UNSW Embryology
Beginnings, Growth and Development - Lecture Endocrine Development
© Dr Mark Hill (2010)
Introduction
2009 BGD-B Please note this lecture will be given on 4th of June 2009 and has been swapped with the Sexual Differentiation Lecture to be given 28th May 2009.
This lecture covers Endocrine Development, note that a better understanding can be made if you understand the adult function of each endocrine organ (though this will not be covered in the
Lecture). Use the links below to either view the Lecture slides (1/page) or print (4/page).
Endocrine development is sometimes divided into Neuroendocrine and Endocrine and is also generally covered piecemeal in all embryology textbooks,
so you may have to look in several different chapters to find supporting textbook information.
You may also find interesting Prof JJ Carmody recent broadcast on the
Centenary of the word 'hormone' . For a more detailed background on endocrine development see also Endocrine Development Notes .
Lecture Slides
2009: BGD-B Endocrines View 1 slide/page |
BGD-B Endocrines View 3 slide/page |
BGD-B Endocrines View 4 slide/page |
BGD-B Endocrines View 6 slide/page
2005 lecture slides BGDL33Endocrines View 1 slide/page (73 pages 1.7 Mb, note large size) | BGDL33Endocrines Print 4 slides/page (19 pages, 1.1 Mb) Movies shown in lecture will not run in these documents and are linked below.
iLecture Broadcast
The external link below is to the lecture iLecture 2005 broadcast of Endocrine Lecture (24 Aug 2005 - 09:00).
iLecture 33 Endocrine Development Broadcast.
Erratum: Please note error in audio when describing the region of Thyroid formation. In Lecture audio I have mistakenly used the term "median eminence" when I meant "hypopharyngeal eminence". Lets see if I make the same mistake again....
Note that Lecture starts 9:30 minutes into broadcast.
iLecture Audio Summary (timing minutes:seconds)
9:30 - Introduction, endocrine system, hormones, organs
18:50 - Pineal
21:50 - Hypothalamus
29:10 - Thyroid (see erratum above)
36:14 - Parathyroid
39:25 - Pancreas
50:30 - Adrenal
55:20 - Gonads
58:20 - Placenta
About UNSW iLecture :
"The Pilot iLecture system will enable automatic audio recording and processing into a variety of streaming media formats."
(both Quicktime and Windows Media are supported)
UNSW BGD Embryology Lectures (2005) Podcast
Listen to Dr Mark Hill 2005 Medicine BGD Lecture 2005-08-24 on Endocrine development. Copy and paste the URL link below into iTunes 4.9 "subscribe to podcast" (in the Advanced menu)
http://embryology.med.unsw.edu.au/Podcast/MHLecture/BGDEmbryology2005.xml
Alternatively, download the MP3 files: Introduction, endocrine system, hormones, organs (2.1 Mb)
| Pineal (700 Kb)
| Hypothalamus (700 Kb)
| Thyroid (1.7 Mb)
| Parathyroid (736 Kb)
| Pancreas (2.5 Mb)
| Adrenal (1.1 Mb)
| Gonads (716 Kb)
| Placenta (432 Kb)
Other embryology audio content is being made available at UNSW Embryology Podcast
Podcast - Listen ABC Radio Ockham's Razor 2005-07-31 Centenary of the word 'hormone' , Sydney medical
scientist and writer Dr John Carmody commemorates the centenary of the entry of the word 'hormone' into the English language.
Slip this MP3 into your player and listen! 13 minutes 32seconds 6.2 Mb mp3
ABC Radio Ockham's Razor Transcript |
ABC Radio Ockham's Razor | About Podcasts (Embryology MP3s)
Textbooks
Histology and Cell Biology Kierszenbaum, AL.
