The nervous system is the decision and communication within your body. The central nervous system (CNS) is made of the brain and spinal cord and the peripheral nervous system (PNS) consists of nerves. Together they control every part of your daily life, from breathing and blinking help memorize facts for a test. The nerves coming from the brain to the face, ears, eyes, nose and spinal cord ... and spinal cord to the rest of your body. Sensory nerves environment information, sending information to the spinal cord, which in turn accelerates the message to the brain meet. Then, the brain makes sense of that message and triggers a response. Motor neurons deliver instructions from the brain to the rest of his body. The spinal cord, made of a bundle of nerves that go up and down the spine, it is similar to a highway, speeding messages to and from the brain every second.
The brain is composed of three main parts: the forebrain, midbrain and hindbrain. The forebrain is the brain, thalamus and hypothalamus (a part of the limbic system). The midbrain consists of the tectum and tegmentum. The hindbrain is the cerebellum, pons and medulla. Often, midbrain, pons and medulla oblongata are collectively referred to as the brain stem. Main Part of Human BrainCerebrum, Cerebellum, Limbic System, Brain Stem. Some Detail.
The Cerebrum
The brain or cortex is the largest part of the human brain associated with higher brain function, such as thinking and action. The cerebral cortex is divided into four sections, called "lobes": the frontal lobe, parietal lobe, occipital lobe, and temporal lobe. Here is a visual representation of the crust:
What do each of these lobes do..?
- Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solving
- Parietal Lobe- associated with movement, orientation, recognition, perception of stimuli
- Occipital Lobe- associated with visual processing
- Temporal Lobe- associated with perception and recognition of auditory stimuli, memory, and speech.
Note that the cortex is wrinkled. Essentially, this makes the brain efficient because it can increase the surface area of the brain and the number of neurons within it. We will discuss the relevance of the degree of cortical folding (or gyrencephalization) later.
A deep groove divides the brain into two halves, known as the left and right hemispheres. The two hemispheres are mostly symmetrical, however, it has proven to work each side slightly different than the other. Sometimes, the right hemisphere is associated with creativity and left hemispheres is associated with logical abilities. The corpus callosum is a bundle of axons that connects the two hemispheres.
Nerve cells form the gray surface of the brain, which is a little thicker than his thumb. below white nerve fibers carry signals between nerve cells and other parts of the brain and body.
The neo cortex occupies most of the brain. This is a structure of six layers of the cerebral cortex found only in mammals. It is believed that the neocortex is a recently developed structure, and is associated with the processing of "higher" information by the fully developed animals (such as humans, primates, dolphins, etc).
The Cerebellum
The cerebellum or "little brain," wing of the brain is similar in that it has two hemispheres and has a highly folded surface or crust. This structure is associated with the regulation and coordination of movements, posture and balance.
The cerebellum is supposed to be much larger than the brain, evolutionarily. What I mean by this? In other words, animals that assume scientists have developed prior to humans, for example, reptiles have developed cerebellum. However, the reptiles have no neocortex.
Limbic System
The limbic system, often referred to as the "emotional brain", is buried in the brain. Like the cerebellum, evolutionarily structure is quite old.
This system includes the thalamus, hypothalamus, amygdala, and hippocampus. Here is a visual representation of this system, from a middle of the human brain sagittal view:
Thalamus
Thalamus- a mass of gray deeply located in the forebrain uppermost part of the diencephalon matter. The structure has sensory and motor functions. Almost all sensory information enters this structure in which neurons send this information to the overlying cortex. The axons of each sensory system (except smell) synapses here as the last place relay before the information reaches the cerebral cortex.
Hypothalamus
Hypothalamus part of the brain, ventral thalamus. The structure is involved in functions including homeostasis, emotion, thirst, hunger, circadian rhythms, and control of the autonomic nervous system. It also controls the pituitary.
Amygdala
Amygdala- of the cerebrum, which is located in the temporal lobe; involved in memory, emotion and fear. The amygdala is great and just below the surface of the front, medial temporal lobe which causes the bulge on the surface called the Uncus. This is part of the limbic system.
Hippocampus
Hippocampal portion of the cerebral hemispheres in basal medial temporal lobe. This part of the brain is important for learning and memory. . . to convert short-term memory to the volatile memory, and remember spatial relationships in the world around us.
Brain Stem
Below the limbic system is the brain stem. This structure is responsible for the basic vital functions of life as breathing, heartbeat and blood pressure. Scientists say this is the "simplest" of human brains, because brains of integers, such as reptiles (which appear early in the evolutionary scale) animals look like our brain stem.
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