Introduction Flashcards
Cell Theory
Idea that the entire body is made of cells except for the brain.
Theorized by Theodore Schwann in 1839.
Golgi Stain
Silver nitrate solution that sparsely labeled neurons.
Discovered by Camillo Golgi
Reticular Theory
Idea that the brain is a network of nerve fibers rather than distinct cells
Theorized by Camillo Golgi
Neuron Doctrine
Idea that the brain is discrete neurons that form dynamically polarized signaling units
Information flows in one direction
Theorized by Ramon Cajal and discovered using Golgi stain
Dendrites
Tapered extensions of the cell body
Collect information from other neurons
Soma
Aka cell body
Composed of one axon and many dendrites
Responsible for synthesis and signal integration
Axon
Aka boutons
Cylindrical in shape and sometimes myelinated
Sending/conducting information
Axon terminal
Vesicle-filled space
Transmitting information to other neurons
Neuron types are defined by…
- morphology
- physiology
- gene expression
Unipolar neuron
Composed of cell body and axon
Exist in early development; rare in adults
Pseudounipolar neuron
Composed of dendrite, cell body, and axon (cell body branches off)
Present in sensory neurons at the spinal cord
AP isn’t propagated at the cell body
Bipolar neuron
Composed of dendrite, cell body, and axon (cell body is in line with dendrite and axon)
Found in the retina and nose
Multipolar
Composed of multiple dendrites branching off of cell body and one axon
Most common type of neuron
Ex. motor neuron, cortical pyramidal cells, interneurons
Synapses can be…
- axodendritic
- axosomatic
- axoaxonic
- dendrodendritic
Glutamate
Abbrev = Glu
Neurotransmitter
Responsible for CNS excitation
GABA
Neurotransmitter
Responsible for CNS inhibition
Key Neurotransmitters
Glutamate - CNS excitation
Aspartate - brain, spinal chord excitation
GABA - CNS inhibition
Glycine - rapid spinal chord inhibition
Acetylcholine - muscle and autonomic activation, attention (present at NMJ)
Key Neuromodulators
Dopamine - reward and movement
Norepinephrine - arousal and smooth muscle activation
Serotonin - relaxation, mood, and sensory processing
Substance P - pain signaling
Neuropeptide Y - appetite control
Opioids - pain modulation
Adenosine triphosphate - misc.
Neuromodulator
A transmitter that works by slow signaling to alter neuron excitability (often through GPCR pathways)
Ionotropic receptors
Works via ion flow
Timescale of ms (fast)
Ex. Glu, GABA
Used mainly by NTs
Metabotropic receptors
Works via signaling pathways
Timescale of 100ms to s (slow)
Ex. DA, 5-HT
Used by NMs and NTs
Glial cells
Majority of cells in brain
Generally no axons, dendrites, or APs
Capable of cell division
Important to brain function and homeostasis
Astrocytes
Buffering the extracellular environment
Metabolic regulation
Blood flow regulation
Oligodendrocytes
Make myelin
Have synaptic potential
Schwann cells
Only present in PNS
Make myelin
Uptake NTs at neuromuscular junction
Microglia
Immune cells of brain
Mobile upon tissue damage
Ependymal
Line the brain ventricles and central canal of the spinal cord that contain cerebral spinal fluid
Types of neuroglia
- ependymal
- microglia
- schwann cells
- oligodendrocytes
- astrocytes
- satellite cells
Rostral
Closer to frontal lobe
Caudal
Closer to bottom of spinal cord
Dorsal
Brain = top
Spinal cord = back
Ventral
Brain = bottom
Spinal cord = front
Coronal plane
Bisected into front and back
Sagittal plane
Bisected into right and left
Horizontal plane
Bisected into top and bottom
Central nervous system includes…
The brain and the spinal chord
Gray matter
Composed of neurons, dendrites, and synapses
Present on the exterior of the brain and interior of the spinal cord
White matter
Composed of axons and fibrous astrocytes
Present on the interior of the brain and exterior of the spinal cord
Sulcus
Groove in the brain
Gyrus
Peak in brain
Corpus callosum
Tissue connecting the right and left hemisphere
Central sulcus
Between the frontal and parietal lobe
Lateral sulcus
Between the frontal and temporal lobe, and the temporal and parietal lobe
Parietoccipital sulcus
Between the occipital, temporal, and parietal lobes
Cingulate sulcus
Between the parietal and limbic lobe