Transcript Central Nervous System (CNS): Basic Facts

Central Nervous System (CNS):
Basic Facts
• Adult human brain is
– 2% body weight
– 20% resting oxygen
– 15-20% blood flow
• Consists of neurons
and glial cells
– Neurons are the
information processors
– Glia provide metabolic
and structural support
to the neurons
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Energetic needs
Myelin
Repair
spinal fluid production
and other functions
Size of Adult Human Brain
• Range: 1000 to 2000 grams
• Average male = 1,350 g
• Average female = 1,200 g
• Anatole France = 1,000 g (20th
century poet)
• Albert Einstein = 1,230 g
• Lord Byron
= 2,380 g
(Romance poet)
Neurons
• 200 cell types
• 10 trillion cells in head
•
25 billion pyramidal neurons,
connects to 1000s of other
neurons
Gray & White Matter
• 60% white matter (axons)
• 40% gray matter (cells)
– 2 mph to 250 mph when myelinated
Neural Structure
Human neocortex has 6 layers,
4.5 mm at deepest point
•
A pinpoint on
the 2,200
square cm
surface area in
adults
52 Brodmann Areas (1906)
based on different cell types and distributions
Bottom to Top
Back to Front
Right and Left
Forebrain =
Cortex & Limbic
General Functions of lobes
• Occipital
– Vision
• Temporal
– Auditory
– Memory
• Parietal
– Touch
– Integration
• Frontal
– Motor
– Executive Function
(goal-oriented, planning,
sequencing)
Central Nervous System
• Fissures (large cleft)
– Lateral or Sylvan fissure
– Longitudinal fissure
– Central fissure or sulcus
• Sulcus (shallow cleft)
• Gyrus (tissue ridge)
Types of Neuroimaging:
Positron Emission Tomography (PET)
Anatomical MRI
(T1-weighted)
Anatomical MRI
(T2-weighted)
MRI examples
Functional MRI
(activation to music)
Structural MRI
(gray matter thickness map)
Diffusion Tensor MRI
(white matter tracts)
Electroencephalography (EEG) – Brainwaves