Thursday, January 23, 2014 4:27 PM
Hippocrates - brain is seat of intelligence
Aristotle- heart is center of intelligence. Brain cools blood from the heart.
Galen- exp with spinal and brain injury and animal dissect. Found 3 structures: cerebrum, cerebellum,
Cerebrum: sense and memory."soft brain" via ventriclesand nerve pathways
Cerebellum: control of movement(initiated by ventricles connected to hollow nerves ie. From heart to
Andreas Vesalius: fluid-mechanical theory: fluid forced out of ventricles to nerves "pump you up" and
cause limbs to move.
Rene Descartes: Human has intellect and soul (mind). Brain is machine but mind is God-given.
*pineal gland, center of brain, is gateway to God.
Nervous system has 2 div:
-CNS (Central Nervous System)
-brain, cerebrum, cerebellum, brainstem, spinal cord.
-PNS (Peripheral Nervous System)
-nerves, nerve cells outside brain and spinal cord
Charles Bell & Francois Magendie- Ablation studies found nerve conduction is unidirectional through
ventral and dorsal roots.
-ventral roots have only motor fibers.
-dorsal roots have only sensory fibers.
Charles Bell proposed:
-cerebrum is destination of sensory fibers
-cerebellum is origin of motorfibers
Franz Joseph Gall- wrote "phrenology". Correlatepersonality traits from skull shape.
Marie Jean-Pierre Flourens- Experimental ablation method: destory brain parts to test function loss
-Rejects Gall's phrenology.
Paul Broca- founded region for speech in cerebrum.
-Broca's area. Damage causes expressive aphasia: understands but cannot speak properly.
"broke" language. "express impaired"
-Wernicke's area damage causes receptive aphasia: cannot understand, can talk fine but makes
no sense. "receive impaired"
THE NEURON-BASIV FUNCTIONALUNIT OF BRAIN THE NEURON-BASIV FUNCTIONALUNIT OF BRAIN
Cell theory- by Theodore Shwann. All tissues are made of cells. Ch. 2
Thursday, January 23, 2014 4:58 PM
-Glia (glue): insulates, supports, and nourishes
neurons (10 times morethan neurons)
-neurons or nerve cells: (10 billion)
• Sense enviro changes through sensors
• Communicatechanges to other neurons
• Command body or other cells response
• Different neurons have different functions
NisslStain- basic dyes to stain nuclei and clumps of
material around it with color.
• To distinguish neurons from glia cells
• For study of cytoarchitecture,or cell structures
in diff parts of CNS.
Golgi stain (CamilloGolgi): silver chromatesolution
Cell body: soma or perikaryon
Neurites: include dendrites (receive
signals) and axons (carry out info)
Idea: Neurites of diff neurons connect
Neuron Doctrine: neurons are the functional units of
the nervous system.
Cajal's Contribution: Neural circuit made of indiv.
Cajal: Neurons communicateby contact (gaps
or clefts between)
Golgi: " by continuity. CLASSIFYINGNEURONS
-Based on number of Neurites. Typicallymultipolar.
Single neurite = unipolar (ie. Primary
2+ neurites = bipolar or multipolar (motor, MOST in
Dendrite- (tree branches) "antennae" synapse =
receptors. Dendritic spines. Postsynaptic(receives
signals from axon terminal)
Axon- communicatethrough neurons. Axon terminal
or terminal button (swollen disk)
Synapse- synaptic transmission: electrical-to-
Chemical synapses (receptors) use
Axon transport- fast axon transport of
1. Anterograde: (soma to terminal) radioactive
amino acid. OUT. Use PHA-L inject. OUT
2. Retrograde: (terminal to soma) transport.
INTO. Use HRP inject.
CELLS OF PNS: Shwann Cells
Each cell forms myelin around small segment of one
Myelin- mult. Layers of cell membrane.
Node of ranvier- section of unmyelinated axon
membrane between 2 shwann cells. CNS: Blood Brain Barrier (BBB)
-formed by astrocytes.
Astrocytefoot processes secrete paracrines that form
Tight junction prevents solute movementb/t endothelial
CELLS OF CNS: Glial cells and functions
1. Oligodendrocytes: forms myelin sheath.
2. Microglia(immune cells):"scavengers"
• provide substrates for ATP prod.
• Form BBB.
• Secrete neurotrophic factors.
• Take up K+, water, neurotransmitters.
• Source of neural stem cells (Ependymal cells
4. Ependymal cells: create barriers between
compartments. Source of neural stem cells. Ch. 3
Thursday, January 23, 2016:27 PM
What is it?
Equilibrium: state of rest/balance