Talk:Carnegie stage 22 - serial sections
Labeled Image Description Table
Section | Name | Description |
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A1L | Description | |
A2L | Description | |
A3L | Description | |
A4L | Description | |
A5L | Description | |
A6L | Description | |
A7L | Description | |
B1L | Description | |
B2L | Description | |
B3L | Description | |
B4L | Description | |
B5L | Description | |
B6L | Description | |
B7L | Description | |
C1L | Description | |
C2L | Description | |
C3L | Description | |
C4L | Description | |
C5L | Description | |
C6L | Description | |
C7L | Description | |
D1L | Description | |
D2L | Description | |
D3L | Description | |
D4L | Description | |
D5L | Description | |
D6L | Description | |
D7L | Description | |
E1L | Description | |
E2L | Description | |
E3L | Description | |
E4L | Description | |
E5L | Description | |
E6L | Description | |
E7L | Description | |
F1L | Description | |
F2L | Description | |
F3L | Description | |
F4L | Description | |
F5L | Description | |
F6L | Description | |
F7L | Description | |
G1L | Description | |
G2L | Description | |
G3L | Description | |
G4L | Description | |
G5L | Description | |
G6L | Description | |
G7L | Description |
Unlabeled Image Files
Stage 22 image 001.jpg | Stage 22 image 002.jpg | Stage 22 image 003.jpg | Stage 22 image 004.jpg | Stage 22 image 005.jpg | Stage 22 image 006.jpg | Stage 22 image 007.jpg | Stage 22 image 008.jpg | Stage 22 image 009.jpg | Stage 22 image 010.jpg | Stage 22 image 011.jpg | Stage 22 image 012.jpg | Stage 22 image 013.jpg | Stage 22 image 014.jpg | Stage 22 image 015.jpg | Stage 22 image 016.jpg | Stage 22 image 017.jpg | Stage 22 image 018.jpg | Stage 22 image 019.jpg | Stage 22 image 020.jpg | Stage 22 image 021.jpg | Stage 22 image 022.jpg | Stage 22 image 023.jpg | Stage 22 image 024.jpg | Stage 22 image 025.jpg | Stage 22 image 026.jpg | Stage 22 image 027.jpg | Stage 22 image 028.jpg | Stage 22 image 029.jpg | Stage 22 image 030.jpg | Stage 22 image 031.jpg | Stage 22 image 032.jpg | Stage 22 image 033.jpg | Stage 22 image 034.jpg | Stage 22 image 035.jpg | Stage 22 image 036.jpg | Stage 22 image 037.jpg | Stage 22 image 038.jpg | Stage 22 image 039.jpg | Stage 22 image 040.jpg | Stage 22 image 041.jpg | Stage 22 image 042.jpg | Stage 22 image 043.jpg | Stage 22 image 044.jpg | Stage 22 image 045.jpg | Stage 22 image 046.jpg | Stage 22 image 047.jpg | Stage 22 image 048.jpg | Stage 22 image 049.jpg
Labeled Image Files
Stage 22 image 050.jpg | Stage 22 image 051.jpg | Stage 22 image 052.jpg | Stage 22 image 053.jpg | Stage 22 image 054.jpg | Stage 22 image 055.jpg | Stage 22 image 056.jpg | Stage 22 image 057.jpg | Stage 22 image 058.jpg | Stage 22 image 059.jpg | Stage 22 image 060.jpg | Stage 22 image 061.jpg | Stage 22 image 062.jpg | Stage 22 image 063.jpg | Stage 22 image 064.jpg | Stage 22 image 065.jpg | Stage 22 image 066.jpg | Stage 22 image 067.jpg | Stage 22 image 068.jpg | Stage 22 image 069.jpg | Stage 22 image 070.jpg | Stage 22 image 071.jpg | Stage 22 image 072.jpg | Stage 22 image 073.jpg | Stage 22 image 074.jpg | Stage 22 image 075.jpg | Stage 22 image 076.jpg | Stage 22 image 077.jpg | Stage 22 image 078.jpg | Stage 22 image 079.jpg | Stage 22 image 080.jpg | Stage 22 image 081.jpg | Stage 22 image 082.jpg | Stage 22 image 083.jpg | Stage 22 image 084.jpg | Stage 22 image 085.jpg | Stage 22 image 086.jpg | Stage 22 image 087.jpg | Stage 22 image 088.jpg | Stage 22 image 089.jpg | Stage 22 image 090.jpg | Stage 22 image 091.jpg | Stage 22 image 092.jpg | Stage 22 image 093.jpg | Stage 22 image 094.jpg | Stage 22 image 095.jpg | Stage 22 image 096.jpg | Stage 22 image 097.jpg | Stage 22 image 098.jpg
