Ch. 2: The Biological Perspective

Nervous system

An extensive network of specialized cells that carries information to and from all parts of the body

Neuroscience

A branch of the life sciences that deals with the structure and function of neurons, nerves, and nervous tissue

Biological psychology or behavioral neuroscience

Branch of neuroscience that focuses on the biological bases of psychological processes, behavior, and learning

Neuron

The basic cell that makes up the nervous system and that receives and sends messages within that system

Dendrites

Branchlike structures of a neuron that receive messages from other neurons

Soma

The cell body of the neuron responsible for maintaining the life of the cell

Axon

Tubelike structure of a neuron that carries the neural message from the cell body to the axon terminals for communication with other cells

Axon terminals

Enlarged ends of axonal branches of the neuron, specialized for communication between cells

Glial cells

Cells that provide support for the neurons to grow on and around, deliver nutrients to neurons, produce myelin to coat axons, clean up waste products and dead neurons, influence information processing, and, during prenatal development, influence the generation of new neurons

Myelin

Fatty substances produced by certain glial cells that coat the axons of neurons to insulate, protect, and speed up the neural impulse

Nerves

Bundles of axons coated in myelin that travel together through the body

Diffusion

Process of molecules moving from areas of high concentration to areas of low concentration

Resting potential

The state of the neuron when not firing a neural impulse

Action potential

The reversal of electrical charge that travels down the axon to the terminals, resulting in the realese of neurotransmitters

All-or-none

Referring to the fact that a neuron either fires completely or does not fire at all

Synaptic vesicles

Saclike structures that contain neurotransmitters and are found within the axon terminal

Neurotransmitter

Chemical found in the synaptic vesicles that, when released, has an effect on the next cell

Synapse (synaptic gap)

Microscopic fluid-filled space between the axon terminal of one cell and the dendrites or soma of the next cell

Receptor sites

Three-dimensional proteins on the surface of the dendrites or certain cells of the muscles and glands, which are shaped to fit only certain neurotransmitters

Excitatory synapse

Synapse at which a neurotransmitter causes the receiving cell to fire

Inhbitory synapse

Synapse at which a neurotransmitter causes the receiving cell to stop firing

Antagonists

Chemical substances that block or reduce a cell’s response to the action of other chemicals or neurotransmitters

Agonists

Chemical substances that mimic or enhance the effects of a neurotransmitter on the receptor sites of the next cell, increasing or decreasing the activity of that cell

reuptake

Process by which neurotransmitters are taken back into the synaptic vesicles

Enzymatic degradation

Process by which the structure of a neurotransmitter is altered so it can no longer act on a receptor

Lesioning

Insertion of a thin, insulated electrode into the brain through which an electrical current is sent, destroying the brain cells at the tip of the wire

Computed tomography (CT)

Brain-imaging method using computer-controlled X-rays of the brain

Magnetic resonance imaging (MRI)

Brain-imaging method using radio waves and magnetic fields of the body to produce detailed images of the brain

Electroencephalogram (EEG)

A recording of the electrical activity of large groups of cortical neurons just below the skull, most often using scalp electrodes

Positron emission tomography (PET)

Brain-imaging method in which a radioactive sugar is injected into the subject and a computer compiles a color-coded image of the activity of the brain

Functional magnetic resonance imaging (fMRI)

MRI-based brain-imaging method that allows for functional examiniation of brain areas through changes in brain oxygenation

Functional near-infrared spectroscopy (fNIRS)

A functional brain imaging method that measures brain activity by using infrared light to determine changes in blood oxygen levels in the brain

Medulla

The first large swelling at the top of the spinal cord, forming the lowest part of the brain, which is responsible for life-sustaining functions such as breathing, swallowing, and heart rate

Pons

The larger swelling above the medulla that connects the top of the brain to the bottom and that plays a part in sleep, dreaming, left-right body coordination, and arousal

Reticular formation (RF)

An area of neurons running through the middle of the medulla and the pons and slightly beyond that is responsible for general attention, alterness, and arousal

Cerebellum

Part of the lower brain located behind the pons that controls and coordinates involuntary, rapid, fine motor movement and may have some cognitive functions

Limbic system

A group of several brain structures located primarly under the cortex and involved in learning, emotion, memory, and motivation

Thalamus

Part of the limbic system located in the ceter of the brain, this structure relays sensory information from the lower part of the brain to the proper areas of the cortex and processes some sensory information before sending it to its proper area

Olfactory bulbs

Two bulb-like projections of the brain located just above the sinus cavity and just below the frontal lobes that receive information from the olfactory receptor cells

Hypothalamus

Small structure in the brain located below the thalamus and directly above the pituitary gland, responsible for motivational behavior such as sleep, hunger, thirst, and se*

Hippocampus

Curved structure located within each temporal lobe, responsible for the formation of long-term declarative memories

