hey welcome back we're all on Chapter two counting the days man that means we only have what like eight more chapters left and the semester will be over anyway chapter two is a depressing chapter it has to deal with all the physical changes you go through when you're aging okay and you might have seen other people do these things and you think oh not gonna happen to me I'm here to tell you yes it is so there's two different kinds of aging of course there's many kinds of aging right we talked about all the different ways you can refer to age in the last chapter now when I'm talking about is the difference between what we call primary aging and secondary aging primary aging are the aspects of the physical changes that happen with age and they're pretty universal they're shared their inevitable and the result they're the result of some biological process so it's the stuff that happens to you it's automatic you're gonna age no matter what secondary aging is the part of the changes that happen with age in physical functioning that's not inevitable but may result from widely shared environmental events and it's gonna be some surprising things in here so like primary aging everyone loses muscle tone even if you're working out in great shape right we're all gonna lose our muscle tone secondary aging really is like things like hearing right we get a loss some hearing and believe it or not you know how old people can hear most of that is the result of our environment it's not really the result of Aging it's a result of abusing our ears there's so many year is listening a loud but it's particularly difficult to separate the effects of disease from normal aging so this chapter is gonna basically focus on primary aging and in the next chapters gonna do a lot of focus on secondary aging so primary aging these are the things that happen to everyone okay that's what primary means it's the things that we really don't have a lot of control over and it's happening across the board so some of you I don't know if you ever thought about it but there's like different theories believe it or not on why do we actually eh so here again I'm gonna go through three theories I'm gonna talk about the oxidative damage genetic limits and what's called the caloric restriction no single theory can actually explain all the changes that occur with primary aging but honestly some people just like with most theories most people think it's a combination of all these things so oxidative damage interesting idea it refers to the random damage that takes place on a cellular level so this involves the release of what we call free radicals there's Rex again my dog I don't know if you met him yet but he's a loud one so what do I mean by free radicals I don't know if you guys are familiar but free radicals are molecules or atoms that possess an unpaired electron and they enter into potentially damaging chemical reactions so what happens is they lose their unpacks top they lose this their pairing right so there are an unpaired electron and then they can enter into damaging chemical reactions that we typically can fight but we get worse at fighting it as we get older because as we get older we're worse' getting fighting off these free radicals and what ends up happening is we get oxidative damage and the oxidative damage is the result of it results in what we would consider primary aging so it's actually damage to the DNA it causes Lippo fusion buildup in cells that's implicated as a cause of a whole bunch of different diseases so free radicals are the byproducts of just normal body metabolism they happen like automatically but could also be the result of diet sunlight x-rays air pollution and the I guess probably the most interesting thing about these free radicals is they are inhibited by acts antioxidants so like when I was kidding I never heard of an antioxidant they didn't really talk about ant accidents but this is what they're talking about like when you see that on a package and it says whoo this is high in antioxidants what it really means is antioxidants in inhibit free radicals free radicals are what caused these damaging chemical connect connections that end up making us age so really antioxidants keep you young by making this change you know making these free radicals not so prominent right so here are some items that are really rich in antioxidants so do you hear the birds I'm outside they're so loud that's actual real bird he's like looking at me so blueberries cherries Kiwis pink grapefruits are enjoyed you can read it right and there's a whole bunch of vegetables that are high in antioxidants they actually did a study in rats and they found improvement on a diet of only blueberries so they gave rats only blueberries they didn't eat anything else and rats didn't age I mean not that they live forever but the Aged much slower than a control group but for humans we seem to need a combination of these things right and humans can't really just live on blueberries but I think that if you're only gonna take one thing home from this class cuz it's quick and you're not gonna remember anything eat a lot of blueberries I'm not kidding if you start eating them at your age and you eat blueberries every day at your age you're gonna look more like bumpkin less like me ha ha as you age right ok the second theory of why we age that we're gonna talk about is called genetic limits and it's it's a really interesting theory I mean I don't know if I'd call it a theory of why we age but it's interesting so it's the idea that each species has a characteristic maximum lifespan so for humans it really seems to be somewhere between 110 and 120 not that most people live that long but no one's actually lived longer than that ever ever ever that we can figure out right and dogs live less and turtles and trees live longer right trees