Icon Table 80px size
Icon Table 100px size
Icon Table 120px size
Image Files
Unlabeled
Stage 22 image 01.jpg Stage 22 image 02.jpg Stage 22 image 03.jpg Stage 22 image 04.jpg Stage 22 image 05.jpg Stage 22 image 06.jpg Stage 22 image 07.jpg Stage 22 image 08.jpg Stage 22 image 09.jpg Stage 22 image 010.jpg Stage 22 image 011.jpg Stage 22 image 012.jpg Stage 22 image 013.jpg Stage 22 image 014.jpg Stage 22 image 015.jpg Stage 22 image 016.jpg Stage 22 image 017.jpg Stage 22 image 018.jpg Stage 22 image 019.jpg Stage 22 image 020.jpg Stage 22 image 021.jpg Stage 22 image 022.jpg Stage 22 image 023.jpg Stage 22 image 024.jpg Stage 22 image 025.jpg Stage 22 image 026.jpg Stage 22 image 027.jpg Stage 22 image 028.jpg Stage 22 image 029.jpg Stage 22 image 030.jpg Stage 22 image 031.jpg Stage 22 image 032.jpg Stage 22 image 033.jpg Stage 22 image 034.jpg Stage 22 image 035.jpg Stage 22 image 036.jpg Stage 22 image 037.jpg Stage 22 image 038.jpg Stage 22 image 039.jpg Stage 22 image 040.jpg Stage 22 image 041.jpg Stage 22 image 042.jpg Stage 22 image 043.jpg Stage 22 image 044.jpg Stage 22 image 045.jpg Stage 22 image 046.jpg Stage 22 image 047.jpg Stage 22 image 048.jpg Stage 22 image 049.jpg
Labeled
Stage 22 image 0aseries.jpg Stage 22 image 0RegisterA.jpg Stage 22 image 0Untitled.txt Stage 22 image 050.jpg Stage 22 image 051.jpg Stage 22 image 052.jpg Stage 22 image 053.jpg Stage 22 image 054.jpg Stage 22 image 055.jpg Stage 22 image 056.jpg Stage 22 image 057.jpg Stage 22 image 058.jpg Stage 22 image 059.jpg Stage 22 image 060.jpg Stage 22 image 061.jpg Stage 22 image 062.jpg Stage 22 image 063.jpg Stage 22 image 064.jpg Stage 22 image 065.jpg Stage 22 image 066.jpg Stage 22 image 067.jpg Stage 22 image 068.jpg Stage 22 image 069.jpg Stage 22 image 070.jpg Stage 22 image 071.jpg Stage 22 image 072.jpg Stage 22 image 073.jpg Stage 22 image 074.jpg Stage 22 image 075.jpg Stage 22 image 076.jpg Stage 22 image 077.jpg Stage 22 image 078.jpg Stage 22 image 079.jpg Stage 22 image 080.jpg Stage 22 image 081.jpg Stage 22 image 082.jpg Stage 22 image 083.jpg Stage 22 image 084.jpg Stage 22 image 085.jpg Stage 22 image 086.jpg Stage 22 image 087.jpg Stage 22 image 088.jpg Stage 22 image 089.jpg Stage 22 image 090.jpg Stage 22 image 091.jpg Stage 22 image 092.jpg Stage 22 image 093.jpg Stage 22 image 094.jpg Stage 22 image 095.jpg Stage 22 image 096.jpg Stage 22 image 097.jpg Stage 22 image 098.jpg
Link Files
Unlabeled
Stage 22 (serial unlabeled images): 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49
Labeled
Stage 22 (serial labeled images): | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 90 | 91 | 92 | 93 | 94 | 95 | 96 | 97 | 98
Table with numbers
1 | 2 | 3 | 4 | 5 | 6 | 7 |
8 | 9 | 10 | 11 | 12 | 13 | 14 |
15 | 16 | 17 | 18 | 19 | 20 | 21 |
22 | 23 | 24 | 25 | 26 | 27 | 28 |
29 | 30 | 31 | 32 | 33 | 34 | 35 |
36 | 37 | 38 | 39 | 40 | 41 | 42 |
43 | 44 | 45 | 46 | 47 | 48 | 49 |
Labeled Icon Table (80px)
Labeled Icon Table (100px)
Labeled Icon Table (120px)
Labeled Icon Table (120px) with numbers
50 | 51 | 52 | 53 | 54 | 55 | 56 |
57 | 58 | 59 | 60 | 61 | 62 | 63 |
64 | 65 | 66 | 67 | 68 | 69 | 70 |
71 | 72 | 73 | 74 | 75 | 76 | 77 |
78 | 79 | 80 | 81 | 82 | 83 | 84 |
85 | 86 | 87 | 88 | 89 | 90 | 91 |
92 | 93 | 94 | 95 | 96 | 97 | 98 |
Original System Descriptions
(Some Links will not function, section naming has been changed)
Cardiovascular System Development- Stage 22
Introduction
This page shows the Carnegie stage 22 embryo images that relate to cardiac development. The small image excerpts show specific features, which can then be observed in the linked complete sections.
