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Current time:0:00Total duration:10:36

Autonomic nervous system (ANS) and physiologic markers of emotion

Video transcript

so if you've ever ridden a roller coaster you've probably experienced the emotion of fear or excitement and accompanying that feeling of fear and excitement you probably felt your heart rate increasing maybe you're breathing a little bit quicker and these physiologic changes that occurred while you're riding a roller coaster they weren't under your conscious control and you didn't tell yourself to start breathing quicker it just happened automatically and these physiologic changes happened automatically through connections in your nervous system and the branch of the nervous system responsible for these automatic reactions is called the autonomic nervous system sometimes autonomic nervous system is shortened as ans and the autonomic nervous system has two branches it has a sympathetic branch called the sympathetic nervous system and the other branch is called the parasympathetic nervous system in each of these arms the autonomic nervous system caused different changes often times opposite changes in different organs of your body so the sympathetic nervous system sometimes people refer to it as performing actions involving fight-or-flight whereas people refer to the parasympathetic nervous system as rest and digest so let's examine what we mean by this the sympathetic nervous system causes changes in your body consistent with the feelings and changes you get when you might be afraid of something so like when you're riding a roller coaster there's some sort of fear response there and all those sorts of changes in your body are often changed automatically by a sympathetic nervous system so let's go over some parts of your body that are affected by the autonomic nervous system especially when it comes to emotions so here we see this gentleman or lady standing here with so many organs exposed you have an eye this is a salivary gland where your saliva comes from you have several of them but I'm just making one here as a representation we have the lungs the heart which of course is not drawn anatomically a liver here are two kidneys and the reason I included them is because on top of the kidney sits a gland called the adrenal gland which I've drawn as yellow triangles and the adrenal gland is responsible for releasing hormones like adrenaline adrenal adrenaline that's where the name comes from and here is your GI tract known as the gastrointestinal tract now I didn't draw the entire thing which goes from top to bottom but I just drew it here to represent that I'm talking about the GI tract so let's go through this one at a time and see how they react and respond to the different arms of the autonomic nervous system here we see an eye and when your sympathetic nervous systems activated your pupils dilate and the reason why you would want your pupils to dilate when they're activated by the sympathetic nervous system is if you think of it in the context of fight or flight if a wild animal is chasing you you want your eyes to be wide so to speak so you can see them better and you can bring in more light to have better vision so that's the idea of your pupils dilating and as I said here this is the salivary gland and the sympathetic nervous system causes decrease in salivation an easy way to remember this is think of a time when you had to do a public speaking presentation if you felt really nervous speaking in public you might notice that you get a dry mouth and have to sip water a lot and that's why people who give lectures sometimes have to drink a lot of water and here we have the lungs and the sympathetic nervous system causes your respiratory rate to increase in other words you breathe quicker the sympathetic nervous system also makes your heart beat quicker so you have an increased heart rate and the reason for having an increased heart rate as well as an increased respiratory rate is so that your body has better oxygenation so more blood can flow easier throughout your body now here's your liver in your liver in a major storage site for glucose and glucose is sugar and two sugar that your body can use to produce energy in the idea behind wanting increased glucose to be released is consistent with the other areas we talked about having increased glucose gives you more energy to fight or flight here as I said earlier are the adrenal glands and the adrenal glands sit on top of each kidney now your kidneys are actually closer to your back then towards your front so I drew a kind of transparent so you get the idea that that they're farther away and during a sympathetic response the adrenal glands are stimulated through hormones to release epinephrine and norepinephrine and another name for epinephrine is adrenaline an adrenaline gives you a real boost of energy and of course that energy is needed in a situation involving fight-or-flight and here's the GI tract and one of its main functions is to digest food but digesting food takes up a lot of energy and in a situation where you know a wild animal is chasing after you you want to divert all your energy towards vital resources in areas of your body that can help you escape so when it comes to the sympathetic nervous system there's actually a decrease in digestion and again that's because the activity of digesting food takes up way too much energy in this sort of situation so that's some of the main effects of the sympathetic nervous system so let's look at the parasympathetic nervous system this is the arm of the autonomic nervous system that's involved with but you can say rest and digest so this is a relaxed state and the parasympathetic nervous system affects many of the same organs and parts of the body that the sympathetic nervous system affects and often times it affects it in the opposite way so when it comes to your pupils this parasympathetic nervous system causes constriction of the pupils so your pupils get smaller and just as your pupils dilated during a sympathetic response so you can get more light in to see better the parasympathetic nervous system causes people constriction because you don't need as much light being brought in because you're not in a situation where you need to run or act quickly because again you're resting and digesting when it comes to salvation you actually have an increase in salivation when it comes to the parasympathetic nervous system and why do you have an increase in salivation well again parasympathetic nervous system is involved with resting and digesting in parque de jesting so part of digestion involves saliva saliva helps break down certain carbohydrates and also helps lubricate the bowls of food that you eat that later gets digested why is an increase in salivation in terms of your respiratory rate it gets slower or goes back to your baseline so they represent that I'll put a down arrow I'll put a downpouring arrow and what I mean by that is if you're sitting on the couch watching television just relaxing you're probably not hyperventilating right rather you're just breathing at a normal moderate pace so in the parasympathetic nervous system you're breathing at a moderate or decrease rate because you don't need the extra oxygenation and the same goes for your heart rate so your heart rate also goes back to normal or at least it decreases compared to when it's in sympathetic state so when the parasympathetic nervous system is activated your heart rate decreases or slows so the parasympathetic nervous system since you're resting and digesting you're trying to extract nutrients from your food and one important component of nutrition is glucose which as we said earlier can be used for energy so in a parasympathetic state you don't have this glucose release from the liver if anything your body's working to increase is glucose store so I'll just say there's an increased glucose storage because you're digesting your food to get their glucose the bottom line is you don't have a huge release of glucose in a parasympathetic State and the same goes for adrenaline when when you look at the adrenal glands since you're not in such a high strong detrimental state you don't need to have the adrenaline coursing through your veins so again there's a decrease in adrenaline release and when it comes to digestion you've probably guessed it in a parasympathetic state your digestion increases because this is the time when you're not in imminent danger and you're able to spend your time digesting the food that you took in so you can extract the nutrients and get the energy from it so your body can function properly and also you'll have plenty of stored energy so when the time comes you'll be able to escape should a predator come so this is some of the basic functions of the parasympathetic nervous system course there are more functions and the ones we listed but I think these are the most relevant when it comes to an emotional response