Pregnancy: genetics, conception, fetal development Lectures 10 N.Petrenko, MD, PhD

Cell Division. Mitosis

Cell Division. Mitosis vs Meiosis

Gametogenesis: Spermatogenesis

Gametogenesis Spermatogenesis primary spermatocytes (46) 2 haploid secondary spermatocyte(22X+22Y) 4 Spermatids

Gametogenesis: Oogenesis

Gametogenesis: Spermatogenesis vs Oogenesis

Ovum

Sperm

Fertilization

Fertilization

Fertilization

Implantation

Implantation

Early Developmental Stages Primary Germ Layers

Ectoderm, Mesoderm and Endoderm During gastrulation, three major cell lineages are being established. They are the Ectoderm (shown in the diagram as blue), Mesoderm (red) and Endoderm (yellow). Following gastrulation, various cell lineages are derrived from these three primary cell types. For example, the Ectoderm gives rise to the epidermis and its derrivatives such as nails, hair and teeth. On the other hand, the Ectoderm also gives rise to the Central Nervous System.

Development of the embrio

Membranes

Umbilical cord

Placenta. Structure

Extraembryonic Membranes & Placenta Formation Figure 29–5 (1 of 3)

G. Fetus at 2-3weeks

I. The Fetus at 5 weeks

K. The Fetus at 7 weeks

L. Fetus at 8-9 weeks old

12 WEEKS(3 months)

14 WEEKS (3 1/2 months)

15-18 WEEKS ( 4-4 1/2 months)

WEEK 22 (2 1/2 months)

WEEK 26 (6 1/2 Months

WEEK 30 (7 1/2 months)

FULL TERM ( weeks)

Respiratory Changes During Pregnancy

Using the “Wheel”

Expected Physical Changes - Reproductive System

Uterine Sizing

Accuracy of Dating by Ultrasound Gestational Age weeks) Ultrasound Measurements Range of Accuracy < 8Sac size+ 10 days 8-12CRL+ 7 days 12-15CRL, BPD+ 14 days 15-20BPD, HC, FL, AC+ 10 days 20-28BPD, HC, FL, AC+ 2 weeks > 28BPD, HC, FL, AC+ 3 weeks

Bones and Joints of the Pelvis

The Diagonal Conjugate

The Ischial Spines

The Pelvic Outlet

Leopold's Maneuvers - are used to determine the orientation of the fetus through abdominal palpation. 1. Using two hands and compressing the maternal abdomen, a sense of fetal direction is obtained (vertical or transverse)..

2. The sides of the uterus are palpated to determine the position of the fetal back and small parts.

3. The presenting part (head or butt) is palpated above the symphysis and degree of engagement determined

4. The fetal occipital prominence is determined.