welcome biology 202 students to our lab 6 um PowerPoint presentation video covering the lymphatic system and the immune response um this is going to be made up from lab exercise 35 which begins on page 519 in your lab manual again if you will take that pre-lab quiz we don't turn that in just to see what you may already know carefully read through pages 519 to 526 this is a really short um exercise comparative to some of the others we've done um and then use the lab guide to help you pick out the important terms as you study and we'll be going through um most of those here I do want to point out that a lot of this is covered in our lecture so I'm just going to be hitting some high points here in our lab this is a lab that we have added in the most recent semester so we don't cover as much in that as we do in some of the others this was just like said again we just added it um so the lymphatic system is made up of a network of lymphatic vessels that are sometimes referred to as the lymphatics lymphoid tissue lymph nodes and lymphoid organs including the tonsil thymus and spleen and we will speak about some of these more in particular all right as blood circulates the body um fluid leaves the capillaries at the arterial end due to pressure differences and returns to at the Venus end however some fluid does remain behind tiny lymphatic capillaries that are scattered throughout the tissue collect the excess fluid and transport it through larger lymphatic vessels and Trunks and eventually that lymph is going to be returned to the bloodstream by one of two larger ducts that are found in the chest and so we have two main lymph ducts the right lymph duct and the thoracic duct the right lymph duct is shown here um it covers the body that's in the portion here in green it drains lymph from the right upper extremity The Head and the thorax and the thoracic duct um receives lymp from the rest of the body and it's going to be here in this portion of this diagram that is kind of shaded in more of the peachish color um it's going to duct is going to be found here at the CNA Kylie which is the enlarged end of the thoracic duct and that's going to be here midpoint of midpoint of the thorax part of the body all right so lymph nodes you see these little I guess bulbous places along these vessels they are small Bean shap structures they're clustered along the lymphatic vessels they filter lymph so as that fluid or lymph is working its way back into the circular Tory system is going to be travel through these vessels and it's going to be filtered through the lymph nodes there are hundreds of those those lymph nodes spread throughout the body but they're usually embedded in connective tissue so you don't normally see them um there are large particularly large collections of LP nodes that are found in three main regions of the body the inguinal region which is going to be here where the upper thigh kind of meets the um at the hip the main portion of the body so where your leg bends that's going to be the inguinal nodes are found in along that region the axillary or the nodes that are closest to the armpit um under the arm this region and then the cervical if you remember your terminology from Anatomy 1 cervical is refers to the neck so you have cervical noes that are in the kind of the neck and lower face area the sites of primary and secondary lymphoid organs um those that are in bold here are the primary lymphoid organs that's going include the thymus the red bone marrow um and then the others the tonsils the Spen and pays patches and appendix are all considered secondary organs and I do want to point out just where these are at just because we are talking about lab um but in lecture we cover those more in depth all right let's look a little bit at the immune response there are two main types of defense mechanisms or systems in your body you have the innate which is your non-specific defense um it's going to include surface barriers like skin mucous membranes um your gut um it is fast acting it includes internal defenses like phagocytes inflammation fever um white blood cells neutrophils respon is non-targeted and Broad acting you are born with those defenses um there is no memory of germs killed in the past you're just born with these um these will go throughout your lifetime but these are non-specific defenses adaptive are specific defenses those are more targeted they develop over time to recognize and fight particular pathogens um creating immunological memory to respond faster upon reexposure and so your second layer is includes your lymphatic system it's slow to respond um it's going to be more specific along the B and t- cells and we're going to talk about those here in a little bit they create antibodies for repeat offenders things that You' become sick with that your body not recognizes the next time you're exposed to it and then mounts an attack against it so it's going to make antibodies that build against specific targets so those antibodies remember and hold a grudge for repeat offenders um there are three characteristics to your adaptive immune response memory it's the capacity to remember past infections amount of faster stronger response upon reexposure let's say that um you got the flu this year and you were really sick well you may come into contact with that same strain again later on and you might feel kind of but not really sick sick it's because your body has already encountered that and so it's going to mount up an immune response very quickly because you've already Expo been exposed to it once before and your body can fight it off much more quickly and so you're not really sick your body you may be tired and kind of laggy a little bit but you may not be the full sick that you were the first time uh specificity the ability to recognize and respond to very specific antigens they are specific to what what they will attack and self- tolerance the ability to distinguish between your body's own self cells and those that are forign Invaders preventing attacks on its own tissue you want your body to be able to recognize itself so it doesn't attack itself um there are two primary cell types of your adaptive immune system and those are the B cells or B lymphocytes and the t- cells or t lymphocytes now the B cells are going to attack Invaders that are outside of a cell and then te cells attack infected cells both types of those cells originate in red bone marrow um they do go through a maturation process that makes them become immunocompetent um which is going to involve the addition of receptors on the cell surface that recognize and bind to a specific antigen and become self- tolerant so both of those B cells and t- cells go through processes to become immunocompetent and self-tolerant so looking at a comparison between B cells and t- cells where they are different um B lymphocytes are going to be found an antibody mediated response um that's also called humeral so if you remember back when we talked about responses in class humeral is going to be blood related um so humeral or liquids involves B cells producing antibodies that circulate in the bloodstream to directly Target neutralize pathogens while cell mediated which is our T lymphocytes um immunity relies on those te- cells that directly attacked infected C attack infected cells or abnormal cells without the involvement of antibodies um essentially antibody mediator immunity fights extracellular pathogens um while cell mediated immunity combats intracellular pathogens um so where they mature at is going to be different be lymphocytes mature in the red bone marrow where they're made but T lymphocytes will travel to the thymus to become mature um the mature cells of the B lympocytes are going to be plasma cells those are those antibody secreting cells that are going to be specific to what they act upon and then t-lymphocytes their acting cells are the cytotoxic te- cells helper te- cells and Regulatory te cells and those we spend more time talking about in lecture um so functions of the B lympocytes they form plasma cells that produce antibodies that inactivate antigens and tag antigens for Destruction and then the T lymphocytes the cytotoxic cytotoxic tea cells attack infected cells and tumor cells whereas helper tea cells activate beef cells and other te cells um some further information B cells and antibody production when a B cell encounters a pathogen with a matching antigen it activates and differentiates into plasma cells which then Mass produce and antibodies specific to the antigen um in cell mediated immunity or te- cells different types of te cells play roles including cytotox cytotoxic tea cells which directly kill infected cells helper tea cells which assist in activating other immune cells so antibodies we Al those are also called imunoglobulin or IG IGS um they are produced by the activated V cells or plasma cells there are five major classes and if you can remember the monic gamed you'll see that IG G IG IGM IG and igd so gamed so I've kind of given you some things to kind of help Point those out to help you remember them so IGG is the most abundant um it goes across the placenta between mother and baby so I think of kind a big G most abundant um goes across placenta between mother and baby IG those are highly concentrated in mucous membrane so think breast milk and I should have capitalized the a in breast milk breast milk saliva and tears so a IG IGM is the first antibody to be made and they are Mega they're the largest of the imunoglobulin IG involved in allergies that's an easy one to remember and then igd um unknown function there's coming around to some functions with that but for our purposes just we we'll just count as D don't know function so igd don't know and then on these they will have antigen binding sites that is going to be a uniquely shaped part of an antibody that binds to an antigen and that's really all we're going to cover on this particular lab um we do want you to complete all questions for this particular exercise 1 through 22 so all pages all questions um watch any videos for this lab that we may have posted other than this one as well um complete any additional review sheets for this slab that are posted and complete the module or unit exam as appropriate and I hope that was helpful