Nervous System: Human Nervous System

Control and coordination of an organism are the results of the unity of various organs, organ systems, and chemicals produced in the organism. Proper coordination gives the best response. All living organisms are made up of different types of cells which help them to control and coordinate with their surroundings.

In an animal body, coordination is the effective outcome of two systems viz. the nervous system and the endocrine system. Neural system together with the endocrine system regulates the body homeostasis. Endocrine glands constitute the endocrine system which coordinates and control the body metabolism by their secretions called hormones. Let us learn about the human neural system and how it coordinates various functions in our body.

Nervous System

The nervous system or the neural is a complex network of nerve cells or neurons specialized to carry messages. The complexity of the nervous system increases as we move towards higher animals.

In simple organisms, especially in the invertebrates, neural system is just a network of neurons. While in the vertebrates like animals, the nervous system is much organized and developed which involves the brain.

In the human body, the neural system integrates the activities of organs based on the stimuli which the neurons detect and transmit. They transmit messages in the form of electrical impulses and convey messages to and from the sense organs. Thus, the nervous coordination involves the participation of the sense organs, nerves, spinal cord, and brain.

Human Nervous System

The central nervous system (CNS) together with the peripheral nervous system (PNS) together constitute the human neural system. CNS consists of the control and information processing units, the brain and the spinal cord. PNS consists of the nerves that connect peripheral parts to the brain and the spinal cord viz. the CNS.

Nervous System

PNS includes two types of nerve fibers. One which transmits messages from tissues and organs to the CNS is called afferent nerve fibers while the nerve fibers which convey messages from CNS to the corresponding peripheral organ are called efferent nerve fibers.

The peripheral neural system is classified into two- somatic nervous system and autonomic nervous system.

  • Somatic neural system: It is the neural system that controls the voluntary actions in the body by transmitting impulses from CNS to skeletal muscle cells. It consists of the somatic nerves.
  • Autonomic neural system: Theautonomic neural system is involved in the involuntary actions like regulation of physiological functions (digestion, respiration, salivation, etc.). It is a self-regulating system which conveys the impulses from the CNS to the smooth muscles and involuntary organs (heart, bladder, pupil, etc.). ANS is further divided into two- sympathetic and parasympathetic nervous system.

Nerves

Nerves are thread-like structures and these emerge from the brain and spinal cord responsible for carrying messages to all the parts of the body. There are three types of nerves.

  1. Sensory nerves send messages from all the senses to the brain.
  2. Motor nerves carry messages from the brain to all the muscles.
  3. Mixed nerves carry both sensory and motor nerves.

Cranial nerves begin from the brain as these nerves carry impulses to start from the central nervous system. Certain cranial nerves belong to the group of mixed nerves while certain ones fall under sensory nerves.

Spinal nerves originate from the spinal cord. All the spinal nerves carry impulses to and from the central nervous system and these are part of mixed nerves.

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Practise This Question

The central nervous system consists of the ____________.