• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11
  12. 12
  13. 13
  14. 14


Extracts from this document...


The Nervous System AN UNDERSTANDING OF THE NERVOUS SYSTEM A Description of the Nervous System Student ID 80001023 Southern Cross International College Path Education Group (Malaysia) The Nervous System 2 An Understanding of the Nervous System The nervous system can be divided into several connected systems that function together. It monitors and controls almost every organ system through a series of positive and negative feedback loops. The nervous system is divided into the Central Nervous System (CNS) includes the brain and spinal cord and the Peripheral Nervous System (PNS) that connects the CNS to other parts of the body, and is composed of nerves (bundles of neurons). At the centre of the nervous system is the brain. The brain sends and receives messages through a network of nerves. The central nervous system is divided into two parts: the brain and the spinal cord. The average adult human brain weighs 1.3 to 1.4 kg (approximately 3 pounds). The brain contains about 100 billion nerve cells (neurons) and trillons of "support cells" called glia. The spinal cord is about 43 cm long in adult women and 45 cm long in adult men and weighs about 35-40 grams. The vertebral column, the collection of bones (back bone) that houses the spinal cord, is about 70 cm long. Therefore, the spinal cord is much shorter than the vertebral column. The peripheral nervous system is divided into two major parts: the somatic nervous system and the autonomic nervous system. The somatic nervous system consists of peripheral nerve fibers that send sensory information to the central nervous system and motor nerve fibers that project to skeletal muscle. The autonomic nervous system is divided into three parts: the sympathetic nervous system, the parasympathetic nervous system and the enteric nervous system. The autonomic nervous system controls smooth muscle of the viscera (internal organs) and glands. The nerve system interacts with other body systems. ...read more.


The others are termed the protoplasmic processes or dendrons; they begin to divide and subdivide soon after they emerge from the cell, and finally end in minute twigs and become lost among the other elements of the nervous tissue. To understanding the nerve message, there is the plasma membrane of neurons, like all other cells, has an unequal distribution of ions and electrical charges between the two sides of the membrane. The outside of the membrane has a positive charge, inside has a negative charge. The charge difference is a resting potential and is measured in millivolts. Passage of ions across the cell membrane passes the electrical charge along the cell. The voltage potential is -65mV (millivolts) of a cell at rest (resting potential). Resting potential results from differences between sodium and potassium positively charged ions and negatively charged ions in the cytoplasm. Sodium ions are more concentrated outside the membrane, while potassium ions are more concentrated inside the membrane. This imbalance is maintained by the active transport of ions to reset the membrane known as the sodium potassium pump. The sodium-potassium pump maintains this unequal concentration by actively transporting ions against their concentration gradients. Action potential is a reversal of the electrical potential in the plasma membrane of a neuron that occurs when a nerve cell is stimulated; caused by rapid changes in membrane permeability to sodium and potassium. Changed polarity of the membrane is the action potential, results in propagation of the nerve impulse along the membrane. An action potential is a temporary reversal of the electrical potential along the membrane for a few milliseconds. Sodium gates and The Nervous System 8 potassium gates open in the membrane to allow their respective ions to cross. Sodium and potassium ions reverse positions by passing through membrane protein channel gates that can be opened or closed to control ion passage. Sodium crosses first. At the height of the membrane potential reversal, potassium channels open to allow potassium ions to pass to the outside of the membrane. ...read more.


Also, a left-brain stroke might cause problems with speech while a right-brain stroke is more likely to cause abnormal/inappropriate emotional responses. Nerves carry messages back and forth between the brain and other parts of the body. All of our nerves together make up the nervous system. Some nerves tell the brain what is happening in the body. For example, when we step on a tack, the nerve in our foot tells the brain about the pain. Other nerves tell the body what to do. For example, nerves from the brain tell our stomach when it is time to move food into your intestines. Every minute of every day, our nervous system is sending and receiving countless messages about what happens both inside and around our body. Right now, our nervous system is receiving sensory input from our eyes about the words on the screen, from our ears about the sound of the computer, from our skin about the feel of our clothes, etc. At the same time, our brain is receiving information from sensors that monitor our heart rate, blood pressure, levels of oxygen and the contents of our stomach and intestines. Our brain then interprets all of these The Nervous System 13 signals, which allows for an understanding of the words on the screen, the recognition of the noise as computer noise, and the development of motor responses such as moving our eyeballs, changing positions in our chair, and decreasing or increasing our heart rate and digestion. In short, our nervous system coordinates all the activities of our body. In general, the nervous system as a whole is a system capable of so many sophisticated and complicated functions that can be extremely complex. This essay cannot possibly present all the information about the nervous system and it will probably take a few trips through the nervous system before the pieces fall into place. To sum it up, the nervous system is in charge of directing and overlooking all bodily functions - keeping us alive and healthy, fighting off diseases and infections, and healing us after we have sustained injury. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level ICT in Business section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level ICT in Business essays

  1. Explain the functions of the central nervous system (CNS), peripheral nervous system (PNS) (including ...

    Nerve cells called neurones connect to make pathways. Each cell body comprises of a nucleus, dendrites that carry messages to the cell body, axons that carry messages to other neurones, axon terminals, and a myelin coating which provides insulation and speeds up the rate of conduction of Electro-chemical impulses.

  2. The purpose of this document is to define the Context of Cain Motors Information ...

    Supporting Documentation: Signature: Date: _______________________ ___/___/____ PLEASE FORWARD TO THE CHANGE MANAGER FOR CHANGE APPROVAL GROUP SUBMISSION Change Request Form Change No: 6 Business Area: Change Requestor: Mr Cain Project Name: Cain Motors Change Request Date: 22/02/03 Project Manager: Mr Shirley Change Urgency: Low Change Manager: Miss J Hanson Change

  1. The history behind the Boots.

    It is for this reason that the matrix structure is extremely beneficial as communication and interaction is strong between the levels so ideas can quickly be picked up on along with problems. This benefits the performance of the business and issues are quickly picked up on.

  2. How the Nervous system the endocrine system and the brain interact in the body.

    There are also hormone producing structures that include; adipose tissue which is connective tissue that mostly consists of fat cells, the wall of the small intestine, the stomach, the kidneys, and the heart. Hormones are chemicals secreted into cellular fluid and then they are absorbed into the bloodstream.

  1. Describe the functions and structural design of the cerebrum.

    The occipital lobe of the cerebrum is associated with visual processing, and contains the visual cortex, which aids in the recognition of objects. It is involved in visual perception, visual memory, and associations, and plays a role in eye movements.

  2. The Use of Geographical Information Systems (GIS) And International Technology Transfer by Non-Governmental ...

    A UN Economic Security Council to provide a decision-making forum at the highest level for global issues of human security. With the 20:20 compact for human developed aid donors are expected to lift their aid allocation for human priority goals to 20 percent of their aid budgets.

  1. The Entourage System: A Feasibility Study

    In order to get the most out of the interfaces, there are certain guidelines we will follow in the design. * Pages should allow excellent picture quality to be displayed whilst paying attention to maintain fast response rates in uploading and downloading.

  2. Report for StGeorges School computer system

    in the school as well would it be more efficient and save money if only one was given to one family? As the school has many young pupils they may loose them or leave them on the bus or even drop them on the playground.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work