Chapter 18 Neuroendocrine System pp477-497
Chapter 19 Endocrine System pp499-527
Human Embryology (3rd ed.) Larson Chapter 9, 10, 12
The Developing Human: Clinically Oriented Embryology (6th ed.) Moore and Persaud
Chapter 10 pp230-233
Chapter 12 pp280-282
Chapter 13 pp319-347
Human Embryology Fitzgerald and Fitzgerald Chapter 24 pp166-167
Development Overview
Links: hypothalamus | Pineal | Pituitary | Thyroid |
Parathyroid | Thymus |Pancreas |
Pancreas | Gonads | Placenta | Maternal | Other Cells
hypothalamus Hypothalamus Development Notes
Neuroectoderm prosenecephalon
Diencephalon ventro-lateral wall intermediate zone proliferation
Mamillary bodies - form pea-sized swellings ventral wall of hypothalamus
Pineal - Pineal Development Notes
Neuroectoderm prosenecephalon
Week 10 - dorsal outpocket of diencephalon, median diverticulum, epiphysis
Hollow diverticulum - cell proliferation to solid, pinealocytes (neuroglia), cone-shaped gland ("pine cone" shaped hence name), innervated by epithalmus
diverticulum - walls thicken pineal recess open to 3rd ventricle
neuroepithelial cells- 2 types pinealocytes, glial-like interstitial cells
CNS meninges form capsule and connective tissue septa
Melatonin- diurnal cycle, inhibits pituitary-gonad axis
Pituitary (Hypophysis, Greek hypo = under, physis = growth) - Pituitary Development Notes
Ectoderm- ectoderm roof of stomodeum, neuroectoderm of diencephalon
Adenohypophysis anterior pituitary, glandular (pars anterior, pars intermedia, pars tuberalis)
Neurohypophysis posterior pituitary, nervous (pars nervosa)
Week 4 hypophysial pouch, Rathkes pouch, diverticulum from roof
Week 5 elongation, contacts infundibulum, diverticulum of diencephalon
Week 6 connecting stalk between pouch and oral cavity degenerates
Adenohypophysis
Anterior wall proliferates - pars distalis
Posterior wall little growth pars intermedia
Rostral growth around infundibular stem pars tuberalis
Neurohypophysis
Infundibulum median eminence, infundibulum, pars nervosa
Week 10 growth hormone and ACTH detectable
Week 16 adenohypophysis fully differentiated
Week 20 to 24 growth hormone levels peak, then decline
Thyroid - Thyroid Development Notes
24 days thyroid median endodermal thickening in the floor of pharynx
outpouch thyroid diverticulum into hypopharyngeal eminence
tongue grows, descend in neck thryoglossal duct (proximal end foramen cecum of tongue)
thyroid diverticulum hollow then solid, right and left lobes, central isthmus
pyramidal lobe from isthmus (50% of people) attached to hyoid bone (distal end of thryoglossal duct)
Week 11 colloid appearance in thyroid follicles, iodine and thyroid hormone (TH) synthesis
growth factors (insulin-like, epidermal) stimulates follicular growth
Fetal TH - Initial secreted biologically inactivated by modification, late fetal secretion develops brown fat
Iodine deficiency- during this period, leads to neurological defects
Birth TSH levels increase, thyroxine (T3) and T4 levels increase to 24 h, then 5-7 days postnatal decline to normal levels
Parathyroid Parathyroid Development Notes
Third and Fourth Pharyngeal Pouches- endoderm (could also have ectoderm and neural crest)
3rd Pharyngeal Pouch inferior parathyroid, initially descends with thymus
4th Pharyngeal Pouch superior parathyroid
Week 6 - diverticulum elongate, hollow then solid, dorsal cell proliferation
Fetal parathyroids- respond to calcium levels, fetal calcium levels higher than maternal
Thymus - Thymus Development Notes
Third Pharyngeal Pouch- endoderm
Week 6 - diverticulum elongate, hollow then solid, ventral cell proliferation
Thymic primordia- surrounded by neural crest mesenchyme
Thymus development - epithelia/mesenchye interaction
Pancreas - Pancreas Development Notes
Functions- exocrine (amylase, alpha-fetoprotein) and endocrine (pancreatic islets)
Pancreatic buds- endoderm, covered in splanchnic mesoderm
Pancreatic bud formation duodenal level endoderm, splanchnic mesoderm forms dorsal and ventral mesentery, dorsal bud (larger, first), ventral bud (smaller, later)
Duodenum growth/rotation brings ventral and dorsal buds together, fusion of buds
Pancreatic duct ventral bud duct and distal part of dorsal bud, exocrine function
Islet cells- cords of endodermal cells form ducts, which cells bud off to form islets
Week 7 to 20 pancreatic hormones secretion increases, small amount maternal insulin
Week 10 glucagon (alpha) differentiate first, somatostatin (delta), insulin (beta) cells differentiate, insulin secretion begins
Week 15 glucagon detectable in fetal plasma
Beta cells - stimulate fetal growth, continue to proliferate through to postnatal in infancy, most abundant
Maternal diabetes mellitus hypertrophy of fetal beta cells, fetal abnormalities (More? Maternal diabetes mellitus
Adrenal (Suprarenal) - Adrenal Development Notes
Cortex mesoderm, medulla neural crest
Fetal and adult cortex
Week 6 fetal cortex forms from mesothelium adjacent to dorsal mesentery, medulla neural crest cells from adjacent sympathetic ganglia
adult cortex mesothelium mesenchyme encloses fetal cortex
Late Fetal Period- differentiates to form cortical zones
Birth - zona glomerulosa, zona fasiculata present
Year 3 zona reticularis present
Fetal Cortex produces- a steriod precursor (DEA) converted by placenta into estrogen
Adult Cortex produces cortisol, etc..
