Chapter 2 Flashcards
Neurons
A nerve cell; the basic building block of the nervous system.
Dendrite
the neuron’s bushy, branching extensions that receive messages and conduct impulses toward the cell body.
Axon
the neurons extension that passes messages through its branching terminal fibers that form junctions with other neurons, muscles, or glands.
Action Potential
A neural impulse; a brief electrical charge that travels down an axon.
Threshold
The level of stimulation required to trigger a neural impulse.
Neurotransmitter
Chemical messagers that cross the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neurons will generate a neural impulse.
Endorphins
“Morphine within” - Natural, opiate like neurotransmitter linked to pain control and to pleasure.
Nervous System
The body speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous system.
Central Nervous System (CNS)
the brain and spinal cord
Peripheral Nervous System (PNS)
the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body.
Nerves
Bundled axons that form neural “cables” connecting the central nervous system with muscles, glands, and sense organs.
Three Types of Neurons
- Sensory Neurons
- Motor Neurons
- Interneurons
Somatic Nervous System
The division of the peripheral nervous system that controls the body’s skeletal muscle. Also called the skeletal nervous system.
Acetlycholine (ACh)
Enables muscle action, learning, and memory.
Dopamine
Influences movement, learning, attention, and emotion.
Serotonin
Affects mood, hunger, sleep, and arousal.
Norepinephrine
Helps control alertness and arousal
Autonomic Nervous System
Controls the glands and the muscles of the internal organs (such as the heart)
Sympathetic Nervous System
the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations.
Parasympathetic Nervous System
The division of the autonomic nervous system that calms the body, conserving the energy.
Reflex
A simple, automatic response to a sensory stimulus, such as the kee-jerk response.