Introduction About Nervous System :
The nervous system is a complex collection of nerves and specialized cells known as neurons that transmit signals between different parts of the body. It is essentially the body’s electrical wiring.To know more about Nervous System,watch Nervous System Video to learn more .
Nervous System :
The nervous system consists of the brain, spinal cord, sensory organs, and all of the nerves that connect these organs with the rest of the body. Together, these organs are responsible for the control of the body and communication among its parts. The brain and spinal cord form the control center known as the central nervous system (C.N.S), where information is evaluated and decisions made. The sensory nerves and sense organs of the peripheral nervous system (P.N.S) monitor. conditions inside and outside of the body and send this information to the C.N.S. Efferent nerves in the P.N.S carry signals from the control center to the muscles, glands, and organs to regulate their functions.
The majority of the nervous system is tissue made up of two classes of cells: neurons and neuroglia.
- Neurons. Neurons, also known as nerve cells, communicate within the body by transmitting electrochemical signals. Neurons look quite different from other cells in the body due to the many long cellular processes that extend from their central cell body. The cell body is the roughly round part of a neuron that contains the nucleus, mitochondria, and most of the cellular organelles. Small tree-like structures called dendrites extend from the cell body to pick up stimuli from the environment, other neurons, or sensory receptor cells. Long transmitting processes called axons extend from the cell body to send signals onward to other neurons or effector cells in the body.
There are 3 basic classes of neurons: afferent neurons, efferent neurons, and interneurons.
- Afferent neurons. Also known as sensory neurons, afferent neurons transmit sensory signals to the central nervous system from receptors in the body.
- Efferent neurons. Also known as motor neurons, efferent neurons transmit signals from the central nervous system to effectors in the body such as muscles and glands.
- Interneurons. Interneurons form complex networks within the central nervous system to integrate the information received from afferent neurons and to direct the function of the body through efferent neurons.
The Brain :
The brain, a soft, wrinkled organ that weighs about 3 pounds, is located inside the cranial cavity, where the bones of the skull surround and protect it. The approximately 100 billion neurons of the brain form the main control center of the body. The brain and spinal cord together form the central nervous system (C.N.S), where information is processed and responses originate. The brain, the seat of higher mental functions such as consciousness, memory, planning, and voluntary actions, also controls lower body functions such as the maintenance of respiration, heart rate, blood pressure, and digestion.
The spinal cord is a long, thin mass of bundled neurons that carries information through the vertebral cavity of the spine beginning at the medulla oblongata of the brain on its superior end and continuing inferiorly to the lumbar region of the spine. In the lumbar region, the spinal cord separates into a bundle of individual nerves called thecauda equina (due to its resemblance to a horse’s tail) that continues inferiorly to thesacrum and coccyx. The white matter of the spinal cord functions as the main conduit of nerve signals to the body from the brain. The grey matter of the spinal cord integrates reflexes to stimuli.
Nerves are bundles of axons in the peripheral nervous system (P.N.S) that act as information highways to carry signals between the brain and spinal cord and the rest of the body. Each axon is wrapped in a connective tissue sheath called the endoneurium. Individual axons of the nerve are bundled into groups of axons called fascicles, wrapped in a sheath of connective tissue called the perineurium. Finally, many fascicles are wrapped together in another layer of connective tissue called the epineurium to form a whole nerve. The wrapping of nerves with connective tissue helps to protect the axons and to increase the speed of their communication within the body.
Useful for CBSE, ICSE, NCERT & International Students
Grade : 5
Subject : Evs
Lesson : Organ Systems
Topic: Nervous System Video
Visit www.oztern.com to find personalized test preparation solutions for Pre Medical – AIPMT, AIIMS, JIPMER, State, Pre Engineering – IIT JEE, JEE MAIN, BITSAT, State and Foundations – Class 6 to 10.