Endocrine GlandsEndocrine Glands
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SUPRARENALSUPRARENAL
GLANDGLAND
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Suprarenal GlandSuprarenal Gland
It has double origin:It has double origin:

Cortex:Cortex: from proliferating coelomicfrom proliferating coelomic
epithelium (mesodermal) in 2 stages:epithelium (mesodermal) in 2 stages:
fetal and permenant.fetal and permenant.

Medulla:Medulla: from neural crest, Chromaffinfrom neural crest, Chromaffin
cells (ectodermal) which invaginate thecells (ectodermal) which invaginate the
cortex.cortex.
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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.
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DEVELOPMENT OFDEVELOPMENT OF
PITUITARY GLANDPITUITARY GLAND
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PITUITARY GLANDPITUITARY GLAND
It has double origin:It has double origin:
1-1- Rathke’s pouch:Rathke’s pouch: from roof offrom roof of
stomodeum.stomodeum.
2-2- Infundibular process:Infundibular process: fromfrom
floor of diencephalon.floor of diencephalon.
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L.S. in folded embryo
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Congenital Anomalies ofCongenital 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: TumourTumour
from persistence of Rathke’sfrom persistence of Rathke’s
pouch.pouch.
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Development of MuscularDevelopment of Muscular
SystemSystem (Page 145)(Page 145)
Skeletal muscles:Skeletal muscles: from paraxialfrom paraxial
mesoderm.mesoderm.
Smooth muscles:Smooth muscles: fromfrom
splanchnic mesoderm aroundsplanchnic mesoderm around
developing gut.developing gut.
Cardiac muscle:Cardiac muscle: from splanchnicfrom splanchnic
mesoderm around heart tube.mesoderm around heart tube.
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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.
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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
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Somites After Folding
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Striated Skeletal MusculatureStriated Skeletal Musculature
Skeletal muscles are developed fromSkeletal muscles are developed from
somites which divides into:somites which divides into:
Hypomeric portion:Hypomeric portion: ventrolateral partventrolateral part
which forms muscles of limbs and bodywhich forms muscles of limbs and body
wall.wall.
Epimeric portion:Epimeric portion: Dorsomedial part whichDorsomedial part which
forms extensor back muscles.forms extensor back muscles.
N.B. Epimeric and hypomeric cells areN.B. Epimeric and hypomeric cells are
called precursor muscle cells.called precursor muscle cells.
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Differentiation of a Somite
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Head Musculature
- All voluntary muscles are developed
from paraxial mesoderm.
- Muscles of iris are developed from
optic cup ectoderm.
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Septum Transversum
Cranial part: Central tendon of
diaphragm.
Central mesenchyme:
Hematopoietic cells in liver.
Caudal region: in ventral
mesogastrium.
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Bucco-pharyngeal
membrane
Cloacal membrane
Cardiogenic area
Notochord
Septum transversumPericardium
Pleura
Pleuro-
peritoneal
membrane
PeritoneumIntra-embryonic
ceolom
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Bucco-pharyngeal
membrane
heart
Pericardium
Septum
transversum
Pharynx
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Development of
Diaphragm
(Page 157)
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Anatomy of Diaphragm
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Lower Aspect Inferior vena cava
Esophagus
Aorta
Rt. crus
Lt. crus
Central
tendon
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DIAPHRAGMDIAPHRAGM
• It is developed from the following structuresIt is developed from the following structures..
1-1- Septum transversum:Septum transversum: It lies firstly infront theIt lies firstly infront the
pharynx in neck and forms central tendon.pharynx in neck and forms central tendon.
2-2- Cervical myotomes (C3,4,5):Cervical myotomes (C3,4,5): Forms theForms the
muscular part around the central tendon andmuscular part around the central tendon and
supplied bysupplied by phrenic nervephrenic nerve..
3-3- Pleuro-peritoneal membrane:Pleuro-peritoneal membrane: forms theforms the
postero-lateral parts of the diaphragm.postero-lateral parts of the diaphragm.
4-4- Meso-esophagus:Meso-esophagus: forms the median posteriorforms the median posterior
part.part.
5-5- Mesoderm of thoracic wall:Mesoderm of thoracic wall: forms theforms the
periphery of diaphragm.periphery of diaphragm.
6-6- Mesoderm around aorta:Mesoderm around aorta: forms the crura.forms the crura.

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CONGENITAL ANOMALIESCONGENITAL ANOMALIES
• 1-1- Congenital Hernia of Bochdalic:Congenital Hernia of Bochdalic: duedue
to failure of formation of pleuro-peritonealto failure of formation of pleuro-peritoneal
membrane.membrane.
• 2-2- Esophageal (Hiatus) Hernia:Esophageal (Hiatus) Hernia: due todue to
wide esophageal opening or shortwide esophageal opening or short
esophagus.esophagus.
• 3-3- Parasternal hernia (of Morgagni):Parasternal hernia (of Morgagni):
wide gap between sternal and costal origin ofwide gap between sternal and costal origin of
diaphragm.diaphragm.
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