Chapter 3: The Biology of Behavior Key Terms Flashcards
DNA (deoxyribonucleic acid):
A large molecule that contains genes.
Chromosome:
A coiled-up thread of DNA; 23 pairs of chromosomes in every cell of your body
Genome:
All the genetic information in DNA.
Genotype:
The entire genetic makeup of an organism.
Phenotype:
An organism’s observed characteristics (gene expression)
Genes:
Small segments of DNA that contain information for producing proteins.
They have a profound level of control shaping how you think and feel.
Polygenic:
The process by which many genes interact to create a single characteristic.
All psychological and almost all physical traits in humans are polygenic.
Monogenic:
The hereditary passing on of traits determined by a single gene.
Humans have very few traits that result from a single gene.
Mutation:
A random change in genetic sequence.
Alleles:
Different forms of a gene.
Example: There are two forms of the gene that is responsible for lactose tolerance/intolerance; one allele causes lactose intolerance, while another allele does not.
Dominant alleles:
Alleles that show their effect even if there is only one allele for that trait in the pair.
Punnett square = One capital letter (Tt) or two capital letters (TT)
Recessive alleles:
Alleles that show their effects only when both alleles are the same.
Punnett square: Two lowercase letters (tt)
Behavioral genetics:
The scientific study of the role of heredity in behavior.
- The relationship between specific genes and behavior is complex, usually with many genes involved in each trait
- Studying twins and adoptees as well as genetic markers = breaks down influences of hereditary (nature) and environmental (nurture) on behavior.
- The ENVIRONMENT influences how and when genes affect behavior.
Heritability:
The extent to which a characteristic is influenced by genetics.
Epigenetics:
The study of changes in the way genes are turned on or off without a change in the sequence of DNA.
Involves heritable changes to DNA that are independent of the genetic sequence (ENVIRONMENT) yet influence its expression = NURTURE shapes NATURE
Central nervous system (CNS):
The part of the nervous system that comprises the brain and spinal cord.
Peripheral nervous system:
The part of the nervous system that comprises all the nerve cells in the body outside the central nervous system.
Somatic nervous system:
Nerve cells of the peripheral nervous system that serve the skeletal muscles.
Somatic nerves transmit from the central nervous system (CNS) to the skeletal muscles and sensory information from the skeletal muscles back to the CNS.
Automatic nervous system (ANS):
All the nerves of the peripheral nervous system that serve involuntary systems of the body, such as the internal organs and glands.
Sympathetic nervous system:
The branch of the autonomic nervous system that activates bodily systems in times of emergency.
Parasympathetic nervous system:
The branch of the autonomic nervous system that usually relaxes or returns the body to a less active, restful state.
Glial cells:
The central nervous system is made up of two types of cells: glial cells and neurons.
Glial cells provide structural support for the CNS, promote efficient communication between neurons, and remove cellular debris.
Neurons:
The cells that process and transmit information in the nervous system.
THREE MAJOR PRINCIPLES CONCERNING NEURAL COMMUNICATION:
- Neurons are the building blocks of the nervous system. All the major structures of the brain are composed of neurons.
- Information travels within a neuron in the form of an electrical signal transmitted by action potentials.
- Information is transmitted between neurons by means of neurotransmitters.
Neurotransmitters:
Chemicals that transmit information between neurons.
Soma:
The cell body of the neuron.
Axon:
A long projection that extends from a neuron’s soma.
It transmits electrical impulses toward the adjacent neuron and stimulates the release of neurotransmitters.
Dendrites:
Fingerlike projections from a neuron’s soma that receive incoming messages from other neurons.
Myelin sheath:
The fatty substance wrapped around some axons, which insulates the axon, making the nerve impulse travel more efficiently.
Synapse:
The junction between an axon and the adjacent neuron, where information is transmitted from one neuron to another.
Terminal button:
A little knob at the end of the axon that contains many sacs of neurotransmitters.
Sensory neurons:
One of three types of neurons: sensory neurons, motor neurons, and interneurons
Nerve cells that receive incoming sensory information from the sense organs (eye, ear, skin, tongue, nose).
Motor neurons:
One of three types of neurons: sensory neurons, motor neurons, and interneurons
Nerve cells that carry commands for movement from the brain to the muscles of the body.
Mirror neurons:
Type of motor neuron; are active when we observe others performing an action as well as when we are performing the same action.
Interneurons:
One of three types of neurons: sensory neurons, motor neurons, and interneurons
Neurons that communicate only with other neurons; the most common kind of neuron in the brain.