PSYC 1001 Chapter Notes - Chapter 3: Mutation, Agonist, Twin Study
Chapter 3 Notes:
Neurons: Individual cells in the nervous system that receives, integrates, and transmits
Soma (Cell body): contains the cell nucleus and much of the chemical machinery
common to most cells
Dendrites: Are parts of a neuron that are specialized to receive information
Axon: a long thin fibre that transmits signals away from the soma to other neurons or to
muscles or glands.
Myelin Sheath: insulating material, derived from glial cells that encases some axons
Terminal Buttons: small knobs that secrete chemicals called neurotransmitters
Synapses: a junction where information is transmitted from one neuron to another
Gila: cells found throughout the nervous system that provides various types of support
Postsynaptic potential (PSP): a voltage change at a receptor site on a postsynaptic cell
Excitatory PSP: a positive voltage shift that increases the likelihood that the
postsynaptic neuron will fire action potentials.
Inhibitory PSP: a negative voltage shift that decreases the likelihood that the
postsynaptic neuron will fire action potentials
Reuptake: a process in which neurotransmitters are sponged up from the synaptic cleft
by the presynaptic membrane
Agonist: a chemical that mimics the action of a neurotransmitter
Antagonist: a chemical that opposed the action of the neurotransmitter
Endorphins: internally produced chemicals that resemble opiates in structure and effects
Peripheral Nervous System: made up of al those nerves that lie outside the brain and
Nerves: bundles of neuron fibers (axons) that are routed together in the peripheral
Somatic Nervous System: made up of nerves that connect voluntary skeletal muscles to
Afferent Nerve Fibres: axons that carry information inward to the central nervous
system from the periphery of the body.
Efferent Nerve Fiberes: are axons that carry information outward from the central
nervous system to the periphery of the body.
Autonomic Nevours System (ANS): made up of nerves that connect to the heart, blood
vessels, smooth muscles, and glands.
Sympathetic Division: is the branch of the autonomic nervous system that mobilizes the
body’s resource for emergencies.
Parasympathetic Division: is the branch of autonomic nervous system that generally
conserves bodily resources.
Central Nervous System (CNS): consists of the brain and the spinal cord
The Cerebrospinal Fluid (CSF): nourishes the brain and provides a protective cushion
The electroencephalograph (EEG): a device that montiors the electrical activity of the
brain over time by means of recording electrodes attached to the surface of the scalp
Hindbrain: includes the cerebellum and two structures found in the lower part of the
brainstem: the medulla and the pons.
Midbrain: the segment of the brainstem that lies between the hindbrain and the forebrain
Forebrain: the largest and most complex region of the brain, encompassing a variety of
structures, including the thalamus, hypothalamus, limbic system, and the cerebrum.
Thalamus: a structure in the forebrain through which all sensory information (except
smell) must pass to het to the cerebral cortex
Hypothalamus: a structure found near the base of the forebrain that is involved in the
regulation of basic biological needs
Limbic System: a loosely connected network of structures located roughly along the
border between the cerebral cortex and deeper subcortical areas.
Cerebral Cortex: is the convoluted outer layer in the cerebrum
Cerebral hemispheres: the right and left halves of the cerebral
Corpus Callosum: the structure that connects the two cerebral hemispheres
Split Brain surgery: the bundle of fibres that connects the cerebral hemispheres (the
corpus callosum) is cut to reduce the severity of epileptic seizures.
Perceptual asymmetries: Left-right imbalances between the cerebral hemispheres in the
speed of visual or auditory processing.
Endocrine system: consists of glands that release hormones into the bloodstream;
hormones help to control bodily functioning.
Pituitary gland: releases a great variety of hormones that fan out around the body,
stimulations actions in the other endocrine glands.
Oxytocin: a hormone released by the pituitary gland, which regulates reproductive
Behavioral Genetics: an interdisciplinary field that studies the influence of genetic
factors on behavioral traits.
Chromosomes: are strands of DNA moleculrd that carry out genetic information
Zygote: a single cell formed by the union of a sperm and an egg
Genes: DNA segments that serve as key functional units in hereditary transmission
Homozygous Condition: the two genes in a specific pair are the same
Heterozygous Condition: the two genes in a specific pair are different
Dominate Gene: is one that is expressed when paired genes are different.
Recessive Gene: is one that is masked when paired genes are different
Genotype: refers to a person’s genetic makeup
Phenotype: refers to the ways in which a persons genotype is manifested in observable
Polygenic Traits: traits or characteristics that are influences by more than one pair of