The Anatomy of the Brain Part 2

In addition to the major lobes we discussed before, there are several very important deep brain structures.  These small important structures are located near the center of the brain and part of the limbic system.

Thalamus is a relay station for all sensory signals, except for smell.  It also regulates sleep and awake cycles.

Hypothalamus is located above the pituitary gland.  It sends a chemical signal that controls the function of the pituitary gland, which is involved in processes such as sleep, body temperature, hunger. 

Pituitary gland is a small gland located behind the nose.  It is involved in control of many hormones produced by the thyroid, ovaries, and testicles.  It also receives chemical signals from the hypothalamus through a connecting stalk.

The amygdala is located under the cerebral hemisphere.  It is part of the limbic system and controls the “fight or flight” response when faced with danger.  It is also important in emotional memory and controlling emotions.

The hippocampus is a seahorse shaped structure located under the temporal lobe.  It is very important in new memory formation and spatial navigation.  This organ plays an important role in Alzheimer’s disease.

The basal ganglia coordinate movement and help us make decisions.  When the cells in this area die, patients can develop tremors and have a hard time with movement, leading to Parkinson’s disease.

The brainstem has three parts and connects the cerebrum, cerebellum, and the spinal cord.  The most superior segment is the midbrain.  The pons are located in the middle.  The medulla is the most inferior, connecting the brain to the spinal cord.  The brain stem function is very complex!  The midbrain is involved in motor functions such as eye movements, hearing, and visual information. The pons connects the cerebral hemisphere to the cerebellum and is involved in movements and balance. The medulla controls many basic life functions such as breathing, heart rate.  Many reflexes such as sneezing and coughing are also controlled by the medulla. In addition, cranial nerves III to XII originate from the brain stem.

Cerebellum is small and located at the back of the head.  It also has two hemispheres.  Its main function is to control balance and maintain posture.  But it is also involved in other functions such as learning skills and emotions. 

The brain is such a complex organ!  And we have barely started to understand it.  I think it is the most fascinating organ.  Underneath all this complex anatomy, the neurons generate tiny electric signals that form our thoughts, emotions, and sense of identity.