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Local Anesthetics
Pharmacokinetics Exam 5
Question | Answer |
---|---|
What is another name for a target cell? | Nerve Cell |
Local anesthetics block what channel? | Sodium aka Sodium Channel Blockers |
True/False - Local anesthetics provide a TEMPORARY block in nerve transmission | True |
How do nerve cells communicate? | Via ionic messages |
What is the excitability of cells based on? | The structure of the cell membrane and its components |
Nerve cells are refered to as what? | Excitable cells |
What is the function of a nerve cell? | Transmission of signals from one place in the body to another |
What are nerve cells as well as all other cells in the body composed of? | 1. Cell body 2. Nucleus 3. Microcellular organelles |
What do organelles contain? | RNA, DNA, mitochondria, golgi bodies...basicaly everything inside the cell |
What happens to the sodum channels when a local anesthetic is given? | The local anesthetic lugs up the sodium channel traping potassium inside and leaving sodium outside |
The communication function of the nerve cell is served by an elongation of the nerve cell body and this is termed? | Axon |
What are the outfoldings of the cell body and located in close proximity to the nucleus? | Dendrites (fingerlike projections) |
What is the term for intracellular fluid? | Axoplasm |
What is the purpose of axoplasm? | Serves a transport function for the active movement of energy and waste material |
What facilitates transport within the axoplasm? | Microtubules |
True/False - microtubules allow the movement of metabolic substances rapidly between the cell body and the end of the axons | True |
What is the dendritic zone? | The receptive part of the neuron or nerve cell that is close to the cell body |
True/False - The dendritic zone is much larger than the cell body | True |
What is composed of many outfoldings of the nerve cell membrane in the area of the cell body? | The Dendritic Zone |
What are dendrites actively involved with? | The synaptic process with other neurons and are sites for initiation of excitability |
What requires an intact nerve cell membrane that is energy dependent? | Neural transmission |
Where is information received from in the nerve cell? | Sensory and motor neurons |
The information is propogated from the _______ and is modified by the structure of the _______. | Original signal, dendritic anatomy |
True/False - Both the ECF around the nerve and the ICF of the axoplasm are fat based and non ionized | False - Both the ECF around the nerve and the ICF of the axoplasm are WATER BASED and highly IONIC |
Highly ionic means? | Highly electrically charged |
The nerve cell membrane is a ________ embedded with _______ and is very _______. | Lipid bilayer, lipoproteins, hydrophobic |
What functions as a barrier to ionic movement? | Nerve Cell Membrane |
Ionic movement only occurs at gaps formed by lipoproteins called _________. | Ion Channels |
True/False - Nerve fibers are all morphologically the same | False - Not all nerve fibers are morphologically the same |
What are the 2 protective cells that cover the axon? | Schwann Cells and oligodendrocytes |
Where are Schwann Cells located? | Peripheral Nervous System |
Where are Oligodendrocytes located? | Central Nervous System |
What do Schwann cells produce? | Schwann cells produce myelin and the myelin insulates nerve cells |
What is the weakest point of the axon termed? | Nodes of Ranvier |
When a local anesthetic is given. where does it tend to migrate to and why? | Nodes of Ranvier because it is the weakest point of the axon and easiest to penetrate |
What 3 jobs do schwann cells have? | 1. Enzyme Synthesis 2. Metabolic needs of the axon 3. Synthesis of myelin |
Schwann cells create the myelin sheath by wrapping spirally around the ______, between __ and ___ revolutions. | Axon, 50, 200 |
What 2 functions does the myelin sheath serve? | 1. Insulating 2. Protective |
Define Nodes of Ranvier | Are defined as gaps between adjacent Schwann cells on the axon occur at regular interval of abut 1mm |
True/False - The density of sodium channels within the Nodes of Ranvier are low | False - The density within the sodium channels is high |
To activate sodium channels at the next adjacent gap, what must happen? | The sodium currents in the areas of the Nodes of Ranvier must be sufficient in order to activate the sodium channels at the next adjacent gap |
Define Saltatory Conduction | Communication between the Nodes of Ranvier involving the sodium currents |
The terminal end of the axon is called? | Synaptic Terminal |
What occurs at the synaptic terminal? | The efferent (exit) neural conduction can be transmitted to other excitable tissues, such as other nerves and motor endplates. |