Stage 22 Embryo
These are scaled image excerpts, click on image or section name to see full size section for details.
File:E4.gif | E4: In centre of picture, portion of left ventricle wall.
Righthandside- body wall. Lefthand side- diaphragm and liver. Centre bottom- oseophagus, thoracic aorta, and inferior vena cava. |
File:E3.gif | E3: Section through all four chambers of heart.
Ventricles. Diaphragm and liver. Pericardium and cavity. R atrium and two cusps of the atrioventricular valve. L atrium and its auricle. Thoracic aorta. Inferior vena cava. Coronary sinus. |
File:E2.gif | E2: Section through all four chambers of heart.
Ventricles. Right venous valve. Between the tiny ridge of the septum secundum of the R atrium and the R venous valve. right atrium- drainage of the inferior vena cava (cf. E3). R atrioventricular canal. Septum primum. left atrium- drainage sites of R and L pulmonary veins. |
File:E1.gif | E1: Section through all four chambers of heart.
left ventricle- outflow tract close to origin of ascending aorta. Deep coronary sulcus and transverse pericardial sinus. right atrium- R venous valve of the inferior vena cava, the small septum secundum, the aperture in the dorsal part of septum primum (ostium secundum). (The foramen ovale arises later with the elongation of the septum secundum). left atrium- entrance of the L and R pulmonary veins and the auricle. |
File:D7.gif | D7: R atrium with R venous valve. R ventricle close to origin of pulmonary trunk. L.ventricular wall and three semilunar valves of aortic ostium. |
File:D6.gif | D6: Superior vena cava. Ascending aorta with transverse pericardial sinus behind. Semilunar valve at origin of pulmonary trunk. L. atrium and auricle. Thoracic aorta. |
File:D5.gif | D5: Superior vena cava. Ascending arch of aorta. Pulmonary trunk with the other two semilunar valves.
Sinus above one valve and branching of pulmonary trunk into L and R pulmonary arteries. |
File:D4.gif | D4: Ascending aorta. Pulmonary trunk and arteries. Thoracic aorta. Oesophagus. Bronchi. Note azygos vein on right, and precursor of hemiazygos vein on left side.
(Image excerpt different scale from previous images) |
File:D3.gif | D3: Ascending aorta attached cranial to transverse pericardial sinus. Superior vena cava expanding into R jugular vein. Trachea (bifurcation). Oesophagus. Azygos (R) and hemiazygos (L) veins. |
File:D2.gif | D2: Aortic arch. L jugular lymph sac lying laterally with hemiazygos joining it. Trachea. Oesophagus. Draining of azygos vein into R jugular vein. |
File:D1.gif | Dl: Aortic arch. Thymus (retrosternal). Trachea. Oesophagus. Large L and R jugular veins. |
File:C7.gif | C7: L brachiocephalic vein (transverse anastomosis of L, R jugular veins). L common carotid artery. Brachiocephalic trunk. |
File:C6.gif | C6: L and R common carotid arteries. L and R internal jugular veins. |
Coelomic Cavity Development
Introduction
The intraembryonic coelom is the primitive cavity that lies within the developing embryo that will form the 3 major body cavities: pericardial, pleural, peritoneal. The coelom forms very early in embryogenesis and is much later paritioned inferiorly by the diaphragm and pleuroperitoneal membrane; and superiorly initially by the pleuropericardial fold between the heart and lungs.
The intraembryonic coelom communicated through coelomic portals (at the level of midgut herniation) with the extraembryonic coelom.
All cavities are fluid filled and developing organs push against a wall of the cavity, generating a double coat (serosal/adventital) surrounding an organ (for example the lungs). The serous membrane is the epithelium (squamous) and its associated underlying loose connective tissue.
==== Stage 22 Embryo (Human) ====
|
In the human embryo, the separation of the three cavities of coelom is complete.
D1-7&E1-4 : The pericardial cavity. Dl-7, E1-7: The pleural cavity, almost the same frames, indicating the nearby equal extent of the two cavities at this stage, but also that eventually the pleural cavities will become much larger. E3-7: The diaphragm can be seen as a thin, distinct membrane around the liver. Two derivatives of the coelomic epithelium are to be observed here. E6-7, F1-3: The adrenal glands. Notice the large fetal cortex, (most of the gland) and the narrow (more compact and darker staining) early permanent cortex encapsulating it. F1-3: The spleen develops in the dorsal mesogastrium and appears as a dense body on it lateral to the left adrenal gland and kidney. Review in Endocrine Development. F3-7, G1: The gonads are also in part derivatives of the coelomic epithelium but they will be discussed with the rest of the genital system. G4-5: The caudal extent of the peritoneal cavity; this appears as the rectovesical pouch in the male or as the rectouterine pouch in the female. |
 
Reading
- Human Embryology (2nd ed.) Larson
- Ch6 p127-146
- The Developing Human: Clinically Oriented Embryology (6th ed.) Moore and Persaud
- Ch9: p174-184
- Before we Are Born (5th ed.) Moore and Persaud
- Ch10 p181-195
- Essentials of Human Embryology Larson
- Ch6 p81-93
- Human Embryology Fitzgerald and Fitzgerald
- Ch5 p29-32, Ch7 p47,48
- Additional References
- Search PubMed- [coelom2.htm#PubMed Medline]
Objectives
- Describe the development of the intra- and extra-embryonic coeloms.
