what do all animals have
a nervous system
cnidarian examples
jellyfish, hydras, anemones
nervous system of cnidarians
simplest of nervous systems
nerve net
nervous system of echinoderms
nervous system of planaria
nervous system of annelids
nervous system of simple mollusks
cephalization
increasingly complex brain in head
brain of drosophila
several subdivisions with separate functions
brain of advanced mollusks
brains with well-developed subdivisions
glial cells/glia function
nourish, support, and regulate neurons
what do embryonic radial glia form
tracks along which newly formed neurons migrate
astrocytes
participate in formation of blood-brain barrier
blood-brain barrier
restricts entry of most substances into the brain
what can radial glial cells and astrocytes both act as
stem cells
where does the CNS develop from
hollow dorsal nerve cord
what does the cavity of the nerve cord give rise to
narrow central canal of the spinal cord and ventricles of the brain
what are the spinal canal and ventricles filled with
cerebrospinal fluid
cerebrospinal fluid
supplies CNS with nutrients and hormones, carries away waste
gray matter
white matter
what does the spinal cord do
reflex
body’s automatic response to a stimulus