The area of the brain that controls movement is in a very narrow strip that goes from near the top of the head right down along where your ear is located.
It's called the motor strip. If I injure that area, I'll have problems controlling half of my body. If I have a stroke in the left hemisphere of my brain, the right side of the body will stop working.
If I have an injury to my right hemisphere in this area, the left side of my body stops working (remember, we have two brains). This is why one half of the face may droop when a person has had a stroke.
Diagram of Brain
There are over 100 types of cancer that can affect the central nervous system (CNS).16 As mentioned previously, cancers that arise in other locations (breast, lung, etc.) and spread (metastasize) to the brain are not considered brain cancer. They are still treated as the cancers of the original site. Here, we will only discuss primary brain cancers (those that originate in the brain).
Gliomas
Malignant gliomas are the most common and deadly brain cancers. They originate in the glial cells of the central nervous system (CNS). Gliomas can be divided into 3 main types:
astrocytomas,
oligodendrogliomas, and
ependymomas.
The median survival of patients with glioma has improved over the past few years but is still only 15 months, with few patients living more than two years.Research indicates that this type of brain cancer may resist treatment because it contains stem cells that are responsible for driving the formation of blood vessels (angiogenesis), spread of the tumor (metastasis), and resistance to treatments.
Astrocytomas:
Astrocytomas are tumors that develop in astrocytes and are found in the cerebrum and the cerebellum. Astrocytomas make up approximately 50% of all primary brain tumors. Glioblastoma multiforme, an astryocytoma subtype, is the most aggressive form of brain cancer and is associated with poor prognosis.
Oligodendrogliomas:
Oligodendrogliomas are tumors that develop in oligodendrocytes, and more often in the oligodendrocytes that are found in the cerebral hemispheres. Oligodendrocytes are glial cells that produce myelin, a component of the brain that increases impulse speed. Oligodendrogliomas make up approximately 4% of primary brain tumors. Approximately 55% of all cases of oligodendrogliomas appear in people between the ages of 40 and 64.
Ependymomas:
Ependymomas are tumors that develop in the ependymal cells. Ependymal cells are the cells in the brain and where ceribrospinal fluid (CSF) is created and stored. 24Ependymomas account for only 2% to 3% of all primary brain tumors but account for 8% to 10% of brain tumors in children. Ependymoma tumors are usually found in ventricle linings, the spinal cord, or the regions near the cerebellum.
Nongliomas
Nongliomas are tumors that do not arise from glial cells. More prevalent examples of nongliomas include meningiomas and medulloblastomas. Less prevalent examples include medullpituitary adenomas, primary CNS lymphomas, and CNS germ cell tumors.
Meningiomas:
Meningiomas are tumors that develop in the meninges, membranes covering the brain and spinal cord. Meningioma tumors are frequently formed from arachnoid cells. These cells are responsible for the absorption of the cerebrospinal fluid (CSF). Meningioma tumors are responsible for 13% to 30% of all tumors arising within the cranium - the bony case surrounding the brain. Tumor arising within the cranium are also called intracranial tumors. Most meningiomas are benign. Malignant meningiomas are extremely rare, with an incidence rate of approximately two out of every million people, per year. The risk for developing meningiomas increases with age and is more prevalent in women.
Medulloblastomas:
Medulloblastomas are the most common brain malignancies in children. These cancers arise in the posterior fossa - a specific region of the space inside the skull (intracranial cavity) that contains the brainstem and the cerebellum. The fourth ventricle region is involved in the development of approximately 80% of childhood cases.
A lot of information comes in through the spinal cord at the base of the brain. Think of a spinal cord as a thick phone cable with thousands of phone lines. If you cut that spinal cord, you won't be able to move or feel anything in your body. Information goes OUT from the brain to make body parts (arms and legs) do their job.
There is also a great deal of INCOMING information (hot, cold, pain, joint sensation, etc.). Vision and hearing do not go through the spinal cord but go directly into the brain. That’s why people can be completely paralyzed (unable to move their arms and legs) but still see and hear with no problems.
Information enters from the spinal cord and comes up the middle of the brain. It branches out like a tree and goes to the surface of the brain. The surface of the brain is gray due to the color of the cell bodies (that's why it's called the gray matter). The wires or axons have a coating on them that's colored white (called white matter).
GETTING INFORMATION IN AND OUT OF THE BRAIN VIDEO :
Is the brain like a big phone system or is it one big computer with ON or OFF states ? Neither of the above is correct.