- Describe the processes involved in the development of the three divisions of the intra-embryonic coelom; pericardium, pleural cavities and peritoneum.
- Describe the fate of the extra embryonic coelom.
- Describe the development of the diaphragm.
Learning activities
- Review the development of the 3-layered embryo, with particular reference to the antero-posterior and lateral folding processes.
- Examine the 6mm pig and 27mm human embryo microfiche cards identifying the main features of the developing coelom.
- Identify the diaphragm in the 27mm human embryo and relate this to the development of the diaphragm.
- Discuss the developmental anomalies associated with the formation of the diaphragm.
Computer Activities
UNSW Embryology: [coelom3.htm Pig coelom sections (st13/14) | ][coelom4.htm Human coelom sections (st22) | ][coelom4.htm#high%20power Selected Human highpower (st22)]
Human Embryology Movies:
Embryo Images Unit: Body Cavities (Early Week 4) | Body Cavities (Late Week 4)
Development Overview
Cartoon of the intraembryonic coelom forming in the lateral plate mesoderm
==== Extraembryonic Coelom ====
|
==== Intraembryonic Coelom ====
|
==== Neural Tube ====
| |
Mesothelia
The epithelial covering of coelomic organs and also line their cavities.
Contribute to the vasculature of the heart and the intestinal tract. Undergo epithelial-mesenchymal transition (EMT), migration, and differentiation into endothelial cells, vascular smooth muscle cells, and pericytes.
Development of the Kidney and Reproduction Systems
Stage 22 Urogenital 3D Model
The individual serial slices have also been incorporated into a 3D model of this embryo [UG3dmodelst22.htm Urogenital System].
Stage 22 Embryo (Human) Urinary System
E6: R,L adrenal glands under diaphragm.
E7: Large adrenal glands. Inferior vena cava. Thoracic aorta. |
File:Hf1.gif | File:Hf2.gif | File:Hf3.gif |
Fl: Adrenal glands. R. Kidney. Autonomic ganglia (partly the adrenal medulla precursors). | F2: Kidneys (note retroperitoneal location). Cortex. Medulla. L. Adrenal gland. Superior mesenteric artery. Inferior vena cava. | F3: R testis (note its location relative to the R adrenal). L adrenal. R renal hilus. large channels are branches of ureteric tree. | |
File:Hf4.gif | File:Hf5.gif | File:Hf6.gif | File:Hf7.gif |
F4: R kidney and R ureter. Inferior vena cava. L. kidney, L renal hilus and L ureter. R testis with R mesonephric duct (precursor of vas deferens). L testis. Umbilical arteries passing into umbilical cord allantois between them. | F5: Kidneys. Ureters. Note umbilical arteries and allantois. Also note how R testis and mesonephric structures are attached to parietal peritoneum by a mesogonad. | F6: Kidneys. Ureters. Note umbilical arteries and allantois. Also note how R testis and mesonephric structures are attached to parietal peritoneum by a mesogonad. | F7: In F7, (dorsal to R testis and liver) note with the distinct lumen of the mesonephric duct, almost solid column of paramesonephric cells and remnants of mesonephric tubules. "mesogonad". Ureters. Bladder with submucosa and detrusor muscle. Umbilical arteries. Division of aorta. |
File:Hg1.gif | File:Hg2.gif | File:Hg3.gif | File:Hg4.gif |
G1: Ureters, Bladder. Umbilical arteries. Testis with remains of mesonephros (dorsal), mesonephric duct and paramesonephric cells. Sigmoid colon and mesocolon. | G2: Ureters being displaced ventrally, crossing common iliac arteries. Sigmoid colon. Bladder. Mesonephric ducts (lateral) and paramesonephric ducts (smaller, medial) located dorsal to bladder. | G3: Ureters (cut twice): descending dorsal to bladder and ascending ventrally to enter the bladder at trigone, through the submucosa). Fusion of paramesonephric ducts. Paired mesonephric ducts. Umbilical arteries looping off common iliac arteries. Pubic symphysis. Colon. | G4: Most caudal part of loop of ureters. Urethra emerging from bladder. Mesonephric ducts. Rectocolic junction. |
File:Hg5.gif | File:Hg6.gif | File:Hg7.gif | |
