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Lecture

BIOB32H3 Lecture Notes - Neurofilament, Oligodendrocyte, Choline


Department
Biological Sciences
Course Code
BIOB32H3
Professor
Kenneth Welch

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Neural tissue
An Overview of the Nervous System
Nervous system overview
Nervous system
Provides swift, brief responses to stimuli
Endocrine system
Adjusts metabolic operations and directs long-term changes
Nervous system includes
All the neural tissue of the body
Basic unit = neuron
Divisions of the Nervous system
CNS (Central Nervous system)
Brain and spinal cord
PNS (Peripheral Nervous system)
Neural tissue outside CNS
Afferent division brings sensory information from receptors
Efferent division carries motor commands to effectors
Efferent division includes somatic nervous system and autonomic nervous
system
Neurons
Neuron structure
Perikaryon
Neurofilaments, neurotubules, neurofibrils
Axon hillock
Soma
Axon
Collaterals with telodendria
Synapse
Site of intercellular communication
Neurotransmitters released from synaptic knob of presynaptic neuron
Neuron classification
Anatomical
Anaxonic
Unipolar
Bipolar
Multipolar
Functional
Sensory neurons
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deliver information from exteroceptors, interoceptors, or proprioceptors
Motor neurons
Form the efferent division of the PNS
Interneurons (association neurons)
Located entirely within the CNS
Distribute sensory input and coordinate motor output
Neuroglia
Neuroglia of the Central Nervous System
Four types of neuroglia in the CNS
Ependymal cells
Related to cerebrospinal fluid
Astrocytes
Largest and most numerous
Oligodendrocytes
Myelination of CNS axons
Microglia
Phagocytic cells
Neuroglia of the Peripheral Nervous System
Two types of neuroglia in the PNS
Satellite cells
Surround neuron cell bodies within ganglia
Schwann cells
Ensheath axons in the PNS
Neurophysiology: Ions and Electrical Signals
The transmembrane potential
Electrochemical gradient
Sum of all chemical and electrical forces acting across the cell membrane
Sodium-potassium exchange pump stabilizes resting potential at ~70 mV
Changes in the transmembrane potential
Membrane contains
Passive (leak) channels that are always open
Active (gated) channels that open and close in response to stimuli
Three types of active channels
Chemically regulated channels
Voltage-regulated channels
Mechanically regulated channels
Graded potential
A change in potential that decreases with distance
Localized depolarization or hyperpolarization
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