2010 BGD Practical 6 - Week 8

From Embryology

Introduction

BGDsmall.jpg

Practical 6: Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8 | Quiz


Key Events of Human Development during the eighth week (week 8) following fertilization or Clinical week 10 (LMP).

Practical Audio

Mark Hill.jpg

BGD Cycle A 2010 Audio - Dr Mark Hill Monday 17th May 2010 3-5pm G2G4.

Note - this is a live unedited recording from the practical and may contain errors in either descriptions or content.

listen Part 5 | download (1.8 Mb MP3 13:14)


This page will give an overview of limb and neural development and look at other system organization compared with the earlier stages.

Limbs

Human Embryo (Stage19) limb rotation
  • Limb upper and lower limbs rotate in different directions (upper limb dorsally, lower limb ventrally)
  • see also Adult dermatomes

Stage20-23 limbs a.jpg

Gastrointestinal Tract

Gastrointestinal tract herniation

Stage22-GIT-icon.jpg

Neural

Cross-section of head (stage 22) Neural - early developing cortex

Stage22-CNS-icon.jpg

Other Embryo Systems

Movies - Embryo Carnegie stage 22 - These are rotating animations based upon reconstruction of a human embryo (stage 22) serial slice images.

Stage22-CVS-icon.jpg Stage22-SK-icon.jpg Stage22-UG-icon.jpg
Cardiovascular Skeletal Urogenital

Critical Periods

Conceptus Embryonic development (weeks) Fetal period (weeks)
1
2
3
4
5
6
7
8
9
16
20-36
38
Early zygote.jpg Week2 001 icon.jpg Stage9 sem4c.jpg Stage13 sem1c.jpg Stage15 bf1c.jpg Stage17 bf1c.jpg Stage19 bf1c.jpg Stage23 bf1c.jpg
Neural
Stage2.jpg Heart
Upper limbs
Lower limbs
Ear
Eye
CSt3.jpg Palate
Teeth
Week2 001 icon.jpg External genitalia
Loss Major abnormalities Functional and Minor abnormalities



BGDsmall.jpg

Practical 6: Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8 | Quiz



   

Additional Information

Additional Information - Content shown under this heading is not part of the material covered in this class. It is provided for those students who would like to know about some concepts or current research in topics related to the current class page.


Detailed Week by Week

The following information is a detailed timeline of embryonic development between week 3 to 8 and content does not form part of the current practical class.

Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8


Embryo Stages and Events

Day Stage Event
50
Stage 20 Stage20 bf1c.jpg

Head scalp vascular plexus visible

Limb upper limbs begin to rotate ventrally

Neural amygdaloid body has at least four individual nuclei PMID: 2268071

oculomotor nerve shows a dorsolateral and a ventromedial portion

rhombic lip (rhombencephalon) formation of the cerebellum (intermediate layer) and of the cochlear nuclei

cerebellum cell layer (future Purkinje cells) develops

choroid plexuses of the fourth and lateral ventricles

51
  Gastrointestinal Tract anal membrane perforates
52
Stage 21 Stage21 bf1c.jpg

Neural cortical plate appears in the area of future insula PMID: 2252222

Limb upper and lower limbs rotate

Intraembryonic Coelom pericardioperitoneal canals close

53
   
54
Stage 22 Stage22 bf1c.jpgNeural neocortical fibres project to epithalamus, to dorsal thalamus, and to mesencephalon PMID: 2252222

Limb fingers and toes lengthen

Sense - Smell Stage 22 to early fetal period - migratory streams of neurons from the subventricular zone of the olfactory bulb towards the future claustrum PMID: 15604533

55
Genital 8 Weeks Testis - mesenchyme, interstitial cells (of Leydig) secrete testosterone, androstenedione

Genital 8 to 12 Weeks - hCG stimulates testosterone production

Tongue Week 8 - nerves penetrate epitheilai basal lamina and synapse with undifferentiated, elongated, epithelial cells (taste bud progenitor cell)

56
Stage 23 Stage23 bf1c.jpg [1]Stage 23 defines the end of the embryonic (organogenesis) period

Mesoderm heart prominence, ossification continues

Head nose, eye, external acoustic meatus, eyelids, external ears, rounded head

Body - straightening of trunk, heart, liver, umbilical cord, intestines herniated at umbilicus

Limb upper limbs longer and bent at elbow, hands and feet turned inward, foot with separated digits, wrist, hand with separated digits

Extraembryonic Coelom chorionic cavity is now lost by fusion with the expanding amniotic cavity

Neural rhombencephalon, pyramidal decussation present, nuclei and tracts similar to those present in the newborn cerebellum present as only a plate connected to midbrain and hindbrain through fibre bundles PMID: 2244584

Axial Skeleton vertebral column 33 or 34 cartilaginous vertebrae (20-33 mm in total length), vertebral pedicles, articular and transverse processes identifiable (no spinous processes) PMID: 7216919

 
Week 8 GIT - Stomach - Week 8 - Gastrin containing cells in stomach antrum. Somatostatin cells in both the antrum and the fundus.


BGDsmall.jpg

Practical 6: Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8 | Quiz



Glossary Links

Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link
2010 BGD: Lecture 1 | Lecture 2 | Practical 3 | Practical 6 | Practical 12

Cite this page: Hill, M.A. (2019, July 18) Embryology 2010 BGD Practical 6 - Week 8. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/2010_BGD_Practical_6_-_Week_8

What Links Here?
© Dr Mark Hill 2019, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G