Template:Endocrine embryo table: Difference between revisions
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| [[Carnegie stage 16|'''Stage 16''']] (week 6) | | [[Carnegie stage 16|'''Stage 16''']] (week 6) | ||
* [[Endocrine - Pituitary Development|Pituitary]] - slight indication of the infundibular recess may be seen in some embryos | * [[Endocrine - Pituitary Development|Pituitary]] - slight indication of the infundibular recess may be seen in some embryos.<ref name=O'Rahilly1973a>{{Ref-O'Rahilly1973a}}</ref> | ||
* [[Endocrine - Pineal Development|Pineal]] - cellular migration in an external direction occurs in the pineal body during stages 16 and 17 (Stadium 2 of Turkewitsch<ref name=Turkewitsch1933>{{Ref-Turkewitsch1933}}</ref> (O'Rahilly 1968). | * [[Endocrine - Pineal Development|Pineal]] - cellular migration in an external direction occurs in the pineal body during stages 16 and 17 (Stadium 2 of Turkewitsch<ref name=Turkewitsch1933>{{Ref-Turkewitsch1933}}</ref> (O'Rahilly 1968). | ||
* Thymus - according to Norris (1938)<ref name=Norris1938>{{Ref-Norris1938}}</ref> , "not until the primordium of the parathyroid [3] has been outlined can the remaining portion of the third pouch be recognized, by exclusion, as the primordium of the endodermal thymus". | * Thymus - according to Norris (1938)<ref name=Norris1938>{{Ref-Norris1938}}</ref> , "not until the primordium of the parathyroid [3] has been outlined can the remaining portion of the third pouch be recognized, by exclusion, as the primordium of the endodermal thymus". | ||
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| [[Carnegie stage 17|'''Stage 17''']] | | [[Carnegie stage 17|'''Stage 17''']] | ||
* [[Endocrine - Pituitary Development|Pituitary]] - juxtacerebral wall of the craniopharyngeal pouch is the thicker. The lateral lobes (future infundibular, or tuberal, part) and the anterior chamber (Vorraum) are clearly visible | * [[Endocrine - Pituitary Development|Pituitary]] - juxtacerebral wall of the craniopharyngeal pouch is the thicker. The lateral lobes (future infundibular, or tuberal, part) and the anterior chamber (Vorraum) are clearly visible.<ref name=O'Rahilly1973a>{{Ref-O'Rahilly1973a}}</ref>The infundibular recess displays a characteristically folded wall, namely the neurohypophysis.<ref name=O'Rahilly1973a>{{Ref-O'Rahilly1973a}}</ref> | ||
* Thymus - connection of the thymus with the pharynx has been severed (Weller 1933). The thymus is intimately approximated to the cervical duct (ibid.) According to Norris (1937), both third and fourth pouches make contact with the ectoderm, although only the third "receives an increment from the ectoderm". | * Thymus - connection of the thymus with the pharynx has been severed (Weller 1933). The thymus is intimately approximated to the cervical duct (ibid.) According to Norris (1937), both third and fourth pouches make contact with the ectoderm, although only the third "receives an increment from the ectoderm". | ||
* [[Endocrine - Parathyroid Development|Parathyroids]] -parathyroid 4 is attached to the lateral surface of what Weller (1933)<ref name=Weller1933>{{Ref-Weller1933}}</ref> termed the "lateral thyroid component" | * [[Endocrine - Parathyroid Development|Parathyroids]] -parathyroid 4 is attached to the lateral surface of what Weller (1933)<ref name=Weller1933>{{Ref-Weller1933}}</ref> termed the "lateral thyroid component" | ||
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| [[Carnegie stage 18|'''Stage 18''']] (week 7) | | [[Carnegie stage 18|'''Stage 18''']] (week 7) | ||
* [[Endocrine - Pineal Development|Pineal]] - cellular migration in the pineal body forms a distinct "anterior lobe" in which follicles appear (Stadium 3 of Turkewitsch<ref name=Turkewitsch1933>{{Ref-Turkewitsch1933}}</ref>) | * [[Endocrine - Pineal Development|Pineal]] - cellular migration in the pineal body forms a distinct "anterior lobe" in which follicles appear (Stadium 3 of Turkewitsch<ref name=Turkewitsch1933>{{Ref-Turkewitsch1933}}</ref>)<ref name=O'Rahilly1973a>{{Ref-O'Rahilly1973a}}</ref> | ||
* Thymus- thymus makes contact with the thyroid gland and contains a series of canals internally (Weller 1933). | * Thymus- thymus makes contact with the thyroid gland and contains a series of canals internally (Weller 1933). | ||
