all right so when you guys uh get your stuff basically what you're going to have is a dissecting tray that the specimen is going to lay in you're also going to be having for your dissection you'll have a scalpel you will have two different types of probes so this is a blunt probe and a fine probe they're basically for moving stuff around on the inside so they don't really actually help you generally open the organism up you'll have a pair of forceps or tweezers um depending on what you want to call them and then you'll have one maybe two pairs of dissecting scissors so the first thing you'll need to do is get your pig and cut open the bag and drain out the fluid so there is some preservative fluid that's preservative on the inside that you're going to want to just drain down the sink and then once you have the most of it drained off then go ahead slide out the pig and put it into your dissecting tray and we want it to be on its back so real quick here just some kind of basic directions and some maybe observations about just the external anatomy of the fetal pig um fetal pigs or pigs in general are mammals and so there's some characteristics that can kind of key you into that some physical characteristics that you can see um a trait of mammals is that they have fur albeit various amounts so if you kind of look closely at the fetal pig you'll notice that it has some fur on the exterior mammals also have mammary glands that females do to feed their young and so regardless of whether you have a male or a female kind of down the inside on the tummy side you should see these mammary papillae um which when the pig is mature and if they have a litter that would ultimately then become the teats that they can get milk from and the males will have that too even though obviously they won't have the ability to produce milk later on mammals are also generally warm-blooded organisms which albeit that's a unifying characteristic it's not something that you can really see it just simply means that they regulate their intern internal body temperature through cellular metabolism and through some other mechanisms as well so they don't let their body change with the external temperature outside like for instance your internal temperature should stay somewhere around the 98 degree ish Mark and not very substantially even if it is dramatically colder or warmer outside when we start to do our dissection we're going to be using terms to kind of Orient you a lot so just real quick kind of to sort of identify with those are on the pig the word anterior is used to refer to Regions towards the head so like this is kind of the anterior end of the pig and then posterior would be used to refer to sort of directions more towards the rear or if you want to think about it as away from the head so anterior posterior basically give you directionality on this axis of the pig and then we have another set of terms for giving you sort of directionality on the uh the axis that runs perpendicular to that so we use the words dorsal in ventral dorsal refers towards the back side of the pig and ventral refers to the tummy side so you can refer to something as being more towards the dorsal end I.E the back or the ventral end I.E the stomach during our Dissection the pig is going to be on its back so it will be what we say ventral side up the entire time you're doing the active dissection just a color couple of other terms the terms proximal and distal will sometimes be used and those are really used generally to refer to how close or far you are from sort of like the the center of the organism so if something is more of say proximal to um this you might say okay well this is proximal to the pig's umbilical cord you're talking about something in close proximity versus if you're saying something is distal you're referring to basically a reference point that's further away so it just kind of gives you a sense of how close something is to a reference point and then finally we still use the good old left and right when we're doing dissections but you have to be a little bit careful because whenever you're using the word right and left when dissecting it's not the dissectors right and left it's the dissect DS right and left that we're referring to so for instance this pig is going to be on its back throughout the entirety of the dissection and during that if I'm referring to something that's on the right hand side that's the pig's right hand side over here but that's my left hand side so you just have to kind of like be the pig all right when you're trying to figure out whether the word right or left is appropriate put yourself in the pig's position and just use whatever term is correct for them now in terms of when you get your pig you'll either have obviously a male or a female there's a couple of things that you can look at to kind of clue you into what you have I guess clue number one which maybe is the most easy is that it will stay on the outside of the bag whether it's a male or a female so there's always that but then there are some things that you can look at as exterior sort of landmarks to help you tell both of the pigs since these are fetal pigs are still going to have the remnants of an umbilical cord kind of right in the middle of their abdomen on the exterior so that's what this is right here that's sort of tied off with this little string that's um the umbilical cord where it got snipped from where it was connected to the placenta if this was a male rat which it's I mean sorry a male Pig which it's not then there would be a eurogenital opening that is just posterior to the umbilical cord so there would be basically another little tiny uh opening right here and that would be where the penis extrudes for the male okay that is not the case here because this is a female sort of the other thing that you can look at is to look to see if there are any sort of uh external um or I guess you could say lumps that would be where the testes are at so if this was a male similarly you would see kind of a protrusion here on the posterior end where the testes would be located which again we don't have because this is a female the female also has a urogenital opening but it is right above the anus for the female whereas for the male it would be just posterior to the umbilical cord all right so we need to get this Pig kind of locked down so to speak so that we can start doing our dissection you guys are going to have some kind of twine at