The Brain

Cerebrum - This is the structure that we normally think of as the brain and is 
responsible for voluntary movements; sensations, learning, remembering, thinking, emotion, and consciousness. It is divided into two hemispheres: Right & Left. The
Cerebral Cortex - the surface of the cerebrum, consists mostly of glia and cell bodies, dendrites and interconnecting axons of neurons and contains centers for our senses: .sight, hearing, taste, smell and touch.  There are areas for thinking, speaking, long and short-term memory.

Hypothalamus - Located just below the thalamus, but is smaller.  It controls the autonomic nervous system and the endocrine system.  It regulates fluids, nutritional storage, body temperature, motivation, emotion, hunger, thirst, sexual behavior, caring for offspring and aggression.   

Medulla - Regulates vital functions such as heart rate, breathing, blood pressure, respiration, sleep, coughing, sneezing, tongue movements, and reflexive
eye movements.  It is here that nerves 'cross over': left nerves go to right hemi-
shere; right nerves go to left hemisphere -- this is 'cross-laterality.'

Corpus Callosum - Band of fibers which connects the two hemispheres of the

Pons -  The 'Bridge' between the spinal cord and the brain.  Considered a part of the Hind Brain, bundles of nerves pass through it transmitting information about body movement, attention, sensory messages and alertness.  The 'cross-
laterality' continues up to the brain.

Thalamus - The relay station to the cortex for all sensory information, it is located  near the center of the brain. It is a large structure with two lobes, connect-ed by a bridge of gray matter. Most neural input to the cerebral cortex is receiv- ed from the thalamus.  The thalamus is divided into a number of nuclei. Neurons in these nuclei then relay the sensory information to  specific sensory projection areas of the cerebral cortex, acting as a 'relay station.' It also is involved in controlling sleep, and attention as well as information from the RAS.

Cerebellum -  Literally means "small brain," and is divided into two hemispheres that are involved in maintaining balance and in controlling motor be-
havior in rapid body movements.  Many eye movements originate here.  It smoothes out movement, and damage can result in tremors.   

Reticular Activating System  -  A network of fibers and cell bodies located inside the medulla and the brainstem.  As nerve impulses flow into the brain,
the RAS gives priority to some messages, while excluding others.  In this way the  RAS influences attention.  Responsible for maintaining vigilance, alertness, and wakefulness.  Damage to the RAS results in a coma.

Limbic System  -  This system governs our emotional responses and our short term memory, hunger, sex and aggression.  The system includes the amygdala, and the hippocampus, the thalamus and the hypothalamus, which are only found in mammals.