developmental biology (embryology) - anatomický...

• Developmental biology (Embryology)

Length of pregnancy ?

- 280 days (40weeks) after the onset of last normal menstrual period

- 266 (38weeks) after fertilization

46 chromosomes (diploid), DNA

20 000 genes

meiosis: germ cells gamets (haploid) : oocyte, sperms

fertilization- diploid again

Developmental biology (Embryology)

Early development (1.- 2. week)

importants terms: fertilization, zygote, cleavage, blastocyst,

implantation

Period of organogenesis = embryonic period (3.- 8. week)

- 3 germ layers: ectoderm, entoderm, mesoderm

- most major organs and organ systems are formed-Size of the embryo – CRL = crown rump length (mm)

importants terms: gastrulation, neurulation, neural crest, paraaxial

mesoderm, somite, intermedial mesoderm., lateral plate mesoderm,

Fetal period - from the 9th week

-maturation and rapid growth -Size of the fetus – CHL = crown heel length (mm)

• genetic background of development

• Genes and gene families: HOX, FGF,

FGFR, BMP, BMPR, PAX, SHH

Teratology - study of abnormalities of physiological development (birth defects).

The term stems from the Greek τέρας teras (genitive τέρατος teratos), meaning 'monster' or 'marvel',

and λόγος logos, meaning 'the word' or, more loosely, 'the study of' . (http://en.wikipedia.org/wiki/Teratology )

Thomas W. Sadler, Langman's Medical Embryology, LWW

Gastrulation – beginning of the 3rd week

Important tems: primitive streak, primitive node, epiblast, hypoblast

Invagination of epiblast 3 germ layers

Thomas W. Sadler, Langman's Medical Embryology, LWW

• 1/ ECTODERM

• EPIDERMIS [INCLUDING HAIR ,NAILS]

• NERVOUS SYSTEM

• NEURAL CREST AND ITS DERIVATIVES

•

•

• 2/MESODERM:

• CONNECTIVE TISSUE

• MUSCLES

• BONES

• CARDIOVASCULAR and LYMPHATIC system

• UROGENITAL system

SEROUS LINING (membranes) OF BODY CAVITIES(peritoneal, pleural)

•

• 3/ENDODERM :

• GUT (digestive) TUBE EPITHELIUM AND DERIVATIVES

• + LIVER and PANCREAS

• LUNG

Neural tube

Neural crest

Epidermis

NEURULATION

Scott F. Gilbert, Developmental Biology, Sinauer

Thomas W. Sadler, Langman's Medical Embryology, LWW

Thomas W. Sadler, Langman's Medical Embryology, LWW

Defects of neurulation anencephalus , spina bifida

Keith L. Moore, Before We Are Born: Essentials of Embryology and Birth Defects, Elsevier

MESODERM

• 1) paraxial mesoderm

• 2) intermediate mesoderm

• 3) lateral plate mesoderm

- parietal layer – body wall, serous mambranes

- visceral layer – gut, blood vessels

Thomas W. Sadler, Langman's Medical Embryology, LWW

angiogenesis – vessels form from blood islands

vasculogenesis – vessels sprout from existing ones

Thomas W. Sadler, Langman's Medical Embryology, LWW

Vessels formation

Endoderm derivatives

Pharyngeal (branchial ) arches – bars of mesenchymal tissue separated by clefts.

No.1,2,3,4-6. A lot of important head and neck structures are derivatives of them

Thomas W. Sadler, Langman's Medical Embryology, LWW

Human embryo (CRL 10 mm, 5th week)Thomas W. Sadler,

Langman's Medical

Embryology, LWW

Pharyngeal arches

Somites on each

side of neural tube

(see next slide)

Somites - segmented series of tissue blocks on each side of neural tube

from paraxial mesoderm

Thomas W. Sadler, Langman's Medical Embryology, LWW

Transverse section through somites

somiteneural

tube

chordalateral plate mesoderm -

somatic

lateral plate mesoderm -

splanchnic

Thomas W. Sadler, Langman's Medical Embryology, LWW

Each somite forms:

myotome

dermatome

sclerotome

Thomas W. Sadler,

Langman's Medical

Embryology, LWW