Although terminology seems to indicate otherwise, there is really only one nervous system in the body. Although each subdivision of the system is also called a "nervous system," all of these smaller systems belong to the single, highly integrated nervous system. Each subdivision has structural and functional characteristics that distinguish it from the others. The nervous system as a whole is divided into two subdivisions: the central nervous system (CNS) and the peripheral nervous system (PNS).
The Central Nervous System
The brain and spinal cord are the organs of the central nervous system. Because they are so vitally important, the brain and spinal cord, located in the dorsal body cavity, are encased in bone for protection. The brain is in the cranial vault, and the spinal cord is in the vertebral canal of the vertebral column. Although considered to be two separate organs, the brain and spinal cord are continuous at the foramen magnum.
The Peripheral Nervous System
The organs of the peripheral nervous system are the nerves and ganglia. Nerves are bundles of nerve fibers, much like muscles are bundles of muscle fibers. Cranial nerves and spinal nerves extend from the CNS to peripheral organs such as muscles and glands. Ganglia are collections, or small knots, of nerve cell bodies outside the CNS.
The peripheral nervous system is further subdivided into an afferent (sensory) division and an efferent (motor) division. The afferent or sensory division transmits impulses from peripheral organs to the CNS. The efferent or motor division transmits impulses from the CNS out to the peripheral organs to cause an effect or action.
Finally, the efferent or motor division is again subdivided into the somatic nervous system and the autonomic nervous system. The somatic nervous system, also called the somatomotor or somatic efferent nervous system, supplies motor impulses to the skeletal muscles. Because these nerves permit conscious control of the skeletal muscles, it is sometimes called the voluntary nervous system. The autonomic nervous system, also called the visceral efferent nervous system, supplies motor impulses to cardiac muscle, to smooth muscle, and to glandular epithelium. It is further subdivided into sympathetic and parasympathetic divisions. Because the autonomic nervous system regulates involuntary or automatic functions, it is called the involuntary nervous system.
FAQs
The central nervous system is made up of the brain and spinal cord. The peripheral nervous system is made up of nerves that branch off from the spinal cord and extend to all parts of the body.
What is the organizational hierarchy of the nervous system? ›
The central nervous system branches into the peripheral nervous system. The peripheral nervous system then branches into two divisions, the sensory division and the motor division. Of the two divisions of the peripheral nervous system, only the motor division branches out.
What is the organization and structure of a nerve? ›
Structure of a Nerve
Nerves are the organs that make up the peripheral nervous system. It consists of a cord-like structure with multiple nerve fibres (also called axons) wrapped in layers of tissue and fat. This axon has layers of connective tissue around it. This connective tissue is called the endoneurium.
What is the organization and cells of the nervous system? ›
At the cellular level, the nervous system is composed of neurons and glial cells (Figure 1–3). Neurons (also called nerve cells or neuronal cells) are the main signaling cells that communicate with other neurons, muscles, or glands.
What is the organization of the nervous system according to morphology? ›
Anatomically, the nervous system is divided into the central nervous system (brain and spinal cord) and the peripherial nervous system (cranial, spinal, and peripherial nerves, ganglia and specialized nerve endings).
How is the nervous system organized? ›
The nervous system has two main parts: The central nervous system is made up of the brain and spinal cord. The peripheral nervous system is made up of nerves that branch off from the spinal cord and extend to all parts of the body.
What is the organization of the nervous system classification? ›
Thus, the nervous system can first be divided into two major parts: the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of neurons associated with central processing and which are located in the brain and spinal cord.
What is the structure and role of the nervous system? ›
The nervous system is divided into the central nervous system (CNS) and the peripheral nervous system. The CNS includes the brain and spinal cord, while the peripheral nervous system consists of everything else. The CNS's responsibilities include receiving, processing, and responding to sensory information (see Image.
What are the structural organization and functional divisions of the nervous system? ›
The nervous system consists of two divisions; Central nervous system (CNS) is the integration and command center of the body. Peripheral nervous system (PNS) represents the conduit between the CNS and the body. It is further subdivided into the somatic nervous system (SNS) and the autonomic nervous system (ANS).
What is the nervous system made up of? ›
The nervous system is made up of the central nervous system and the peripheral nervous system: The central nervous system includes the brain and spinal cord. The peripheral nervous system includes the nerves that run throughout the whole body.
The term that best describes the organization of the nervous system is "hierarchical."Explanation:The nervous system is a complex system that consists of the brain, spinal cord, and a network of nerves that spread throughout the body.
What is the biological organization of nervous system? ›
The nervous system consists of two major divisions: The central nervous system (CNS) consists of the brain and the spinal cord, which are enclosed in the skull and vertebral column, respectively. The peripheral nervous system (PNS) consists of all the neural tissue outside of the brain and spinal cord.
What is the basic Organisation of the central nervous system? ›
The CNS consists of the brain and spinal cord. The brain is the most complex organ in the body and uses 20% of the total oxygen we breathe. The brain consists of an estimated 100 billion neurons connected to thousands more. The brain can be divided into four main lobes: temporal, parietal, occipital, and frontal.
What is the organizational level of the nervous system? ›
The primary organization of the nervous system is into the central and peripheral nervous systems. The central nervous system (CNS) consists of the brain and spinal cord. The brain is located in the skull and it the central control point of the nervous system.
How the structures of the nervous system are organized in a hierarchy? ›
Answer: Functionally, the nervous system is organised hierarchically; this is analogous to a business corporation with workers and managers. The hierarchy consists of effectors (sensory and motor) and different levels of information processing and integration in the spinal cord, brainstem and forebrain.
How is the nervous system organized and why does this matter physiologically? ›
The nervous system can be broken down into the central nervous system (CNS), made up of the brain and spinal cord, and the peripheral nervous system (PNS), made up of all the nerves outside of the brain and spinal cord. Together, these systems sense stimuli, make sense of these stimuli, and coordinate a response.
What level of organization is the nervous system? ›
On the highest level of organization the nervous system is split into two parts, central and peripheral. The central nervous system, or CNS, includes your brain and your spinal cord.
What is the boss of the nervous system? ›
Think of the brain as a central computer that controls all the body's functions. The rest of the nervous system is like a network that relays messages back and forth from the brain to different parts of the body. It does this via the spinal cord, which runs from the brain down through the back.
What is the neural hierarchy? ›
This level of the hierarchy is concerned with organized groups of neurons—“areas” of the cerebral cortex and “nuclei” of subcortical regions. Groups of nuclei and areas make up the major systems of the brain, and vast networks of connections link these components.
What is hierarchical organization in the brain? ›
Hierarchical cortical organization is found in all sensory systems, in the reward system, and in the memory systems. Adjacent cortical areas in the hierarchy are connected by strong forward connections, and weaker backprojections which have synapses in cortical layer 1.
