After I posted the scores for quizzes 2 and 3 to Canvas yesterday, some of you noticed errors in your scores. I looked into it, and it turns out Canvas had a glitch that made some of the scores load incorrectly – so I fixed the issue and uploaded the scores again. It looks like that fixed the problem – but please check your scores when you have a moment just to make sure they look right to you. Thank you!
Just a quick update – all the scores for all three of our quizzes are now posted on Canvas.
I have a couple comments about quiz 3. First: please note that Quiz 3 ended up only having 10 points instead of 15 (so your score for that quiz is out of a total of 10 points).
Second: there was one question on Quiz 3 that was problematic for quite a few people because of a misleading lecture slide – so I made a grade adjustment, and I want to be sure that you understand the concept correctly.
Here’s the question:
4. When a tumor is “well-differentiated,” that means:
A. The tumor cells look very similar to their cell of origin
B. The tumor cells look very different from each other
C. The tumor is benign
D. The tumor probably has a poor prognosis
The correct answer is A (The tumor cells look very similar to their cell of origin). “Differentiation” refers to how closely a tumor’s cells resemble their cell of origin. Well-differentiated tumors are composed of cells that closely resemble their cell of origin, whereas poorly-differentiated tumors are composed of cells that hardly resemble their cell of origin at all.
Quite a few of you answered C (The tumor is benign). That answer is incorrect – but I can see why you may have chosen that answer based on this slide (slide 8 from the Neoplasia I: Tumor Nomenclature ppt):
This slide is misleading, because it seems to be saying that benign tumors are always well-differentiated, and malignant tumors are always poorly-differentiated (which isn’t true).
What I was trying to do on this slide was to list the general characteristics of benign vs. malignant tumors (for example: benign tumors tend to grow slowly, whereas malignant tumors tend to grow quickly). And with regard to differentiation, benign tumors tend to be well-differentiated, and malignant tumors tend to be poorly differentiated. But those are just big-picture trends! In real life, benign tumors are occasionally poorly-differentiated, and malignant tumors are sometimes well-differentiated.
Back to the quiz question. Choice C is incorrect because while it’s true that benign tumors tend to be well-differentiated, you can also see well-differentiated malignant tumors too! So just because a tumor is well-differentiated, that doesn’t automatically mean it is benign. It kind of makes you think in that direction – but it’s just a general rule of thumb (not an absolute rule).
I hope that makes sense. If not, please shoot me an email and I’ll be happy to explain it further.
Given the misleading slide, I went in and added a point to the score of everyone who answered C 🙂
Just got an email from one of you about this show, and I wanted to pass it along to the rest of the class in case anyone needs a new Netflix series. Here’s the scoop: It’s a documentary about the neurosurgery department at Lenox Hill Hospital but because of the surgeries they are doing they are constantly bringing specimens to the pathology department and talking about neoplastic tissue. In the first episode, they diagnosed an adenocarcinoma and glioblastoma. It was very fitting giving the recent lectures so if anyone is looking for a mindless way of ‘studying’ it’s a good way to kill some time!
Q. I had a question about the increased estrogen exposure and increased risk for breast and endometrial cancer. Is birth control an increased estrogen exposure? Or does it simulate the hormones of being pregnant? Or something completely different.
A. Good question! No, birth control pills do not expose you to excess estrogen. In fact, they may actually decrease your overall estrogen exposure.
There are many different types of oral contraceptive pills (OCPs) – but basically they boil down to two formulations: they either contain a combination of estrogen and progesterone, or they just contain progesterone. They prevent pregnancy by preventing follicle maturation and ovulation.
Here’s how they work. Progesterone inhibits the release of GnRH from the hypothalamus – which means that you’ll release less FSH and LH from your pituitary, which means that both follicular maturation (controlled by FSH) and ovulation (controlled by LH) are inhibited. This means that you’re also making less estrogen (follicles make estrogen as they develop; that’s what actually triggers the LH surge that leads to ovulation).
Estrogen has an inhibitory effect on FSH release – so that’s why some OCPs also have a little estrogen in them. But that little bit of estrogen in the pill doesn’t increase your overall estrogen exposure, because at the same time, you’re inhibiting your own estrogen production (by the follicles) – so the net effect is an estrogen deficit.
So that’s why OCPs don’t increase the risk of developing estrogen-related cancers like breast and endometrial cancer. In fact, they may even be protective against some cancers (ovarian cancer in particular), although this hasn’t been definitively proven yet.
