Interdependence: Nervous and Muscular Systems

   The nervous and muscular systems, two unique and crucial components of our complete body system, work together to help us function daily. The muscular system receives messages from the nervous system, giving it information about when to perform an action and how to perform the action. Without the nervous system, the muscular system would not be able to function in aiding our movement, because it would have nothing to guide it. Furthermore, without the muscular system, we wouldn't be able to  move even if we did have the nervous system. Also, the nervous system would be at a loss for what to do, as it wouldn't have anything to signal to move. Therefore, without either of these systems, we wouldn't be able to move properly.

    Your conscious mind relays a command to your central nervous system, which translates the command into electrical impulses. When the muscles are ready, a chemical, acetylene, is released from the nerve endings, stimulating the membranes of muscle fibers, thus causing them to contract.

    Some axons, where impulses are conducted from the cell body to other cells,  are covered in a myelin sheath formed from the plasma membranes of specialized glial cells known as Schwann cells. Schwann cells are another name for the basic nerve cell. 

     Lastly, some of you might be wondering what the terms involuntary and voluntary mean. They are two different types of muscles that are named voluntary and involuntary because of their actions and the way they perform the actions. You see, a voluntary muscle is controllable by us. Our nervous system can directly send chemical messages and signal our voluntary muscles what to do. On the other hand, involuntary muscles are not controllable; our nerves cannot tell involuntary muscles what to do. These muscles act more by reflex and instinct. This is why sometimes you may be caught off guard when your body jerks because of involuntary muscles. If you are still having trouble understanding some of the concepts explained in this article, comment below and I will try to help you. 

The Nervous System

    The Nervous system, as we all know, is basically the master controller of the body. It sends messages to every part of the body, telling the different areas what to do, and how to react. One major part of the Nervous system is the spinal cord. The spinal cord can move a lot of data very quickly. Its job is to carry messages to and from the body to the brain. There are 32 different nerves that connect directly into the spinal cord. Reflexes are processed straight into the spinal cord as well.
   
    Neurons send signals to the other cells as electro-chemical waves. These waves travel along thin fibers called axons which cause chemicals called neuro-transmitters to be released at junctions called synapses. Some axons are wrapped in a myelin sheath.

     Some more important parts of the Nervous system are the cerebrum, cerebellum, and brain stem. The cerebrum is the largest portion of the brain responsible for all the voluntary processes that occur every day. The cerebrum is broken into 2 parts: left & right. The left side of the cerebrum is responsible for problem solving and analytical thought, while the right side is responsible for creative thought. The cerebellum is there to aid the cerebrum in the task of moving muscles, and it also helps in maintaining balance in the body. The last part we are going to talk about is the brain stem. The brain stem sits at the base of the brain and connects it to the spinal cord, and it also controls flow into the brain and body.

   The Somatic Nervous system controls functions that are under conscious voluntary control such as skeletal muscles and sensory neurons of the skin. The Autonomic Nervous system, mostly motor nerves, controls functions of the involuntary smooth muscles, cardiac muscles, and glands. The Autonomic Nervous system provides almost every organ with a double set of nerves. The 3 types of neurons are arranged in circuits and networks, the simplest of which is the reflex arc. In a simple reflex arc, such as the knee jerk, a stimulus is detected by a receptor cell. A sensory neuron carries the impulse from the site of the stimulus to the central nervous system (the brain or spinal cord) where it synapses with an inter-neuron. The inter-neuron synapses with a motor neuron, which carries the nerve impulse to an effector, such as a muscle, which responds by contracting. 

The Muscular System

Muscular System Model

       Our Muscular Sysytem's most obvious role is to help us move. That's probably what most of you know without us telling you anything. However, did you know that there are a variety of very large muscles and very small muscles in our body? There is such a variety of these little and big muscles, that scientists believe that 40% of our  body is muscle. But even though muscles are really important and efficient, they don't do it all on their own. Tendons and ligaments help out a lot. At every joint, there are tendons and ligaments to help out. As muscles don't connect directly to bones, they wouldn't be that useful alone. When they would contract, the muscles wouldn't really move anything. That is why muscles are connected to tendons instead. Now when the muscles contract, the tendons pull back on the muscles and cause the reaction of movement. However, ligaments are pretty important too. Ligaments are what connect bones. They connect at the end of the muscles, to prevent the bones from slipping and sliding, and force them to bend. 

      There are three types of muscles in our muscular system: Smooth Muscles, Skeletal Muscles, and Cardiac  Muscles. Each type of muscle is different, because it has a different job to perform. Also, each muscle type is specialized to do a different task. 

Smooth Muscles

      Smooth muscles operate on their own, and are not under the control of the brain. They are called Smooth muscles because they appear smoother than the other types of muscles. Smooth muscles are found in the stomach, blood vessels, eyes, and digestive system. They are used to move food through the digestive system, regulate blood flow, and decrease the size of pupils when too much light is present. Smooth muscles only have one nuclei. They are connected to each other, allowing electric pulses to pass through them.

Skeletal Muscles

      Skeletal muscles are usually attached to bones. They are often called Striated muscles because of their striped appearance. The brain operates them, and tells them what to do. The cells of the Skeletal muscles are long (sometimes over 30 cm), and unlike the Smooth muscles, contain many different nuclei. 

Cardiac Muscles

      Cardiac muscles are special types of tissue that are found only in the heart. They are striped like the Skeletal muscles, and not under the control of the brain like the Smooth muscles. They operate independently.  They are also connected to one another, allowing electric pulses to pass through them, like the Smooth muscles as well.


Lactic Acid
    Working muscles generate energy anaerobically. This energy comes from glucose through a process called glycosis, in which glucose is broken down or metabolized into a substance called pyruvate through a series of steps. When the body has plenty of oxygen, pyruvate is shuttled to an aerobic pathway to be further broken down for more energy. When oxygen is limited in the body, pyruvate converts to a substance called lactate, which allows glucose breakdown to continue. During the time of high anaerobic energy production, lactate levels can reach high levels. A side effect of high lactate level is an increase in the acidity of the muscle cells.
     

Thanks to kidsbiology.com, and library.thinkquest.org for the information. If you have anything to add or complain about, please feel free to comment. 

Interrelationships

Hi there! Are you a body system? Do you have a friend that is also a body system? And lastly, do you and your friend hang out a lot, or in other words, "Interact"? If so, please write on this brand new blog about your experiences together, or your interactions with each other. If you even want to talk with your friend on this blog about how you are going to meet up or anything of the kind, feel free to do so. Try to go into detail about how you guys hang out, and exactly how you help each other out in order to make our bodies work.

Please respond to this blog post with your body system name. Thank you.