* [[Endocrine - Thyroid Development|Thyroid]] - median thyroid is in contact with "lateral thyroid components"<ref name=Weller1933>{{Ref-Weller1933}}</ref>but others have maintained that the telopharyngeal body should not be regarded as a thyroid component (Bejdl and Politzer 1953). The lobes of the thyroid are "composed of series of continuously communicating solid annectent bars" this is "the earliest stage of the definitive thyroid".<ref name=Weller1933>{{Ref-Weller1933}}</ref> First differentiation occurs in Weller's (1933) "lateral thyroid component," which is beginning to "blend into uniformly constituted thyroid tissue". Weller (1933) illustrated (Fig. 11) a thyroid gland that still showed continuity between its pedicle and the epithelium of the pharynx. | * [[Endocrine - Thyroid Development|Thyroid]] - median thyroid is in contact with "lateral thyroid components"<ref name=Weller1933>{{Ref-Weller1933}}</ref>but others have maintained that the telopharyngeal body should not be regarded as a thyroid component (Bejdl and Politzer 1953). The lobes of the thyroid are "composed of series of continuously communicating solid annectent bars" this is "the earliest stage of the definitive thyroid".<ref name=Weller1933>{{Ref-Weller1933}}</ref> First differentiation occurs in Weller's (1933) "lateral thyroid component," which is beginning to "blend into uniformly constituted thyroid tissue". Weller (1933) illustrated (Fig. 11) a thyroid gland that still showed continuity between its pedicle and the epithelium of the pharynx. | ||
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| [[Carnegie stage 19|'''Stage 19''']] | | [[Carnegie stage 19|'''Stage 19''']] | ||
* [[Endocrine - Pituitary Development|Pituitary]] - the caudal part of the craniopharyngeal pouch is reduced to a closed epithelial stem | * [[Endocrine - Pituitary Development|Pituitary]] - the caudal part of the craniopharyngeal pouch is reduced to a closed epithelial stem.<ref name=Andersen1971>{{Ref-Andersen1971}}</ref> | ||
* [[Endocrine - Pineal Development|Epiphysis]] - the "anterior lobe" of the pineal body shows a characteristic step and wedge appearance (Stadium 4 of Turkewitsch<ref name=Turkewitsch1933>{{Ref-Turkewitsch1933}}</ref>) (O'Rahilly 1968). | * [[Endocrine - Pineal Development|Epiphysis]] - the "anterior lobe" of the pineal body shows a characteristic step and wedge appearance (Stadium 4 of Turkewitsch<ref name=Turkewitsch1933>{{Ref-Turkewitsch1933}}</ref>) (O'Rahilly 1968). | ||
* [[Endocrine - Parathyroid Development|Parathyroids]] - 3 become detached from the pharyngeal | * [[Endocrine - Parathyroid Development|Parathyroids]] - 3 become detached from the pharyngeal endoderm.<ref name=Jirasek1980>{{Ref-Jirasek1980}}</ref> | ||
* Adrenal Cortex - C2 cells lie on the surface of the gland and form a "capsule".<ref name=Crowder1957>{{Ref-Crowder1957}}</ref> | * Adrenal Cortex - C2 cells lie on the surface of the gland and form a "capsule".<ref name=Crowder1957>{{Ref-Crowder1957}}</ref> | ||
* Adrenal Medulla - Sympathicoblasts penetrate the cortex at stages 19 and 20, and form scattered islets of medullary tissue throughout the cortex | * Adrenal Medulla - Sympathicoblasts penetrate the cortex at stages 19 and 20, and form scattered islets of medullary tissue throughout the cortex.<ref name=Jirasek1980>{{Ref-Jirasek1980}}</ref> | ||
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| [[Carnegie stage 20|'''Stage 20''']] (week 8) | | [[Carnegie stage 20|'''Stage 20''']] (week 8) | ||
* [[Endocrine - Pituitary Development|Pituitary]] - the adenohypophysial epithelium adjacent to the neurohy- pophysis constitutes the beginning pars intermedia | * [[Endocrine - Pituitary Development|Pituitary]] - the adenohypophysial epithelium adjacent to the neurohy- pophysis constitutes the beginning pars intermedia.<ref name=O'Rahilly1973a>{{Ref-O'Rahilly1973a}}</ref> The walls of the craniopharyngeal pouch bud into the mesenchyme.<ref name=Andersen1971>{{Ref-Andersen1971}}</ref><ref name=Jirasek1980>{{Ref-Jirasek1980}}</ref> | ||
* Thymus - the right and left components are in contact with each other<ref name=Weller1933>{{Ref-Weller1933}}</ref> but are "never completely fused"<ref name=Norris1938>{{Ref-Norris1938}}</ref> <ref name=Siegler1969>{{Ref-Siegler1969}}</ref>). Thymic cortex appears (in stages 20-22) as a result, according to Norris | * Thymus - the right and left components are in contact with each other<ref name=Weller1933>{{Ref-Weller1933}}</ref> but are "never completely fused"<ref name=Norris1938>{{Ref-Norris1938}}</ref> <ref name=Siegler1969>{{Ref-Siegler1969}}</ref>). Thymic cortex appears (in stages 20-22) as a result, according to Norris | ||
(1938), of migration of and covering by "cells derived from the cervical sinus". | (1938), of migration of and covering by "cells derived from the cervical sinus". | ||
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| [[Carnegie stage 21|'''Stage 21''']] | | [[Carnegie stage 21|'''Stage 21''']] | ||
* [[Endocrine - Pituitary Development|Hypophysis]] - the pharyngeal stalk becomes fragmented | * [[Endocrine - Pituitary Development|Hypophysis]] - the pharyngeal stalk becomes fragmented.<ref name=Jirasek1980>{{Ref-Jirasek1980}}</ref> | ||
* [[Endocrine - Adrenal Development|Adrenal]] | * [[Endocrine - Adrenal Development|Adrenal]] | ||