your desk so kind of the easiest thing to do is to run the twine on the underside of the dissection tray this is actually one of those things where having Lab Partners can sometimes be handy we're going to tie one end to one of the legs now I guess a little disclaimer right so these pigs um are going to be feeling very rigid and they might kind of want to fall into a position that's kind of awkward based on the position they were in when they died and so you kind of want to give yourself some space to work so you're going to want to pull back a little bit and make sure that you have this rope relatively taunt you might have to pull a little bit to kind of open it up and you know just kind of as a forewarning for those of you who are squeamish depending on what you're pulling you could very well um fracture a bone and hear just kind of a cracking noise kind of just part of the nature of a dissection it's not my favorite part but you know if you're expecting it sometimes it's not as bad so then on the other end similarly kind of we're gonna cut it off because we don't want it attached to this spool but make sure that you have enough again you want to make sure that the legs are pulled back fairly taunt before you tie it off you can in Theory start doing your Cuts without having the legs tied back and that actually might be something that's a little easier to do if you have Lab Partners that are assisting you but I always kind of like to just have things situated so that I have a clear kind of feel to work with and then we're going to do the same thing for the back set of legs again we're going to kind of feed it under the tray based on the way that you have the pig situated in the tray the back legs are sometimes a little harder to kind of tie off because the Rope wants to slip underneath I wish I could give you some really vast wisdom that would show you how to do it exactly the correct way but a little bit it's just trial and error if you can kind of hike up the Rope a little bit on the leg and don't put it near the ankles of the the pig it's better to have it kind of higher up near their haunches so that it doesn't slip down and you might have to adjust as you go in the beginning when you're just making General cuts the way that it's in the tray right now might just be all hunky-dory but then maybe when you're starting to do some of the reproductive Anatomy that's at the most posterior end you might need to do a little Shuffle so yeah and you want to make sure it's nice and tight before you kind of tie it off and as you're going throughout the dissection um just kind of keep in mind like you know this this was a living organism it's obviously been sacrificed for your educational purposes but it was a living thing and we just kind of want to be respectful of that as we go throughout the dissection all right so now that we have it kind of situated we're ready to go ahead and start making our Cuts basically what we're going to do I'll kind of trace it with my scalpel and then start actually making the cuts themselves we're gonna start the cut kind of way up here at the top um you really can't go too high honestly so we're going to start this cup kind of right about below the chin we're going to go all the way down and then when we get to around this umbilical cord basically we are going to create like a flap with that so we're going to go around one side around the other side so that they can kind of flap backwards like this and then we're going to make some Cuts going the other direction so that we can create flaps that open up okay so that's kind of the goal to start you're going to want to do something called tenting so with tenting you are trying to kind of pull up on the skin to give yourself a space to do an initial cut so you want to kind of if you can use your forceps to pinch up a big chunk of skin and use your scalpel to create a small incision where you can then insert surgical scissors there are quite a few layers of tissue so you're going to have to potentially kind of keep making the cut deeper and deeper until you're all the way through kind of one thing I tell students is you can make a cup deeper you can't make a cut shallower so if you're really kind of nervous to start with which a lot of people are I guess first thing to keep in mind is the pig is already dead you can't really hurt it anymore then it already has been at this point um and just start slow and and make the cup progressively deeper once you've gotten through um then you can probably switch to surgical scissors as a safer sort of way to elongate the cut yes in theory you could just kind of go with the scalpel and make all of your cuts that way but what's really difficult sometimes is knowing how much pressure to apply and not Nick up the underlying organs it takes practice to know how much pressure it's going to take to get through a tissue layer without damaging the organs that are directly under the tissue which is why I kind of advocate and not everybody kind of follows this same prescription but I always say make a small initial cut and then switch to Scissors because my guess is in life you have spent more time at exercise or practicing your scissor skills right then you have using a scalpel So in theory your fine motor skills are a little bit more refined when it comes to the scissors okay so kind of one thing that I recommend while you're making these Cuts is kind of as you go through and cut with the scissors cut and kind of pull up again we're trying as much as possible not to Nick a ton of underlying organs sometimes I'll even make my initial cut kind of slightly off center a lot of things we're going to want to look at are kind of like smack dab in the middle of the pig and so that kind of gives me a little bit of leeway too if I make a mistake tell right now that I'm through tissue layers but I'm not all the way into the body cavity how will you know if you're all the way into the body cavity you'll actually see an open space on the inside name there on this top piece all that's underlined right here is a bunch of ribs so honestly it's a little bit harder to open up this upper thoracic cavity where the lungs and the heart are located because not only are we gonna have to cut through some tissue but there are some bones there that protect those really important organs that we're gonna have to get through as well but I kind of have my at least initial sort of line that I'm following and now that