Biological Perspective

• Nervous System:

  • An extensive network of specialized cells that carry information to and from all parts of the body
  • Neuroscience deals with the structure and function of neurons, nerves, and nervous tissue
  • Relationship to behavior and learning
• Structure of the Neuron:

  • Neurons are the basic cells that make up the nervous system and receive/send messages
  • Parts of a Neuron:
  • Dendrites: branch-like structures that receive messages
  • Soma: the cell body responsible for maintaining the life of the cell
  • Axon: long tube-like structure that carries the neural message to other cells
• Other Types of Brain Cells:

  • Glial cells provide support for neurons, deliver nutrients, produce myelin, and clean up waste products
  • Myelin is a fatty substance that coats axons to insulate, protect, and speed up the neural impulse
• Generating the Message: Neural Impulse:

  • Ions are charged particles
  • Resting potential is the state of the neuron when not firing a neural impulse
  • Action potential is the release of the neural impulse consisting of a reversal of the electrical charge within the axon
• Sending the Message to Other Cells:

  • Axon terminals are branches at the end of the axon
  • Synaptic vesicles contain neurotransmitters that affect the next cell
  • Synapse/synaptic gap is the fluid-filled space between cells
• Neuron Communication:

  • Neurons must be turned ON and OFF
  • Excitatory neurotransmitters cause the receiving cell to fire
  • Inhibitory neurotransmitters cause the receiving cell to stop firing
• Types of neurotransmitters:

  • Agonists mimic or enhance the effects of a neurotransmitter
  • Antagonists block or reduce a cell’s response to other chemicals
• Cleaning up the Synapse:

  • Reuptake is the process by which neurotransmitters are taken back into the synaptic vesicles
  • Enzymes break up neurotransmitters like acetylcholine
• Central Nervous System:

  • Consists of the brain and spinal cord
  • Spinal cord carries messages to and from the body to the brain
• Peripheral Nervous System:

  • All nerves and neurons not in the brain and spinal cord
  • Divided into Somatic nervous system and Autonomic nervous system
• Somatic Nervous System:

  • Division of the PNS consisting of nerves that carry information to and from the CNS and voluntary muscles
• Autonomic Nervous System:

  • Division of the PNS controlling involuntary muscles, organs, and glands
  • Sympathetic division reacts to stress, while Parasympathetic division restores normal functioning
• Peeking Inside the Brain:

  • Clinical studies involve deep lesioning and electrical stimulation of the brain
  • EEG records brain wave patterns
  • Brain-imaging methods include CT, PET, MRI, and fMRI
• Structures of the Bottom Part of the Brain:

  • Medulla is responsible for life-sustaining functions
  • Pons plays a part in sleep, dreaming, and arousal
  • Reticular formation is responsible for selective attention
  • Cerebellum controls rapid, fine motor movement
• Structures Under the Cortex:

  • Limbic system is involved in learning, emotion, memory, and motivation
  • Thalamus relays sensory information to the cortex
  • Hypothalamus is responsible for motivational behavior
  • Hippocampus is for long-term memory
  • Amygdala is for fear responses
• Cortex:

  • Outermost covering of the brain responsible for higher thought processes
  • Cerebral hemispheres are the two sections on the left and right sides of the brain
  • Corpus callosum connects the right and left cerebral hemispheres
• Four Lobes of the Brain:

  • Occipital lobe is for visual centers
  • Parietal lobes are for touch, taste, and temperature sensations
  • Temporal lobes are for hearing and speech
  • Frontal lobes are for higher mental processes and decision making
• Association Areas of Cortex:

  • Responsible for coordination and interpretation of information
  • Broca’s aphasia results from damage to Broca’s area
  • Wernicke’s aphasia results from damage to Wernicke’s area
  • Spatial neglect results from damage to the right hemisphere
• Split Brain Research:

  • Cerebrum consists of the two hemispheres and structures that connect them
  • Study of patients with severed corpus callosum demonstrates right and left brain functions
• Split brain research involves studying patients with a severed corpus callosum
• Messages are sent to only one side of the brain
• Demonstrates right and left brain specialization
• Split-brain subjects viewed a composite of two faces and chose different faces based on the hemisphere receiving the image
• Language is primarily a left hemisphere activity for most individuals
• Left side of the brain controls language, writing, logical thought, analysis, and mathematical abilities, processes information sequentially, and can speak
• Right side of the brain controls emotional expression, spatial perception, recognition of faces, patterns, melodies, and emotions, processes information globally, and cannot speak
• Endocrine glands secrete chemicals called hormones directly into the bloodstream
• Pituitary gland secretes human growth hormone and influences all other hormone-secreting glands
• Pineal gland secretes melatonin
• Thyroid gland regulates metabolism
• Pancreas controls the levels of sugar in the blood
• Gonads are the sex glands that regulate sexual development and behavior as well as reproduction
• Ovaries are the female gonads
• Testes are the male gonads
• Adrenal glands secrete over 30 different hormones to deal with stress, regulate salt intake, and provide a secondary source of sex hormones affecting sexual changes during adolescence