Flashcards in ToB 19 Embryology 3 - Mesoderm Deck (37)
Which germ layer present at the end of week 3 will give rise to the biggest variety of tissues and structures?
Which germ layer present at the end of week 3 will give rise to tissues and structures that maintain contact between the inside and outside world? Ie: Brain, spinal cord, epidermis, retina etc.
Which germ layer present at the end of week 3 will give rise to the neural tube?
Why does part of the ectoderm layer become neuroectoderm?
The ectoderm directly above the notochord is changed to neuroectoderm via signal molcules released by the notochord.
The newly formed neuroectoderm forms a plate called:
How does the neural plate become the neural tube?
The notochord signals for the neural plate to thicken.
What shape is the neural plate?
What is the name given to the part of the mesoderm layer which arranges itself around the neural tube?
After formation of the neural tube, 4 different types of mesoderm are created. Name them:
What is the name of the u-shaped cavity which separates part of the mesoderm, creating the somatic mesoderm and splanchnic mesoderm?
In which week after fertilisation does the neural tube and intaembryonic coelom form?
Relating to the viscera/ internal organs
What is the name of the part of the mesoderm layer which is segmented into somites?
Bilaterally paired blocks of paraxial mesoderm which form along the head-to-tail axis
On which day after fertilisation do the first somites appear?
Where do the first pair of somites appear?
Occipital region (base of skull)
Approximately how many somite pairs are present by the end of week 5 (after fertilisation)?
~ 42-44 pairs
The somites give rise to which tissue types?
Which 2 bone structures are formed from the Sclerotome?
What is the final number of somites formed?
What is the difference between the epimere and hypomere?
- Formed from DORSAL myotome cells
- Innervated by DORSAL branch of spinal nerve
- Forms back muscles
- Formed from VENTRAL myotome cells
- Innervated by VENTRAL branch of spinal nerve
- Forms muscles of ventral body wall and limbs
The epimere is innervated by which branch of the spinal nerve?
The hypomere is innervated by which branch of the spinal nerve?
The epimere will give rise to muscles where?
The hypomere will give rise to muscles where?
Ventral body wall and limbs
How many pairs of spinal nerves present in a body?
What can a single spinal nerve innervate?
The myotome or dermatome which differentiated from the same somite as the specific spinal nerve. (Same derivative)
How is there no overlap between the presence of spinal nerves?
Due to segmentation the spinal nerves can only innervate tissue from the same derivative (as the nerve)
What system does the intermediate mesoderm give rise to?
What tissue doe the somatic mesoderm give rise to?
Connective tissue of limbs
What tissues does the splanchnic mesoderm give rise to?
Smooth muscle, connective tissue and vasculature of gut
What of the 3 germ layers grows the fastest?
In which week after fertilisation does embryonic folding occur?
What name is given to the embryonic folding that results in the head and tail end of the embryo to be folded under?
What are the names of the 2 embryonic folds which create a body encased in ectoderm, with one opening for the umbilical cord?
1- Cephalocaudal folding
2- Lateral folding
Embryonic folding only creates one opening into the embryo. What is this opening for?