G5: Urethra (in region of future prostate gland - note crescentic shape). Rectum. Rectovesical pouch. Between G4 and G5, each mesonephric duct (vas deferens) has joined the prostatic urethra (caudal to the ureters), thereby increasing the caliber of the latter. | G6: Penile urethra, emerging inferiorly to the glans penis. Scrotal swellings (appear before testis descends). | G7: Penile urethra, emerging inferiorly to the glans penis. Scrotal swellings (appear before testis descends). | Note F7 MS term: "inebriated Puffin" (dorsal to R testis and liver) lumen of the mesonephric duct (eye), almost solid column of paramesonephric cells (beak) and remnants of mesonephric tubules (body). |
Stage 22 Embryo (Human) Genital System (Male) ([#Female also see Female]) | |||
File:Hf3.gif | File:Hf4.gif | File:Hf5.gif | File:Hf6.gif |
F3: R testis with thick tunica albuginea (pale) and thin urogenital mesentery.Note spleen on L. | F4: Testes. Narrow urogenital mesentery. Remains of mesonephric tubules near hilus (future efferent ductules at mediastinum testis). | F5: Broader urogenital mesentery on R (still narrow on L). | F6: On R: Remnants of mesonephric tubules (primordia of ductuli efferentes). Mesonephric duct (origin of vas deferens). Laterally, the paramesonephric duct (primordia of appendix testis). Note abdominal location of testes in relation to adjacent structures. |
File:Hf7.gif | File:Hg1.gif | File:Hg2.gif | File:Hg3.gif |
F7: Developing efferent ductules, mesonephric duct and medially, the paramesonephric duct (appearing solid). Note how the paramesonephric duct crossed the mesonephric duct ventromedially. Urogenital mesentery - note how testis is attached to the developing efferent ductules by a separate narrow flange,the mesorchium. | G1: On R: Lateral mesonephric duct and medial paramesonephric groove. (Changing from a tube to a groove). On L: testis (lower than on R), mesonephric tubules, mesonephric duct (lateral), paramesonephric duct (ventromedial - appearing solid).Bladder. Umbilical arteries. Sigmoid colon and mesocolon. | G2: Transition from abdominal cavity to superior pelvis. note iliac crest, femoral nerve, psoas major muscle, internal iliac vein and artery. Medial convergence of paramesonephric cords and more laterally-located mesonephric ducts, ventral to the colon and dorsal to the bladder. Note position of ureters. N.B. Testis lies above this level which is close to the plane of the future inguinal canal. | G3: Transition from superior (major) pelvis to inferior (minor) pelvis. Rectovesical pouch. Note wide expanse of loose tissue ventral to the pubic symphysis: site of testicular descent. |
File:Hg4.gif | File:Hg5.gif | File:Hg6.gif | File:Hg7.gif |
G4: Transition from superior (major) pelvis to inferior (minor) pelvis. Rectovesical pouch. Note wide expanse of loose tissue ventral to the pubic symphysis: site of testicular descent. | External genitalia (male)G5: Minor pelvis. Obturator foramen. Ischium. Head of femur. Acetabulum. Ganglion cells of pelvis plexus. Obturator externus muscle. Urogenital sinus (the caudal enlargement is due to junction of mesonephric ducts). | G6:Level of pelvic floor. Pelvic plexus. Recto-anal junction. Ischium. obturator internus muscle. Greater sciatic notch. Alar of sacrum. Sacro-iliac joint. | G7: Urethra opening ventrally. Genital tubercle (embryonic glans penis). |
Endocrine Development Stage 22
Introduction
By stage 22 thre are now visible many components of the endocrine system. Note the appearance and position of the glands within the embryo. In particular, the now more mature Thyroid and the more structured Pituitary.
Both these and other endocrine glands of this stage can be seen in more detail on the [endocrine5.htm Selected Stage 22] page.
Stage 22
List of serial section images containing endocrine components.
A6: Thalamus/hypothalamus.
B2: Neurohyophysis and adenohypophysis. Remnant of Rathke's pouch (residual lumen) in adenohypophysis.
B3: Adenohypophysis.
C3: Glottic region with cricoid cartilage and descending process of thyroid cartilage laterally.
C4: Section damaged, but shows thyroid gland lateral to trachea.
C5: Thyroidgland.
Dl: Thymus gland.
E6: R,L adrenal glands under diaphragm.
E7: Large adrenal glands.
Fl: Adrenal glands. R. Kidney. Autonomic ganglia (partly the adrenal medulla precursors).
F2: Kidneys (note retroperitoneal location). Cortex. Medulla. L. Adrenal gland.
