Nervous System Overview
What is the Nervous System?
The nervous system is a collection of nerves and specialized cells that transmits signals throughout the whole body. It is basically the body's electrical wiring and consists of the brain, spinal cord, sensory organs, and nerves.
Nervous System description
Nerves are cylindrical bundles of fibers that start at the brain and central cord and branch out to every other part of the body. Neurons send signals to other cells through thin fibers called axons, which cause chemicals known as neurotransmitters to be released at junctions called synapses. A synapse gives a command to the cell and the entire communication process typically takes only a fraction of a millisecond. Sensory neurons react to physical stimuli such as light, sound and touch and send feedback to the central nervous system about the body’s surrounding environment. Motor neurons, located in the central nervous system or in peripheral ganglia, transmit signals to activate the muscles or glands. Glial cells, derived from the Greek word for "glue," are specialized cells that support, protect or nourish nerve cells.
What makes up the Nervous System?
Structurally: The nervous system is made up of two parts: the central nervous system and the peripheral nervous system. The central nervous system is made up by the spinal cord and the the brain, the CNS also takes the role of decision making and evaluating information. The CNS is responsible for language, memory, emotions, and maintaining the body's homeostasis. Most importantly it is responsible for ensuring survival. While the peripheral nervous system is made up by the nerves and the sensory neurons, it sends information to the CNS about the internal/external environment. The peripheral system also sends signals to muscles, glands, and organs to regulate their functions.
Functionally: The nervous system is made up of two subdivisions, which make up the peripheral nervous system. The first subdivision includes, the somatic system. The somatic system includes all the voluntary efferent neurons and is responsible for stimulating the skeletal muscles. The second subdivision, the autonomic system, includes the involuntary efferent neurons. Controls subconscious effectors such as visceral muscle tissue, cardiac muscle tissue, and glandular tissue.
The nervous system also consists of: nerves, neurons, axons, synapses, and glial cells. Nerves send signals to other cells through thin cells known as axons. There are two types of
What makes up the Autonomic System?
The autonomic system is made up by two divisions: the sympathetic division and the parasympathetic division. The sympathetic division makes up the "fight or flight" response to stress, danger, excitement, exercise, emotions, and embarrassment. It affects the respiration rate, by increasing it and heart rate as well. It also releases adrenaline as well as other stress hormones and even decreases digestion to cope with situations. Then the parasympathetic division creates the "rest and digest" response, which takes place when the body is fully relaxed or even while eating. It works to undo the work of the sympathetic division, after a stressful situation, Unlike sympathetic, parasympathetic works to decrease the respiration and heart rate and increase digestion as well.
Nervous System and Diseases
Patients with nerve disorders experience functional difficulties, which result in conditions such as:
Patients with nerve disorders experience functional difficulties, which result in conditions such as:
- cause seizures
- Parkinson's disease, which is a progressive nerve disease that affects movement
- Multiple Sclerosis (MS), in which the protective lining of the nerves is attacked by the body’s immune system
- Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig's disease, is a motor neuron disease which weakens the muscles and progressively hampers physical function
- Huntington's disease, which is an inherited condition that cause the nerve cells in the brain to degenerate
- Alzheimer's disease, which covers a wide range of disorders that impacts mental functions, particularly memory.
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By: Denisse