have a longer lifespan so it's this genetic limit that we have right and there seems to be a correlation between the longevity of a species so human dog turtle tree right and the number of times its cells actually divide this is called the hayflick limit I don't know if you've ever heard of it but human cells can to divide only about 50 times which leads to this lifespan of about a hundred years right it's kind of cool idea right so if we only divide about 50 times it leaves us to this at the crux of this theory is the idea telomeres that's the length of repeating DNA at the tips of the cell and the idea is that as you get older the lengths of repeating DNA are shorter so the telomeres in infants have very very long telomeres and old people have very very short telomeres and they're once they're all used up your cells stop dividing so it's kind of like you're born with this long telomere that keeps dividing and dividing and dividing and like let's say there was no disease and there was no getting run over by a truck and there was no pandemic right then what you're waiting for is a natural death to occur and it's gonna happen when your telomeres are done dividing when you have this the length of your telomere stop dividing and you can actually then you've got to die so stem cells can divide an unlimited number of times which is one of the reasons people find stem cell research really cool and the idea that a stem cell can divide an unlimited number of times really leads to a crazy potential that you good I mean down the road they could file applying the Fountain of Youth you could live forever right because you can keep those telomeres going if somehow they were replaced with stem cells I mean that's not happening right now but it's really cool you should stop that Rex it's really kind of interesting prospect right so genetic climates may be integral part of normal development for some cells so we talked about the oxidative damage we talked about the generic genetic limits let me talk about kal kal Erick restriction so age seems to be related to differences in the number of calories metabolized by the body and so there is some research that suggests that dietary restrictions will show longevity in lab rats so they found that reducing the number of calories in studies using rats greatly increased their lifespan and actually their quality of life but unfortunately to really have an impact on humans you would have to reduce intake by like maybe 30 percent so you're down to about 1,500 calories a day research researchers are now looking for a substance that would give the same health benefit as a caloric restriction but without making you eat so little because 1,500 calories man that's like I don't know I'm not really good that kind of thing but I think it's like one meal like a Big Mac in a nice shake and that's it that's all you get all day right I saw a I was keep meaning to find it for this class I saw her like a TLC special on this family it was a couple that did this cow they were part of a study when they were in like graduate school where they reduced the number of calories they took in and they also only ate like like nuts and berries and they ended up living like they were like I want to say they were like in their late 80s early 90s and they they look terrible I do have to say they looked so emaciated because they were taking a 1,500 calories a day since they were like 20 years old but they could run like marathons they were like in incredible they look terrible but they were in incredible shape they were like living life they were living like in Vermont looked like they smoked a lot of pot they were they were a funny group I should take it up one day but it's an interesting theory because it's it has to do with how we metabolize and that's something I'm going to talk about I think in the next chapter where you know no matter what man I used to be skinny you just end up putting on weight as you age Jim I mean in general because your metabolism changes so unless you really you could eat the exact same thing you you've got to change your diet to actually make it work okay so what I'm gonna talk about three different things I want to talk about the difference I like they're different I want to talk about the idea of longevity that is the average expected length of a life at any particular time in history so in a particular culture and it longevity has increased significantly in most of the world so longevity is like what is the average expected length of a life and I don't know whether you realize it but like like go back to the time like Jesus was here the average life was only like I don't think people live much past 40 that was old you know and so this kind of longevity has changed right across history life expectancy refers to the average number of years a person of a given age can still expect to live so that's risen dramatically primarily through eradication of most infectious disease so not like the average longevity is like the average expected length of life of a particular time in history where life expectancy is like my life expectancy is shorter than yours right God willing you're gonna live a lot longer than me cuz I'm older than you that's what they're talking about and then lifespan it refers to the upper boundary of years a given species can expect to live so despite increases in longevity and life expectancy lifespan has never really shown change so let me repeat this again cuz these things get really confusing longevity is the average expected length of life at any particular time in history right life expectancy is how long you are particular like a 20 year old is expected to live both of these things have increased significantly but lifespans like the caste and again lifespan that's like the absolute upper boundary people never live past 110 