Let's look at the brain as an orchestra. In an orchestra, you have different musical sections. There is a percussion section, a string section, a woodwind section, and so on. Each has its own job to do and must work closely with the other sections. When playing music, each section waits for the conductor. The conductor raises a baton and all the members of the orchestra begin playing at the same time playing on the same note. If the drum section hasn't been practicing, they don't play as well as the rest of the orchestra. The overall sound of the music seems "off" or plays poorly at certain times. This is a better model of how the brain works. We used to think of the brain as a big computer, but it's really like millions of little computers all working together.
Diagram of Brain
Let's start looking at the building blocks of the brain. As previously stated, the brain consists of about 100 billion cells. Most of these cells are called neurons. A neuron is basically an on/off switch just like the one you use to control the lights in your home. It is either in a resting state (off) or it is shooting an electrical impulse down a wire (on). It has a cell body, a long little wire (the "wire" is called an axon), and at the very end it has a little part that shoots out a chemical. This chemical goes across a gap (synapse) where it triggers another neuron to send a message.
There are a lot of these neurons sending messages down a wire (axon). By the way, each of these billions of axons is generating a small amount of electrical charge; this total power has been estimated to equal a 60 watt bulb. Doctors have learned that measuring this electrical activity can tell how the brain is working. A device that measures electrical activity in the brain is called an EEG (electroencephalograph).
Each of the billions of neurons "spit out" chemicals that trigger other neurons. Different neurons use different types of chemicals. These chemicals are called "transmitters" and are given names like epinephrine, norepinephrine, or dopamine.
Diagram of Brain
THE BRAIN: AN ELECTRICAL AND CHEMICAL MACHINE VIDEO :
Cerebellum - The portion of the brain (located at the back) which helps coordinate human movement (balance and muscle coordination). Damage may result in ataxia which is a problem of muscle coordination. This can interfere with a person's ability to walk, talk, eat, and to perform other self care tasks.
Diagram of brain.....diagram-of-brain-frontal-lobe.
Brain Information
AMYGDALA: Lying deep in the center of the limbic emotional brain, this powerful structure, the size and shape of an almond, is constantly alert to the needs of basic survival including sex, emotional reactions such as anger and fear. Consequently it inspires aversive cues, such as sweaty palms, and has recently been associated with a range of mental conditions including depression to even autism. It is larger in male brains, often enlarged in the brains of sociopaths and it shrinks in the elderly.
BRAIN STEM: The part of the brain that connects to the spinal cord. The brain stem controls functions basic to the survival of all animals, such as heart rate, breathing, digesting foods, and sleeping. It is the lowest, most primitive area of the human brain.
CEREBELLUM: Two peach-size mounds of folded tissue located at the top of the brain stem, the cerebellum is the guru of skilled, coordinated movement (e.g., returning a tennis serve or throwing a slider down and in) and is involved in some learning pathways.
CEREBRUM: This is the largest brain structure in humans and accounts for about two-thirds of the brain’s mass. It is divided into two sides — the left and right hemispheres—that are separated by a deep groove down the center from the back of the brain to the forehead. These two halves are connected by long neuron branches called the corpus callosum which is relatively larger in women’s brains than in men’s. The cerebrum is positioned over and around most other brain structures, and its four lobes are specialized by function but are richly connected. The outer 3 millimeters of “gray matter” is the cerebral cortex which consists of closely packed neurons that control most of our body functions, including the mysterious state of consciousness, the senses, the body’s motor skills, reasoning and language.
The Frontal Lobe is the most recently-evolved part of the brain and the last to develop in young adulthood. It’s dorso-lateral prefrontal circuit is the brain’s top executive. It organizes responses to complex problems, plans steps to an objective, searches memory for relevant experience, adapts strategies to accommodate new data, guides behavior with verbal skills and houses working memory. Its orbitofrontal circuit manages emotional impulses in socially appropriate ways for productive behaviors including empathy, altruism, interpretation of facial expressions. Stroke in this area typically releases foul language and fatuous behavior patterns.
The Temporal Lobe controls memory storage area, emotion, hearing, and, on the left side, language.
The Parietal Lobe receives and processes sensory information from the body including calculating location and speed of objects.
The Occipital Lobe processes visual data and routes it to other parts of the brain for identification and storage.
HIPPOCAMPUS: located deep within the brain, it processes new memories for long-term storage. If you didn't have it, you couldn't live in the present, you'd be stuck in the past of old memories. It is among the first functions to falter in Alzheimer's.
HYPOTHALAMUS: Located at the base of the brain where signals from the brain and the body’s hormonal system interact, the hypothalamus maintains the body’s status quo. It monitors numerous bodily functions such as blood pressure and body temperature, as well as controlling body weight and appetite.
THALAMUS: Located at the top of the brain stem, the thalamus acts as a two-way relay station, sorting, processing, and directing signals from the spinal cord and mid-brain structures up to the cerebrum, and, conversely, from the cerebrum down the spinal cord to the nervous system.
