Biology Ch 4. The Nervous System Flashcards
Neurons
Highly specialized cells responsible for the conduction of impulses, communicate using both electrical and chemical forms
Electrical communication neurons
Electrical communication occurs via ion exchange in the generation of membrane potential’s down the length of an axon
Chemical communication neurons
Chemical communication occurs via neurotransmitters released from the presynaptic cell in the binding of these neurotransmitters to the postsynaptic cell
Dendrites
Appendages on the soma that receives signals from other cells
Soma
Cell body, the location of the nucleus as well as organelles such as the endoplasmic reticulum and ribosomes
Axon hillock
We are the cell body transitions from the soma to the axon and where the action potential’s are initiated
Axon
A long appendage down which an action potential travels
Nerve terminal
aka synaptic bouton, at the end of an axon from which neurotransmitters are released, enlarged and flattened to maximize transmission and ensure proper release of neurotransmitters
Synaptic bouton
aka nerve terminal, the end of an axon from which neurotransmitters are released, enlarged and flattened to maximize transmission and ensure proper release of neurotransmitters
Nodes of Ranvier
Exposed areas of myelinated axons that permit saltatory conduction, critical for rapid signal conduction
Synapse
Consist of the nerve terminal of the presynaptic neuron, the membrane of the postsynaptic cell, and the space between the two (synaptic cleft)
Synaptic cleft
Space between one neurons nerve terminal and the others membrane
Myelin
Insulating/fatty substance that prevents signal loss, created by oligodendrocytes in the CNS and Schwann cells in the PNS, prevents dissipation of the neural impulse and crossing of neural impulses from adjacent neurons, increases the speed of conduction in the axon
Oligodendrocytes
Creates myelin in the central nervous system
Schwann cells
Creates myelin in the peripheral nervous system
Nerves
What neurons can be bundled into in the PNS, may carry multiple types of information including sensory, motor, or both, cell bodies of the same type are clustered together into ganglia
Tracts
What neurons can be bundled into in the CNS, only contain one type of information, cell bodies of neurons in the same tract are grouped into nuclei
Ganglia
Where cell bodies of neurons of the same type on nerves cluster together in the PNS
Nuclei nerves
Where cell bodies of individual neurons within a tract cluster together in the CNS
Neuroglia
aka glial cells, other cells within the nervous system, include astrocytes, ependymal cells, microglia, oligodendrocytes, and Schwann cells
Astrocytes
Nourish neurons and form the blood-brain barrier which controls the transmission of solutes from the bloodstream into nervous tissue
Ependymal Cells
Line the ventricles of the brain and produce cerebrospinal fluid, which physically supports the brain and serves as a shock absorber
Microglia
Phagocytic cells that ingesting break down waste products and pathogens in the central nervous system
Resting membrane potential
Potential for all neurons, approximately -70 mV, maintained using selective permeability of Na+ and K+ and Na+/K+ ATPase
Na+/K+ ATPase
Times three sodium ions out of the cell for every two potassium ions pumped in