File:Stage 22 image 217.jpg
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Human Embryo Developing Cortex
|Human embryo, Week 8, Carnegie stage 22 section from the neural tube at the level of the developing cortex. Inset (upper right) shows section overview and approximate level of section (red line). Developing cerebrum layer thicknesses are shown in microns.
Developing cortex will form from the thin outer layer called the cortical plate. The underlying layers transient structures that continue to supply cells to the cortex through fetal period, most of these layers will eventually be lost, except for a thin ventricular layer. Cells migrate out along radial glia that establish the initial columnar and layered structure of the cortex. Layers are named according to the nervous system revised terminology (1970)
A number of blood vessels can also be seen spanning the developing layers. In the adult, these vessels will be lined with non-fenestrated endothelial cells that together with other vascular cells (pericytes and vascular smooth muscle cells), glial cells (astrocytes and microglia) and neurons will form the "blood-brain barrier".
Developing ventricular space is cerebrospinal fluid (CSF) filled and the lateral ventricles form within the cortical region. The inset image shows lying within the lateral ventricles, the choroid plexus the modified vascular structure that forms and secretes the CSF.
Developing meninges layers lie outside the neural tube. The thin pia mater that closely covers the entire brain. The mesh-like arachnoid mater and the sub-arachnoid space that will also be CSF filled. The dense dura mater lies outside these 2 layers and under the skull, it cannot be seen in the enlarged image.
Low resolution image
|Neural Tube||Primary Vesicles||Secondary Vesicles||Adult Structures|
|week 3||week 4||week 5||adult|
|prosencephalon (forebrain)||telencephalon||Rhinencephalon, Amygdala, hippocampus, cerebrum (cortex), hypothalamus, pituitary | Basal Ganglia, lateral ventricles|
|diencephalon||epithalamus, thalamus, Subthalamus, pineal, posterior commissure, pretectum, third ventricle|
|mesencephalon (midbrain)||mesencephalon||tectum, Cerebral peduncle, cerebral aqueduct, pons|
|myelencephalon||medulla oblongata, isthmus|
|spinal cord, pyramidal decussation, central canal|
- Links: Image - cortex overview | Image - cortex layers | Image - high resolution version | Cerebrum Development | Meninges Development
Note this section image is vertically flipped compared with original serial section images.
|Selected Embryo Histology - Week 8 (Stage 22)|
|Links: Carnegie stage 22 | Week 8|
|Stage 22 Links: Week 8 | System Development | Lecture - Limb | Lecture - Head Development | Lecture - Sensory | Science Practical - Head | Science Practical - Sensory | Science Practical - Urogenital | Historic - Skull Development | Carnegie Embryos | Madrid Embryos | Category:Carnegie Stage 22 | Next Stage 23|
|Week 8, GA week 10, 54 - 56 days, CRL 23 - 28 mm, Carnegie Embryos|
|Historic Papers: 1914 | 1954 Stage 19-23|
- Carnegie Stages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | About Stages | Timeline
|Carnegie stage:||1 2 3 4||5 6||7 8 9||10 11 12 13||14 15||16 17||18 19||20 21 22 23|
Cite this page: Hill, M.A. (2020, February 29) Embryology Stage 22 image 217.jpg. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/File:Stage_22_image_217.jpg
- © Dr Mark Hill 2020, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G
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|current||02:09, 23 August 2011||1,200 × 820 (323 KB)||S8600021||==Human Embryo Developing Cortex== * Week 8, Carnegie stage 22 * Note this section image is vertically flipped compared with serial original serial images. :Links: Neural System Development Cortex-with-section-insert-4.jpg (scan 35815 cropped and sc|