Describe the embryonic development of the nervous system.
What will be an ideal response?
The earliest neural structure is the neural plate, a flat sheet of tissue located on the dorsal surface of the embryo, clearly visible at day 20 post-fertilization. The edges of the plate fold and cells of the neural crest migrate toward the midline, until a hollow neural tube is formed from the plate by about day 23. The lumen will become the fluid-filled central cavities of the CNS. The lumen is lined with ependymal cells and neural stem cells. Cells of the neural crest will continue to migrate, forming the structures of the PNS. The rest of the tube will become the CNS.
By 4 weeks, three discrete swellings will form in the anterior end of the tube: forebrain, midbrain, and hindbrain. The remainder of the tube becomes the spinal cord. By 6 weeks, the cerebrum, diencephalon, midbrain, cerebellum, pons, and medulla oblongata are distinct. By 11 weeks the cerebrum is noticeably enlarged.
You might also like to view...
Muscular tissue consists of what type of cells or fibers?
A. spherical cells designed for storage B. elongated fibers (cells) that are specialized to contract C. elongated fibers (cells) surrounded by abundant matrix D. cells with multiple processes that are specialized to send electrical signals
Stem cells taken from a person to be used to treat a disease in that same person come
from A) existing cell populations or reprogrammed cells. B) the person or a blood relative. C) two different cell types. D) embryos or fetuses.
What are the two components of the biliary system?
a. small and large intestines b. stomach and small intestine c. endocrine and exocrine glands d. liver and pancreas e. liver and gallbladder
To palpate literally means to ________
A) massage B) visually inspect C) touch D) listen