So I couldn’t find the exact scene I wanted to show you guys (the one where Fletch says “He has melanoma…carcinoma…some kind of noma”), probably because it wasn’t nearly as funny as the rest of the film. But I did find a couple good clips, in case you need a laugh.
This is just silly, stupid humor, but actually, that’s exactly why I like it.
This is great because it’s exactly how I felt at my first autopsy. I could tolerate the sight of the body, and even the sound (barely) of the bone saw – but the smell…that pathologist is right, you just never get used to the smell.
Hi everyone! Here’s a good question I got by email – thought I’d share it with you in case someone else had the same question.
Q. Hello, I was wondering if you could send me the question that had the answer “Type 2” hypersensitivity. I got it wrong and I think the reason behind it was because of the “platelet” term and I took it maybe too literal by thinking that in the illustration of Type 3 in your notes where there is platelet aggregation in the picture. I also factored Type 2 out because it only mentioned red blood cells under type 2 which I took maybe more literal once again because I didn’t see anything about platelets.
A. Yes! I’ll explain why type II hypersensitivity is the correct answer for that question…and then I’ll answer your questions specifically. Here’s the question you’re referring to from quiz 2 (I also posted a link to the Quiz 2 Kahoot on our Kahoots page):
This patient is making antibodies against her own platelets, and those antibodies are coating (opsonizing) her platelets, making the platelets yummy to macrophages. This is an example of type II hypersensitivity, because there are antibodies coating a cell, leading to problems (in this case, consumption by macrophages). Here’s the slide from lecture showing how this process works:
This is exactly what’s going on in the patient in this quiz question – you could just cross out “opsonized cell” in the diagram above and put “platelet” and that would be a diagram specific for this patient.
I hope that makes sense! Just for completeness, here’s your email, with my responses to your questions in bold:
Hello, I was wondering if you could send me the question that had the answer “Type 2” hypersensitivity. I got it wrong and I think the reason behind it was because of the “platelet” term and I took it maybe too literal by thinking that in the illustration of Type 3 in your notes where there is platelet aggregation in the picture. You’re right – there is platelet aggregation in the picture illustrating type III hypersensitivity! But in type III hypersensitivity, the patient has immune complexes floating around, lodging in vessels, and the platelets are there because of all the damage to the vascular endothelium. The platelets are kind of a secondary thing – they’re not coated with antibodies, or anything – they’re just showing up because of tissue damage. The patient in our quiz question, on the other hand, doesn’t have immune complexes – she has platelets that are coated with antibodies! Here, the platelets aren’t just showing up because there is damage – they are actually being targeted by antibodies – so their role in this patient is very different. I also factored Type 2 out because it only mentioned red blood cells under type 2 which I took maybe more literal once again because I didn’t see anything about platelets. Oh – actually type II hypersensitivity reactions aren’t limited to just red cells! They can target any cell – red cells, thyroid cells, platelets, neurons – literally any cell in the body!
Hi again everyone – this is my last update today, I promise! I just remembered that you guys are having your discussion about racial inequality during our lecture time today – so I apologize for emailing you unnecessarily about our lectures/office hours this morning! Everything is all set up for you to view now, whenever it’s convenient. I’ll schedule more Zoom office hours for next week – but in the meantime, if you have any questions, just drop me an email.
Another quick update! Our second lecture (Neoplasia II: Tumor Characteristics) is still being processed by YouTube – and as soon as it is finished (hopefully in about 15 mins), I’ll post the link on our lectures page. Thanks for your patience! Also, just a reminder – if you have any questions, hop onto today’s Zoom Office Hours meeting (link on lectures page). I’m in the meeting now, and it will run until 11:00 🙂
Hi everyone – just waiting on YouTube to finalize processing of our first lecture video – so instead of starting at 9:05 today we’ll start at 9:15. Sorry for the delay! Grab another cup of coffee – we’ll be on in just a few minutes 🙂
Hi everyone – just a couple updates. First, a note on lecture format – it seems like the YouTube videos are working well, but the mp4 files are causing problems (probably because of their size). So for today’s lecture, I’ve just posted the YouTube link, not the mp4 file. Let me know if that works for you guys.
Second – I haven’t been able to schedule office hours during lecture this week because of prior commitments – but please just drop me an email if you have any questions on the material. We can always set up a quick zoom meeting to chat if that would help.