Synesthesia: Cross sensory experience (like a visual image having a
taste). Synesthete a person who experiences synesthesia.is
Genetics: a term usually used to describe characteristics such as
height, hair color etc are passed along through inheritance.
Biology and environment mutually influence each other.
Human Genome Project: an international research effort. Mapping
of the entire structure of the human genetic material. The genome
is the master blueprint that provides detailed instructions to
multiple options within our body from how to grow a gall baldder to
where the nose is placed. And our environment determines which
option is taken.
Chromosomes: structures within the cel boy that are made up of
Gene: the unit of hereditary that determines a particular
characteristic in an organism.
» Dominant gene: a gene that is expressed in the offspring
whenever it is present.
» Recessive gene: a gene that is expressed only when it sis
matched with a similar gene from the other parent.
The human body down to its genes: each cell in the human body
includes pairs of chromosomes, which consist of DNA strands. DNA
has a double helix shape and is composed of genes. The 23rs
chromosome pair determines sex: two X chromosomes makes a
female while one X and one Y make a male.
Genotype: the genetic constitution determined at the moment of
conception.( possible genetic combinations)
Phenotype: observable physical characteristics that result from both
genetic and environmental influences. (result of a combination of
genotypes) Mendel’s flower experiment in 1866. Experimental technique used
was selective breeding. Purple vs. white flowers. Purple won.
Polygenic characteristic: when a population displays a range of
variability for a certain characteristic i.e. it is influenced by many
Monozygotic twins: twin siblings who result from one zygote
splitting in two and therefore share the same genes. Identical
Dizygotic twins: twin siblings that result from two separately
fertilized eggs. Fraternal twins.
Heredity: transmission f chracteristics from parents to offspring by
means of genes.
Heritability: a statistical estimate of the variation, caused by
differences in heredity, in a trait within a population.
Genetic modifications: methods that enhance or interrupt gene
expression by selectively knocking out specific genes to reveal
which behaviors were affected.
Neurons: the as unit of the nervous system; it operates through
electrical impulses which communicate with other neurons through
chemical signals. Neurons receive, integrate and transmit
information in the nervous system.3 types:
» Sensor neurons: afferent neurons detect information from the
physical world and pass that information along to the brain.
» Motor neurons: these efferent neurons direct muscles to
contract or relax, thereby producing movement.
» Interneurons: these neurons communicate only with other
neurons, typically within a specific brain region.
Neuron structure: neurons don’t touch each other. Messages are
received by the dendrites, processed in the cell body and sent along
the axon to other neurons via chemicals released from the terminal
buttons across the synapse. » Dendrites: short branch like extensions of the neuron that
increase neuron’s receptive field and detect information
(chemical signals) from other neurons.
» Cell body: in the neuron, where information from thousands of
other neurons is collected and processed.
» Axon: a long narrow outgrowth of a neuron by which
information is transmitted to other neurons. Vary in length
from a few mm to more than a meter.
» Myelin sheath: a fatty material, made up of gilal cells, that
insulates the axon and allows for the rapid movement of
electrical impulses along the axon. Short segments.
» Nodes of Ranvier: small gaps of exposed axon, between the
segments of myelin sheath, where action potentials
(negatively or positively charged ions are allowed to pass in or
out when the neuron transmits the signal) are transmitted.
» Terminal buttons: small nodules, at the ends of axons, that
release chemical signals from the neuron to the synapse.
» Synapse/Synaptic cleft: the site for chemical communication
between neurons, which contains extracellular fluid.
Resting membrane potential: the electrical charge of a neuron
when it is not active. The ratio of negative ions to positive ions is
greater inside than outside.
Polarization: The change in differential electrical charges inside and
outside the neuron. It creates the energy necessary to power the
firing of the neuron.
Action potential: the neural impulse that passes along the axon and
subsequently causes the release of chemicals from the terminal
buttons. The electrical charge inside the neuron starts out slightly
negative. as the neuron fires, it allows more positive ions inside the
» Two signals work by affecting polarization:
Excitatory: signals that depolarize the cell membrane,
increasing the likelihood that the neuron will fire. Inhibitory: signals that hyperpolarize the cell and
decrease the likelihood that the neuron will fire.
Sodium ions enter negative to positively charged, potassium ions
exit back to negatively charged.
Myelin sheath deterioration may start n young adulthood and leaves
the person severely (starts with blurry vision/numbness in limbs)
impaired by the end of it.
All or none principle: the principle where the neuron fires with the
same potency each time, although frequency can vary; it either
fires or not. It cannot partially fire.
Presynaptic: neuron that sends the signal to the synaptic cleft.
Postsynaptic: neuron that receives the signal.
Neurotransmitter: a chemical substance that carries signals from
one neuron to another.
Receptors: in neurons, specialized protein molecules, on the
postsynaptic membrane, that neurotransmitters bind to after
passing across the synaptic cleft.
3 major events that terminate the transmitters influence in the
» Reuptake: the process whereby a neurotransmitter is taken
back into the presynaptic terminal buttons, thereby stopping
its activity. (Taken back for recycling).
» Enzyme deactivation: when an enzyme destroys the
transmitter substance in the synapse. Different enzymes break
down different neurotransmitters.
» Auto receptors: they monitor how much neurotransmitter is
released in the synapse. If excess is detected, they signal the
presynaptic neuron to stop releasing the neurotransmitter.
Agonist: any drugs that enhances the actions of a specific
Antagonist: any drugs that inhibits the action of a specific
Common neurotransmitters and t