chapter 3 - BioPsych

• NEURONS

  ·        Specialized cells for the reception, conduction, and transmission of electrochemical signals

  ·        Many sizes and shapes

   
• There are about 100 billion neurons in the nervous system
• -Neurons are some of the longest-lived cells in the body
• Neurons are irreplaceable
• Neurons have huge appetites
• about 25 percent of the calories

  That you take in every day are

  Consumed by your brain's activity
• : Classes of Neurons

          A unipolar neuron, a bipolar neuron, a multipolar neuron, and an interneuron.

   
• UNIPOLAR NEURON

  ·        These neurons have a SINGLE LONG AXON that is responsible for sending electrical signals.
• Axon - is a thin fiber that connects neurons (nerve cells) to that they can communicate.
• Neurons communicate via electrical impulses that trigger the release of "chemical messengers" called neurotransmitters.

   
•    Axon: long, tube-like structure that carries the neural message to other cells.

   
• BIPOLAR NEURON

  Type of neuron that has two extensions (one axon and one dendrites).
• Many bipolar cells are specialized sensory neurons for the transmission of sense. As such they are part pf the sensory pathways for smell, sight, taste, hearing, touch, balance.
• • Dendrites receive input from many other neurons and carry those signals to the cell body.
• Dendrites: branch-like structures that receive messages from other neurons.
• MULTIPOLAR

  It constitutes the majority of neurons in the central nervous system.
• These neurons can receive impulses from multiple neurons via dendrites. multipolar
• The dendrites transmit the signals through the neuron via an electrical signal that is spread.

   
• INTERNEURON

  Interneurons are the ones in between - they connect spinal motor and sensory neurons. As well as transferring signals between sensory and motor neurons.

   
• Soma: the cell body of the neuron, responsible for maintaining the life of the cell.
•    Nucleus: it controls and regulates the activities of the cell.
• They include motor neurons and interneurons/relaying neurons are most commonly found in the cortex of the brain and the spinal cord.
• Frequency - they've only got one signal they can send, and it only transmits at one uniform strength and speed.

   
• NEURONAL TRANSMISSION

  ·        The brain can translate these signals reading them like binary codes.

  ·        Organizing them by location, sensation, magnitude, & importance.
• Action potential - name for the electrical charge generated by the ions which sends messages down the axon.
• • Ions transmit nerve signals, and contract muscles including the heart, etc.
• Resting potential: the state of the neuron when not firing a neural impulse.
• -         Second Step Sending messages between neurons is a chemical process
• ·        Synapse - small gap or space between 2 neurons. Neurons never touch

  ·        Because of the synaptic gap, the electrical impulse cannot cross the gap and a chemical process must take the message across the gap.
• Neurotransmitters are chemical messengers that your body can't function without.
• NEUROTRANSMITTERS

  Their job is to carry chemical signals ("messages") from one neuron (nerve cell) to the next target cell.
• Psychopharmacology is the study of how drugs affect behavior. If a drug changes your perception, or the way you feel or think, the drug exerts effects on your brain and nervous system.
•   Psychoactive drugs are substances that, when taken in or administered into one's system, affect mental processes, e.g. perception, consciousness, cognition or mood and emotions.
• Example of Psychoactive Drugs

  Cocaine

  Nicotine

  Alcohol

  CaffeineEcstasy

   
• in which part of the brain and spinal cord are multipolar neurons commonly found?

  cortex of the brain and spinal cord
• What is the primary function of neurons? Reception, conduction, and transmission of electrochemical signals
• neurotransmitter - Carry chemical signals between neurons
• acetylcholine - muscle action, memory
• beta-endorphin - pain and pleasure
• dopamine - mood, sleep, learning