Brains, Bodies, Behavior Flashcards
central nervous system
made up of the brain and spinal cord, is the major controller of the body’s functions, charged with interpreting sensory information and responding to it with its own directives
peripheral nervous system
the neurons that link the CNS to our skin, muscles, and glands.
PNS links the CNS to the body’s sense receptors, muscles, and glands
divided into autonomic and somatic nervous systems
endocrine system
the chemical regulator of the body that consists of glands that secrete hormones.
works together with the nervous system to influence many aspects of human behavior, including growth, reproduction, and metabolism. And the endocrine system plays a vital role in emotions
neuron
cell in the nervous system whose function it is to receive and transmit information
soma
contains the nucleus of the cell and keeps the cell alive
dendrite
collects information from other cells and sends the information to the soma
axon
transmits information away from the cell body toward other neurons or to the muscles and glands
have terminal buttons at end that form junctions with other cells
myelin sheath
a layer of fatty tissue surrounding the axon of a neuron that both acts as an insulator and allows faster transmission of the electrical signal.
neurotransmitters
a chemical that relays signals across the synapses between neurons
travel across the synaptic space between the terminal button of one neuron and the dendrites of other neurons, where they bind to the dendrites in the neighboring neurons
synapses
areas where the terminal buttons at the end of the axon of one neuron nearly, but don’t quite, touch the dendrites of another
resting potential
a state in which the interior of the neuron contains a greater number of negatively charged ions than does the area outside the cell.
action potential
change in electrical charge that occurs in a neuron when a nerve impulse is transmitted
When the segment of the axon that is closest to the cell body is stimulated by an electrical signal from the dendrites, and if this electrical signal is strong enough that it passes a certain level or threshold, the cell membrane in this first segment opens its gates, allowing positively charged sodium ions that were previously kept out to enter.
it operates in an all or nothing manner. What this means is that the neuron either fires completely, such that the action potential moves all the way down the axon, or it does not fire at all.
node of Ranvier
a series of breaks between the sausage-like segments of the myelin sheath.
refractory period
a brief time after the firing of the axon in which the axon cannot fire again because the neuron has not yet returned to its resting potential
excitatory or inhibitory effects of neurotransmitters
When neurotransmitters are accepted by the receptors on the receiving neurons their effect may be either excitatory (i.e., they make the cell more likely to fire) or inhibitory (i.e., they make the cell less likely to fire). Furthermore, if the receiving neuron is able to accept more than one neurotransmitter, then it will be influenced by the excitatory and inhibitory processes of each. If the excitatory effects of the neurotransmitters are greater than the inhibitory influences of the neurotransmitters, the neuron moves closer to its firing threshold, and if it reaches the threshold, the action potential and the process of transferring information through the neuron begins.
reuptake
a process in which neurotransmitters that are in the synapse are reabsorbed into the transmitting terminal buttons, ready to again be released after the neuron fires
agonist
a drug that has chemical properties similar to a particular neurotransmitter and thus mimics the effects of the neurotransmitter.
cocaine is an agonist for the neurotransmitter dopamine
antagonist
a drug that reduces or stops the normal effects of a neurotransmitter.
Acetylcholine
A common neurotransmitter used in the spinal cord and motor neurons to stimulate muscle contractions. It’s also used in the brain to regulate memory, sleeping, and dreaming.
Dopamine
Involved in movement, motivation, and emotion, Dopamine produces feelings of pleasure when released by the brain’s reward system, and it’s also involved in learning.
Endorphins
Released in response to behaviors such as vigorous exercise, orgasm, and eating spicy foods.
GABA (gamma-aminobutyric acid)
The major inhibitory neurotransmitter in the brain.
Alcohol stimulates the release of GABA, which inhibits the nervous system and makes us feel drunk. Low levels of GABA can produce anxiety, and GABA agonists (tranquilizers) are used to reduce anxiety.
Glutamate
The most common neurotransmitter, it’s released in more than 90% of the brain’s synapses. Glutamate is found in the food additive MSG
Excess glutamate can cause overstimulation, migraines and seizures.
Serotonin
Involved in many functions, including mood, appetite, sleep, and aggression.
Low levels of serotonin are associated with depression, and some drugs designed to treat depression (known as selective serotonin reuptake inhibitors, or SSRIs) serve to prevent their reuptake.
brain stem
oldest and innermost region of the brain
basic functions of life, including breathing, attention, and motor responses
consists of medulla, pons and reticular formation
medulla
the area of the brain stem that controls heart rate and breathing, where the spinal cord enters the skull
pons
spherical shape above the medulla
a structure in the brain stem that helps control the movements of the body, playing a particularly important role in balance and walking
reticular formation
Running through the medulla and the pons is a long, narrow network of neurons
filter out some of the stimuli that are coming into the brain from the spinal cord and to relay the remainder of the signals to other areas of the brain
important roles in walking, eating, sexual activity, and sleeping
thalamus
above brain stem;
the egg-shaped structure above the brain stem that applies still more filtering to the sensory information that is coming up from the spinal cord and through the reticular formation, and it relays some of these remaining signals to the higher brain levels
thalamus also receives some of the higher brain’s replies, forwarding them to the medulla and the cerebellum. The thalamus is also important in sleep because it shuts off incoming signals from the senses, allowing us to rest.