maybe a little past you know but not much right it's you don't see anyone 140 and that's been for as long as record-keeping has been so it's very interesting that we have this upper boundary that doesn't move so on average women live longer than men do right women just tend to live longer than men do because there's a lot of reasons but women are less likely to inherit um sex linked genetic disorders women are naturally protected from some diseases that men aren't women survive difficult conditions better believe it or not so extreme heat extreme cold women like survive these conditions better women are less likely to participate in high-risk behaviors you know like jumping off cliffs or dudes doing heroin right women are more likely to have safer jobs so they in general they don't tend to do very dangerous jobs and women engage in more health oriented behaviors they you know they go to the gym they go you know to yoga women just Ken and I mean I put this lady up there she's so cute because think about it most of you know you probably at some point had a grandmother right you see the matriarch of the family where grand fathers tend to die before grandmothers or it you know it it really is even in your family should be seeing that the women can to live longer than the men okay so I'm gonna talk about all these changes but again I know you hate this I'm going to take them just one at a time not that I know you hate it I just assumed you do so I don't know why I keep doing it but I do so these are all the physical changes over over adulthood and when I get through these because they're gonna take a long time to get through then I have a couple more slides so it's not the end of the chapter but what I think I'm gonna do is I'm not gonna go through all of these in this first video I'm gonna try to break it up into two because honestly I don't think who the hell wants to listen to me and all these birds screaming in one sitting right so I try to by oh and Rex I forgot who wants to listen to Rex blog right so I'm gonna break it up probably after the sentence census because getting through them is a little long once I get to there we'll have a break all right so outward appearances what happens as we age so there's a age-related changes in height weight skin elasticity hair color and hair loss so what are they none of them are good as we get older you get shorter you get fatter you get more wrinkles and you lose your hair and it turns gray and what are wrinkles you might wonder wrinkles are just a redistribution of body fat and a loss of OS I was elasticity like your skin starts becoming loose starts around 40 so you guys you look good now enjoy how you looking cuz things go downhill I know I've already told you this but you you're at the prime here okay I mean height you don't start shrinking until you're old I remember my mom was so sharp at the time she died we were almost same height at one point not that I'm very tall but but the time she was like in her 80s I was like looking down at her right and I told you already once you hit 30 he start getting fat I don't know what the hell it is and your skin gets looser and then you know hair we'll talk about it I think again another chapter but hair loss very common for men hair going gray all happens at different ages like my niece oh my god my poor brother's daughter she started going gray in high school crazy right so my family tends to go gray young but we have a lot of hair the women but the men oh my god my father he went he was in World War two they shaved his head you know when he went in he joined he actually forged my grandmother's signature and joined the army when he was I think was 17 or 16 like it was before he was allowed to and they shaved his head and it just never grew back like he had this giant bald spot and my brother's got a bit of a receding hairline but most of that is genetic so when will you lose your hair when will you not but we'll talk a little bit about that the next chapter - okay let's talk about the census so things change and I told you this we tend to our eyesight changes and our hearing changes and even your sense of taste and smell actually change as you age vision is probably the clearest one all of a sudden you just go blind it's crazy I mean not completely blind I'm definitely exaggerating but what happens is what happens is in general vision is the last sense to develop in children but it's the first sense to decline in aging so we have our vision for the shortest amount of time when as you age what happens is the lens thickens and yellows around that you're looking through so the lens is that area if you're looking at this picture of the eye you see where the lenses it Dickens and yellows and the pupils lose their ability to open in response to reduce light so less light goes to our retina right and so the lenses also lose the elasticity interfering with his ability to accommodate on mere objects or a small print and that tends to happen around 45 so around 45 years old you'll see everyone all of a sudden squinting I don't know if you've ever gone out to a restaurant with people in their 40s all of a sudden they're all pulling the menu really far away because they're losing the ability to see things up close right and then as you get older oh my god all of a sudden you have a real hard time seeing in the dark right and that's why all the early bird specials go on and old people never want to go out at night they don't want to drive at night they can't see well at night they say things like that because it's true so I show you this i if I wish I had a pointer on this I don't have a pointer but I'm assuming you know how vision works right so the light comes in you see the light comes in and it hits the back of your eye right where your retina is right and if all the signals go out to your