Chapter 8 Learning Objectives

Map the organization of the nervous system in detail.

CNS is connected to the brain and the spinal cord. The PNS is then split into two different systems, afferent(sensory) and efferent. The efferent systems are then split up into autonomic and somatic motor. The autonomic controls the rest digest and the fight or flight mechanisms. The somatic controls skeletal movement.

Draw and describe the parts of a neuron and give their functions.

Describe the parts of a synapse and their functions.

This is the region where the terminal axon meets the dendrite of another neuron. The synapse is where signals are transferred between two cells.

Name the types and functions of glial cells.

-Schwann cell (PNS) Oligodendrocytes (CNS)

-Satellite cells (PNS)

-Astrocytes (CNS): Blood-brain Barrier

-Microglia (CNS): Specialized immune cells.

-Ependymal cells: Cerebral spinal fluid.

Explain in words how the Goldman-Hodgkin-Katz equation relates to the membrane potential of a cell.

The equation helps find the membrane potential by using the concentrations of ions inside and outside of the cell.

Explain the relationships between the following terms: current flow, conductance,resistance, Ohm's law.

The current flow is the current going down an axon, conductance is the high speed movement of an action potential down an axon, resistance is the force that opposes the current flow.

Compare and contrast graded potentials and action potentials.

Graded potentials are what allows action potentials to occur. Graded potentials decrease as they get closer to the trigger zone, where as action potentials keep the same amount of energy down the axon.

Explain the changes in ion permeability and ion flow that take place during an action potential.

An increase of sodium will cause the inside of a cell to depolarize and allow an action potential to occur. When the action potential occurs the flow of sodium into the cell will stop and the flow of potassium outside of the cell will increase to repolarize the cell. Eventually the potassium channel will close when the cell is back to its resting potential.

Describe and compare absolute and relative refractory periods.

Absolute refractory period is due to voltage-gated sodium channels resetting and relative refractory period follows an absolute refractory period.

Explain the role of myelin in the conduction of action potentials.

Myelin wraps around cells in order to increase the cells conduction speed.

Distinguish between electrical and chemical synapses.

-Electrical synapses pass electrical signals through gap junctions, the signal can be bi-directional, synchronizes the activity of a network of cells.

-Chemical synapses use neurotransmitters that cross synaptic clefts.

List and give examples of the seven groups of neurocrine secretions.

-Chemical: Acetylcholine

-Amines: Dopamine

-Amino acids: Glutamate

-Purines: Adenosine

-Gases: Nitric Oxide

-Peptides: Vasopressin

-Lipids: Eicosonoids

Describe different patterns for neurotransmitter synthesis, recycling, release, and termination of action.

The synthesis occurs in the axon terminals of neurons, recycling allows some of the neurotransmitters to go back into the cell and be used again. , release happens when calcium enters the axon terminal and allows the neurotransmitter that is inside a vesicle to bind to the membrane of the cell, and termination occurs by diffusion, enzymatic break down.

Describe the role of the following in synaptic communication: ionotropic and metabotropic receptors, neurotransmitters and neuromodulators, fast and slow synaptic potentials, excitatory and inhibitory postsynaptic potentials.

Fast synaptic potentials involve the use of ion channels and slow synaptic potentials involve the use of GPCR and second messenger systemes, Ionotropic receptors are also called receptor channels, metabotropic receptors are GPCR for neuromodulators, Neurotransmitters bind to specific receptors.

Compare temporal and spatial summation.

-Spatial summation is when two or more neurons simultaneously fire and have an additive effect.

- Temporal summation is when graded potentials overlap in time and have an additive effect.

Compare presynaptic and postsynaptic inhibition.

Presynaptic inhibition is when the cell that is going to transfer the signal to another cell is inhibited and postsynaptic inhibition is where the cell that received the signal is inhibited.

Explain the mechanism of long-term potentiation mediated by AMPA and NMDA receptors.

Glutamate binds to AMPA and NMDA channels, the net sodium entry through AMPA channels depolarizes postsynaptic cell, depolarization ejects magnesium from NMDA receptor-channel and opens channel, calcium enters cytoplasm through NMDA channel, Calcium activates second messenger pathways, paracrine from postsynaptic cell enhances glutamate release.