The nervous system consists of the brain, spinal cord, and a complex network of neurons. This system is responsible for sending, receiving, and interpreting information from all parts of the body. The nervous system monitors and coordinates internal organ function and responds to changes in the external environment. This system can be divided into two parts: the central nervous system and the peripheral nervous system.
Let's take a look at the central nervous system.
The Central Nervous System (CNS) is the processing center for the nervous system. It receives information from and sends information to the Peripheral Nervous system. The two main organs of the CNS are the brain and spinal cord. The brain processes and interprets sensory information sent from the spinal cord. Both the brain and spinal cord are protected by three layers of connective tissue called the meninges.
Brain: The brain is the control center of the body. It consists of three main components: the forebrain, the brainstem, and the hindbrain. The forebrain is responsible for a variety of functions including receiving and processing sensory information, thinking, perceiving, producing and understanding language, and controlling motor function. The forebrain contains structures such as the thalamus and hypothalamus which are responsible for such functions as motor control, relaying sensory information, and controlling autonomic functions. It also contains the largest part of the brain, the cerebrum. Most of the actual information processing in the brain takes place in the cerebral cortex.
Spinal Cord: The spinal cord is a cylindrical shaped bundle of nerve fibers that is connected to the brain. The spinal cord runs down the center of the protective spinal column extending from the neck to the lower back. Spinal cord nerves transmit information from body organs and external stimuli to the brain and send information from the brain to other areas of the body. The nerves of the spinal cord are grouped into bundles of nerve fibers that travel in two pathways. Ascending and descending.
Let's take a look at the central nervous system.
The Central Nervous System (CNS) is the processing center for the nervous system. It receives information from and sends information to the Peripheral Nervous system. The two main organs of the CNS are the brain and spinal cord. The brain processes and interprets sensory information sent from the spinal cord. Both the brain and spinal cord are protected by three layers of connective tissue called the meninges.
Brain: The brain is the control center of the body. It consists of three main components: the forebrain, the brainstem, and the hindbrain. The forebrain is responsible for a variety of functions including receiving and processing sensory information, thinking, perceiving, producing and understanding language, and controlling motor function. The forebrain contains structures such as the thalamus and hypothalamus which are responsible for such functions as motor control, relaying sensory information, and controlling autonomic functions. It also contains the largest part of the brain, the cerebrum. Most of the actual information processing in the brain takes place in the cerebral cortex.
Spinal Cord: The spinal cord is a cylindrical shaped bundle of nerve fibers that is connected to the brain. The spinal cord runs down the center of the protective spinal column extending from the neck to the lower back. Spinal cord nerves transmit information from body organs and external stimuli to the brain and send information from the brain to other areas of the body. The nerves of the spinal cord are grouped into bundles of nerve fibers that travel in two pathways. Ascending and descending.
Peripheral Nervous System
There are two types of cells in the peripheral nervous system. These cells carry information to (sensory nervous cells) and from (motor nervous cells) the central nervous system . Cells of the sensory nervous system send information to the central nervous system from internal organs or from external stimuli. Think of the peripheral nervous system as a highway system. Sensory neurons pick up signals and it loops the system with a signal for the motor neurons to execute.
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The Somatic Nervous System
The somatic nervous system controls skeletal muscles as well as outside sensory organs such as the skin. This system is said to be voluntary because the responses can be controlled consciously. Reflex reactions of skeletal muscle however are an exception. These are involuntary reactions to external stimuli.
The Autonomic Nervous System
The autonomic nervous system controls involuntary muscles, such as smooth and cardiac muscles. This system is also called the involuntary nervous system.
The autonomic nervous system can further be divided into the parasympathetic and sympathetic divisions.
The parasympathetic division controls various functions which include inhibiting heart rate, constricting pupils, and contracting the bladder. The nerves of the sympathetic division often have an opposite effect when they are located within the same organs as parasympathetic nerves. Nerves of the sympathetic division speed up heart rate, dilate pupils, and relax the bladder. The sympathetic system is also involved in the flight or fight response. This is a response to potential danger that results in accelerated heart rate and an increase in metabolic rate.
The autonomic nervous system can further be divided into the parasympathetic and sympathetic divisions.
The parasympathetic division controls various functions which include inhibiting heart rate, constricting pupils, and contracting the bladder. The nerves of the sympathetic division often have an opposite effect when they are located within the same organs as parasympathetic nerves. Nerves of the sympathetic division speed up heart rate, dilate pupils, and relax the bladder. The sympathetic system is also involved in the flight or fight response. This is a response to potential danger that results in accelerated heart rate and an increase in metabolic rate.