Question 14

small amount of vaginal spotting appears on the day of implantation because capillaries are ruptured by the implanting

Answer 14

trophoblast

Question 15

serves as the fetal lungs, kidneys, and digestive tract in utero
helps provide protection for the uterus; begin growth in early pregnancy in coordination with the embryo growth

Answer 15

i. placenta and membranes

Question 16

influences the continuous function of the corpus luteum (appears right after egg is fertilized) after fertilization
causes uterine endometrium to continue to grow in thickness and vascularity instead of shedding off as in menstruation

Answer 16

ii. decidua/uterine lining

Question 17

miniature villi like probing fingers — reach out from the trophoblast cells into the uterine endometrium to begin formation of the placenta ( 11th-12th day after fertilization)
has central core consisting of connective tissues and capillaries surrounded by a double layer of cells; produce various placental hormones

Answer 17

iii. chorionic villi

Question 18

second function protects the embryo and fetus from certain infectious organisms such as spirochete of syphilis in early pregnancy; disappears after 20th-24th week of pregnancy
appears to have little protection against viral invasion

Answer 18

iv. cytotrophoblast (Langhan’s layer)

Question 19

grows from few identifiable trophoblastic cells from the beginning of pregnancy to an organ 15-20 cm in diameter, 2-3 cm depth covering half the surface area of the internal uterus at term
COTYLEDONS - maternal portion of the placenta that is rough
at term placenta weighs about 400-600g (1lb) or 1/6 the weight of the baby
a smaller placenta means circulation to the fetus must have been compromised and a bigger placenta means that circulation to the fetus was threatened

Answer 19

i. placenta (latin: pancake)

Question 20

serves as the source of oxygen and nutrients of the fetus

Answer 20

ii. endocrine system

Question 21

first placental hormone produced
found in maternal blood and urine as early as the first menstrual period shortly after implantation
fail-safe measure to ensure the corpus luteum continues to produce estrogen and progesterone so the endometrium is maintained and after the 8th week hCG production decreases

Answer 21

human chorionic gonadotropin (hCG):

Question 22

hormone that maintains pregnancy as well as the endometrial lining during pregnancy and reduces contractility of the uterus reducing premature labor

Answer 22

Progesterone

Question 23

woman’s hormone and contributes to the mammary gland development

Answer 23

estrogen:

Question 24

hormone promoting growth and lactogenic properties
produced by the placenta on the 6th week increasing to a peak at term
regulates maternal glucose, protein and fat levels

Answer 24

human placental lactogen:

Question 25

plasma protein produced by the placenta
contributes to decreasing the immunologic impact of the growing placenta
helps prevent hypertension of pregnancy

Answer 25

placental protein:

Question 26

(outermost fetal membrane)
formed from the chorionic villi

Answer 26

chorionic membrane

Question 27

(inner layer):
produces amniotic fluid
no nerve supply
produces a phospholipid that initiates the formation of prostaglandins which may trigger labor

Answer 27

amniotic membrane/amnion

Question 28

shield the fetus against pressure of the mother’s abdomen
protects the fetus from changes of temperature
aids in muscular development
allows the fetus freedom to move
protects the umbilical cord from pressure

Answer 28

amniotic fluid:

Question 29

formed from the fetal membranes, amnion and chorion
provides circulatory pathway that connects the embryo to the chorionic villi of the placenta
transport oxygen and nutrients to the fetus from the placenta

Answer 29

iv. umbilical cord

Question 30

gelatinous mucopolysaccharide
bulk of the cord; protects the umbilical cord’s arteries and vein

Answer 30

Wharton jelly: