Brain, Body and Behavior

Focus Questions  How do the different hemispheres of the brain function?  Where are significant parts of the brain and what are their functions?  How do neurons cue the body?  Where and what purpose do different glandular systems serve?

The Make-up of the Brain  Controls every thought, action and feeling – psychologists are interested in human behavior so must understanding the working of the brain  20% of oxygen, most of sugar intake (junky sugar, junky brain), 20 watts of electrical power

 The Hemispheres:  Divided into two halves – depression in middle called the fissure  Right hemisphere controls left side of body and Left hemisphere controls right side of body  Midway down two halves is a bundle of fibers called the corpus

 The Lobes  Four major sections  mid way from front to back is another fissure – marks boundary between two lobes

 Frontmost lobe – frontal lobe  Remaining area – parietal lobe  Frontal lobe has the motor strip – controls every part of the body that is capable of moving  Parietal lobe has the sensory strip – controls the feeling of sensations in different areas (a pin prick on your leg, a poke on the arm, etc.)  Back of the brain – occipital lobe – what we see  ‘Thumb’ area – temporal lobe – major centers for hearing and some related to speech  There is a special circular spot that creates sentences – even when ‘talking’ silently to ourselves  For most people this is found only in the left hemisphere, 25% of lefties have them in the right hemisphere  Brain sits in fluid to act as a shock absorber – when hit hard, brain sloshes around and occipital lobe hits skull, causing the electrical system to stir itself up and causes you to see strange images

 The Frontal Association  Front of the frontal lobe – heavily packed with nerve cells due to complex task  Interprets what is going on and tells us what to and to feel  Forms the core a person’s personality  Tries to make sense of the environment  How developed tells how advanced the animal is – dog=7%; chimp=15%; humans=30% 

 Handedness and the brain  10% of population is left handed  Small, fine movements tend to favor one hemisphere – dominant and controls majority of actions  Left-handers will probably be better at art, music and math Famous left handers: many presidents, including G.W. Bus, Obama and Bill Clinton Oprah Winfrey Jimi Hendrix Bill Gates Babe Ruth Da Vinci

Tasks of Hemispheres  Left: verbal and speech  Right: objects in space, art, music, math and emotional material  Work together in everything we do

 Cerebral cortex: contain all parts already discussed  Outermost layer of brain  Controls very high-level thought  2/3 of the brain’s nerve cells – 100 BILLION of them  Number of possible different connections the brain can make is greater than the number of particles in the universe   Lower Brain: keeps the body running  Cerebral cortex fits over and around it (like bark on a tree)  Basic functions – animal like lower units 

Other Terms to Know  Thalamus: oval mass of nerve cells; relay station to send incoming and outgoing messages  Cerebellum: looks like ball of yarn larger than a golf ball; hooks into base of brain below the occipital lobe; balance, coordination  Hypothalamus: below the thalamus; size of a large pea; control rage, pleasure, hunger, thirst and sexual desire  Reticular activating system (RAS): base of brain inside spinal cord; looks like a net; catches nerve impulses; regulates how sleepy or alert we are

 Neuron: each nerve cell  Dendrites: receive information form other nerve cells and sends it to cell body  Axon: carries message from cell to other neurons  Synapse: space between axon and dendrites  Vesicles: area where axon ends and before synapse – containers that look like bubbles  Neurotransmitters: transmit nerve information from the end of the axon over the synapse to the dendrite receptor  Most common is acetylcholine (ACH) – sends info whenever we more a body part  Dopamine: involved in motor functions or movement – Parkinson’s  Endorphins: exist to relieve pain and increase our sense of well-being; act as a natural form of morphine  Spinal cord: all nerve impulses enter and leave here  Reflex: spinal cord activates movement before we even register it