1.1
These individuals develop from a single fertilized egg that splits in two, making them genetically identical.
What are identical (monozygotic) twins?
Composed of the brain and spinal cord, this primary division processes incoming sensory information and makes bodily decisions.
What is the Central Nervous System (CNS)?
This neural firing principle dictates that a neuron either fires completely or does not fire at all—there are no partial firings.
What is the all-or-none response (or principle)?
Severing this large band of axon fibers that connects the left and right cerebral hemispheres creates a split-brain condition.
What is the corpus callosum?
This natural 24-hour biological cycle regulates bodily processes like body temperature, alertness, and sleepiness.
What is the circadian rhythm?
This field studies how environmental factors influence gene expression without altering the underlying DNA sequence.
What is epigenetics?
This division of the nervous system consists of sensory and motor neurons connecting the brain and spinal cord to the rest of the body.
What is the Peripheral Nervous System (PNS)?
This brief electrical impulse travels down the length of an axon when a neuron reaches its excitation threshold.
What is an action potential?
Located in the limbic system, this neural structure is crucial for consolidating new explicit, declarative memories.
What is the hippocampus?
This stage of sleep is characterized by rapid eye movements, temporary bodily muscle paralysis, and vivid dreams.
What is REM sleep (or paradoxical sleep)?
This evolutionary principle states that inherited traits promoting survival and reproduction are more likely to be passed on to future generations.
What is natural selection?
This division of the autonomic nervous system prepares the body for action by increasing heart rate and dilating pupils during a threat.
What is the sympathetic nervous system?
This fatty tissue layer segmentally encasing a neuron's axon speeds up the transmission of electrical impulses.
What is the myelin sheath?
These two almond-shaped neural clusters in the limbic system play a key role in processing emotions like fear and aggression.
What is the amygdala?
Secreted by the pineal gland when light levels drop, this hormone induces drowsiness and helps regulate the sleep-wake cycle.
What is melatonin?
This mathematical proportion estimates how much of the variation among individuals in a group can be attributed to genetic differences.
What is heritability?
This branch of the autonomic nervous system lowers heart rate and stimulates digestion to calm the body and conserve energy.
What is the parasympathetic nervous system?
This process involves the reabsorption of excess neurotransmitters by the sending axon terminal after a signal is sent.
What is reuptake?
This term describes the brain's capacity to modify its structure and reorganize neural pathways following experience or injury.
What is neuroplasticity (or brain plasticity)?
This sleep disorder causes sudden, uncontrollable sleep attacks during normal waking hours, often jumping directly into REM sleep.
What is narcolepsy?
These individuals develop from two separate eggs fertilized by two different sperm, sharing roughly 50% of their genetic material like standard biological siblings.
What are fraternal (dizygotic) twins?
This subdivision of the peripheral nervous system controls the voluntary movement of skeletal muscles.
What is the somatic nervous system?
This type of chemical compound binds to a receptor site on a postsynaptic neuron to mimic or amplify the action of a neurotransmitter.
What is an agonist?
Damage to this specific area in the left frontal lobe causes motor speech impairment while leaving language comprehension intact.
What is Broca's area?
This dream model proposes that dreams are the cerebral cortex's attempt to synthesize and make sense of random neural firing from the brainstem.
What is the activation-synthesis theory?