brain through that optic nerve right and then the iris is the colored part the pupil is the black part and you've got the cornea surrounding it so what can happen to your vision a couple of different things press presbyopia is the reduced visual acuity this is what can be corrected with glasses what typically reading glasses almost everyone in their 40s about starts needing reading glasses if not earlier by 60 threateners get only about 30% of the light they got in their 20s and because of that so by sixty years old you've lost thirty percent of the light that you get near 20's and so by sixty you start having this problem of dark avocation so it starts declining around sixty it's this gradual loss of dark adaptation dark adaptation is like you remember have you ever gone in it's like a movie theater and a movie already started and everything's really dark and you can't see anything oh my god I'm blind and you're trying to find a way your seed and then you sit down for like a minute and all of a sudden you can see like everything you see the popcorn on the floor you can see everything like or at night I turn all the lights off in my house and I'm like trying to find the way in my bedroom and I'm knocking in I'm like oh my god and then I get in bed and it's like lit up my bed because what happens is your eyes adapt to the dark that's dark out that fusion but the ability to do that really significantly decreases as you age another problem that happens as you get older is cataracts that involves the gradual clouding of the lens of the eye so that images are no longer transmitted sharply to the retina now a lot of people let get cataract surgery and that corrects that pretty simple and easy to do these days a much more serious problem is glaucoma it's a very dangerous buildup of pressure inside the eye which can actually do it absolutely destroy the optic nerve and lead to blindness I I always screw those two up so cataracts is super common very easy to fix glaucoma is horrific and so you know when you go to a doctor to like did your parents have you know cataracts I'm like yeah did either of your parents have glaucoma I always go yeah they go well which one I might Oh both of them and then the doctor looks at me horrified and I'm like oh no maybe it was cataracts because glaucoma is not common right there's actually no gender differences in visual declines vision involved issues are responsible for older adults not wanting to drive at night they prefer matinees and as I said they love the early bird dinner specials they like to be out right this is from your book it shows you the risk factors associated with different things so cataracts if there's a family history female gender tends to get it if you have hypertension diabetes right glaucoma it's increased with age but you have to have a family history very common in more common I should say very common its more common in african-american ancestry and if you have diabetes and then age-related macular degeneration which is when you go blind it's not good up one eye at a time that is increased with age my father had that and it definitely has a genetic component so he was by the time he was like in his 80s he couldn't read anymore because he was blind in one eye I hope that doesn't happen to me I really like to read anyway hearing I'm sure we all know that people as they get older they can't hear right hearing loss in high tones and the shortening of loud its loudness scale is very very very common by age 65 25% of adults have some significant hearing impairment and the rates rise sharply from there on so around 65 about 25% and then it just goes up and up and up and men are more likely than women to suffer from hearing loss basically it's the result of these tiny little hair cells inside the cochlea which makes it difficult to distinguish why it makes a different called distinguish sounds so I'm hoping these videos work I should have tried them out let me see sometimes they every sound begins as a vibration as the tuning fork vibrates it causes the air around it to alternately compress and expand this compression and expansion in turn sets up a series of pressure waves that move away from the tuning fork as the pressure waves reach the listener they enter the outer ear which consists of the external ear and the auditory canal the outer ear funnels the changes in pressure toward the middle ear so hearing starts by that big thing on the outside of your head which I guess some of you call it the ear but it's called the pinna and it funnels the air pressure hearing is just all about pressure here pressure changes reach the middle ear they cause the eardrum to start vibrating which in turn causes three small bones in the middle ear to begin vibrating first the hammer then the anvil and finally the stirrup begin to vibrate the stirrup is attached to a small membrane known as the oval window which separates the middle and inner ear as the stirrup vibrates it causes the oval window to begin vibrating the oval window is part of a larger structure known as the cochlea so I'm just trying to get you to really understand how hearing works so you get this air pressure it comes in through that big funnel it comes down you have a your drum which is like a drum it's tight and it starts vibrating based on that pressure which closes those three little bones to move they start pounding on that cochlear and this is what happens kaalia consists of a fluid-filled tube that has coiled much like a snail's shell it is attached to the auditory nerve inside the tube is a membrane lined with hairlike receptor cells known as cilia as the oval window vibrates the fluid the cochlea begins to move in waves causing the cilia to move as the cilia move they cause neurons to fire these neural impulses then travel over the auditory nerve to specialized centers