Adult Medulla produces adrenalin (epinephrine), noradrenalin (norepinephrine)
Fetal adrenal hormones - influence lung maturation
Gonads (Covered in Sexual Differentiation) - Endocrine Gonad Notes | Genital Development
Gonad- mesoderm (mesothelium and underlying mesenchyme) and primordial germ cells
Gonadal ridge mesothelium thickening, medial mesonephros
Primordial Germ cells- yolk sac, to mesentery of hindgut, to genital ridge of developing kidney
Gonad differentiation - dependent on presence (testes) or absence (ovaries) of expression of testis-determining factor (TDF) from Y chromosome
Testis
8 Weeks mesenchyme, interstitial cells (of Leydig) secrete testosterone, androstenedione
8 to 12 Weeks - hCG stimulates testosterone production
Sustentacular cells- produce anti-mullerian hormone to puberty
Ovary
X chromosome genes regulate ovary development
Placenta - Endocrine Placenta Notes | Placenta Development
Maternal (decidua) and Fetal (trophoblastic cells, extraembryonic mesoderm) components
Endocrine function- maternal and fetal precursors, synthesis and secretion
Hormones- protein and steroidal
Protein Hormones- chorionic gonadotropin (hCG), chorionic somatomammotropin (hCS) or placental lactogen (hPL), chorionic thyrotropin (hCT), chorionic corticotropin (hCACTH)
Steroid Hormones- progesterone (maintains pregnancy), estrogens (fetal adrenal/placenta)
hCG - up to 20 weeks, fetal adrenal cortex growth and maintenance
hCS rise through pregnancy, stimulates maternal metabolic processes, breast growth
Maternal
Maternal hormones - can cross the placental barrier, contribute precursors to placental hormone production.
Other Cells - Endocrine Other Cells Notes
Selected cells within the following organs also contribute to endocrine regulation. The development of their endocrine function is related to the development of the
organ or tissue and their development will not be covered in the Lecture. The list below covers the types of hormones produced for more detail use the Endocrinology link.
Endocrinology: An Integrated Approach Cardiovascular and renal endocrinology
Heart - Atrial natriuretic peptide, Endothelins
Kidney
Renin (Increase Angiotensin-aldosterone system)
Prostaglandins (decrease Na+ reabsorption)
Erythropoietin (Increase Erythrocyte (rbc) production), 1,25 (OH)2 vitamin D (Calcium homeostasis)
Prekallikreins (Increase Kinin production)
Digestive Tract
Gastrin: from the stomach, control of gastric acid secretion
Cholecystokinin: small intestinal hormone, stimulates secretion of pancreatic enzymes and bile
Secretin: small intestinal hormone, stimulates secretion of a bicarbonate-rich fluids from the pancreas and liver
Adipose Tissue - Endocrine Adipose Notes
Leptin: polypeptide hormone produced in adipose and many other tissues with also many different roles
Adiponectin: regulation of energy homeostasis and glucose and lipid metabolism, as well as acting as an anti-inflammatory on the cellular vascular wall
Resistin: (for resistance to insulin, RETN) a 108 amino acid polypeptide and the related resistin-like protein-beta (Resistin-like molecule-beta, RELMbeta) stimulate endogenous glucose production
Histology
Blue Histology (UWA) Endocrines
Acronyms
Listed below are some common acronyms used in the endocrine system.
Acronym hormone full name (hormone type source)
ACTH adrenocorticotropin or corticotropin (peptide anterior pituitary)
ADH antidiuretic hormone (peptide hypothalamus)
ANP atrial natriuretic factor (peptide heart)
CT calcitonin (peptide - C cells of thyroid)
FSH follicle stimulating hormone (protein - pituitary)
GH growth hormone (peptide - pituitary)
LH lutenizing hormone (protein - pituitary)
MSH melaocyte stimulating hormone (peptide - pituitary)
PRL prolactin (peptide - pituitary)
PTH parathyroid hormone (peptide - parathyroid)
TH thyroid hormone (amino acid derivative - thyroid)
TSH thyroid stimulating hormone (pituitary - protein)
Glossary
Use the alphabetical list below to find definitions of terms that are new to you or use the Google search window to search UNSW Embryology site.
UNSW Embryology ISBN: 978 0 7334 2609 4
UNSW CRICOS Provider Code No. 00098G
Comments
Everything Medicine 2009
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Found - Intro Embryo Lecture
Found - Intro Embryo Practical
Found Expert Tutorial-Histology
SH - Respiratory Lecture
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BGD - GIT Lecture
BGD - GIT Practical
Prac1 GIT Manual PDF
GIT Development
GIT Abnormalities
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BGD - Head Lecture
BGD - Head Practical
Prac6 Head Manual PDF
Head and Neck Development
Face Development
Ear Development
Face Abnormalities
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BGD - Endocrine Lecture
Endocrine Development
Endocrine Abnormalities
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BDG - Male/Female Lecture
BGD - Male/Female Practical
Prac12 Male/Female Manual PDF
Genital Development
Male Development
Female Development
Genital Abnormalities
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BGD-B Full Prac Manual PDF
BGD-B FAQs
BGD Phase 2 - Tutorial CBL ILPs 2009
eMed -----------------
Week by Week
Movies
Audio
Development Notes
System Notes
Some lecture slides within the Lecture Slide PDFs were not shown during the lecture and are provided to aid your understanding.
Page currently under development for 2009 Lab. (notice removed when complete)
These notes and linked materials have been prepared for Educational purposes only .
Please email Dr Mark Hill if you wish to make a comment about this current project.