central nervous system (CNS)spinal cord The CNS is made up of the brain and the spinal cord. The spinal cord is a series of nerves that run along the spine and transmit messages between the body and the brain. The body provides protection for both the brain and the spinal cord nerves in order to protect its functioning. Any damage to the spinal cord could result in paralysis.
peripheral nervous system (PNS) The PNS are the nerves that branch out from the spinal cord.
neurons Neurons are long, thin cells of nerve tissue along which messages travel to and from the brain. The neuron has three basic parts: cell body – contains the nucleus and produces energy dendrites – short, thin fibers that stick out from the cell body axon – long fiber that carries impulses away from the cell body towards the dendrites of the next neuron
synapse and neurotransmitters The synapse is the gap between the individual cell nerves. In order for one neuron to pass information to another neuron, it sends out chemicals called neurotransmitters. These neurotransmitters can either spur a neuron into activity or stop it from doing something. There are various types of neurotransmitters: norepinephrine – involved with memory and learning endorphin – involved with pain acetylcholine – involved with memory and movement (associated with paralysis and Alzheimer’s disease) dopamine – involved with learning, arousal and movement (associated with Parkinson’s disease)
somatic nervous system (SNS) The somatic nervous system (SNS) is a part of the peripheral nervous system that controls voluntary movement of the skeletal muscles. It is also referred to the voluntary nervous system. It carries motor and sensory information both to and from the central nervous system. On a completely useless but interesting side, the term stems from the Greek word for body – soma.
autonomic nervous system (ANS) The autonomic nervous system (ANS) is the part of the peripheral nervous system that controls internal biological functions. The ANS is made up of two parts: one, the sympathetic nervous system preps the body to deal with dangerous or stressful situations by speeding up the heart rate and increasing oxygen intake. Blood flow is sent to those parts of the body that needs it the most; two, the parasympathetic nervous system, in contrast, conserves energy and helps the body recover from strenuous activity.
hindbrain The hindbrain is a part of the brain, found near the back of the skull, responsible for the basic necessities of life. It is made up of the cerebellum, medulla and the pons. The cerebellum is behind the spinal cord and responsible for posture, balance and other voluntary movements. The medulla controls heart rate, breathing and other reflexes. The pons bridges the gap between the brain and the spinal cord.
midbrain The midbrain sits atop the hindbrain (the pons and medulla go into the midbrain) that sends sensory information upward into the brain. Together with the medulla and pons, the midbrain is made up of the brain stem and the reticular activating system (RAS) that coats the entire area and alerts the brain to incoming signals as well as controls awake and sleep functions.
forebrain The forebrain covers the brain’s central core. It includes the following: thalamus – integrates sensory input hypothalamus – controls hunger, thirst, sexual behavior and reactions to temperatures cerebral cortex – the outer layer of the forebrain; gives you the ability to learn and store information and abstract thoughts cerebrum – the inner layer of the forebrain; home to your conscious thinking processes limbic system – regulates our emotions and motivations
lobes Lobes are the different components of the cerebral cortex. The lobes include: Occipital lobe – vision Parietal lobe – body sensations Primary somatosensory cortex – touch Primary motor cortex – fine movement control Frontal lobe – planning of movements, working memory (recent memory) Temporal lobe – hearing, advanced visual processing
left and right hemispheres The first thing to understand is that the two hemispheres are not as cut and dry as popular opinion would suggest. While each has its strengths, both sides work in concert to perform all tasks and should be understood in that light. The left hemisphere: Location of speech Specialization of math, calculation and logic Controls movement on right side of the body The right hemisphere: Controls movement on left side of the body Adept at the visual and spatial relations Recognizing patterns Music and art are better understood Creativity and intuition
electroencephalograph (EEG) An EEG refers to a machine that can record the electrical impulses of most of the brain. An EEG can monitory brain waves or rhythms. By being able to monitor and stimulate with electrical currents certain parts of the brain, it can trick the brain in accentuating or ignoring certain signals. It has been used in the past to eliminate the pain of cancer patients as well as curbing violent tendencies. Check out the story of Phineas Gage to discover the impact when certain parts of the brain are damaged.
computerized axial tomography (CAT) CAT scans are used to locate injuries and other issues related to brain deterioration. The computer uses the radiation output to create a three-dimensional look at the brain.
positron emission tomography (PET) A PET scan is designed to showcase the brain as its different parts are engaged in different functions. Active neurons absorb more of the radioactive solution that is injected into the blood than non-active neurons – ergo, the ability to see what part of the brain is being engaged.
magnetic resonance imaging (MRI) A MRI is designed to combine the functions of CAT and PET by showing the structure and the function of the brain. A new component of MRI technology is the functional magnetic resonance imaging (fMRI) which highlights the signals the brain receives and the neural activity it engenders. However, the fMRI does not use radio frequencies to do its job as the MRI does.
