Upcoming Midterm!

Hey everyone!

I just wanted to post to make sure everyone is up to speed on the midterm next week. The midterm will be very similar to your other in-lab quizzes with a few minor exceptions. First, (obviously) the midterm will cover everything that we have covered so far this semester. Don't forget to go back and study the development material (e.g. 24, 48, 72 hour chick slides). Also, the quiz will have a few extra slide questions, which will make the "U-finds" worth a half point each this week instead of a full point. To make it to the ten points, we will also have two "We-Find" questions where we point to a structure on a microscope in the back of the room, and you have to identify the structure. The slide label will be covered and you won't be able to change the zoom or move the slide. You can adjust the focus if you need to :) Besides those small differences, the midterm quiz will feel totally normal for you guys and will be great practice for the final!

My biggest suggestion for doing well on the midterm is identifying landmarks for each of the organs you have learned (what makes each organ unique, ex: thymus vs. the liver, spleen vs. lymph node, hyaline cartilage vs. fibrocartilage). The hardest thing for students is often figuring out what organ the picture is showing. If you have good landmarks for each organ, it will make this step a lot easier. Once you figure out which organ you are in, attack the question. If you are coming up blank on the question, it helps to think about what structures you have learned for that specific organ and then go from there. If you are having trouble finding a landmark on the slide and identifying the organ, look for the most noticeable characteristics (i.e. epithelium, glands, cartilage, etc.) and go through process-of-elimination-style in your head which organs have those characteristics (e.g. what structures have I learned that have stratified squamous epithelium and glands in the submucosa??). Once you get good at that, you are normally only a couple of steps away (at most) from figuring out which organ you're in. If you are having trouble coming up with good landmarks, feel free to contact us! My last suggestion before I get off my soap box: try to look at as many pictures of the structures as you can as you're studying. Looking at the same picture over and over can only help you so much. The links on the right are great for practice with this. Good luck! You guys are all going to do great.

Blood & Lymph

I hope you all enjoyed looking at your own blood cells during class last week :) Good news, this week is one of the lightest of the semester. Take advantage of that and everyone get a 10 on the quiz! As always, feel free to submit a question if you have one!

Important things for this week:
-MEMORIZE the chart that was on the board with the info about relative amounts of each white blood cell, life span, and function. This will get you easy points on this week's quiz, the midterm, and the final. A good mnemonic to remember the different types of WBCs is "Never let monkeys eat bananas!!!"
-Make sure that you can identify each type of blood cell (all of the WBCs, erythrocytes, megakaryocytes, reticulocytes) in a picture, that you can find the most common cell types (erythrocytes, neutrophils, and lymphocytes) on your slides, and that you know what processes each cell type is involved in.
For instance - Neutrophils = acute inflammation - remember, they're the white stuff in pus
                       Eosinophils = parasitic invasion
                       Basophils = related to mast cells - very involved in allergies - remember, they secrete
                                           histamine and heparin
                       Monocytes = they're all about eating
                       Lymphocytes = these are the T-cells and B-cells of immunity - they're involved with
                                                 your adaptive immune system
 You can use your blood slide or one of the generic ones in your box.
- Also, which WBCs are granulocytes ("B-E-N")? agranulocytes (M-L)?

Cool EM of erythrocytes and leukocytes! Can you guess which are the WHITE blood cells?? :)

What your blood slide will look like at about 4x mag. Zoom in on the purple spots (what are they stained with???) to pick out specific WBCs.

What do you see here? Here's a hint: the one at the middle-left is the MOST common WBC (notice the multi-lobulated nucleus). The one on the right is the second most common WBC (notice the big, dark nucleus with the halo-like cytoplasm and no visible granules). What do you guys think the small dark spots are? (Hint: They're the result of thrombopoiesis).

Someone that has leukemia... SOO many lymphocytes.

-On your own slides, be sure to know where to find the structures shown in the pictures above.
-Neutrophils are by far the most common and have he multilobulated nucleus (looks like several kidney beans connected by a small extension). Although most of your pictures in the manual only show 2 lobules, they can have several.
-Eosinophils can look similar to neutrophils, but are much brighter.
-Monocytes - remember the butt-print! (What it looks like when you're wet and sit on a dry chair and stand up).
-Basophils are dark and have lots of granules... usually so many that you can't see the nucleus.

