Psych&100 - Brain and Behavior

The nervous system: The system that regulates the body’s responses to internal and external stimuli. Consists of:

• Central nervous system

• Peripheral nervous system

Neurons: Nerve cells that provide communication. Each of us has more than 100 billion neurons in

our body, most of which are found in the brain.

Components of a Neuron

• Cell Body: Produces energy for the cell

• Dendrites: Receives impulses and conducts them to the cell body

• Axon: Carries messages away from the cell body

• Myelin: Insulates and protects the axon.

Communication Process

• Synapse: The junction between the axon terminals of one neuron & the dendrites of another neuron

• Neurotransmitter: A chemical messenger that carries impulses across the synaptic gap across transmitters

Fast Fact - Abuse of the drug ecstasy, inhibits the natural production of the neurotransmitters Endorphins; when off of the drug, depression is a chronic disorder

Small fiber: sensation, aging will destroy Large fiber: motor, not much of a decrease w/o condition

The Nervous System: The system that regulates the body's responses to internal &

external stimuli. Consists of the following:

• Central Nervous System:

  • Brain

  • Spinal cord - columns of nerves within the spine that transmit messages to and from the brain

• Peripheral Nervous System:

  • Communicates between the central nervous system and all body parts.

    • Somatic NS: transmits senses to the central nervous system. temp – pressure

    • Automatic NS: regulates the body’s vital functions, Ex. heartbeat, breathing, digestion, & blood pressure

Fast Fact: The spinal cord is as thick as a thumb.

The Brain

• Divided into 3 sections:

  • Hindbrain

  • Midbrain

  • Forebrain

Hindbrain

1. Lower portions - vital functions, heart rate, respirations, and balance

   1. Medulla: vital function

   2. Pons: body movement, attention, sleep

   3. Cerebellum: balance and coordination

Midbrain

1. Involved with vision and hearing

   1. Reticular activating system - attention, sleep, arousal

Forebrain

1. Thalamus: is a relay station for sensory info.

2. Hypothalamus: Regulates body temp., motivation, & emotion. Also involved in hunger, thirst, & sex behavior.

3. Limbic System: memory, emotion, sex, aggression. - Hippocampus & Amygdala

4. Cerebrum: Large part of the brain - 70% of vol.

   1. Coordination of voluntary activity in the body.

Fast Fact - The lower brain functions do not require any conscious thought or effort and are not aware of these activities. Imagine if we were aware of all this information processed by our brain.

Fast Fact - Alcohol affects the Reticular Activating System to depress our reaction time.

Cerebral Cortex: Wrinkled part of the brain - controls mental processes like thought.

• 4 lobes of the Cerebral Cortex

1. Frontal Lobe - Movement & thinking

2. Parietal lobe - touch sensation & spatial relationships

3. Occipital lobe - visual cortex

4. Temporal lobe - process sounds, including speech

• Motor Cortex: an area behind the frontal lobes that controls movement

• Sensory Cortex: receives info from skin senses and from the movement of body parts

• Association Areas: involved in higher mental functions: learning, remembering, thinking, and speaking.

  • Broca’s Area - Producing language, Lft hemisphere

    • Broca’s Aphasia: understand language, hard to find words, aware of their problems

  • Wernicke’s area: speech comprehension

    • Wernicke’s Aphasia: a disorder caused by damage to Wernicke’s area

      • difficultly understanding speech

      • Speech is intelligible-nonsense words

      • unaware of their disability

• Corpus Callosum: the structure that connects the two hemispheres of the brain.

  • Left hemisphere: controls language, logic, problem solving & math

  • Right hemisphere: deals w/imagination, feelings, art, & spatial relations.

Fast Fact - The brain is protected by the skull and three membranes, called meninges. Also, a fluid surrounds the brain and acts as a shock absorber