Physiology of Sleep

Physiology of Sleep

The brain

      The brain is divided in three major divisions: the forebrain, the midbrain and the hindbrain or brainstem.

      The forebrain is divided in two hemispheres: left and right. Each has four major areas or lobes.

      The occipital lobe is involved in processing and creating visual information. The temporal lobe is involved in hearing, memory, emotion, language comprehension, and it further processes visual information. The Frontal lobe is involved in thought, imagination, planning (including planning and execution of movements), language, acting, learning, etc. The Parietal lobe is involved in further processing of visual information, it also receives motor and sensory information from the rest of the body. Both hemispheres connect and share information. The activities of each lobe are not exclusive. The brain is interconnected, interdependent and flexible. This means that event though each lobe carries its own activities, functions are allways shared.

The brain stem

      The brain stem is responsible for vital functions: it keeps our heart pumping, our lungs breathing. It controls our digestion, blood pressure and other autonomic functions. It also controls the information that goes into and out the brain through the spinal chord. Many neurotransmitters are produced in the brainstem. Including many of those involved in keeping us awake or asleep.

The neuron

      The neuron is the nervous system cell. It is the working unit of our nervous system. The neuron carries, processes and transmits electrical signals at incredible speeds. Neurons connect with thousands of other neurons. Their connections are called synapses.

      When an electrical signal is received by the neuron, the neuron carries it through its axon. If the electrical signal is strong enough to reach the terminal buttons, where the synapses are, the neuron secretes neurotransmitters in the synapses. There are many neurotransmitters, each one has a particular effect depending on where it is being secreted and how much. We will study them as we go through, so don't worry.