I'm kind of close to this umbilical cord now I'm going to do sort of that flap where I go down on either side and again if you can kind of pull up on the skin while you cut you're less likely to damage the underlying organs making them look prettier so to speak for when you are trying to find everything all right so I'm starting that flap now I've kind of reached a little bit of an impasse yeah you can probably see on the video that there is this cord-like looking structure that is connected to that umbilical cord and is clearly connected to something on the inside and so that's basically preventing my flap that I'm trying to make from falling backwards what this is is this is the umbilical vein so the umbilical cord is basically a collection of a couple of blood vessels that connect the baby's circulatory system to the placenta which is the interface between Mom and baby circulatory system and so there is a set of arteries that take blood out to the baby which we have not exposed yet so that be taking oxygen-rich blood to the baby that'd be taking nutrients that the mom has consumed to the baby and then the vein is bringing back the blood from uh it's not bringing the direct blood but it's bringing back uh sort of waste products that the mom needs to get rid of so for instance this is blood coming um this is kind of the return Loop where carbon dioxide is then going to basically diffuse into the mother circulatory system so that it can be exhaled uh for the fetal pig right so what we need to do is in order to make this flat go back we are going to have to snip the umbilical vein so I'm going to kind of just cut up here so I can leave remnants of it to find where it connected in right below where the liver is at and now that I've done that I've kind of freed up this flap to be able to sort of flap backwards all right so that piece can kind of just go that direction I'm going to want to make some cuts from the ventral to the dorsal side of the pig so you're going to want to cut these back as far as you possibly can so you kind of want to create that cut really deep down towards the pig's spine and I'm going to do the same thing on the other side cut through the tissue down around that back hatch and the the farther back you can go the easier it's going to be to pull back these flaps I'm going to do the same thing up here at the bottom of the rib cage I'm basically going to create this flap that goes from ventral to Dorsal and again if I can take that back that would be good now there's going to be fluid on the inside of the organism that's normal what's going to make your life easier in terms of trying to find everything and also kind of keep things a little bit cleaner is to when you're opening up this cavity you start to see all this fluid grab some paper towel from the side counter and just kind of pack it around the organs and let it absorb the liquid so I just kind of push it into the sides there people get a little kind of worried they're going to damage things as long as you're not like I don't know really beating up on it remember it's already dead so a little bit of pressure here or there and gonna cause any harm and then once you have these paper towels that are soaked just keep in mind that we're going to be disposing of them in the bags that are on the side counter this we try to keep stuff that is soaked in formaldehyde out of the trash because the the formaldehyde which is used as a a way to preserve the organism is just not really something you want to throw away in something that's going to go to a landfill right so kind of got it cleaned out pretty well you might even try to absorb some of the liquid that's in your tray I'm actually just going to shove this into the side there right now and that way if more leaks out it kind of can pick it up all right I'm going to go back even a little bit farther all right so at this point at this point the abdominal cavity is looking pretty good for the most part I've got it opened up enough where I can see all of the major organs in the abdominal cavity if I simply just kind of move things side to side the only thing that you'll really need to kind of work at is in terms of the abdominal cavity and your instructor can kind of help guide you through this but you might need to extend Some Cuts downward to expose some of the reproductive organs when you get to that and you also have to cut through another sheet of tissue if you want to expose the kidneys so you can see the kidneys right here but there's actually a thin kind of covering of tissue over top of them because they're not truly in the body cap the abdominal cavity with the rest of the organs in a fetal pig so you would just need to Simply kind of use your scalpel to make an incision along the edge of that to peel back that tissue layer and expose it entirely but I'll leave that fun stuff to you guys when you do your dissection in class at this point kind of the next step is going to be to open up the thoracic cavity which is going to require a little bit more work because remember we got this rib cage to kind of contend with so whatever your beefiest pair of dissection scissors are that you have been given that is going to be what you want to kind of whip out at this point now in order to get into that upper part you're going to have to cut through this really thin sheet of tissue which is called the diaphragm so you can kind of see it right here it's sitting right above this liver which has taken up a lot of space that's it right there I'm kind of poking it it's it's like really thick paper basically is kind of its consistency it separates the abdominal cavity from the thoracic cavity but its function is to help you with respiration so it's a it's a it's a muscle a muscle that you're capable of Contracting and relaxing on your own hence you can decide when to breathe and when it contracts and relaxes it basically is what helps you inhale and exhale so it is key in allowing you to breathe so I basically just went around the edges and I I snipped that really thin diaphragm so that it's still there I can still look at it and see it and practice identifying it and now I kind of see that I've just got this rib cage that's in the way so I'm just simply going to take my thicker pair of scissors and I'm going to start kind of working my way through those ribs they're going to be thinnest towards the middle and therefore easiest to snip so again you kind of put your scissors in and