Final practice questions Flashcards
When does gastrulation occur in gestation?
3rd week of gestation
What event signals the onset of gastrulation?
formation of the primitive streak
What is the primary goal of gastrulation?
establish the 3 primary germ layers
Which surface of the embryonic disc does the primitive streak appear?
dorsal
Which end of the embryonic disc does the primitive streak first appear?
caudal
Which structure establishes the major axis of the embryo?
primitive streak
Which end is the primitive node located?
cephalic
What causes the elongation of the primitive streak?
epiblast cells migrating through the streak into the median plane
What is invagination during gastrulation?
migration of epiblast cells through the primitive streak into the median plane
What does the hypoblast layer become?
the endoderm layer
What happens in the epiblast cells that invaginate after the hypoblast layer has been displaced?
they differentiate into mesoderm
What germ layer does the epiblast layer become after the mesoderm layer has formed?
ectoderm
What is the result of invagination?
3 primary germ layers are formed
What germ layers are produced during gastrulation?
ectoderm, mesoderm, endoderm
Which germ layer gives rise to the epithelial lining of the digestive tract?
endoderm
Which embryonic tissue gives rise to the ectoderm, mesoderm, and endoderm?
epiblast
Which event initiates the development of the notochord?
aggregation of mesoderm cells immediately beneath the primitive streak
Around which embryonic structure do vertebral bodies eventually form?
notochord
What is the remnant of the notochord in the developed vertebral column?
nucleus pulposus
When in utero does neurulation occur?
around the 3rd week
What is the ultimate goal of neurulation?
formation of the brain and spinal cord
Which primary germ layer gives rise to the brain and spinal cord during neurulation?
ectoderm
What triggers neurulation?
chemical signals from the notochord
What cells develop at the lateral margins of the neural plate?
neural crest cells
As the neural groove deepens, it forms _____________
neural folds
When do somites disappear?
during neurulation as the neural tube is forming
What type of embryonic tissue forms neural crest cells?
ectoderm and neuroectoderm (ectoderm is general answer, neuroectoderm is specific answer)
What structure gives rise to neural crest cells?
neural plate
What nervous system structures do neural crest cells form?
PNS, ganglia, glia cells, meninges
How does the neural tube form?
neural folds fuse with each other in the midline
When do the neural folds begin to close to form the neural tube?
in week 4
Which region on the trilaminar disc does the neural tube initially close?
cervical
When is neurulation complete?
when the caudate pore closes
What does the cranial/rostral end of the neural tube become?
brain
What does the portion distal to the cranial/rostral end of the neural tube become?
spinal cord
When does development of the vertebral column occur in the embryo?
during the 4th week of development
Which portion of the embryonic vertebrae does the sclerotome become that surrounds the notochord?
centrum (which becomes the vertebral body after ossification)
Which portion of the embryonic vertebrae does the sclerotome become that surrounds the neural tube?
neural arch (which becomes the vertebral arch after ossification)
Which embryonic structure forms the nucleus pulposus?
remnant of notochord
What type of embryonic tissue gives rise to neuroblast cells?
neuroepithelial cells
What type of cell give rise to gray mater?
neuroblast cells
When do the clusters of gray matter appear in the primordial spinal cord?
around the 6th week of development
What are the names of the 2 clusters of gray matter in embryonic spinal cord?
alar plate and basal plate
What type of cells give rise to the alar and basal plates of the primordial spinal cord?
neuroblast cells
Interneuron cell bodies are found in the _________ cluster of gray matter and motor neuron cell bodies are found in the _________ cluster of gray matter of the developing spinal cord
alar, basal
Which vertebral structures begin to fuse during the first year of life?
neural arches
What is the name of the nerve that innervates the vertebral column?
recurrent meningeal n.
What types of fibers are found in recurrent meningeal nerves?
both sensory and motor fibers
What are the names of the 2 branches that come off the dorsal rami?
medial branch and lateral branch
What are the names of the 3 connective tissue membranes that protect the spinal cord and nerve roots?
dura mater, arachnoid mater, and pia mater
What is the name of the structure that wraps around nerve roots as they exit the IVF?
dural root sheath
What space is found between the vertebral periosteum and the dura mater?
epidural space