=== Development of the organs of Vision, Audition, Equilibrium and Olfaction
Introduction
Embryo Stage 22 - Eye
File:Ha6.gif | A6:Interorbital ligament. Nose. uppereyelids. Cornea. Anteriorchamber. Lens. Vitreous body. Sensory retina. optic ventricle (artefact). Pigment epithelium. Conjunctivalsac. Primordium of lacrimal glands (near lateral fornix of conjunctival sac). |
File:Ha7.gif | A7: Medial rectus m. Primordium of nasolacrimal ducts. Upper eyelid (lateral). Lower eyelid (medial). |
File:Hb1.gif | B1: Optic nerve. Note extensive temporal region of retina. Primordium of nasolacrimal ducts. |
File:Hb2.gif | B2: Medial and lateral rectus muscles. Pigment epithelium. Note relationship of eye to nasal capsule, sphenoid cartilage and trigeminal ganglion. Primordium of nasolacrimal ducts (cut obliquely). |
File:Hb3.gif | B3: On left, note course of maxillary division of trigeminal in relation to position of eye (superior to this level). |
Embryo Stage 22 - Ear
File:Hb3ear.gif | B3: Rhombic lip (developing cerebellum). IVth ventricle. Trigeminal ganglion. Adenohypophysis. Sphenoid cartilage. |
File:Hb4ear.gif | B4: Cochlear duct and temporal cartilage. Semicircular duct (ampulla on L). precartilage of auricle (pinna). malleus (medial, L). Incus (lateral, L). |
File:Hb5.gif | B5: Extemal auditory meatus. Auricle. Incus (dorsal). Malleus (ventral). Tubotympanic recess (auditory rube). Tensor tympani m. (L). Utricle. Semicircular ducts. Intemal auditory meatus (R), containing vestibular and spiral ganglia. Endolymphatic sac (L). Note proximity of sac to choroid plexus of 4th ventricle. |
File:Hb6.gif | B6: External auditory meatus. Primordium of tympanic membrane (L). Manubrium of malleus(L). Basal turn of cochlea duct (L). Endolymphatic sac (R). Common crus (R). Junction of utricle and saccule (R). Meckel's cartilage. Stapes (R). Auditory tube. |
Embryo Stage 22 - Nose
File:Ha6n.gif | A6: Interorbital ligament. nasal septum. primitive olefactory epithelium |
File:Ha7n.gif | A7: Interorbital ligament. nasal septum. superior concha and meatus. primitive olefactory epithelium |
File:Hb1n.gif | B1: |
File:Hb2n.gif | B2: vomeronasal organs (dark spots) beside nasal septum |
File:Hb3n.gif | B3: nasolacrimal ducts |
File:Hb4n.gif | B4: tongue |
File:Hb5n.gif | B5: unfused palatale shelves either side of tongue. section through mandible (top of image). |
Head and Neck Development - Stage 22
Introduction
This current page gives a brief overview of late embryonic development (Carnegie stage 22) in the head and neck region.
Stage 22 Embryo
Optic and Nasal region of head.
Stage 22 Embryo - Sections by Text
A text description linked to the actual embryo cross-section.
A5: Root of nose with interorbital ligament behind. Developing calvaria. Olfactory bulbs.
A6: Nose. Interorbital ligament. Nasal septum and nasal capsule. Eyes and eyelids. Thalamus/hypothalamus. Part of circle of Willis.
A7: Eyes. Nasal septum. Middle conchae. Sphenoid cartilage.
B1: Optic nerve.
B2: Neurohyophysis and adenohypophysis. Remnant of Rathke's pouch (residual lumen) in adenohypophysis. Trigeminal ganglion. Internal carotid arteries. Vomeronasal organs, lateral to nasal septum. Nasal plug (transient). Nasal conchae.
B3: Trigeminal nerve and ganglion, with maxillary division emerging. Pterygopalatine ganglion. Nasalconchae. Adenohypophysis.
B4: Tongue. Otic capsule. Cochlea. Between B3 and B4, the junction of nasopharynx and oropharynx.
B5: Tongue with palatal process either side. Pharyngotympanic tubes (Eustachian tube -derived from pharyngeal pouch 1). External ear pinna.
Overview of Pharynx
From level of tongue (B6) to bifurcation of the bronchi (D5-D6).
B4: Tongue. Otic capsule. Cochlea. Between B3 and B4, the junction of nasopharynx and oropharynx.
B5: Tongue with palatal process either side. Pharyngotympanic tubes (Eustachian tube -derived from pharyngeal pouch 1). External ear pinna.
B6: External auditory meatus (from pharyngeal groove 1). Meckel's cartilage with mandible ossifying lateral to it. Tongue with intrinsic muscles. palatal processes.Developing teeth.
B7: Pharynx (compressed dorsoventrally). Mylohyoid muscle and submandibular gland. Platysma muscle (R side). Junction of sigmoid sinus and internal jugular vein on one side. Vagal ganglia (medial). Vertebral arteries.
C1: Pharynx. Carotid neurovascular bundle with prominent ganglia.
C2: Pharynx. Carotidneurovascularbundle. Sternomastoidmuscle.
C3: Glottic region with cricoid cartilage and descending process of thyroid cartilage laterally. Carotidneurovascularbundle.
C4: Section damaged, but shows thyroid gland lateral to trachea. Oesophagus.
