ANAT2341 Lab 11 - Embryo to Fetus

From Embryology
Lab 11: Introduction | Heart | Heart Abnormalities | Individual Assessment
Group Projects - Assessor Final review before next week submission. Signalling: 1 Wnt | 2 Notch | 3 FGF Receptor | 4 Hedgehog | 5 T-box | 6 TGF-Beta

Introduction

  • Week 8 Stage 22 and 23
  • Selected Stage 22 cross-sections and animations
  • Week 10 Fetus

Week 8 Stage 22

Stage22 bf1c.jpg
stage 22, Week 8, 54 - 56 days, 23 - 28 mm

Mesoderm: heart prominence, ossification continues

Head: nose, eye, external acoustic meatus

Body:straightening of trunk, heart, liver, umbilicus: placental cord, midgut herniation, allantois, vitelline duct

Limb: upper limbs longer and bent at elbow, foot plate with webbed digits, wrist, hand plate with separated digits

Straightening of trunk, pigmented eye, eyelid, nose, external acoustic meatus, ear auricle, scalp vascular plexus, separated digits (fingers), thigh, ankle, umbilical cord

Embryo Anatomy

Now examine selected regions of the Stage 22 embryo and their overall development in the 3D animations.


Stage22 ALL3d.jpg
 ‎‎Systems
Page | Play
Stage22-GIT-icon.jpg
 ‎‎GIT Stage 22
Page | Play
Stage22-CVS-icon.jpg
 ‎‎Cardiovascular
Page | Play
Stage22-CNS-icon.jpg
 ‎‎Stage 22 Neural
Page | Play
Stage22-CNS-icon.jpg
 ‎‎Urogenital
Page | Play
Stage22-CNS-icon.jpg
 ‎‎Skeletal
Page | Play

Week 8 Stage 23

Stage23 bf1c.jpg
Week 8, 56 - 60 days, 27 - 31 mm

scalp vascular plexus, eylid, eye, nose, auricle of external ear, mouth, sholder, arm, elbow, wrist, toes separated, sole of foot, umbilical cord

Mesoderm: ossification continues

Head: eyelids, external ears, rounded head

Body: straightening of trunk, intestines herniated at umbilicus

Limbs: hands and feet turned inward

Week 10 Fetus (40mm)

Human week 10 fetus 01.jpg

Size comparison embryo-fetus actual.jpg This is an image of the actual size comparison shown in the introduction of the Embryonic stage 13, 23 and Fetal stage 10 week 40mm. This stage of development is after the embryonic period (up to week 8), but only 2 weeks into early fetal development.
Size comparison embryo-fetus.jpg The fetal period is a time of extensive growth in size and mass as well as differentiation of organ systems established in the embryonic period. In particular, the brain continues to grow and develop, the respiratory system differentiates, the urogenital system further differentiates between male/female, endocrine and gastrointestinal tract begins to function.

Compare this 10 week fetus with the earlier Carnegie stage embryos: size, head/body proportions, brain, head, skeletal development.

Note that in the early fetus the midgut remains herniated and will only be taken into the peritoneal cavity on further body wall growth.

There are 4 sections taken in the sagittal plane (moving from the right at Plane A towards the midline at Plane D). Click on the small images (or the text below) to open the linked large image pages.

Fetal 10wk urogenital 3.jpg

Midgut Herniation


Related Images

Human- fetal week 10 planes icon.jpg

Fetus (week 10) Planes A (most lateral), B (lateral), C (medial) and D (midline) from lateral towards the midline.

Image Source: UNSW Embryology, no reproduction without permission.


Week 12

Links: Ultrasound

Size

  • Crown Rump Length (CRL) 85 mm (week 10 CRL 40mm), femur length 15 mm, biparietal diameter 25 mm
  • Biparietal diameter
  • Head circumference
  • Abdominal circumference
  • Femur length
  • Foot length (correlates with CRL)
  • Placental parameters (covered in next practical)

Head

Fetal head lateral.jpg Fetal head medial.jpg
Fetal head lateral Fetal head medial

Fetal head section 01.jpg

  • Tongue Week 12 - first differentiated epithelial cells


Lab 11: Introduction | Heart | Heart Abnormalities | Individual Assessment
Group Projects - Assessor Final review before next week submission. Signalling: 1 Wnt | 2 Notch | 3 FGF Receptor | 4 Hedgehog | 5 T-box | 6 TGF-Beta