Chapter 7 Flashcards
Association Neuron
A neuron within the CNS that conducts action potentials from one neuron to another within the CNS
Ganglia
Collections of neuron cell bodies that are found outside of the CNS
Nerves
Bundles of axons and their sheaths that extend out from the CNS
Potential Difference
A measure of the charge difference across the cell membrane
Excitability
The ability to undergo an action potential in response to a stimulus
Sympathetic Division
Division of neurons of the ANS that prepare the body for increased energy expenditure
Parasympathetic Division
Division of the neurons of the ANS that stimulate resting and nutrition related functions such as digestion, defecation, and urination
Autonomic Nervous System
PNS neurons that transmit action potentials from the CNS to the smooth muscles, cardiac muscles, and glands
Somatic Motor Nervous System
PNS neurons that transmit action potentials from the CNS to the skeletal muscles
Spinal Nerves
Nerves of the PNS that originate from the spinal cord
Cranial Nerves
Nerves from the PNS that originate from the brain
Efferent Neurons
Neurons that transmit action potentials from the CNS to the effector organs
Afferent Neurons
Neurons that transmit action potentials from sensory receptors to the CNS
What is an Inhibitory Synapse?
Graded potentials that push the neuron further from threshold and make an action potential harder to achieve (hyperpolarization)
What is an Excitatory Synapse?
It’s a graded potential that pushes the the neuron closer to the threshold and makes an action potential more likely (depolarization)
What is depolarization?
The charge in the cell shifts from negative to positive-stimulates an action potential
What is Repolarization?
Change in a membrane potential that returns it to a negative value just after the depolarization phase of an action potential has changed the membrane potential to a positive value
What is Hyperpolarization?
A charge that takes a neuron farther away from producing an action potential
What is an after-discharge response?
Persistence of response of muscle or neural elements after cessation of stimulation. Prolongs the effect of stimulus
What is the sodium potassium exchange pump?
Sodium and Potassium ions are pumped in opposite directions across the membrane building up a chemical and electrical gradient for each. Functions to maintain electrical charge within the cell.
What is a local potential?
A stimulus not strong enough to trigger an action potential-also known as a sub threshold stimulus
What is temporal summation?
A single axon carries several action potentials within a small amount of time
What is spatial summation?
Many axons all carry an action potential to the same neuron all at once. The sub threshold stimuli all come from different points in space.
What is absolute refractory period?
The time during which another stimulus given to the neuron, no matter how strong, will not lead to a second action potential
What is the difference between afferent and efferent Neurons?
Afferent-carries signals from the sensory receptors to the CNS
Efferent - carries signals from the CNS to effector organs, which are the muscles and glands
What are the three kinds of circuits that can be formed by neurons?
Converging-many inputs are reduced to a limited output
Diverging-one input stimulates many outputs
Oscillating- prolongs the effect of a stimulus; it re stimulates itself