C5: Thyroidgland. Trachea. Oesophagus. Recurrent laryngeal nerve. Common carotid arteries. Jugular veins. Vagus nerves.
C6,C7: Jugular veins. In C7 brachiocephalic vein.
Dl: Thymus gland.
Musculoskeletal Development - Stage 22
Introduction
This page looks at musculoskeletal structure and events that occur at late embryonic Carnegie stage 22.
Axial Skeleton
The axial skeleton consists of: Skull, Auditory Ossicles, Hyoid bone, Vertebral column, Chest (sternum, ribs)
The vertebral column is a series of bone segments (vertebra) separated by specialized joints (intervertebral disc). In the adult, these vertebral elements are made up of rostro-caudally: 7 cervical, 12 thoracic, 5 lumbar, 1 sacrum, coccyx.
The axial skeleton is derived from mesoderm forming paraxial mesoderm forming somites from which part forms scleretomes forming vertebra and intervertebral discs (More? [../MolDev/vertebra.htm Molecular - Vertebral Column]).
File:Hd1.gif | D1,D2: Vertebral body (centrum). Head of rib. Lamina of vertebral arch. Transverse processes. Vertebral canal. Spinal cord. Dura. Intervertebral foramen containing dorsal root ganglion (now in a ventral position!). Ribs. Sympathetic ganglia. Costovertebral and costotransverse joints. Note that laminae of the arches have not fused dorsally but are united by a connective tissue membrane (dorsal uniting membrane or ligament) which provides the guide-path for the growth and subsequent fusion of the laminae. The dura constitutes the ventral uniting membrane or ligament. Part of intervertebral disc seen in D2. |
File:Hd3.gif | D3: Ganglia in intervertebral foramina. Costovertebral joint. |
File:Hd4no2.gif[1]File:Hd4.gif | D4: Anteriorly, note ribs joining the sternum and intercostal muscles
D4: Pedicle of vertebral arch. The dark, fibrous tissue at the anterior margin of the vertebral column is the intervertebral disc (derived from dark part of sclerotome). Note erector spinae group of muscles. |
File:He4.gif | E4: Vertebral body with intervertebral disc ventrally. Notochord remnant at junction of body and intervertebral disc. |
File:He6.gif | E6: Next vertebral body (notochord incorporated into cartilage). |
File:Hf1.gif | F1: Mostly intervertebral disc with notochord remnant |
File:Hf2.gif | F2: Transverse abdominal muscle, internal and external oblique abdominal muscle, rectus abdominis muscles. |
File:Hf7.gif File:Hg1.gif | F7,G1: (Lumbar cross-section). Vertebral body and I.V. disc. Psoas major muscle. Erector spinae muscles. Note short laminae of the arches and wide dorsal uniting ligament. |
Links: [../MolDev/vertebra.htm Molecular - Vertebral Column] |
Appendicular Skeleton
The appendicular skeleton consists of: Shoulder girdle, Upper limb (arm, hand), Pelvic girdle, Lower limb (leg, foot).
==== Lower limb (Row G) ==== | |
File:Hg1no2.gif | File:Hg2.gif |
G1: Knee mesenchyme | G2: Patella. Femur. Flexor and extensor muscles. |
File:Hg4.gif | File:Hg5.gif |
G4: Knee joint. Tibia and femur. Hip bone: pubis, ischium, ilium, head of femur. Developing acetabulum. Adductor group of muscles. | G5: Hip joint. Acetabulum. Head and greater trochanter of femur. Sacro-iliac joint. |
File:Hg6.gif | File:Hg7.gif |
G6: Heel. Ischium. Sacro-iliac joint. | G7: Tarsal cartilages (note inverted position of feet). Heel. Phalangeal cartilages. |
Musculoskeletal Development - Stage 22
Introduction
This page looks at musculoskeletal structure and events that occur at late embryonic Carnegie stage 22.
Axial Skeleton
The axial skeleton consists of: Skull, Auditory Ossicles, Hyoid bone, Vertebral column, Chest (sternum, ribs)
The vertebral column is a series of bone segments (vertebra) separated by specialized joints (intervertebral disc). In the adult, these vertebral elements are made up of rostro-caudally: 7 cervical, 12 thoracic, 5 lumbar, 1 sacrum, coccyx.
The axial skeleton is derived from mesoderm forming paraxial mesoderm forming somites from which part forms scleretomes forming vertebra and intervertebral discs (More? [../MolDev/vertebra.htm Molecular - Vertebral Column]).
