SHS 280 Lecture 7

At about 3 days post-fertilization the _____ forms

blastocyst cavity

At about 3 days post-fertilization the blastocyst cavity forms and this marks the ______ stage

blastocyst

in the 2nd week, the ____ forms

bilaminar embryo

in the 3rd week, the ____ forms

trilaminar embryo

ectoderm -->

skin and nervous system

mesoderm -->

muscles, connective tissue, skeleton

endoderm -->

digestive and respiratory tracts

the ectoderm, mesoderm, and endoderm form during the

trilaminar embryo (3rd week)

tissue forms into neural groove and it closes and forms

neural tube

neural tube is formed after the

3rd week

motility issues and spina bifida can occur when the neural tube does ____

not close

the neural tube is critical for neural development because it develops in to the

brain and spinal cord

the neural tube differentiates into the

alar plate and the basal plate

The alar plate will form ______ of the spinal cord (dorsal horn)

sensory portions

The basal plate will form _____ of the spinal cord (ventral horn)

motor portions

sensory portions of the spinal cord of the alar plate

dorsal horn

motor portion of the spinal cord of the basal plate

ventral horn

What causes some cells in the neural tube to form part of the sensory system and others form part of the motor system?

chemical gradient signal (how close they are to that when it is released)

T/F rostral is the direction toward the face (anterior?)

true

rostral 2/3 of the neural tube will become the

brain

caudal 1/3 of the neural tube will become the

spinal cord

prosencephalon will become

telencephalon and diencephalon

contains the cerebral hemispheres, basal ganglia, and limbic lobe

telencephalon

contains the thalamus and hypothalamus

diencephalon

mesencephalon will become the

midbrain

rhombencephalon will become the

hindbrain

consists of the pons, cerebellum, medulla

hindbrain

How does the location of parts of the neural tube relate to their final locations in the adult brain?

does not (really) change

smooth brain surface

week 20

formation of the basic sulci-gyri

week 24

full complement of brain neurons

week 25

well marked lobes

3rd trimester

presence of all adult brain structures

birth

How do neurons search out the appropriate connections?

growth cones

T/F While developing connections, neurons search out the appropriate connections

true

sniffs out different chemical signals and use them to guide the neuron to where it is supposed to go (attractive and repulsive signals)

growth cones

all the neurons you will have are there by the _____ gestational week

25th

T/F after the 25th gestational week, brain growth reflects increased synaptic connections and myelination

true

T/F myelination ends before the age of 10

false (continues until you're in your 20s)

Gradually, both the number of neurons and the number of connections decreases

pruning

this is critical for learning

pruning