endocrine system and hormones The endocrine system is a chemical communication system, whereby hormones (messages) are carried to and from the brain. Hormones are created in the endocrine glands and are carried by blood or other bodily fluids.
pituitary glands Pituitary glands control the endocrine system and is responsible for secreting a large number of hormones. The pituitary gland is directed by the hypothalamus. The hypothalamus monitors how many hormones are being sent into the blood stream and corrects any imbalances. Typically, the hormones interact with the organs on matters of regulating and storing nutrients. They also control growth and reproduction (ovulation and lactation in females).
thyroid gland The thyroid gland produces the hormone thyroxin. Not enough thyroxin and a person feels lazy or lethargic. Too much thyroxin can create hyperthyroidism – leads to weight and sleep loss as well as over-activeness.
adrenal and sex glands The adrenal gland activates during times of anger or fright. Releasing epinephrine and norepinephrine into the bloodstream, the heartbeat and breathing increases. This, in turn, provides extra energy to deal with a potential problem. The sex glands are divided into two major types – testes in males and ovaries in females. Ovaries produce eggs and the female hormone estrogen and progesterone. Testes produces sperm and the male hormone testosterone.
heredity Heredity is the passage of genetic characteristics from the parents to the offspring. Early scientists felt that heredity was a key component to the development and eventual character of the individual. However, the prevailing thought today is that environment has a large influence on the development of people. Give me a dozen healthy infants, well-informed and my own specified world to bring them up in and I’ll guarantee to take any one at random and train him to become any type of specialist I might select – a doctor, lawyer, artist, merchant-chief, and yes, even beggarman and thief, regardless of his talents, penchants, tendencies, abilities, vocations and race of his ancestors. John Watson, founder of behaviorism, 1930
identical and fraternal twins Identical twins are those who came from the same fertilized egg. Fraternal twins are those who came from two different eggs, fertilized by two different sperm.
genes Genes are the basic building blocks of heredity.
consciousness Consciousness refers to a state of awareness, including a person’s feelings, sensations, ideas and perceptions. “(Consciousness is) a fascinating but elusive phenomenon: it is impossible to specify what it is, what it does, or why it evolved. Nothing worth reading has been written about it.” 20th-century British psychologist Stuart Sutherland
stages of sleep Stage 1 – During this stage, there is a general relaxation with irregular breathing and brain waves. Typically, this lasts 10 minutes. Stage 2 – Here, the brain shifts from low-amplitude, high frequency waves to high amplitude, low frequency waves; this is accompanied by the slow, side-to-side movement of the eyes. This tends to last 30 minutes. Stage 3 – During this stage, large amplitude delta waves begin sweeping the brain every couple of seconds or so. Stage 4 – This stage is the deepest sleep a person experiences. Suddenly awaken from this stage creates disorientation. During this stage, night terrors, sleepwalking and bed-wetting occur. REM – Lasting 15-45 minutes a night, this is the most active period where one’s body responds as if awake to the images produced in your consciousness.
circadian rhythm The circadian rhythm is a term describing one’s biological clock – the time of activity and non-activity over the course of twenty-four hours. This pattern of behavior is established, created by one’s environment and the twenty-four day.
insomnia and sleep apnea Insomnia is the condition of seldom getting more than one or two hours of sleep a night on a regular basis. The causes of this are a varied as the people who suffer with the condition. Long-term insomnia can create serious health conditions. Sleep apnea is a disorder where a person has difficulty breathing while sleeping. This is typically accompanied by snoring, a condition where the person is actually choking. Most of the causes center on physical defects, as opposed the mental stress that causes insomnia.
narcolepsy Narcolepsy is a condition where one falls asleep often or is very tired throughout the period of being awake. Irregular sleep patterns can cause narcolepsy and such a condition can cause serious problems with work and leisure time, as well as interpersonal relationships.
nightmares and night terrors Nightmares are common but scary dreams that occur during REM sleep. Typically, people will awake before the worst happens in such a dream. Night terrors, which occur in Stage IV sleep, can last as long as twenty minutes and is typically accompanied by screaming, sweating and confusion, as well as rapid heart rate. Unlike nightmares, people seldom have memories of the terror itself.
sleepwalking Sleepwalking is a condition where the person is part awake, part asleep. There is no memory left over by the sleepwalker of what they did or how long. It is typically seen in children though adults also can suffer. Scientists have linked sleep walking to stress and the use of sedatives but there is also proof that it is inherited. In theory, it is harmless but if the person falls or walks into a dangerous situation (into a street), it can be quite harmful.
