we will briefly talk about the function of the nervous system and the overall structural organization of the nervous system so the nervous system I want you to think about the feedback cycle when we discuss the feedback cycle we have sensory receptors input control center output and effectors so when we talk about functions of the nervous system they're going to actually align with the feedback cycle so sensory receptors would be basically something telling someone hey they're thirsty we have input that's going to be nervous input so electrical signals that will go to the control center where the information is going to be analyzed and evaluated and then we're going to have motor outputs the motor output is going to be also an electrical signal to some type of effector now remember effectors can be muscles and glands and they can actually be almost any cell in the body so what makes this unique is that all the signaling the input and the output will be controlled by the nervous system so again you see something s so that's the receptor would be in this case the ey we have nervous system input electrical signals to where the control center could be where we're going to integrate this information and then send motor output again electrical signals to an affector in this case is also a muscle so the three major functions of the nervous system are sensory integrative and motor the sensory function is going to be taking information from the peripheral portions of your body to the central portions of your body sensory in function is going to be performed by Sensory neurons and these Sensory neurons are also known as aarant neurons now the sensory function is going to actually send the information into the control center the control center is where integration occurs and for the nervous system the control center is always going to be either the brain or the spinal cord and it's always going to be performed by what we term interneurons interneurons are also known as Association neurons I prefer using the word interneurons because inter neurons intergrative function so it can help remember what's happening in this area analyzing now inner neurons are only going to be found in what we call Gray matter of your brain and spinal cord and we'll discuss that a little bit later on but in general gray matter are going to be neurons which are cells that do not have any milon sheath or are this fatty protein covering thems and then last is the motor function motor function is going to be taking information from your brain and spinal cord to the peripheral per um area of your body the motor neurons are going to serve this function and motor neurons are also known as epher neurons now since these words epher and aeren sound a lot alike an easy way to remember which is which is the term same sensor is the same as aent Motors the same as eant so this is a good way to remember that these two mean the same term they're taking information into the brain and spinal cord motor and eperen are the same they're taking information away from the brain and spinal cord so if we go back to that original picture we can see that there's always a pathway from the peripheral into the brain and spinal cord that's going to be sensories are aarant and then motor is going to be from the brain and spinal cord to the peripheral area of your body motor or e arent now your nervous system is going to be divided into two major regions the central nervous system and then what we term the peripheral nervous system so the central nervous system is going to consist of your brain and spinal cord and they are centrally located in the body the peral nervous system is going to consist of everything else the peral nervous system is going going to consist of cranial nerves spinal nerves ganglia receptors and it's going to be subdivided further and further so just a quick picture here central nervous system brain and then spinal cord peripheral nervous system are going to be the cranial nerves coming off of the brains 12 pairs spinal nerves coming off of the spinal cord ganglia which we will talk about soon and then receptors in the skin and then the enteric plexus is basically just a braided network of nerves that's going to innervate your digestive tract so the nervous system is broken into the Central and then the peripheral now the peripheral is going to continue to be subdivided it's divided into two major regions autonomic and sematic anytime you see the word sematic this means that these neurons whether they're motor or sensory are only serving skeletal muscle so somatic Sensory neurons are going to take information from skeletal muscle to the brain and spinal cord whereas sematic motor neurons are going to take information from the brain and spinal cord to the skeletal muscles sematic another way to think of it is voluntary we're actually controlling con that Movement we are in conscious awareness then we have the autonomic nervous system system the autonomic nervous system think about what that word sounds like autonomic sounds like automatic this nervous system is going to inovate so send neurons to and have neurons coming away from your smooth muscle cardiac muscle and glands okay all of these are involuntary with meaning that we don't consciously control now the autonomic nervous system is going to be subdivided into two different divisions sympathetic and parasympathetic and these are going to be what we call antagonist systems so they basically have opposite effects on each other sympathetic is fight and flight so it's going to be high energy emergency exercising so very situations that require tons and tons of energy whereas parasympathetics going to be rest and digest meaning that this is the system that is going to be in charge when you're calm sitting after you eat big meals um we call it the D's it increases digestion defecation diuresis so urination pooping and then digestion sympathetic system is going to take the nutrients that you gain from digestion convert it into usable energy and then use it in high energy sit situations so in the peripheral nervous system it's everything but your brain and spinal cord we subdivide it into sematic and autonomic sematic only goes to skeletal muscles autonomic goes to involuntary um components of your body smooth cardiac and glands the autonomic is going to be divided into basically antagonistic so opposite systems the sympathetic fight flight High Energy emergency situations and Par parasympathetic rest digest conserving the energy situations