Menstrual Cycle & Fetal Development (Week 1 OB)

Overian Cycle

the monthly process by which a female's ovary develops and releases a mature egg in preparation for possible fertilization

Menstrual cycle

Mood swings, irritation, anxiety, depression, difficulty concentrating

follicular phase (day 1-14)

Pituitary releases FSH.
Follicles grow

Ovulation (Day 14)

Surge of LH

luteal phase (day 15-28)

Corpus luteum forms → produces progesterone.
If no pregnancy → corpus luteum breaks down → menstruation

menstruation or menses (day 1-5)

shedding of inner lining (period)

Uterine cycle

The cycle that prepares the lining of the uterus for the growth of an embryo

Proliferative Phase (Days 6-14)

Estrogen from developing egg → thickening of lining.

Secretory Phase (Days 15-28)

Progesterone from corpus luteum → lining continues to thicken

FSH

Follicle growth

LH

Ovulation

Estrogen

Builds lining

Progesterone

Maintains lining of uterus

human chorionic gonadotrophin hormone (HCG)

indicates pregnancy

Signals corpus luteum to produce progesterone

Preserves the corpus luteum

Conception

the moment at which a female becomes pregnant (sperm cell into egg cell)

Fetal Development (Lasts 40 Weeks)

Growth and maturation of the fetus during pregnancy.

Pre Embryonic

lasts conception to 2 weeks
Morula turns into blastocyst then implants into uterine wall

embryonic period

between 3-8 weeks
forms major structures and organs

Fetal stage

Week 9 until birth

Grows into recognizable human form

Where organs finalize

Ectoderm

nervous system and skin

Mesoderm

Muscle
skeleton
kidney
reproductive system

Endoderm

lungs
liver
digestive tract

Placenta

exchange of oxygen, promotes development, removes waste from fetus

gas exchange is present here

Umbilical Cord

2 arteries (unoxygenated) and 1 vein (oxygenated)

Fetal membrane

protection and support

amniotic fluid

green fluid means first bowel movement (caused by stress, infection, distress, too early or late birth)

cushions fetus

Maintains tempature

Allows movement

keeps sterile

Fetal Circulation Adaptations

structural and functional changes that allow the developing fetus to receive oxygen and nutrients from the mother and bypass non-functioning organs

Ductus venosus

Umbilical vein → Inferior vena cava (bypasses liver)

Foramen ovale

Right atrium → Left atrium (bypasses right ventricle)

Ductus arteriosus

Pulmonary artery → Aorta (bypasses lungs)

Surfactant

chemical produced in the lungs to maintain the surface tension of the alveoli and keep them from collapsing

HORMONES PRODUCED BY THE PLACENTA

• Chorionic gonadotropin
• Prolactin
• Estrogen
• Progesterone
• Relaxin

Prolactin

stimulates breast milk production

Relaxin

softens and widens the cervix

3 Week milestone

Development of Brain, spinal cord

4th Week milestone

the blastocyst implants in the uterus, forming three distinct layers (endoderm, mesoderm, ectoderm)

5 week milestone

Regular heart beat detectable

Beginning structure of eyes and ears

6 week milestone

Beginning formation of lungs

7 week milestone

Elbows and toes visable

8 week milestone

umbilical cord is fully developed

10 Week Milestone

heart fully developed

beginnings of hair

12 Week Milestone

urine production

Week 16 milestone

facial movements

Week 20 milestone

movement

Insulin production

24 Week Milestone

Surfactant produced

Hearing

28 Week Milestone

gas exchange possible

Sleep wake cycle

36 Week Milestone

Lungs mature

32 Week Milestone

Bones are developed