File:Hd1.gif | D1,D2: Vertebral body (centrum). Head of rib. Lamina of vertebral arch. Transverse processes. Vertebral canal. Spinal cord. Dura. Intervertebral foramen containing dorsal root ganglion (now in a ventral position!). Ribs. Sympathetic ganglia. Costovertebral and costotransverse joints. Note that laminae of the arches have not fused dorsally but are united by a connective tissue membrane (dorsal uniting membrane or ligament) which provides the guide-path for the growth and subsequent fusion of the laminae. The dura constitutes the ventral uniting membrane or ligament. Part of intervertebral disc seen in D2. |
File:Hd3.gif | D3: Ganglia in intervertebral foramina. Costovertebral joint. |
File:Hd4no2.gif[2]File:Hd4.gif | D4: Anteriorly, note ribs joining the sternum and intercostal muscles
D4: Pedicle of vertebral arch. The dark, fibrous tissue at the anterior margin of the vertebral column is the intervertebral disc (derived from dark part of sclerotome). Note erector spinae group of muscles. |
File:He4.gif | E4: Vertebral body with intervertebral disc ventrally. Notochord remnant at junction of body and intervertebral disc. |
File:He6.gif | E6: Next vertebral body (notochord incorporated into cartilage). |
File:Hf1.gif | F1: Mostly intervertebral disc with notochord remnant |
File:Hf2.gif | F2: Transverse abdominal muscle, internal and external oblique abdominal muscle, rectus abdominis muscles. |
File:Hf7.gif File:Hg1.gif | F7,G1: (Lumbar cross-section). Vertebral body and I.V. disc. Psoas major muscle. Erector spinae muscles. Note short laminae of the arches and wide dorsal uniting ligament. |
Links: [../MolDev/vertebra.htm Molecular - Vertebral Column] |
Appendicular Skeleton
The appendicular skeleton consists of: Shoulder girdle, Upper limb (arm, hand), Pelvic girdle, Lower limb (leg, foot).
==== Lower limb (Row G) ==== | |
File:Hg1no2.gif | File:Hg2.gif |
G1: Knee mesenchyme | G2: Patella. Femur. Flexor and extensor muscles. |
File:Hg4.gif | File:Hg5.gif |
G4: Knee joint. Tibia and femur. Hip bone: pubis, ischium, ilium, head of femur. Developing acetabulum. Adductor group of muscles. | G5: Hip joint. Acetabulum. Head and greater trochanter of femur. Sacro-iliac joint. |
File:Hg6.gif | File:Hg7.gif |
G6: Heel. Ischium. Sacro-iliac joint. | G7: Tarsal cartilages (note inverted position of feet). Heel. Phalangeal cartilages. |
Neural System Development- Stage 22
Stage 22 Neural 3D Model
The individual serial slices have also been incorporated into a 3D model of this embryo [../Movies/CNS3dmodelst22.htm Neural System].
Serial Section Descriptions
Al-4 In the human embryo identify the large telencephalic vesicles and the choroid plexus. The cavity in these (the lateral ventricles) communicate with the ventricle of the diencephalon (3rd ventricle) through the interventricular foramen
A3: inside the lateral ventricle
Al-2: Distinguish the wall of the forebrain.
A3-4: The basal part of the telencephalon forms the basal ganglia, a solid mass. Posteromedially these basal ganglia are in contact with the diencephalon. The large masses in either side of the diencephalon form the thalami.
Al-7, B1: The diencephalon. In these levels the brain comes into section twice, because of the cephalic flexure, but in A2-4 the two parts are connected.
Al-5: Ventral to the thalamus you can identify the hypothalamus.
A6-7, B1: The hypothalamus
A6: the lamina terminalis, original anterior end of the neural tube. Notice the position of the optic nerves in relation to the hypothalamic part of the diencephalon (B1).
B2-3: Further caudally the pituitary gland is seen, the neural part of which is a derivative of the diencephalon.
Al-7: The midbrain (mesencephalon). Its dorsal part is the mesencephalic vesicle, a large, thin-walled structure (A2-6) which overlaps the initial part of the metencephalon (A6-7).( The ventral part of the mesencephalon is seen to be continuous with the diencephalon in A3-4. The tectal recess, an extension of the roof the mesencephalic vesicle is seen in A6.
A6: The junction between the mesencephalon and metencephalon is called the isthmus. The main metencephalic derivatives are the pons and cerebellum.
The ventricular lumen of the hind brain is the 4th ventricle (A7, B1-7, C1-3). The roof of the metencephalic part of the 4th ventricle is formed by the developing cerebellum (B2-3), beyond which the ventricle forms two large lateral recesses (B2-3). In more caudal sections the roof of the ventricle is seen as a thin membrane only, bearing choroid plexus.
B2-3: the root of the trigeminal nerve and its ganglion.
The myelencephalic part of the hind brain will form the medulla oblongata, the embryonic appearance of which is hardly different from the fully developed structure. The vagus nerve and its ganglion are seen to leave the base of the brain in B7, through the jugular foramen.
At all levels where the brain is present notice the meninges enveloping it and creating the large subarachnoid space which is filled with cerebrospinal fluid.
Study the histological appearance of the spinal cord. Note the alar and basal laminae, the dorsal root ganglia and the sympathetic trunk.