3.Human Physiology
3.6 Neuronal Coordination
Neuronal coordination
Dr V Malathi
Human neuronal coordination involves the complex interaction between the nervous system and various parts of the body to maintain homeostasis and respond to external stimuli.
The neural system of all animals is composed of neurons . These neurons detect, receive and transmit different types of stimuli.
Components of the Nervous System
- Central Nervous System (CNS): Comprising the brain and spinal cord, the CNS processes information and coordinates activities.
- Peripheral Nervous System (PNS): Consists of nerves that connect the CNS to the rest of the body. It includes:
- Somatic Nervous System: Controls voluntary movements.
- Autonomic Nervous System: Regulates involuntary functions and is further divided into:
- Sympathetic Nervous System: Prepares the body for ‘fight or flight’ responses. The sympathetic nervous system prepares the body in response to stress by activating the organs and glands in the endocrine system.
- Parasympathetic Nervous System : This functions opposite to the sympathetic system and allows the body to recover , for example clams the body by slowing the heart and breathing.
“Overview of Nervous System” by OpenStax via Wikimedia Commons is licensed under CC BY 4.0
Video Link for further Understanding
Neuronal Communication
- Neurons: The basic units of the nervous system. The nervous system comprises about 100 billions of neurons. The function of neurons is to receive and transmit signals .Neurons transmit signals through electrochemical impulses.
- The structure of neurons include three majorts namely
- a cell body or soma : contains nucleus of the cell and keeps the cell alive.
- Dendrite : This has a branching tree like structure . It collects information from other cells and sends it to soma. Some neurons have hundreds or even thousands of dendrite
- axon: This is a long, segmented fibre . This tranmits information away from soma to other neurons or to muscles and glands.
- Myelin sheath : is a layer of fatty tissue surrounding the axon of a neuron that both acts as an insulator and allows faster transmission of the electrical signal.
- terminal button : Axons branch out toward their ends, and at the tip of each branch is a terminal button.
- Synapses : These are junctions where neurons communicate with other neurons, muscles or glands through neurotransmitters.A synaptic connection between a neuron and a muscle cell is called a neuromuscular junction. Also called: neuronal junction. Synapses can be chemical i.e. these synapses communicate using chemical messengers.
- Or can be electrical; in these synapses, ions flow directly between cells.
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At a chemical synapse, an action potential triggers the presynaptic neuron to release neurotransmitters. These molecules bind to receptors on the postsynaptic cell and make it more or less likely to fire an action potential.
- Upon binding with its receptor on a receiving cell, a neurotransmitter ope