** Adrenal Cortex - the cellular "capsule" becomes covered by a layer of fibrous tissue.<ref name=Crowder1957>{{Ref-Crowder1957}}</ref> | ** Adrenal Cortex - the cellular "capsule" becomes covered by a layer of fibrous tissue.<ref name=Crowder1957>{{Ref-Crowder1957}}</ref> | ||
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| [[Carnegie stage 22|'''Stage 22''']] | | [[Carnegie stage 22|'''Stage 22''']] | ||
* [[Endocrine - Parathyroid Development|Parathyroids]] - Parathyroids 4 become detached from the pharyngeal endoderm | * [[Endocrine - Parathyroid Development|Parathyroids]] - Parathyroids 4 become detached from the pharyngeal endoderm.<ref name=Jirasek1980>{{Ref-Jirasek1980}}</ref> | ||
* [[Endocrine - Adrenal Development|Adrenal]] | * [[Endocrine - Adrenal Development|Adrenal]] | ||
** Adrenal Cortex - the C2 cells have changed and resemble fibrocytes.<ref name=Crowder1957>{{Ref-Crowder1957}}</ref> | ** Adrenal Cortex - the C2 cells have changed and resemble fibrocytes.<ref name=Crowder1957>{{Ref-Crowder1957}}</ref> | ||
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| [[Carnegie stage 23|'''Stage 23''']] | | [[Carnegie stage 23|'''Stage 23''']] | ||
* Pituitary - adenohypophysis loss of the stalk and lobules of epithelium project into the mesodermal component of the gland, and oriented epithelial follicles are present (Streeter, 1951, plate 2). Abundant angioblasts and capillaries are found. | * Pituitary - adenohypophysis loss of the stalk and lobules of epithelium project into the mesodermal component of the gland, and oriented epithelial follicles are present (Streeter, 1951, plate 2). Abundant angioblasts and capillaries are found. | ||
* [[Endocrine - Pineal Development|Epiphysis]] - The pineal body has reached Stadium 5 of Turkewitsch | * [[Endocrine - Pineal Development|Epiphysis]] - The pineal body has reached Stadium 5 of Turkewitsch<ref name=Turkewitsch1933>{{Ref-Turkewitsch1933}}</ref><ref name=O'Rahilly1968>{{Ref-O'Rahilly1968}}</ref> | ||
* Thymus - The cortex is well-developed, "true lobulation" has begun with the appearance of" fine superficial scallops," lymphocytes are present sparsely in the subcortical zone, and vessels are found within the thymus | * Thymus - The cortex is well-developed, "true lobulation" has begun with the appearance of" fine superficial scallops," lymphocytes are present sparsely in the subcortical zone, and vessels are found within the thymus.<ref name=Norris1938>{{Ref-Norris1938}}</ref> | ||
* [[Endocrine - Adrenal Development|Adrenal]] | * [[Endocrine - Adrenal Development|Adrenal]] | ||
** Adrenal Cortex - It appears that C2 cells first enter the body of the gland at this stage. The pattern of the arterial supply is established. The cellular "capsule" is penetrated by arterial capillaries which join the sinusoids. Their points of entry give the surface of the gland an appearance of cobblestones. The zona glomerulosa is formed of CI and C3 cells. Cells from this zone and from the "capsule" migrate centrally into the cords.<ref name=Crowder1957>{{Ref-Crowder1957}}</ref> | ** Adrenal Cortex - It appears that C2 cells first enter the body of the gland at this stage. The pattern of the arterial supply is established. The cellular "capsule" is penetrated by arterial capillaries which join the sinusoids. Their points of entry give the surface of the gland an appearance of cobblestones. The zona glomerulosa is formed of CI and C3 cells. Cells from this zone and from the "capsule" migrate centrally into the cords.<ref name=Crowder1957>{{Ref-Crowder1957}}</ref> |
Revision as of 14:26, 1 November 2016
Human Embryonic Endocrine |
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Data based on data from O'Rahilly (1983).[1] |
Stage 13 (week 4)
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Stage 14 (week 5)
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Stage 15
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Stage 16 (week 6)
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Stage 17
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Stage 18 (week 7)
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Stage 19
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Stage 20 (week 8)
(1938), of migration of and covering by "cells derived from the cervical sinus".
Weller (1933, Fig. 23) showed parathyroid 3 still rostral to parathyroid 4 at 23 mm, whereas (presumably due to variation in the "descent" of the thymus) (Norris 1937, Fig. 4[14]) showed parathyroid 3 rostral to, level with, and caudal to parathyroid 4 in embryos of 16-17 mm. |
Stage 21
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Stage 22
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Stage 23
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References
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