Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.
Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
The brain is perhaps the most important organ in the
body, responsible for the unconscious autonomic activities like breathing, blood
pressure and temperature control, sensation, movement, and thought
process.
Neurons and glia are the two types of cells that make
up the brain,
Each area of the brain has a responsibility for brain
function.
A brain lesion describes an area of damaged brain. It
may be isolated or there may be numerous areas affected.
Symptoms of a brain lesion depend upon what part of
the brain is affected and may be minimal or life-threatening.
Diagnosis of brain lesions begin with a careful history and physical
examination of the affected individual. The brain may be imaged in a variety of ways including CT,
MRI and
angiography.
Treatment and prognosis of brain lesions depend upon the underlying
illness or injury, and the amount of damage sustained by the brain.
Brain anatomy
The brain is responsible for regulation the functions of the body, from the
unconscious (controlling blood pressure, heart rate and respiratory rate) to
the conscious acts like walking and talking. Add the intellectual processes of
thought and the brain is a busy part of the human body.
The brain has many parts. The cerebrum consists of two hemispheres which are
responsible for movement, sensation, thought, judgment, problem solving, and
emotion. The brain stem sits beneath the cerebrum and connects it to the spinal
cord. The brain stem houses the structures that are responsible for the
unconscious regulation of the body such as wakefulness, heart and lung function, hunger, temperature control, and swallowing. The cerebellum is located beneath
and behind the cerebrum and is responsible for posture, balance, and
coordination.
While the brainstem is important in maintaining body function, the cerebrum
allows body motion and most importantly, is responsible for all the things that
make humans special, like thinking and emotion. There are four lobes in each
hemisphere: frontal, parietal, temporal, and occipital.
Frontal lobe is the area responsible for personality and movement. The
pre-frontal portion is perhaps the most evolved part of the brain and
specifically allows judgment, planning and organization, problem solving, and
critical thinking. This is the area that gives us the ability to feel emotion and have
empathy. Finally, this is where impulse control resides.
Parietal lobes are where sensation is processed and interpreted. Aside from
touch, pressure and pain, there is also the concept of spatial cognition, where
the brain recognizes where the body is in relationship to the area around it.
Temporal lobes are where the functions of memory, speech, and hearing are
located.
Occipital lobes are where vision is located.
Brain cells use glucose almost exclusively for their energy needs and unlike
other organs in the body, the brain cannot store glucose for future use. If
blood sugar levels fall, brain function can be immediately compromised.
The brain gets its blood supply through four major arteries, the right and
left carotids and the right and left vertebral arteries. They join together at the base
of the brain at the Circle of Willis. Smaller blood vessels then branch out to
provide oxygen and glucose rich blood to all regions of the brain.
Brain Cell Anatomy
The brain is composed of billions of cells that use chemicals and electricity
to communicate between themselves and the rest of the body. There are two major
types of cells, neurons and glial cells; there are subtypes of these cells.
Neurons
Neurons are the cells that process and transmit information in the brain.
Each cell has two connectors, the axon and dendrite. The axon of one neuron
connects with the dendrite of another at junction or synapse. Special chemicals
called neurotransmitters help transfer the electrical impulse across the synapse
so that one neuron can excite another.
Glial cells
Glial cells are located between neurons and help support their activity.
Microglial cells are part of the immune system within brain tissue helping clear
dead cells and other debris.
Astrocytes help clear neurotransmitter chemicals so
that the synapse can be ready to react to the next signal that might arrive.
Oligodendrocytes produce and maintain the myelin sheath that coats and insulates
the axon making electrical conduction more efficient.
Ependymal cells produce
CSF (cerebrospinal fluid) which is located within the ventricles of the brain
and in the subarachnoid space that surrounds the brain and spinal cord. Aside
from allowing the brain to float in the skull, CSF acts as a cushion against
trauma and also helps wash away some of the metabolic waster protects that are
produced with brain function.
Reviewed by Charles Patrick Davis, MD, PhD on 6/30/2011
Medical Author: Charles Davis, MD, PhD
Medical Editor: Melissa Conrad Stöppler, MD
Benign brain tumors are usually defined as a group of similar cells that do
not follow normal cell division and growth patterns and develop into a mass of
cells that microscopically do not have the characteristic appearance of a
cancer. Most benign brain tumors are found by CT or MRI brain scans. These
tumors usually grow slowly, do not invade surrounding tissues or spread to other
organs, and often have a border or edge that can be seen on CT scans. These
tumors rarely develop into metastatic (cancerous or spreading) tumors. Most
benign brain tumors can be removed; the benign tumors usually do not reoccur
after removal. The exact causes of benign brain tumors are not known, but
investigators have suggested that family history, radiation exposure, or
exposure to chemicals (for example, vinyl chloride, formaldehyde) may be risk
factors.
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