brain part 2
The central brain;
Lateral ventricles form in the cerebral hemispheres; choroid
plexuses make cerebrospinal fluid (CSF). Brain is a hollow tube,
this tube if filled with this fluid.
The fluid is taken up by the arachnoid granulations
Cerebral aqueduct (of Sylvius) between ventricles in the
brain to the spinal cord.
Hydrocephaly; blocked circulation of the fluid, usually at the
cerebral aqueduct → growth of the skull.
Hydrocephalus can also be observed in spina bifida.
5 vesicle stage differentiation;
Telencephalon; cerebral hemispheres (lateral ventricles)
Diencephalon; thalamus, hypothalamus, pituitary (3e
ventricle)
Mesencephalon; cerebral aqueduct (of Sylvius). Anterior
(visual) & posterior (auditory) colliculi
Metencephalon; cerebellum and pons. (4e ventricle)
Myelencephalon; medulla oblongata
Hind brain; (integration of info)
Rhombomeres are divided segment of developing neural
tube within hindbrain region.
They are swellings in the neural tube, caudal to the
cephalic flexure (cefale buiging)
Present at day 29.
Rhombomeres induce neural crest cells (PNS) to form pharyngeal arches that give
rise to the face (bones)
Rhombomeres express Hox genes, genes at most 3’ of Hox cluster
(earliest expression) have most anterior boundaries.
Myelencephalon;
Rhombomeres 3-8; medulla oblongata (home to many cranial nerves, relay central
spinal cord & higher regions, centers for heartbeat, reflex, respiration, vomiting)
Metencephalon;
Rhombomeres 1-2; cerebellum (coordination, balance) and pons (relay center)