in this video we're gonna talk about functions of the nervous system we learned earlier that the nervous system is the master control and communicating center of your body and that the cells of our nervous system can communicate around your body with electrical and chemical signals that are both rapid and specific because these electrical signals can travel very quickly like up to 300 feet per second and they're specific because they there's nerves that attach to very specific cells within organs of your body now because it's rapid it usually causes almost an immediate response now the nervous system has three overlapping functions that are all interrelated we have sensory input which goes to the brain for integration and then we have processing and interpretation of that information which then goes out to you know motor output we call this efferent output because it goes to effector organs which include things like muscles and glands so just to summarize this pathway remember we have sensory input sensory input is where we have receptors somewhere in our body like in the you know retina of your eye we have photoreceptors that can pick up light that information set to the brain where your brain can process and integrate that information so we might interpret that glass as being a glass full of water and then with that information then we can integrate that to form a decision and that decision could lead to a motor output so then your brain can communicate with the appropriate of nerves that then stimulate the proper muscles that allow you to maybe raise that glass and take a drink of water and so in a very basic way our nervous system functions like this where we have sensory input integration within the brain and spinal cord and then motor output too you know a muscle or gland somewhere in the body now we can divide the nervous system into two principal parts you know structurally the nervous system has a central and peripheral nervous system so the central nervous system is your brain and spinal cord you know the containment of the dorsal body cavity and we think of the central nervous system is like the integration and control center where interpretation of sensory input can help dictate the appropriate motor output and this type of processing could be either conscious or unconscious but it's still an integration and control center of your body now the peripheral nervous system is the portion of your nervous system outside of the central nervous system so basically everything that's made of nerves that's attached to your brain and spinal cord is part of the P and s or peripheral nervous system and that includes both spinal nerves and cranial nerves they're called spinal nerves because the originate from the spinal cord and cranial nerves because they come from the brain so just to summarize this you November your brain and spinal cord are located within the dorsal body cavity and this is what makes up your central nervous system and then all these yellow nerves that are attached are part of the peripheral nervous system which is involved with communicating information whether that information is motor or sensory or even both so in terms of functionally the nervous system can be divided into sensory and motor divisions member structurally we had a central and peripheral nervous system but functionally we have sensory or afferent division and motor or efferent division now often nerves carry a mix of both but it's important to have these distinctions because it tells you which way the information is going and where it came from so if it's sensory or afferent information this is information that's coming from somatic sensory fibers which you know relay information from your skin muscles joints and visceral sensory fibers that actually you know relay information from your organs and both of these pathways here somatic and visceral sensory pathways which are a ferrant bring information towards the central nervous system that's why we use the word a ferret because a ferret means going to the central nervous system so for instance a somatic sensory fiber from your skin is going to relay touch information towards the brain where you'd interpret that as hey there's a mosquito on my skin now the motor or efferent division is basically what transmit impulses from the central nervous system like away from the brain spinal cord out to effector organs like muscles and glands and there's two major subdivisions we have the somatic and autonomic nervous systems now the somatic nervous system is what transmits motor impulses to scout a muscle and the autonomic nervous system is what transmits motor impulses to you know the smooth muscle cardiac muscle and glands around your body so the somatic nervous system is basically what conducts you know the basically the nerve fibers that conduct information from your brain and spinal cord out to scale a muscle we think of the somatic nervous system is The Vow pterri nervous system because it's under conscious control now it's not that these nerves are particularly special it's just that the somatic nervous system links up with a part of your brain that's under voluntary or conscious control and so therefore it controls skeletal muscles you know with volition or consciousness now the autonomic nervous system consists of visceral motor fibers you know and it regulates things like smooth muscle cardiac muscle and glands we think of this as being an involuntary portion of your nervous system because it links up with parts of the brain that are under involuntary or subconscious control we can divide the autonomic nervous system into two key subdivisions we have the sympathetic and parasympathetic divisions and these are actually antagonistic and therefore work in opposition to each other so the sympathetic nervous system is going to do one thing to an organ while the parasympathetic nervous system is going to do another now just to kind of summarize this whole structure here remember structurally we said there's a central in peripheral nervous system the central nervous system is made of your brain and spinal cord but functionally acts as the integrative and control center think of this is like the computer or the processing center for your brain now it receives a ferret information from the peripheral nervous system and then transmits efferent information towards the peripheral nervous system as well so your peripheral nervous system intimately links with the central however the peripheral is made of all the Associated nerves whether it's cranial nerves or spinal nerves and these communicate basically information between the rest of your body and the brain and vice versa now we can divide the peripheral nervous system into two key subdivisions we got the sensory or afferent division in the motor or efferent division the sensory division is what basically transmits either somatic sensory or visceral sensory fibers it basically brings information towards the central nervous system for integration processing and decision making and planning now and I think that can actually be both conscious and unconscious now the efferent or motor division here is what's basically going to transmit information out to muscle and glands of your body and we can divide this into two key categories we have the somatic nervous system and the autonomic nervous system member somatic is voluntary and it conducts or and it conducts information towards skeletal muscle so your skeletal muscles are under conscious control because they're connected by a branch of your nervous system that you know links up with the parts of your brain that are conscious and the autonomic nervous system or ans is the visceral motor system and it conducts impulses from your central nervous system but specifically to things like cardiac muscles smooth muscle and glands on your body and what's interesting is that this is kind of one of the key regulators of homeostasis or internal balance because it goes to most organ systems now we can divide the ANS into two key categories we have sympathetic and parasympathetic nervous system we think of the sympathetic nervous system as being like the fight/flight response so if you're just scared or frightened or alerted and excited in some way you're typically going to be more sympathetically active because this branch of your ANS is more active and it mobilizes your body's systems during this activity so it's going to promote the appropriate response by your organs the parasympathetic nervous system is the opposite you know it's think of this is like the rest and digest it's more involved with conservation of energy you know and it promotes housekeeping functions like energy storage and digestion so it makes sense how the parasympathetic nervous system you know opposes the sympathetic but you need both divisions to help regulate homeostasis because each of these divisions has a role on the same organs you know for instance your heart is connected to both the sympathetic and parasympathetic nervous systems so your sympathetic nervous system would speed your heart rate up whereas your parasympathetic nervous system which is rest and digest we'd actually slow your heart rate down if your organs are in this dynamic balance between the two branches of your ANS however it's under unconscious control