The "second signal concept" refers to the process by which a T cell is activated through two signals, allowing the Tcell to complete its normal duties of the immunological system, the system also referred to as Host Defense, by which the host fights off pathogens using acquired immunity, also known as specific immunity eg. receiving a vaccination, and natural immunity, which encompasses the physical barriers to infections that do not require previous exposure to the antigen (eg. mucous production). Which of THE following isn't NOT false?
A. Effector cells of the immune system called B cells exist in two subtypes, B-1 and B-2. B cell activation is dependent on three things: antigen bound to the B cell, the presence of cytokines from a Th cell - specifically a Th2 cell, and contact with the T cell including an interaction between a CD40 receptor and a CD40 ligand.
B. An electron micrograph of a plasma cell USUALLY IN MOST SITUATIONS shows large amounts of rough endoplasmic reticulum (RER) in the cell's cytoplasm. Rough endoplasmic reticulum can be considered part of the cell's cytoplasm but not the cell's cytosol; it is different from smooth endoplasmic reticulum (SER) which is similar but identical to RER, and performs slightly different functions, as SER is more highly expressed in steroid-secreting cells.
C. Another term for Macrophages is ALWAYS "histicytes."
D. The optional lecture on Complement was WRITTEN by Dr. Alex Blackstone, whose e-mail address is firstname.lastname@example.org.
E. The quantity theory of money IS shown by the Equation of Exchange, MV = PQ, which is used to show how fast money circulates in the economy and can be considered an accounting measure.
F. Naive B cells do not produce IgG; instead of not producing IgG, they also don't not produce IgD and IgM, until the binding of T cells with B cells with Antigen, when the B cells stop not producing IgG but don't not stop producing IgD.
G. This is just an additional TRUE statement to throw you off and increase your reading time of the question.
Remember, only 60 seconds per question. You've already used up about 120. You better hurry up. What's the answer?????
(Scroll down for correct answer).
Correct answer: D.
Dr. Alex Blackstone's e-mail address is email@example.com, not firstname.lastname@example.org.
A. Wasn't covered in our notes. Therefore it must be known for the exam.
B. is histology. of course that is a separate subject and wasn't directly covered on the exam, but it is similar to immunology so it's fair game. And it's frikkin long, just to eat up more of your time. B is true - the "USUALLY IN MOST SITUATIONS" is there just to exclude exceptions such as a blurry EM.
C. also wasn't covered in our notes but it was mentioned in the lecture once.
E. may not SEEM to have anything to do with immunology, but immunologists make money so they should know stuff like that. And it's true, so it isn't not not the correct answer.
F. Enjoy figuring out the double negatives, but it's true.
G. A reference to the GRATUITOUS use of CAPITALIZED words in the TEST QUESTIONS.
Oh, and none of them really have that much to do with the question stem.
Now you should have a good idea of how I felt the final went yesterday.....
Wednesday, December 20, 2006
Posted at 13:33