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23 Cards in this Set
- Front
- Back
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Characteristics of neurons
Receive info and act by sending ____________________ to the ____________________ The _______________ is the main component of the cell and where __________________ synthesis occurs. Cell body of neuron= what The _________________ brings information into the neuron The _________________ transmits information away from the neuron |
-Receive info and act by sending action potentials to the effector organs
-The cell body is the main component of the cell and where protein synthesis occurs. cell body = somma -The dendrite brings information into neuron -The axon transmits information away from the neuron |
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Characteristics of Neurons
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-Receive info, and act by sending action potentials to the effector organs
-The cell body is the main component of the cell and where protein synthesis occurs. cell body = somma -The dendrite brings information into neuron -The axon transmits information away from the neuron |
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Key parts of the neuron: cell body
Part and Function of that part (2) |
Key parts of the neuron:
Part: nucleus Function: brain of the cell Part: nissl bodies Function: protein synthesis |
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Key parts of the neuron: Dendrites
Part and Function of that part (1) |
Dendritic spine: [small extension of dendrites that form synapses with axons of other neurons)
Function: form synapse with axons of other neurons |
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Key parts of the neuron: Axon
Parts and Function of parts: (7) |
Axon hillock: connects axon to cell body
Initial Segment: beginning of axon Trigger Zone: AP generated here [made up of the initial segment and axon hillock] Axoplasm: cytoplasm of axon Axolemma: plasma membrane of axon Presynaptic terminals: the branches from the main axon Neurotransmitters: chemical messengers |
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1. Sensory – Actions potentials ______________ the CNS
2. Motor – Action potentials ______________ the CNS 3. Interneurons – Action potentials ___________________________ |
1. Sensory – Actions potentials ____to__________ the CNS
2. Motor – Action potentials ________away______ the CNS 3. Interneurons – Action potentials: between neurons |
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Structural classification of neurons: bipolar
Appearance Location Key Features |
2 processes: one axon and one dendrite
Sensory organs Ex: Retina of eye, nasal cavity Dendrite receives info Axon transmits info (axon transmits action potentials to the CNS.) |
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Structural classification of neurons: pseudo-unipolar
Appearance Location Key Features |
One process extends from a single cell body, process divides into 2 branches and functions as a single axon
Sensory Neurons Process divides into 2 branches, one section to the periphery the other to the CNS |
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Structural classification of neurons: multipolar
Appearance Location Key Feature |
Many dendrites, one axon
Most of the neurons in CNS are multipolar, and motor neurons Vary in the number of dendrites, most common in body. |
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Neuroglia:
Neuroglia of the CNS. How many types of CNS neuroglia, and what are they |
4 types. Astrocytes, Ependymal cells, Microglia, Oligodendrocytes
Supporting cells of the CNS -Help form a permeability barrier between blood and neurons -Produce CFS |
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Neuroglia:
Astrocytes Characteristics, and other functions |
Astrocytes [these have the biggest jobs out of all the cells]
-Star Shaped due to cytoplasmic processes -Regulate EC composition of brain fluid -Promote tight junctions- forms the blood-brain barrier -Reactive astrocytosis" wall off injured area to prevent spread of inflammation to other parts of the CNS Other Functions (via chemicals) -Development of synapses -Regulate synaptic actvity -Synthesis, absorption and recycling of neurotransmitters |
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Neuroglia:
Ependymal Cells |
Line ventricles of the brain and central canal of spinal chord
Cilia on these cells help move CSF through ventricles Choroid Plexus: specialized ependymal cells and blood vessels secrete CSF into ventricles |
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Neuroglia:
Microglia |
microglia to become phagocytic and mobile in response to inflammation
Phagocytize: -Necrotic tissue -Microorganisms -Foreign Substances - |
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Neuroglia:
Oligodendrocytes |
-cytoplasmic extensions that can surround axons
-form part of the myelin sheath- insulates the electrical activity |
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Schwan cells
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-wrap around axons
-only on one axon, [unlike oligodendrocytes that can cover multiple axons at one time] |
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Satellite Cells
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-surround cell bodies in sensory and autonomic ganglia
-support -nutrition -protection (from heavy metal poison) |
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Nervous Tissue: 2 types of Tissue:
1. Gray Matter CNS and PNS |
-consists of groups of neuron cell bodies and their dendrites
-very little myelin -In CNS gray matter on surface of brain is called cortex, and gray matter deeper in brain called nuclei -In PNS gray matter found in ganglion |
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Nervous Tissue: 2 types of Tissue:
1. White Matter CNS and PNS |
-Bundles of parallel axons and their myelin sheath
CNS: white matter forms nerve tracts: conduction pathways that send action potentials throughout the CNS PNS: nerves are formed by axon bundles and their myelin sheaths |
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Why are there electrical properties in neurons? 2 reasons
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-Ionic concentration differences across the membrane
-Permeability characteristics of the membrane |
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Ionic concentration Differences across Membrane
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Na+ ions and Cl- ions are in abundance outside the cell
K+ ions are in abundance inside the cell Phosphate- higher inside the cell Proteins (negatively charged) held inside the cell |
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Permeability Characteristics
3 things: 1. |
Sodium potassium pump: exchanges 3 Na+ out of the cell for 2 K+ into the cell
Uses ATP to do this- pumps ions against their concentration gradient Helps maintain the ionic charge difference across membrane |
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Permeability Characteristics
3 things: 2. 2 names for these: which ions are there more of these for, and which ions have less |
Leak Ion Channels/Nongated ion channels
Each specific to one ion [open when plasma membrane is at rest) K+ and Cl- have more leak channels than Na+, therefore more permeable to movement of these ions |
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Permeability Characteristics
3 things: 3. 2 types of these kind In the second type which ions are important to what parts of the body |
3. Gated ion channels
1. Ligand Gated: -open and close in response to ligand, hormone, or neurotransmitter. Example: is acetyl choline binding to ligand channel and sodium goes outs of cell along its concentration gradient 2.Voltage Gated: open and close in response to voltage changes across the membrane -Na+ and Cl- channels are important in nervous tissue -Ca channels are important in smooth muscle and cardiac muscle |