Amygdala

Brain structure located near the hippocampus, responsible for fear responses and memory of fear

Cortex

Outermost covering of the brain consisting of densely packed neurons, responsible for higher thought processes and interpretation of sensory input

Cerebrum

The upper part of the brain consisting of the two hemispheres and the structures that connect them

Cerebral hemispheres

The two sections of the cortex on the left and right sides of the brain

Corpus Callosum

Thick band of neural fibers that connects the right and left cerebral hemispheres

Occipital lobe

Section of the brain located at the rear and bottom of each cerebral hemisphere containing the primary visual centers of the brain

Paritetal lobes

Sections of the brain located at the top and back of each cerebral hemisphere containing the centers for touch, temperature, and body position

Somatosensory cortex

Area of cortex at the front of the parietal lobes responsible for processing information from the skin and internal body receptors for touch, temperature, and body position

Temporal lobes

Areas of the cortex located along the side of the brain, starting just behind the temples, containing the neurons responsible for the sense of hearing and meaningful speech

Frontal lobes

Areas of the brain located in the front and top, responsible for higher mental processes and decision-making as well as the production of fluent speech

Motor cortex

Rear section of the frontal lobe, responsible for sending motor commands to the muscles of the somatic nervous system

Mirror neurons

Neurons that fire when a nonhuman animal or person performs an action and also when an animal or person observes that same action being performed by another

Association areas

Areas within each lobe of the cortex responsible for the coordination and interpretation of information, as well as higher mental processing

Broca’s aphasia

Condition resulting from damage to Broca’s area, causing the affected person to be unable to speak fluently, to mispronounce words, and to speak haltingly

Wernicke’s aphasia

Condition resulting from damage to Wernicke’s area, causing the affected person to be unable to understand or produce meaningful language

Central nervous system (CNS)

Part of the nervous system consisting of the brain and spinal cord

Spinal cord

A long bundle of neurons that carries messages between the body and the brain and is responsible for very fast, lifesaving reflexes

Afferent (sensory) neurons

A neuron that carries information from the senses to the central nervous system

Efferent (motor) neuron

A neuron that carries messages from the central nervous system to the muscles of the body

Interneuron

A neuron found in the center of the spinal cord that receives information from the afferent neurons and sends commands to the muscles through the efferent neurons. Interneurons also make up the bulk of the neurons in the brain

Reflex arc

The connection of the afferent neurons to the interneurons to the efferent neurons, resulting in a reflex action

Neuroplasticity

The ability within the brain to constantly change both the structure and function of many cells in response to experience of trauma

Neurogenesis

The formation of new neurons; occurs primarily during prenatal development but may also occur at lesser levels in some brain areas during adulthood

Stem cells

Special cells found in all the tissues of the body that are capable of becoming other cell types when those cells need to be replaced due to damage or wear and tear

Epgenetics

The interaction between genes and environmental factors that influence gene activity; environmental factors include diet, life experiences, and physical surroundings

Peripheral nervous system (PNS)

All nerves and neurons that are not contained in the brain and spinal cord but that run through the body itself

Somatic nervous system

Division of the PNS consisting of nerves that carry information from the senses to the CNS and from the CNS to the voluntary muscles of the body

Autonomic nervous system (ANS)

Division of the PNS consisting of nerves that control all of the involuntary muscles, organs, and glands

Sensory pathway

Nerves coming from the sensory organs to the CNS consisting of afferent neurons

Motor pathway

Nerves coming from the CNS to the voluntary muscles, consisting of efferent neurons

Sympathetic division (fight of flight system)

Also called the sympathetic nervous system (SNS), part of the ANS that is responsible for reacting to stressful events and bodily arousal

Parasympathetic division (eat, drink, and rest system)

Also called the parasympathetic nervous system (PNS), part of ANS that restores the body to normal functioning after arousal and is responsible for the day-to-day functioning of the organs and glands

Endocrine glands

Glands that secrete chemicals called hormones directly into the bloodstream

Hormones

Chemicals released into the bloodstream by endocrine glands

Pitutiary gland

Gland located in the brain that secretes human growth hormone and influences all other hormone-secreting glands

Oxytocin

Hormone released by the posterior pituitary gland that is involed in reproductive and parental behaviors

Pineal gland

Endocrine gland located near the base of the cerebrum; secretes melatonin

Thyroid gland

Endocrine gland found in the neck; regulates metabolism

Pancreas

Endocrine gland; controls the levels of sugar in the blood

Gonads

Sex glands; secrete hormones that regulate sexual development and behavior as well as reproduction

Ovaries

The female gonads or sex glands

Testes (testicles)

The male gonads or sex glands

Adrenal glands

Endocrine glands located on top of each kidney that secrete over 30 different hormones to deal with stress, regulate salt intake, and provide a secondary source of sex hormones affecting the sexual changes that occur during adolescence