Chapter 15 Brain and Cranial Nerves
adult brain weight
1.35-1.4 kg (~3 pounds) 1200 cc volume
cranial meninges
3 connective tissue layers - separates soft tissue
meninges
CT membrane, provides protection, support, partition
outer superficial region of gray matter, covers most of adult brain
cerebral cortex
discrete internal clusters of gray matter
cerebral nuclei
what structures protect and isolate the brain
cranium, meninges, CSF, blood-brain barrier
cerebral spinal fluid
cushioning fluid
insula lobe
deep to the lateral sulcus
developing brain growth
disproportionate, different rates depending on different regions
how is neural tissue organized
gray and white matter
motor neuron and interneuron cell bodies, unmyelinated axons
gray matter
where does the brain sit in the head?
in the top half of head, top of eye brows
why are gyrus and sulcus important?
increase surface area in the brain so there are enough neurons to have a properly functioning brain
2 flexures that bend brain toward brainstem
mid brain and cervical flexure
blood-brain barrier
prevents entry of harmful materials from blood stream
bony cranium
provides rigid support and CT membranes
issues in different growth rates
restricted by skull, so growing structure is limited
where does brain development been?
rostral end of neural tube
Lessencephaly
smooth brain, neuron migration disorder - severely mentally retarded, seizures, short lifespan
what determines intelligence?
the number of active synapses and wiring in brain
rostral/anterior
toward the nose
caudal/posterior
toward the tail
open areas in the brain
ventricles
deep to outer gray matter
white matter
myelinated axons
white matter