Nerves

A:

The average size of an adult human brain weighs 3 pounds and is about 6 inches long. At birth, the human brain weighs only ¾ pound.

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  • How does a nerve impulse travel along a neuron?

    Q: How does a nerve impulse travel along a neuron?

    A: The dendrites, or "tentacles," of a neuron pick up an electrical nerve impulse and conduct it toward the soma, or cell body. The nerve impulse travels through the soma and is then conducted down a threadlike fiber called the axon. At the end of the axon, the impulse travels over a gap called a synapse to reach the dendrites of the next cell.
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  • What age does the human brain stop growing?

    Q: What age does the human brain stop growing?

    A: The human brain continues developing until a person is around 25, according to the NPR website. An 18-year-old person is only halfway through the process of brain development and change that begins with puberty.
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  • What disability does Stephen Hawking have?

    Q: What disability does Stephen Hawking have?

    A: Stephen Hawking was diagnosed with amyotrophic lateral sclerosis, or Lou Gehrig's Disease, in 1963. Doctors told Hawking that he would live only two more years as a result of this motor neuron disease, but he is still alive as of August 2014.
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  • What is the average size of a human brain?

    Q: What is the average size of a human brain?

    A: The average size of an adult human brain weighs 3 pounds and is about 6 inches long. At birth, the human brain weighs only ¾ pound.
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  • What is a nerve doctor called?

    Q: What is a nerve doctor called?

    A: A nerve doctor is called a neurologist. A neurologist who specializes in surgical care of nerve-related injuries is called a neurosurgeon. Neurology is a branch of medicine that studies the nerves, brain, nervous system and spine, according to the Johns Hopkins Medicine Health Library.
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  • How does the nervous system work with other body systems?

    Q: How does the nervous system work with other body systems?

    A: According to the University of Washington, the nervous systems works with other body systems by sending commands to the other systems and receiving information back from them. Additionally, some of the body’s systems and structures, such as the vertebrae and skull, help to protect the central nervous system.
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  • Why do my legs fall asleep all the time?

    Q: Why do my legs fall asleep all the time?

    A: According to chronic pain specialist Dr. Blair Lamb, the sensation of legs or arms falling asleep is usually the result of nerve entrapment or neuropathy. While the condition is often no cause for concern, it can also indicate a stroke, multiple sclerosis, hyperventilation, anxiety, vitamin deficiencies or anemia. Ultimately, many different conditions can combine to cause paresthesia, or the feeling of “pins and needles” associated with a limb falling asleep.
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  • Why is a reflex arc important?

    Q: Why is a reflex arc important?

    A: The BBC describes a reflex arc as the nerve pathway through which neural impulses travel to cause a quick autonomic response known as a reflex. Reflexes are not something people think about, rather, they are impulsive reactions to stimuli.
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  • What is the function of the frontal sinus?

    Q: What is the function of the frontal sinus?

    A: As one of the four pairs of sinuses, the frontal sinuses serve the purpose of producing and draining mucus to the nose. They are located above the eyes on either side of the forehead area.
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  • What is the main job of the nervous system?

    Q: What is the main job of the nervous system?

    A: The main job of the nervous system is to send and receive messages throughout the body, explains the Monroe County Women’s Disability Network. It is responsible for controlling and coordinating body functions.
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  • How many nerves do we have in our bodies?

    Q: How many nerves do we have in our bodies?

    A: According to Neurogenetics at the University of Tennessee Health Science Center, the human body has 95 to 100 billion neurons or nerve cells. The brain alone has at least 85 billion of these cells, although estimates go as high as 1 trillion.
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  • What is the function of nerve cells?

    Q: What is the function of nerve cells?

    A: According to the BBC, the function of nerve cells is to transmit electrical messages and signals throughout the body. There are three types of nerve cells. Sensory neurons collect and transmit information about stimuli, such as sound, light and temperature. Motor neurons transmit electrical impulses from the brain to the rest of the body and are connected to sensory neurons by specialized cells called association neurons.
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  • What is interesting about Albert Einstein's brain?

    Q: What is interesting about Albert Einstein's brain?

    A: Albert Einstein's brain was cut into 240 pieces after his death in 1955, and scientists determined that the physicist's parietal lobe was 15 percent larger than normal, and that part of his brain was missing the Sylvian fissure. The parietal lobe deals with spatial, mathematical and three-dimensional abilities. A missing Sylvian fissure allows brain cells to communicate faster in the parietal lobe.
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  • How many pairs of cranial nerves are there?

    Q: How many pairs of cranial nerves are there?

    A: In higher vertebrates, such as reptiles, birds and mammals, there are 12 pairs of cranial nerves. Lower vertebrates, such as fish and amphibians, have 10 pairs of cranial nerves.
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  • What is the function of the abducens nerve?

    Q: What is the function of the abducens nerve?

    A: The abducens nerve is the sixth cranial nerve. Its main function is to control the lateral rectus muscle of both eyes. By innervating the lateral rectus muscle, the abducens nerve helps move the pupil of the eye, according to Healthline.
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  • What part of the brain controls heart rate?

    Q: What part of the brain controls heart rate?

    A: The brain stem controls heart rate and other automatic functions. It connects the brain to the spinal cord and is composed of the midbrain, the pons, the medulla oblongata and the cranial nerves.
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  • Which nerve innervates the deltoid muscle?

    Q: Which nerve innervates the deltoid muscle?

    A: The deltoid muscle is innervated by the axillary nerve. The deltoid is a triangular muscle located at the uppermost part of the arm and gives the shoulder its rounded contour. The axillary nerve extends from the brachial plexus, carrying nerve impulses to the deltoid muscle.
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  • What type of tissue carries messages throughout the body?

    Q: What type of tissue carries messages throughout the body?

    A: Nerve tissue transports messages throughout the body. It is composed of two types of nerve cells: neurons and glial cells. Neurons are the functional units of the nervous system, while the glial cells help the neurons function correctly.
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  • What happens when the brain is deprived of oxygen?

    Q: What happens when the brain is deprived of oxygen?

    A: The New York University Langone Medical Center explains that brain cells begin to die after about four minutes without oxygen. Brain damage caused from a lack of oxygen is called anoxic damage, while hypoxia describes a low-oxygen condition. In other words, someone suffering from a lack of oxygen is said to be hypoxic, but any damage sustained is anoxic damage.
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  • Q: What is the part of the neuron that normally receives stimuli?

    A: The part of the neuron that normally receives stimuli is the dendrite. The dendrites, which are numerous short-branched extensions, come together at the cell body. The purpose of the dendrites is to receive and combine the messages coming from other neurons.
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  • How does EMG testing evaluate nerve damage?

    Q: How does EMG testing evaluate nerve damage?

    A: Electromyography, or EMG, measures the electrical activity of the nerves that send signals within and between muscles, called motor neurons, and shows a decrease in electrical activity if nerves are damaged, according to Mayo Clinic. Nerves communicate throughout the body with electrochemical signals.
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