2.2/2.3 Flashcards
(38 cards)
Motor (efferent) neurons
Neurons that carry incoming information from the central nervous system to the muscles and glands (multipolar)
Sensory neurons (afferent)
Neurons that carry incoming info from the sensory receptors to the brain and spinal cord (unipolar)
Interneurons
CNS neurons that internally communicate and intervene between the sensory inputs and motor outputs (multipolar)
Action potential
A neural impulse; a brief electrical charge that travels down an axon
How does an action potential occur?
Occurs when the inside of the cell suddenly reacts the max positive charge of +30 millivolt
Resting potential
The state of a neuron when not firing a neutral impulse. -70 multivolts
Stimulation stage
Neurons can be stimulated by… Chemicals Light Heat Mechanical distortion of the membrane
Depolarization
The process during the action potential when sodium is rushing into the cell causing the interior to become more positive while the outside becomes negative. K+ ions are left inside so the outside is almost completely negative. Na+/sodium channel opens
Channels open or close during the action potential stage
False
Repolarization
Return of the cell to the resting state, the K+ ions will leave the cell trying to balance everything out. Na+/sodium channel closes. K+/potassium channel opens
Refractory period
Returning to resting period; this is where the Na/K pump is used, pumps 3 Na+ ions out of the cell and pumps 2 K+ ions into the cell. ATP must be used since we go from low concentration to high concentration
How does the Na+/K+ pump work?
Pumps 3 Na+ out of the cell, 2 K+ in
What happens in a 2 neuron arc?
Simple reflexes are prompt, short-lived, and automatic
Ex. Contraction of a muscle, blink of an eye when the cornea is touched
2 neuron arc
Sensory to motor, true reflex
3 neuron arc
Sensory, interneurons, motor neurons
What happens in a 3 neuron arc?
The three types of neurons work together in a reflex action
Receptors
Detect stimuli
Speed of processing
The speed with which a person can mentally process information
Why do activities that require more thought, make the body react slower?
Most actions require a large amount of brain activity, the brain needs time to receive, process, and interpret the same information. Therefore, more complex tasks take longer to process.
Description of Parkinson’s disease
A progressive neurological disease
Breaks down certain parts of the brain
Impairs certain functions of the body, especially muscular coordination
What happens to the neurons when someone has Parkinson’s
Nerve cells in basal ganglia die or become damaged
Brain produces less dopamine
Norepinephrine is produced less (causes fatigue and irregular blood pressure)
Symptoms of Parkinson’s disease
Tremors, muscle rigidity, bradykinesia, postural instability, affective flattening
Treatments for Parkinson’s
Levodopa (converted into dopamine) Carbidopa (reduces breakdown of levodopa) Dopamine agonists (mimics dopamine)
Prognosis for Parkinson’s
Rate of progression varies from person (mild symptoms can last years, while some may evolve rapidly)
Life expectancy stays normal
Mental disorders also arise in patients with Parkinson’s (depression, anxiety, etc)
