General Anatomy Flashcards
What are the three germinal layers?
Endoderm
Mesoderm
Ectoderm
What are the four parts of mesoderm?
- Paraxial
- Intermediate
- Head
- Lateral plate
What does the paraxial mesoderm give rise to?
Somites (31 pairs)
What does the intermediate mesoderm create?
Urogenital system and KIDNEYS
What does the head mesoderm create?
Skull
Muscles
Connective tissue of the head
Dentine
What arises from the lateral plate mesoderm?
ADRENAL CORTEX, SPLEEN, blood and lymph cells, connective tissue, cardiovascular and lymphatics, serous membranes of pleura and pericardium.
What does the endoderm give rise to?
Gut
Respiratory tract
“Tubular structures”
What does ectoderm give rise to?
Surface ectoderm
Neuroectoderm
What does the surface ectoderm form?
Epidermis, enamel, hair, nails
ANTERIOR PITUITARY
LENS OF EYE
What makes up the neuroectoderm?
Neural tube
Neural crest
What are the structures derived from the neural tube?
CNS
POSTERIOR PITUITARY
RETINA OF EYE
pineal body
Which structures are derived from neural crest cells?
Dorsal Root Ganglion (DRG)
ANS
Parafollicular cells of thyroid
Adrenal Medulla
What are the embryological stages of development?
Mesodermal -> Chondrification -> Ossification
What makes up the major two parts of mesodermal embryological development?
- Notochord persists as nucleus pulposus
2. 31 pairs of mesodermal somites from paraxial mesoderm
What are the types of paraxial mesoderm?
Sclerotome
Myotome
Dermatome
What is sclerotome?
The membranous vertebral column formed during paraxial mesodermal embryological development.
What is myotome, and what are the myotomes?
Myotome = Muscle
- Somatic
- Splanchnic
- EPIMERE
- HYPOMERE
What does somatic myotome become?
Skeletal muscle
What does splanchnic myotome become?
“Visceral” smooth muscle
What is derived from the EPIMERE myotome?
Dorsal, Posterior muscles, Extensors
What does the HYPOMERE myotome become?
Ventral, anterior muscles, flexors
What is chondrification?
Mesoderm being replaced by cartilage.
What is ossification?
Cartilage being replaced by bone.
What are the two types of ossification?
Primary ossification = before birth
Secondary ossification = after birth
What happens during intramembranous/intramedullary ossification?
Mesenchymal tissue turns into bone
The clavicle and all flat bones of the skull are formed (e.g. parietal).
What happens during endochondral ossification?
Preformed in cartilage
Ossification for all other bones
What type of ossification leads to the creation of the scapula?
Intramembranous and Endochondral
