Brain Anatomy- Internal Structures
The central nervous system consists of the brain and spinal cord. The peripheral nervous system is made up of the nerves which connect the brain and spinal cord with the rest of the body.
The principal parts of the brain are the cerebrum, brainstem, diencephalon, and cerebellum.
The cerebrum is made of both white matter and gray matter. The surface of the cerebrum (the cortex) is composed of a thin layer of gray matter (nerve cell bodies), underneath which are the white matter tracts (myelinated nerve cell axons).
The diencephalon consists of the thalamus and hypothalamus.
The brainstem is the lowest part of the brain just above the spinal cord. It consists of the midbrain, pons and medulla. It controls many of the basic involuntary body functions necessary for life, such as breathing, sleeping and rate of heartbeat.
It is in the medulla where the left and right white matter tracts to and from the brain cross over. Nerve impulses to and from the left side of the body are processed in the right side of the brain, while right side body impulses are processed in the left. This is why an injury in the left side of the brain such as a stroke, creates symptoms (loss of sensation, paralysis) on the right side of the body.
The reticular formation is a complex network of nerve cell fibers. It is involved with determining our level of wakefulness and sleep.
Thalamus
The thalamus is an olive shaped structure about one inch in length. It serves as a relay station for impulses traveling to and from the spinal cord, brain stem, cerebellum and cerebrum. It has an important function in directing sensory input to the appropriate place in the cerebral cortex. Sensory input from the body, the eyes, ears and other senses (except for smell) pass through the thalamus.
Hypothalamus
The hypothalamus is located below the thalamus. The hypothalamus is an important center for many critical internal body functions. The hypothalamus monitors water concentration, hormone concentrations and body temperature. It is associated with feelings of rage, aggression, hunger and thirst.
The hypothalamus also plays an important role as an intermediary between the nervous system and the endocrine system (hormones). The hypothalamus has many connections with the pituitary gland and can produce and regulate hormones.
The limbic system, sometimes called “the emotional brain”, controls many of the complex emotional behaviors we think of as instinct. Different areas of the limbic system have a strong control over emotions such as pleasure, pain, anger, fear, sadness, sexual feelings and affection. It is an important system in animals which have a less developed intellectual ability than humans.
Structures of the limbic system include the thalamus, hypothalamus, amygdala, septum and hippocampus.
The amygdala is involved with strong feelings of rage or aggression.
The hippocampus helps control the transferring of present experiences into permanent memories. People with hippocampal damage can not remember recent events for very long and can not create new long term memories. The only long term memories they have is of what happened before their injury.
Know more about brain:
http://science.nationalgeographic.com/science/health-and-human-body/human-body/brain-article/
References:
http://www.medicalartlibrary.com/brain-anatomy.html
http://www.innerbody.com/image/nerv02.html
Images via Medical Library
Thank you Corina Marinescu
ReplyDeleteSome medical students would like to get a brain to walk around.