Biol 373 Unit 2: CNS Development
CNS development - cnidaria - correct answer ✔✔Show radial symmetry, no identifiable control center
CNS development - flatworms - correct answer ✔✔Rudimentary brain in head, bilateral symmetry,
senses cluster around the "food end", distinction b/w CNS + PNS is not yet clear.
CNS development - earthworms - correct answer ✔✔Show signs of spinal reflexes, more advanced
nervous system
Most dramatic change seen in vertebrate brain evolution - correct answer ✔✔Change in forebrain region
(cerebrum), also cerebellum of the hindbrain
Neurulation def'n - correct answer ✔✔The process whereby the neural plate forms into a neural
tube...marks beginning of CNS formation
Neurulation process - correct answer ✔✔At 3 weeks, the neural plate begins to form into a neural fold
and when convergence occurs, it becomes the neural tube. Neural crest cells migrate off of the tube to
become the PNS. The neural tube is the precursor of the CNS.
Development of CNS at 4 weeks - correct answer ✔✔Anterior end of the neural tube is specialized into 3
regions at this week period - forebrain, midbrain, hindbrain (the posterior part is the spinal cord).
Development of CNS at 6 weeks - correct answer ✔✔The neural tube has differentiated into the major
brain regions present at birth at this week period.
Forebrain - diencephalon, cerebrum.
Hindbrain - medulla, cerebellum, pons.
Midbrain - not much.
Development of CNS at 11 weeks - correct answer ✔✔At this week period, the growth of the cerebrum
has much outpaced that of other regions. Diencephalon is hidden under the cerebrum.
, Reason why the brain has convulsions - correct answer ✔✔Caused by the rapid growth of the brain in a
confined space (skull).
By week 6, the CNS has formed the 7 major divisions that are present at birth: - correct answer
✔✔Cerebrum (forebrain)
Diencephalon (forebrain)
Midbrain
Cerebellum (hindbrain)
Pons (hindbrain)
Medulla oblongata (hindbrain)
Spinal cord
Name the 3 meninges of the CNS - correct answer ✔✔Dura mater
Arachnoid membrane
Pia mater
Dura mater - correct answer ✔✔Outermost meninge of CNS
Durable + thick
Associated w/ veins that drain blood from the brain
Arachnoid membrane - correct answer ✔✔Middle meninge of CNS
Lots of blood vessels here
Branchy material in between, cobweb-like
Pia mater - correct answer ✔✔Innermost meninge of CNS
Thin + adheres to surface of brain and spinal cord
Associated w/ arteries that supply blood to brain
Contains interstitial fluid
CNS development - cnidaria - correct answer ✔✔Show radial symmetry, no identifiable control center
CNS development - flatworms - correct answer ✔✔Rudimentary brain in head, bilateral symmetry,
senses cluster around the "food end", distinction b/w CNS + PNS is not yet clear.
CNS development - earthworms - correct answer ✔✔Show signs of spinal reflexes, more advanced
nervous system
Most dramatic change seen in vertebrate brain evolution - correct answer ✔✔Change in forebrain region
(cerebrum), also cerebellum of the hindbrain
Neurulation def'n - correct answer ✔✔The process whereby the neural plate forms into a neural
tube...marks beginning of CNS formation
Neurulation process - correct answer ✔✔At 3 weeks, the neural plate begins to form into a neural fold
and when convergence occurs, it becomes the neural tube. Neural crest cells migrate off of the tube to
become the PNS. The neural tube is the precursor of the CNS.
Development of CNS at 4 weeks - correct answer ✔✔Anterior end of the neural tube is specialized into 3
regions at this week period - forebrain, midbrain, hindbrain (the posterior part is the spinal cord).
Development of CNS at 6 weeks - correct answer ✔✔The neural tube has differentiated into the major
brain regions present at birth at this week period.
Forebrain - diencephalon, cerebrum.
Hindbrain - medulla, cerebellum, pons.
Midbrain - not much.
Development of CNS at 11 weeks - correct answer ✔✔At this week period, the growth of the cerebrum
has much outpaced that of other regions. Diencephalon is hidden under the cerebrum.
, Reason why the brain has convulsions - correct answer ✔✔Caused by the rapid growth of the brain in a
confined space (skull).
By week 6, the CNS has formed the 7 major divisions that are present at birth: - correct answer
✔✔Cerebrum (forebrain)
Diencephalon (forebrain)
Midbrain
Cerebellum (hindbrain)
Pons (hindbrain)
Medulla oblongata (hindbrain)
Spinal cord
Name the 3 meninges of the CNS - correct answer ✔✔Dura mater
Arachnoid membrane
Pia mater
Dura mater - correct answer ✔✔Outermost meninge of CNS
Durable + thick
Associated w/ veins that drain blood from the brain
Arachnoid membrane - correct answer ✔✔Middle meninge of CNS
Lots of blood vessels here
Branchy material in between, cobweb-like
Pia mater - correct answer ✔✔Innermost meninge of CNS
Thin + adheres to surface of brain and spinal cord
Associated w/ arteries that supply blood to brain
Contains interstitial fluid