Can you pick out all the different ones here? The two on the left are the same... Here's a hint, ID the following WBCs: neutrophil, basophil, lymphocyte, and eosinophil.

-The key for the lymphatic system is knowing what makes each organ unique, because they all have the lymph nodules.
-Lymph nodules are characteristically darker around the outside edges and lighter on the inside.

-Besides the capsules and epithelium taught in this chapter, almost everything is histologically named  dense lymphatic tissue.
-One common confusion: lymph nodes are larger than lymph nodules and house many lymph nodules within them.
-The center of the lymph nodule is the germinal center, and almost always will have lymphoblasts and monoblasts (except for in the spleen where they have t cells and b cells).
-What makes each organ unique:

• Lymph node: lymph nodules around the outside (cortex). The medulla does NOT have lymph nodules.

See how the lymph nodules are limited to the outside (cortex)??

• Ileum (Peyer's patches): Lymph nodules limited to the submucosal area. Look for the evaginations that are so characteristic of the small intestine. REMEMBER that peyer's patches are not found in the duodenum or jejunum, so if you see lymph nodules in the submucosa of the small intestine, it has to be the ileum. 

• Appendix: trash in the lumen, epithelium (simple columnar w/striated...), lymph nodules in the submucosa. 

Good shots of the appendix. Notice the invaginations as opposed to the evaginations in the small intestine.

• Spleen: Can look similar to the other organs (lymph node, liver, etc.), BUT it is the only one that has lymph nodules spread throughout the entire organ (lymph node only has them around the outside, etc.). Remember that the spleen has unique cells in the germinal center (t & b cells). 

See the nodules all over? Compare this to the lymph node.

• Thymus: LOBES that have the characteristic darker outside with lighter inside. Hassall's corpuscles (noticeable cells at the center of the germinal center). Be careful, the thymus can look very similar to the liver, but is distinguishable because the liver does not have the lighter centers and darker outsides of the lobes. The liver can have vasculature running down the center of the lobes which can look like Hassall's corpuscle so keep that in mind for the midterm/final! Use the shading of the lobes as your guide. See how the bottom pictures look similar??? The one on the right is the liver, the left is the thymus. The point of differentiation is the shading of the lobes. 

Hassall's Corpuscle - See how it looks different than vasculature? (no noticeable lumen, no RBCs

• Tonsils: Epithelium=strat. squamous (why??), though not always visible. TONS of nodules, generally arranged in rows.

Good luck everyone!!

Terms List: (key: know the histological names for the structures with [h] after them; assume you must be able to find these structures on your own slides unless indicated by [x])

I also included links to digital microscope slides for several of the structures. If the structure is harder to find, I set the link to automatically zoom to the place with the structure. On those, it would be wise to zoom out and make sure you can find it on your own. As always, feel free to email me with questions!

***This list is not guaranteed to be exhaustive, and only includes terms from this week. While we will not directly quiz information from previous weeks, knowledge of previous material will help a lot***

***Make sure you know everything on the chart that was on the board about WBCs***

RBC (erythrocyte)

                Erythropoiesis

Reticulocyte [x]

***A note about the WBC’s: You should be able to find a neutrophil and lymphocyte on your own blood slide. It might be harder to find the other three WBC’s. With that said, your blood smear slide in your box will oftentimes have the others as well.

Neutrophil

Eosinophil

Basophil

Monocyte

Lymphocyte

Megakaryocyte [x]

                Thrombocyte

                Thrombopoiesis

Lymph node [h]

                Medulla

                Cortex

                Lymph nodule [h]

                Germinal center [h]  – what cells are found there?

Ileum

                Peyer’s patches [h]

                Germinal center [h]

Appendix [h]

                Lymph nodule [h]

                Germinal center [h]

Spleen

                White pulp [h]

                Red pulp

                Trabeculae [h]

Thymus 

                Cortex [h]

                Medulla

                Interlobular septa [h]

                Hassall’s corpuscle

Tonsil

                Lymph nodule [h]

                Germinal center

                Epithelium [h]

Lymphatic vessel [h] [x]