hypnosis and posthypnotic suggestion Hypnosis is a state of consciousness characterized by focused attention and increased suggestibility. It is not sleep. Rather, it is an extreme focus on internal stimuli. Hypnosis is commonly used by psychologists. Theodore Barber (1965) suggested nothing special about hypnosis but rather, it is something that can be achieved with effort. Ernest Hilgard (1986) felt that hypnosis, in contrast, was quite constructive and potentially helpful. Posthypnotic suggestion is one made while under hypnosis that influences the patient’s behavior afterwards.
biofeedback Biofeedback is the process of learning to control bodily states with the help of specialized machines. Whether it is a machine to produce a light when heart rate rises beyond a certain point or to prevent headaches. Over time, people can learn to control physiological processes without medicine.
meditation Meditation requires the focusing of attention to clear the mind and to induce relaxation. There are three types of meditation: Transcendental – repetition of a mantra for roughly 20 minutes, twice a day Mindfulness – the meditation focuses on different parts of the body, from head to toe with particular attention on those parts that cause pain Breath – concentration on inhaling and exhaling
psychoactive drugs The purpose of psychoactive drugs is to impact the central nervous system and produce an alternate consciousness. These drugs can range from the ubiquitous (coffee) to the prescribed (Ambien) to the illegal and dangerous (marijuana and LSD).
marijuana Marijuana refers to the dried leaves of Indian hemp or cannibus sativa. When smoked, it can produce an altered state of consciousness.
hallucinations and hallucinogens Hallucinations are perceptions of reality without any external causation. Those who feel they hear, see or sense things without external stimuli, are reacting to internal causations. Drugs, hypnosis and meditation can create these conditions. Hallucinations are also caused by sensory and physical depravations. Hallucinogens (also known as psychedelics) are drugs that can create hallucinations, such as LSD. There are other opiates that can also produce hallucinations.
lysergic acid diethylamide (LSD) LSD is one of the most powerful drugs, psychedelic or otherwise, known. This synthetic drug can produce noticeable affects with only a few millionths of a gram. A regular does is between 100 to 300 micrograms. It was originally prescribed and used by psychologists and championed by Harvard Professor Timothy Leary but its dangers drove it from experimental use by the late 1950s.
sensation and perception Sensation is the process of a stimuli activates with a receptor. Each of the sensory perceptions notice different things and react differently. Perception is how one’s mind organizes sensory information into meaningful experiences. Psychophysics is a science to explain the relationship between sensory experiences and the physical stimuli that engender them.
absolute threshold In order to determine how people detect stimuli from the outside world, psychologists first had to figure out at what point can a person detect stimuli in the first place. A test might include pin pricking the skin or showing a low beam light against the wall. Absolute threshold is the weakest point a person can detect the stimuli half the time or more. The results? Vision – a candle flickering 30 miles away on a clear night Hearing – a watch ticking 20 feet a way Taste – 1 teaspoon of sugar dissolved in 2 gallons of water Smell – 1 drop of perfume in a 3-room house Touch – A bee’s wing falling 1 centimeter upon one’s cheek
difference threshold Difference threshold is the smallest change in physical stimuli that can be detected by a person.
Weber’s law Weber’s Law states that the larger or stronger a stimulus, the longer it takes for a person to notice a change within the stimulus. Some people are more sensitive to changes in stimuli than others so individual differences vary greatly.
signal-detection theory The single-detection theory attempts to study and quantify people’s ability to perceive the presence or absence of stimuli.
the human eye(pupil, lens, retina, optic nerve) The human eye is made up of many parts, including: Pupil – the opening within the iris that regulates how much light enters the eye Lens – a flexible, transparent structure in the eye that changes its shape to focus light upon the retina Retina – the innermost coating at the back of the eye that contains light-sensitive receptor cells Optic nerve – the nerve that carries impulses from the retina to the brain
binocular fusion and retinal disparity The binocular fusion is the bringing together the two images picked up by the two eyes into a single image. However, though we pick up an image twice, the two eyes pick up a different image. This is called retinal disparity. The difference is accounted for by the different eyes perception and viewpoint. Retinal disparity is key to depth perception. A large retinal disparity means an object is near while a small retinal disparity means the object is far away.
auditory nerve The auditory nerve carries impulses from the ear to the brain. Sound is measured in two ways: decibels – the strength of a sound wave pitch – the rate of vibration of the medium through which a sound wave is transmitted
vestibular system The vestibular system regulates the body’s sense of balance. It is located within the inner ear. Movements serve as the stimuli for the system but overstimulation through excessive spinning, falling or tilting the head or body can lead to dizziness or motion sickness.
olfactory nerve The olfactory nerve carries impulses from the nose to the brain. The ability to smell is directly related to the sense of taste. It is one reason why a stopped up nose or congestion can lead to an inability to taste.