hThe brain has three main parts, the cerebrum, the cerebellum, and the brain stem. The brain is divided into regions that control specific functions.
THE CEREBRUM:
Frontal Lobe
- Behavior
- Abstract thought processes
- Problem solving
- Attention
- Creative thought
- Some emotion
- Intellect
- Reflection
- Judgment
- Initiative
- Inhibition
- Coordination of movements
- Generalized and mass movements
- Some eye movements
- Sense of smell
- Muscle movements
- Skilled movements
- Some motor skills
- Physical reaction
- Libido (s*xual urges)
Occipital Lobe
- Vision
- Reading
Parietal Lobe
- Sense of touch (tactile senstation)
- Appreciation of form through touch (stereognosis)
- Response to internal stimuli (proprioception)
- Sensory combination and comprehension
- Some language and reading functions
- Some visual functions
Temporal Lobe
- Auditory memories
- Some hearing
- Visual memories
- Some vision pathways
- Other memory
- Music
- Fear
- Some language
- Some speech
- Some behavior amd emotions
- Sense of identity
Right Hemisphere (the representational hemisphere)
- The right hemisphere controls the left side of the body
- Temporal and spatial relationships
- Analyzing nonverbal information
- Communicating emotion
Left Hemisphere (the categorical hemisphere)
- The left hemisphere controls the right side of the body
- Produce and understand language
Corpus Callosum
- Communication between the left and right side of the brain
THE CEREBELLUM
- Balance
- Posture
- Cardiac, respiratory, and vasomotor centers
THE BRAIN STEM
- Motor and sensory pathway to body and face
- Vital centers: cardiac, respiratory, vasomotor
Hypothalamus
- Moods and motivation
- Sexual maturation
- Temperature regulation
- Hormonal body processes
Optic Chiasm
- Vision and the optic nerve
Pituitary Gland
- Hormonal body processes
- Physical maturation
- Growth (height and form)
- Sexual maturation
- Sexual functioning
Spinal Cord
- Conduit and source of sensation and movement
Pineal Body
- Unknown
Ventricles and Cerebral Aqueduct
- Contains the cerebrospinal fluid that bathes the brain and spinal cord
THE FUNCTIONS OF THE BRAIN
The human brain is a complex organ that allows us to think, move, feel, see, hear, taste, and smell. It controls our body, receives information, analyzes information, and stores information (our memories).
The brain produces electrical signals, which, together with chemical reactions, let the parts of the body communicate. Nerves send these signals throughout the body.
SIZE OF THE HUMAN BRAIN
The average human brain weighs about 3 pounds (1300-1400 g).
At birth, the human brain weighs less than a pound (0.78-0.88 pounds or 350-400 g). As a child grows, the number of cell remains relatively stable, but the cells grow in size and the number of connections increases. The human brain reaches its full size at about 6 years of age.
COMPOSITION OF THE BRAIN
The brain consists of gray matter (40%) and white matter (60%) contained within the skull. Brain cells include neurons and glial cells.
The brain has three main parts: the cerebrum, the cerebellum, and the brain stem (medulla).
NOURISHMENT OF THE BRAIN
Although the brain is only 2% of the body's weight, it uses 20% of the oxygen supply and gets 20% of the blood flow. Blood vessels (arteries, capillaries, and veins) supply the brain with oxygen and nourishment, and take away wastes. If brain cells do not get oxygen for 3 to 5 minutes, they begin to die.
Cerebrospinal fluid (CSF) surrounds the brain.
THE NERVOUS SYSTEM
The brain and spinal cord make up the central nervous system (CNS). The brain is connected to the spinal cord, which runs from the neck to the hip area. The spinal cord carries nerve messages between the brain and the body.
The nerves that connect the CNS to the rest of the body are called the peripheral nervous system.
The autonomic nervous system controls our life support systems that we don't consciously control, like breathing, digesting food, blood circulation, etc.
PROTECTION
The cells of the nervous system are quite fragile and need extensive protection from being crushed, being infected by disease organisms, and other harm. The brain and spinal cord are covered by a tough, translucent membrane, called the dura matter. Cerebrospinal fluid (CSF) is a clear, watery liquid that surrounds the brain and spinal cord, and is also found throughout the ventricle (brain cavities and tunnels). CSF cushions the brain and spinal cord from jolts.
The cranium (the top of the skull) surrounds and protects the brain. The spinal cord is surrounded by vertebrae (hollow spinal bones). Also, some muscles serve to pad and support the spine.
More subtly, the blood-brain barrier protects the brain from chemical intrusion from the rest of the body. Blood flowing into the brain is filtered so that many harmful chemicals cannot enter the brain.
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