as much as possible try to kind of pull upwards as you cut so that you're not damaging everything underneath the sternum is right around here which is a bit thicker than some of those ribs might give you a little bit of resistance and then as unsavory as it might sound once you kind of get to a certain point the best thing to do is just put your hands in there and pull and this is probably like if you're someone who's really wigged out about the dissection is not like something you're super jazzed about this would be probably the part where you maybe take like a little walk out in the hallway because this is going to be where you're most likely to hear some bones breaking some of those ribs are inevitably gonna crack as you kind of pull backwards and it's it's kind of a necessary evil to get full visualization of the thoracic cavity I personally like the bones cracking is the worst part for me so I just kind of do like a one two three and I just go for it and it's better than drawing it out okay but you can see that doing that has all of a sudden kind of really exposed a lot of things that we couldn't see before just kind of pushing outwards all right so that's kind of the in my opinion the least fun part and similarly with some of this tissue kind of up in the the neck of the pig you can use your for you can use your dissecting scissors you can use your scalpel people have different levels of comfort you can also just kind of pull things back with your hands a little bit to get some sense of where things are at the nice thing about pulling with your hands is it's harder to damage things that you need to keep if you're just simply pulling on them and this also will be kind of where your instructor will provide some expertise in terms of yeah cut there don't cut there because if it's your first time doing it then you might have a good sense of is this something that I need to keep or is this a like a layer of tissue that I get rid of but it should look something like this when you have it all opened up well kind of your major landmark is you want to go upward until there we go it's looking pretty good you want to go upward until you can see the layer next and the larynx is going to be a pretty noticeable uh Benchmark it's this guy right between my fingers it's it's pretty hard it's full of a lot of cartilage so it feels pretty rigid and it's kind of bows outwards so it's it's a nice Landmark to use because it's decent in size and that is connected to the trachea another tube that you want to make sure that you get down to that point and the trachea is pretty distinct again a fairly wide tube but it also has all of these card cartilage rings collagenous Rings If you will that help keep it open and so you can almost even just like run your finger along the exterior of it and you can feel that ribbed feeling kind of underneath your finger and then of course we've got the heart here you will if you want to get the heart exposed one thing you'll notice is if you like take a pair of forceps it looks like there's like a film over the heart that is the pericardial Sac the pericardial Sac holds fluid in around the heart and if you want to be able to see all of the details of the heart you're going to have to snip that as well and usually for this I just recommend using forceps and pull up on it and just make little tiny Nicks with a scalpel to pull away at it it's super thin tissue so once you've started a hole and created kind of it loses its Integrity then you can honestly almost just rip it off kind of like cellophane but if you want to kind of chip away at it with either the scissors or the scalpel you can I would just recommend with whatever Implement you're using pull up on it with forceps as you are cutting so that you don't end up like cutting it all up at this point you more or less have everything exposed and then it's it's essentially an organ scavenger hunt where we try to make sure that you can identify everything in this in this pig and you also will be given a list of what's expected so for the list that you're given basically you need to know how to find and identify all of the things on that list and you also need to be able to know the function of the things on that list so really make sure that you're taking your time in class to feel comfortable navigating throughout the pigs because on the final that's what you're going to have you are going to have pigs on the side counter that have little pins sticking in them with letters on it and basically there will be a piece of paper that says something like what is the name of the organ indicated by letter a and you'd have to write in the name of the organ in that place okay just kind of some additional final things before you get uh to class this week one be really careful kind of as you go throughout the dissection right you're using sharp things to cut through tissue well you are also a whole bunch of tissue right and we really don't want you to be cutting into yourself we already have something to dissect here so just be really cautious about where you are making your Cuts especially with the scalpel and you don't get too happy with that make sure that anywhere that you are cutting with a scalpel that you are cutting away from your hand or you are using the forceps to hold the skin to make your cuts the other thing to keep in mind body parts okay because at some point you're not going to remove organs on purpose let's just put that out there okay this is not you're not a transplant team you're just exploring the body cavities and what they have so we really shouldn't be removing entire organs but there will be cases where like you maybe cut off a little tiny piece of tissue to better illustrate where something is at and if you do that we don't want to be throwing any of that in the trash right all of that stuff is Laden with um formaldehyde and so that's gonna have to go in one of those special bags at the side counter if at any point you feel like this is really getting to you like you feel like you're gonna faint or you feel like you're gonna be sick well if you feel like you're gonna be sick try to get to a trash can if you feel like you're gonna faint sit on the floor okay and if you need to there's no shame in stepping outside and just taking a couple deep breaths sometimes just a little bit of fresh air in a moment away is enough to kind of help you reset and with that we will see you guys for the pig die section this week