Chapter 2: The Biology of Mind

Vocabulary flashcards covering biological psychology, neural structure, neurotransmission, nervous and endocrine systems, brain imaging techniques, brainstem, limbic system, and cerebral cortex structures.

Biopsychosocial System

A system in which biological, psychological, and social-cultural factors interact to influence human behavior.

Phrenology

An ill-founded theory proposed by Franz Gall claiming that bumps on the skull reveal mental abilities and character traits.

Neuroplasticity

The brain's ability to change throughout life by reorganizing after damage or by building new neural pathways based on personal experience.

Neuron

An elementary nerve cell that acts as a fundamental component of the body's speedy electrochemical nervous system.

Dendrites

Branching extensions of a neuron that receive incoming messages and conduct impulses toward the cell body.

Axon

The neuron extension that passes electrical messages away from the cell body to other neurons, muscles, or glands.

Myelin Sheath

A layer of fatty tissue encasing the axons of some neurons that enables significantly faster transmission speeds of neural signals.

Glial Cells (Glia)

Cells in the nervous system that support, nourish, and protect neurons, provide myelin, and play an active role in thinking and learning.

Threshold

The minimum level of combined neural stimulation (triggering at $-55 tribunal mV$) required to activate an action potential.

Action Potential

A neural impulse consisting of a brief electrical charge that travels down an axon produced by depolarization.

All-or-None Response

A neuron's reaction process of either firing at full strength or not firing at all.

Synapse

The tiny junction between the axon terminal of the sending neuron and the dendrite or cell body of the receiving neuron, discovered by Sir Charles Sherrington.

Reuptake

The process by which excess neurotransmitters are reabsorbed by the sending neuron.

Acetylcholine (ACh)

A neurotransmitter that enables muscle action, learning, and memory, which deteriorates in Alzheimer's disease.

Dopamine

A neurotransmitter that influences movement, learning, attention, and emotion; oversupply is linked to schizophrenia, while undersupply is linked to Parkinson's disease.

Serotonin

A neurotransmitter that affects mood, hunger, sleep, and arousal, with an undersupply linked to depression.

Norepinephrine

A neurotransmitter that helps control alertness and arousal, where an undersupply can depress mood.

GABA (gamma-aminobutyric acid)

A major inhibitory neurotransmitter whose undersupply is linked to seizures, tremors, and insomnia.

Glutamate

A major excitatory neurotransmitter involved in memory; oversupply can overstimulate the brain, causing migraines or seizures.

Endorphins

Natural, opiate-like neurotransmitters released in response to pain and exercise that influence the perception of pain or pleasure.

Agonist

A molecule that increases a neurotransmitter's action by binding to receptors or blocking reuptake, mimicking excitatory or inhibitory effects.

Antagonist

A molecule that inhibits or blocks a neurotransmitter's action by occupying its receptor site.

Central Nervous System (CNS)

The division of the nervous system comprising the brain (containing approximately $86\,\text{billion}$ neurons, using $20\,\%$ of energy) and spinal cord, acting as the body's primary decision maker.

Peripheral Nervous System (PNS)

The sensory and motor neurons that connect the central nervous system to the rest of the body for gathering and transmitting information.

Sensory Neurons

Neurons that carry incoming messages from body tissues and sensory receptors inward to the spinal cord and brain.

Motor Neurons

Neurons that carry outgoing instructions from the central nervous system to the body's muscles and glands.

Interneurons

Neurons within the brain and spinal cord that communicate internally and process information between sensory inputs and motor outputs.

Somatic Nervous System

The division of the peripheral nervous system that enables voluntary control of skeletal muscles.

Autonomic Nervous System

The division of the peripheral nervous system that controls self-regulated actions of internal organs and glands.

Sympathetic Nervous System

The subdivision of the autonomic nervous system that arouses the body, expends energy, and mobilizes fight-or-flight responses.

Parasympathetic Nervous System

The subdivision of the autonomic nervous system that calms the body, conserves energy, and allows routine maintenance activity.

Endocrine System

The body's chemical communication system, consisting of glands that secrete hormones directly into the bloodstream.

Hormones

Chemical messengers produced by endocrine glands that travel through the bloodstream and affect other tissues, including the brain.

Pituitary Gland

The endocrine system's master gland; regulated by the hypothalamus, it releases hormones that influence growth and direct other endocrine glands.

Electroencephalogram (EEG)

A diagnostic recording technique using electrodes placed on the scalp to measure electrical activity sweeping across brain neurons.

Magnetoencephalography (MEG)

A brain-imaging technique using a head coil to measure magnetic fields generated by the brain's natural electrical currents.

Positron Emission Tomography (PET)

A visual imaging display tracking where a temporarily radioactive form of glucose travels in the brain during specific tasks.

Magnetic Resonance Imaging (MRI)

A neuroimaging technique that utilizes magnetic fields and radio waves to generate detailed maps of brain structure.

Functional Magnetic Resonance Imaging (fMRI)

A technique measuring brain activity and blood flow by comparing successive MRI scans.

Medulla

The base of the brainstem that controls vital autonomic functions such as heartbeat and breathing.

Pons

A brainstem structure located above the medulla that assists in coordinating movement and controlling sleep.

Thalamus

The brain's sensory control center at the top of the brainstem, routing sensory messages to the cortex and replies to the cerebellum and medulla.

Reticular Formation

A nerve network extending through the brainstem and thalamus that plays a crucial role in controlling arousal.

Cerebellum

The structure located at the rear of the brainstem that coordinates voluntary movement and balance, judges time, discriminates sounds and textures, and processes nonverbal memories.

Limbic System

A neural system located below the cerebral hemispheres comprising the hippocampus, amygdala, and hypothalamus, linked to emotions, memory, and drives.

Amygdala

Two lima-bean-sized neural clusters in the limbic system linked to emotional processing, particularly aggression and fear.

Hypothalamus

A limbic structure below the thalamus directing maintenance activities (hunger, thirst, sex), governing the endocrine system via the pituitary, and linked to reward.

Hippocampus

A neural center in the limbic system that processes explicit, conscious memories for long-term storage.

Frontal Lobes

Cortical regions involved in decision making, planning, speaking, muscle movements, and social restraint.

Parietal Lobes

Cortical regions receiving sensory input for touch and body position, as well as enabling mathematical and spatial reasoning.

Occipital Lobes

Cortical regions located at the back of the head that receive and process visual information from the eyes.

Temporal Lobes

Cortical regions located above the ears that process auditory information primarily from the opposite ear.

Motor Cortex

An area at the rear of the frontal lobes that controls voluntary movements across opposite sides of the body.

Somatosensory Cortex

An area at the front of the parietal lobes that registers and processes body touch and movement sensations.

Corpus Callosum

A large band of neural axon fibers connecting the left and right cerebral hemispheres, enabling communication between them.

Split Brain

A condition resulting from surgery that severs the corpus callosum fibers, isolating the brain's two hemispheres.