The nervous system is a complex network of cells and nerves which carry messages to and from the spinal cord and brain to various parts of the body.
Here Are The Top Fun & Interesting Facts About The Nervous System:
#1 The nervous system has two main parts:
- the central nervous system – it is made up of the spinal cord and brain;
- the peripheral nervous system – it is made up of nerves that branch off from the spinal cord and extend to all parts of the body.
#2 These two components cooperate at all times to ensure our lively functions.
The Central Nervous System
#3 The central nervous system consists of the spinal cord and brain. The olfactory epithelium, olfactory nerves, optic nerve, and retina, are occasionally considered to be part of the central nervous system alongside the spinal cord and brain.
#4 The central nervous system is referred to as “central” since it combines information from the entire body and coordinates activity across the entire organism.
#5 Your brain generates approximately 12-25 watts of electricity.
#6 The human brain contains about 100 billion neurons and these neurons have 100 trillion connections, forming functional and definable circuits.
#7 A piece of brain tissue the size of a grain of sand contains around 1 billion synapses and 100,000 neurons, all communicating with each other.
#8 Like all vertebrate brains, the human brain develops from 3 sections known as the hindbrain, midbrain, and forebrain.
#10 The brain makes up about 3% of a human’s body weight. Your brain might account for only about 3% of your body weight, however, it receives around 30% of the blood being pumped by your heart.
#11 Your brain uses about 20% of the oxygen and blood in your body.
#12 The average female brain has a volume of 1,131 cm3.
#13 The average male has a brain volume of 1,274 cm3.
#14 A 2-year-old’s brain is 80 percent of adult size.
#15 The brain can’t feel pain, but it interprets pain signals sent to it.
#16 The brain weighs approximately 3.3 lbs. (1.5 kilograms).
#17 About 75% of the brain is made up of water. This actually means that dehydration (even in small amounts) can have a significant negative effect on the brain functions.
#18 The human brain is the largest brain of all vertebrates relative to body size.
#19 The spinal cord is a long bundle of nerve cells and fibers which runs through the bony center of the vertebral column.
#20 The spinal cord is the primary source of communication between the brain and the body.
#21 Every year, between 250,000 and 500,000 individuals suffer a spinal cord injury worldwide.
#22 When the spinal cord is severed at any point due to injury, a number of resulting forms of paralysis can occur:
- incomplete – when you still have some motor or sensory function below the injury;
- complete – when almost all sensory feeling and ability to control movement are lost below the spinal cord injury.
#23 The National Spinal Cord Injury Statistical Center estimates that between 247,000 to 358,000 individuals are living with spinal cord injuries in the US.
#24 The main causes of spinal cord injury are – violence (including attempted suicide), falls, and road traffic crashes.
The Peripheral Nervous System
#25 The peripheral nervous system is the division of the nervous system containing all the nerves which lie outside of the CNS.
#26 The PNS includes the spinal nerves, cranial nerves, and their roots and branches, neuromuscular junctions, and peripheral nerves.
#27 Unlike the CNS, the peripheral nervous system is not protected by the blood-brain barrier or bone, leaving it exposed to mechanical injuries and toxins.
#28 The PNS is itself classified into two systems:
- the somatic nervous system;
- the autonomic nervous system.
The Somatic Nervous System
#29 The somatic nervous system (SoNS), also known as the voluntary nervous system, is a system that is responsible for processing sensory information which arrives via external stimuli including sight, touch, and hearing, as well as for nearly all voluntary muscle movements.
#30 SoNS is made up of nerves which connect to the sensory organs, skin, and all skeletal muscles.
#31 SoNS contains two major types of neurons:
- motor neurons – they are responsible for carrying information from the brain and spinal cord to muscle fibers throughout the body;
- sensory neurons – they are responsible for carrying information from the nerves to the central nervous system.
The Autonomic Nervous System
#32 It serves as the relay between the central nervous system and the internal organs.
#33 It controls internal body processes such as the following:
- sexual response;
- blood pressure;
- heart and breathing rates;
- body temperature;
- the production of body fluids (sweat, saliva, and tears);
- the balance of water and electrolytes (such as calcium and sodium);
- metabolism (therefore affecting body weight);
#34 The autonomic nervous system controls the internal organs largely without conscious control.
#35 The autonomic nervous system is divided into 3 branches:
- the enteric nervous system;
- the parasympathetic system;
- the sympathetic system.
#36 The enteric nervous system is confined to the gastrointestinal tract. It is capable of acting independently of the parasympathetic and sympathetic nervous systems. The enteric nervous system function can be damaged by ischemia.
#37 The parasympathetic division of the autonomic nervous system performs tasks such as constricting eye pupils, slowing down heart rate, and controlling the bladder. This division also conserves physical resources and helps maintain normal body functions.
#38 The sympathetic division of the autonomic nervous system performs tasks such as dilating eye pupils, speeding up heart rate, and relaxing the bladder. This division also regulates the flight-or-fight responses.
#39 The nervous system also includes non-neuron cells, called glia. The word “glia” literally means “neural glue.” According to research, neurons and their synapses fail to function properly without glial cells.
#40 Glia perform a variety of functions which keep the nervous system working correctly. For instance, glia:
- regulate neurotransmitters;
- trim out dead neurons;
- help support and hold neurons in place;
- help restore neuron function;
- repair neurons;
- create insulation called myelin, that helps move nerve impulses;
- protect neurons.
#41 There are several types of glial cells, including:
- radial glia;
- ependymal cells;
- satellite cells;
- Schwann cells;