in the brain where they are interpreted as sound so they go to the auditory nerves over in the temporal lobe right but it's those cilia cells so you get the whole thing you get this air pressure it comes in through you have big thing on the side of your head and it narrows down it makes tension around the eardrum right then the bones start moving those bones moving hit the cochlear cell it it makes that fluid inside your inner inner ear start to move those hair cells that my friends is the problem so here's a picture if you were to open up the cochlea right this is what it would look like there be millions and millions and millions of these little tiny hair cells they're almost microscopic they're so little right and when they move you get a nerve impulse that goes to your temporal lobe right and makes you hear that bird you hear that bird or hear Rex barking right that's what makes you hear those sounds now the problem is why are old people going deaf is that damaged almost all the problem is due to damage damage to those hair cells how do you damage those hair cells loud noises damage to hair cells think about it have you ever been in a nightclub or I don't know hanging out with loud people or saving your head right by a speaker and you actually can you walk out and you can still feel the pressure in your ear right or you can still hear the sound in your ear that is your cilia cells still reacting to that sound so the the think of the fluid is pushed down on the hair cells pushing down on the hair cells and they push them to the point that the hair cells don't get back up they're just staying down there and what can happen is they can actually crack right and this is a picture of one of them cracking right and if they crack they never grow back it's not like something that replenishes itself so you go through a lifetime of loud noise and we have millions of them so you like so big right unfortunately we go through a lifetime of loud noises in those cells crack and crack and crack those little cilia cells to the point that all of a sudden you're not hearing because those cells don't work anymore now you might wonder hello does something have to be to crack my cilia cell they said the sound of a lawn mower can break your cilia so so it is not that loud I wish you guys were here with me not in my backyard with the birds and stuff but I'd like to see you put your hands up because I always like to ask this question which is they are predicting that your generation your cohort is going to go deaf earlier that anyone else has ever gone deaf do you know why that's right I heard you say it it's those ear buds not that we all haven't had headphones and headsets on but it's when you actually take those ear buds and shove them in your ears to make amplify the sound you're just killing you cilia cells if I can hear your music your cells are cracking like that's pretty much what you've got a go by so I mean luckily they digitized it used to be that they would give us hearing aids to help us hear right and the hearing aids we're really just amplifying sounds and if the cilia cells aren't there doesn't matter how loud you make it you're not going to hear it but now hearing aids are getting better and better and now hearing aids are actually targeted to specific areas in your cochlea and they're digitized so lucky for you there'll be good hearing aids but chances are you're gonna have to wear them pretty young I used to I wouldn't let Megan my daughter I wouldn't let her wear I wouldn't let her wear those ear buds the little ear ones the ones like that went in even though everyone was wearing them she's like what 24 so roughly around you guys age so remember everyone wearing them I sent her out to middle school with giant giant giant headphones like you would wear like a DJ would wear like I think people are now coming to wear bigger than beats though and the beats weren't around then she was like way before her time no wonder why yeah I'm surprised she didn't get beat up by bus you know cuz she was like mom I can't wear these I'm like you're not putting those other little things in your ear you know anyway that's terrible mother okay what other senses so we did vision we did hearing taste and smell by 70 we have half the taste buds we added 20 I don't know whether you've ever noticed old people eat gross them right so there's four basic flavors we have salty bitter sweet and sour those that detects sweet and salty decline more rapidly and our our sense of smell and taste are connected and smell peaks at about between the ages of 20 and 40 and then starts dropping it between 40 and 70 but after 70 it drops significantly and many lose this more than women and smokers lose this more than anyone because you're like making I don't know I guess you're destroying your ability to taste and smell I remember my mother when she was in her 80s would eat the most disgusting combinations I also moved her in with me so we'll talk a lot about that because I can oh like I said I can only talk about my family but she's got old and I don't really like old people I know that's a terrible thing to say but I never have but she was my mother so I had to move her with me right and when I did I come home and she'd have like the gas on the whole house would smell like gas and because the pilot like they can go on and I was like mom ma you're gonna pull the house up and she's like I don't smell anything no sense of smell no sense of taste it was like amazing and I don't know maybe view experience that - all right so we have a lot more to go through but I I feel like this is a good place to break why don't you go get a beverage go to the bathroom do whatever you got to do and I'll make the second part of part two where we talk about bones I got to figure out how to stop this I'm really bad at stopping this