Development of Endocrine glands & Muscles (Special Embryology)

Endocrine GlandsEndocrine Glands(51)(Page 151)

Dr.Sherif Fahmy

SUPRARENAL SUPRARENAL GLANDGLAND

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Suprarenal GlandSuprarenal Gland It has double origin:It has double origin:

Cortex:Cortex: from proliferating coelomic from proliferating coelomic epithelium (mesodermal) in 2 stages: epithelium (mesodermal) in 2 stages: fetal and permenant.fetal and permenant.

Medulla:Medulla: from neural crest, Chromaffin from neural crest, Chromaffin cells (ectodermal) which invaginate the cells (ectodermal) which invaginate the cortex.cortex.

Dr.Sherif Fahmy

Fate of adrenal cortex:1- Fetal cortex: regress rapidly leaving outer part to form zona reticularis.2- Permenant cortex: differentiate into zona glomerulosa and zona fasiculata.N.B. Zona glomerulosa and fasiculata are present since birth while reticularis becomes recognisable at 3rd year.

Dr.Sherif Fahmy

DEVELOPMENT OF DEVELOPMENT OF PITUITARY GLANDPITUITARY GLAND

(Page 153)(Page 153)

Dr.Sherif Fahmy

PITUITARY GLANDPITUITARY GLANDIt has double origin:It has double origin:1- 1- Rathke’s pouch:Rathke’s pouch: from roof of from roof of

stomodeum.stomodeum.2- 2- Infundibular process:Infundibular process: from from

floor of diencephalon.floor of diencephalon.Dr.Sherif Fahmy

L.S. in folded embryo

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Congenital Anomalies of Congenital Anomalies of Pituitary GlandPituitary Gland

1- 1- Agenesis:Agenesis: Failure of formation. Failure of formation.2- 2- Absent anterior lobe.Absent anterior lobe.3- 3- Craniopharyngioma:Craniopharyngioma: Tumour Tumour

from persistence of Rathke’s from persistence of Rathke’s pouch.pouch.

Dr.Sherif Fahmy

Development of Muscular Development of Muscular System System (Page 145)(Page 145)

Skeletal muscles:Skeletal muscles: from paraxial from paraxial mesoderm.mesoderm.

Smooth muscles: Smooth muscles: from from splanchnic mesoderm around splanchnic mesoderm around developing gut.developing gut.

Cardiac muscle:Cardiac muscle: from splanchnic from splanchnic mesoderm around heart tube.mesoderm around heart tube.

Dr.Sherif Fahmy

EMBRYONIC DISC• It is composed of three layers:

–Ectoderm which give rise to epidermis of skin, nervous system.

–Mesoderm which gives rise to skeletal, muscular and vascular systems.

–Endoderm which gives rise to mucosal lining of digestive, respiratory, heart and primitive germ cells.

Dr.Sherif Fahmy

INTRA-EMBRYONIC MESODERM• It is divided into 3 columns on each side

of notochord.1- Paraxial mesoderm which forms somites.2- Intermediate mesoderm forms uro-genital

system.3- Lateral plate mesoderm which forms

serous membranes of the body and muscles of body wall and limbs.

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Divisions of Intraembryonic Mesoderm

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Somites After Folding

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Striated Skeletal MusculatureStriated Skeletal MusculatureSkeletal muscles are developed from Skeletal muscles are developed from

somites which divides into:somites which divides into:Hypomeric portion:Hypomeric portion: ventrolateral part which ventrolateral part which

forms muscles of limbs and body wall. forms muscles of limbs and body wall. Epimeric portion:Epimeric portion: Dorsomedial part which Dorsomedial part which

forms extensor back muscles.forms extensor back muscles.N.B. Epimeric and hypomeric cells are called N.B. Epimeric and hypomeric cells are called

precursor muscle cells.precursor muscle cells...

Dr.Sherif Fahmy

Differentiation of a Somite

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Head Musculature- All voluntary muscles are developed

from paraxial mesoderm.- Muscles of iris are developed from

optic cup ectoderm.

Dr.Sherif Fahmy

Septum TransversumCranial part: Central tendon of diaphragm.Central mesenchyme: Hematopoietic cells in liver.Caudal region: in ventral mesogastrium.

Dr.Sherif Fahmy

Bucco-pharyngeal membrane

Cloacal membrane

Cardiogenic area

Notochord

Septum transversumPericardium

Pleura

Pleuro-peritoneal membrane

PeritoneumIntra-embryonic ceolom

Dr.Sherif Fahmy

Bucco-pharyngeal membrane

heart

Pericardium

Septum transversum

Pharynx

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Development of Diaphragm

(Page 157)Dr.Sherif Fahmy

Anatomy of Diaphragm

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Lower Aspect Inferior vena cava

Esophagus

Aorta

Rt. crusLt. crus

Central tendon

Dr.Sherif Fahmy

DIAPHRAGMDIAPHRAGM• It is developed from the following It is developed from the following

structuresstructures..1-1- Septum transversum:Septum transversum: It lies firstly infront It lies firstly infront

the pharynx in neck and forms central tendon.the pharynx in neck and forms central tendon.2- 2- Cervical myotomes (C3,4,5):Cervical myotomes (C3,4,5): Forms the Forms the

muscular part around the central tendon and muscular part around the central tendon and supplied by supplied by phrenic nervephrenic nerve..

3- 3- Pleuro-peritoneal membrane:Pleuro-peritoneal membrane: forms the forms the postero-lateral parts of the diaphragm.postero-lateral parts of the diaphragm.

4- 4- Meso-esophagus:Meso-esophagus: forms the median forms the median posterior part.posterior part.

5- 5- Mesoderm of thoracic wall:Mesoderm of thoracic wall: forms the forms the periphery of diaphragm.periphery of diaphragm.

6- 6- Mesoderm around aorta:Mesoderm around aorta: forms the crura.forms the crura. Dr.Sherif Fahmy

Dr.Sherif Fahmy

CONGENITAL ANOMALIESCONGENITAL ANOMALIES

• 1- 1- Congenital Hernia of Bochdalic:Congenital Hernia of Bochdalic: due to failure of formation of pleuro-due to failure of formation of pleuro-peritoneal membrane.peritoneal membrane.

• 2- 2- Esophageal (Hiatus) Hernia:Esophageal (Hiatus) Hernia: due due to wide esophageal opening or short to wide esophageal opening or short esophagus.esophagus.

• 3- 3- Parasternal hernia (of Parasternal hernia (of Morgagni):Morgagni): wide gap between sternal wide gap between sternal and costal origin of diaphragm.and costal origin of diaphragm.Dr.Sherif

Fahmy

Dr.Sherif Fahmy

Development of Endocrine glands & Muscles (Special Embryology)

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