Summary summery introduction to psychology

H1: The science of psychology
What Is Psychological Science?
 Psychological science = the study, through research, of mind, brain, and behaviour.
- Mind refers to mental activity. Mental activity results from biological processes within
the brain.
- Behaviour describes the totality of observable human (or animal) actions.

How do the mind and the brain relate?
The mind (mental activity) is produced by biochemical processes in the brain



H3: Biology and Behavior
How does the nervous system operate?
 The entire nervous system is divided into two basic units: the central nervous system and the
peripheral nervous system
- The central nervous system (CNS)= the brain and the spinal cord
- The peripheral nervous system (PNS)= all nerve cells in the body that are not part of the
central nervous system includes the somatic and automatic nervous system
- The somatic component is involved in voluntary behaviour (reaching for an object)
- The automatic component is responsible for less voluntary actions of your body
(controlling your heart rate)
 The CNS and PNS are automatically separate, but their functions are highly interdependent
- PNS send variety of information to CNS, and the CNS organizes and evaluates that
information and then directs the PNS to perform specific behaviours or make bodily
adjustments




Neurons are the basic units of the nervous system.

,  Neurons= the basic units of the nervous system; cells that receive, integrate, and transmit
information. They operate trough electrical impulses, communicate with other neurons
through chemical signals, and form neural networks
- They communicate selectively with other neurons to form circuits or neural
networks. These networks develop through genetic influence, maturation and
experience and repeated firing.

Function of neurons
 Neurons are excitable, they are powered by electrical impulses and communicate with other
nerve cells through chemical signals

 Reception phase= neurons take chemical signals from neighbouring neurons

 Integration= incoming signals are assessed

 Transmission= neurons pass their own signals to yet other receiving neurons

 Sensory and motor neurons work together to control movements
- Sensory neurons= detect information from the physical word and pass that info along
the brain (you touching something hot)
- Somatosensory nerves= sensory nerves that provide information from skin and
muscles
- Motor neurons= direct muscles to contract or relax, thereby producing movement
 Inter neurons= act as relay stations facilitating communication between sensory and motor
neurons

Neuron structure
 A typical neuron has four structural regions that participate in communication functions:
dendrites, the cell body, the axon, and the terminal buttons
- Dendrites= branchlike extensions of the neuron that detect information from other
neurons
- Cell body (soma)= the site in the neuron where information from thousands of other
neurons is collected and integrated
- Axon= a long, narrow outgrowth of a neuron by which information is conducted
from the cell body to the terminal buttons

 Terminal buttons= at the end of axons, small nodules that release chemical signals from the
neuron into the synapse

 Synapse= the gap between the terminal buttons of a sending neuron and the dendrites of a
receiving neuron where chemical communication occurs between the neurons

 The outer surface of a neuron is a membrane: a fatty barrier that does not dissolve in the
watery environment inside and outside the neuron
- Some substances move in or out of the membrane and some do not

 Located on the membrane are ion cells: these specialized pores allow ions to pass in and out
of the cell when the neuron transmits signals down the axon
 By controlling the movement of ions, the membrane plays an important role in
communication between neurons: it regulates the concentration of electrically charged
molecules that are the basic of neurons electrical activity

,What is the positional order of neuronal cell structures (cell body, dendrites, terminal buttons, and
axon) from receiving component to sending component?
Between the synapses the positional order is dendrites, cell body, axon, and terminal buttons




Action potentials produce neural communication
 Action potential= the electrical signal that passes along the axon and subsequently causes
the release of chemicals from the terminal buttons

Resting membrane potential
 Resting membrane potential= the electrical charge of a neuron when it is not active
(difference between the electrical charge inside the neuron and outside the neuron)
- The difference occurs because ratio of negative tot positive ions is greater inside the
neuron than outside
 Polarized neuron= when there are more negative ions in the inside of a neuron then the
outside
- The polarized state of the resting neuron creates the electrical energy necessary to
power the firing of the neuron
 Two types of ions that contributes to a neuron’s resting membrane potential: sodium ions
and potassium ions

 The flow of ions through each channel is controlled by a gating mechanism
- When the gate is open ions flow in and out of the neuron through the cell membrane
 membrane selective permeability= the membrane allows some ions to cross more
easily than others
 Sodium- potassium pump= increases potassium and decreases sodium inside the neuron,
thus helping maintain the resting membrane potential

Changes in electrical potential lead to an action potential
 Excitatory signals= depolarize the cell membrane (decrease polarization by decreasing the
negative charge inside the cell relative to outside the cell) it increases the likelihood that the
neuron will fire

 Inhibitory signals= hyperpolarize the cell (increase polarization by increasing the negative
charge inside the cell relative to outside the cell) it decreases the likelihood that the neuron
will fire

,  When a neuron fires the sodium gates in the cell membrane open. This allows the sodium
ions to rush into the neuron. This causes the inside of the neuron be more positively charge
then the outside  this change from negative charge to positive charge is the basis of the
action potential

 After the sodium ions rush into the neuron  potassium channels open to let the potassium
ions rush out of the cell membrane  sodium channels start to close, so sodium ions stop
entering  potassium ions still rushing out  the membrane potential becomes more
negative again  potassium channels close, so potassium ions stop exciting the cell  the
membrane potential is slightly more negative than the resting potential

 Relative refractory period= the brief period of time following action potential when a
neuron’s membrane potential is more negative, or hyperpolarized, making it harder to fire
again

 All-or-none principle= the principle that when a neuron fires, it fires with the same potency
each time; a neuron either fires or not, although the frequency of firing can vary

 The stronger the stimulation the more frequently action potentials are generated, but the
strength of firing stays the same




Action potentials travel down the axon
 When a neuron fires, the cell membrane’s depolarization moves along the axon like a wave.

 Absolute refractory period= the brief period of time following an action potential when the
ion channel is unable to respond again

 Because the absolute and relative refractory periods prevent ion channels from responding
again after they were just active, the action potential always moves in one direction: down
the axon away from the cell body to the terminal buttons

 Myelin sheath= a fatty material, made up of glial cells, that insulates some axons to allow for
faster movement of electrical impulses along the axon