Ch. 3 Brain Structure and Functions BBBRRAINSSSS Ch. 3 Brain Structure and Functions Goals: Identify and Analyze functions of the lower Brain Identify and Analyze functions of the Cerebral Cortex. Identify the Four Lobes of the Brain and describe their functions. Analyze the connection between the two hemispheres of the brain and their relationship with each other.

Uses 20% of our bodies oxygen intake Weighs about 3 pounds Human Brain Uses 20% of our bodies oxygen intake Weighs about 3 pounds Made up of 100 billion nerve cells Operates on 20 watts of electrical power

Cerebral Cortex Outermost layer of brain- size of a bath towel all twisted up Higher level thought processes

Hemispheres Brain is divided up into two hemispheres (hemi=half) Connected by the Corpus Callosum – which allows the halves to communicate with each other Hemispheres are further divided up into the 4 lobes of the brain

4 Lobes Both hemispheres- Frontal, Occipital, Parietal, Temporal Frontal Lobe- Responsible for some memory, strategizing, planning and associations, affects our personality and social control Contains the Motor Strip along the border between parietal and Frontal – controls all movements made by the body. (motor cortex) Also contains the Prefrontal Area – contains sensory memories of our personal past- allows us to re-live our past experiences Frontal Association Area- interpret surroundings and respond with appropriate actions and feelings Larger generally = more advanced

Parietal Lobe- Responsible for general processing / association and sensory (touch) input and interpretation Sensory Strip- located just behind border between Frontal and Parietal lobes- contains the center of all sensory (touch) information coming in to the brain (somatosensory cortex) Occipital Lobe- Responsible for all visual/optic info coming into the brain and its interpretation. (Stars and dark room) Temporal Lobe – major centers for hearing and some of the speech areas (speech overlaps with other areas)

Lower Brain Often called the Animal Brain- because all mammals share a similar lower brain structure Within the Brainstem are the: Medulla- area where controls for basic life-support functions are located (heartbeat, breathing, circulation etc.) Reticular Activating System (RAS) or Reticular Formation- controls and maintains alertness- (waking up)

Lower Brain Cont. Cerebellum- helps to controls balance, muscle co-ordination and muscle memory and make movements smooth- without you could still move, but it would be awkward and clumsy Thalamus- sits just above the brainstem, acts as body’s switchboard-funneling all the incoming sensory information (except smell) and directing it to the correct brain area for processing

Lower Brain cont. Hypothalamus – (below the thalamus)- regulates body’s survival drives and functions (i.e. hunger, thirst, fight or flight etc. ) - also plays a large role in experiences of emotion, pleasure and sexual attraction Hippocampus- wraps around Thalamus and is key player in processing memories (Alzheimer’s patients often have damage to this area) Amygdala- emotional control center, especially fear and anger Phineas Gage

Right Brained vs. Left Brained Most tasks require the two hemispheres to work together- but we can have preferred ways of functioning but the idea of “right brained” or “left-brained” people is changing. Left-Hemisphere- language focused Broca’s Area – w/i left frontal lobe, directs muscle movements used in speech-damage to this area affects ability to speak correctly (strokes) Wernicke’s Area – in left temporal lobe- helps control receptive language- ability to understand others’ speech Right-Hemisphere- Spatial relationship focused Judging distance, shapes, volumes etc. Also source of word connections- what word goes with painting, ring, & nail? Split Brain Dude

Brain Plasticity The ability of brain tissue to take on new functions-usually due to injury or disease If a brain has damage to one of its lobes- other parts of the brain can learn to take on that areas functions Younger brains have a greater ability to do this, but the brain never completely loses the capacity. Jody