The Immune System Flashcards
True or false. When you suffer an injury, white blood cells near the injury site initiate the inflammatory response.
False.
The injured tissue releases chemicals that begin the inflammatory response.
Inflamed tissue turns red because ________.
a. an increased number of white blood cells is formed and begins circulating in the blood, particularly in the area of the injury
b. there is an increased blood flow to the injured tissues due to dilation of arterioles in the injured area
c. fluid, that is generally red, moves into tissues across “leaky” capillary walls
d. macrophages engulf bacterial cells and in so doing develop a reddish hue that can be seen on the body surface
b. there is an increased blood flow to the injured tissues due to dilation of arterioles in the injured area
The localized increase in blood flow is often seen as redness surrounding the injured tissue as histamine relaxes the smooth muscle in the vessels.
Mast cells release _________, which causes ________ of arterioles and leads to ________ blood flow to the injured tissue.
histamine…dilation… increased
The pain associated with the inflammatory response is the direct result of ________.
a. the swelling of the tissue and the chemicals released from certain cells
b. the clot that seals the wound
c. the mast cells touching and thus stimulating the sensory neurons
d. chemical messengers within the bloodstream that carry “pain messages” to the brain
a. the swelling of the tissue and the chemicals released from certain cells
The swelling and the chemicals may both stimulate surrounding sensory neurons and this brings about pain.
The direct cause of the heat generated by a wound or local infection is ________.
a. histamine, which causes the smooth muscle cells of the arterioles to relax; this leads to a cascade of events causing the tissue to become hot
b. the engulfing of the bacteria
c. clotting factors in the blood that begin to seal the wound
d. the presence of the bacteria or the foreign object
e. white blood cells that leak through the capillary walls
a. histamine, which causes the smooth muscle cells of the arterioles to relax; this leads to a cascade of events causing the tissue to become hot
Histamine, released by the mast cells, causes the smooth muscle cells of the arterioles to relax and ultimately leads to the heat apparent in the infected tissue.
Viral DNA makes mRNA by the process of _____.
a. replication
b. infection
c. translation
d. lysis
e. transcription
e. transcription
Viral DNA co-opts the cell’s reproductive machinery.
Which structure helps bacteria to attach within the tissues that they will infect?
a. Nucleoid
b. Capsule
c. Flagella
d. Cell wall
b. Capsule
The gelatinous capsule that covers some bacteria helps them attach to the tissues that they will infect.
True or false. Bacteria reproduce by an asexual process in which one parent cell gives rise to identical daughter cells.
True.
Bacteria reproduce by binary fission, which is an asexual process in which one parent cell splits in two to give rise to identical daughter cells.
There are four bacteria in an egg salad that is left out at room temperature. After two hours, how many bacteria will be in the egg salad?
a. 256
b. 2048
c. 32
d. 8
a. 256
The bacteria would double 6 times in 2 hours, so the total number of bacteria in the egg salad would be 256.
Which of the following represents the first line of defense against unwanted pathogens?
a. intact skin
b. antibody-mediated immunity
c. T cell-mediated immunity
d. phagocytes
a. intact skin
Skin represents an obstacle to entry by microbes. This is because the cells are tightly packed together, acting as a physical barrier to invasion. In addition, the skin also secretes chemicals that have antimicrobial properties, further protecting the host.
Which of the following act(s) as a neighborhood watch group, looking for specific invaders in the blood or other fluids that have compromised the first two lines of defense?
a. T cell-mediated immunity
b. intact skin
c. antibody-mediated immunity
d. phagocytes
c. antibody-mediated immunity
Antibody-mediated immunity represents a third line of defense that is more specific in its response. These antibodies target specific pathogens freely circulating in blood or other fluids.
Plasma cells are effector _______ and not part of the MHC system.
Plasma cells secrete _____ into the blood.
Plasma cells are part of the______ stage of the immune response.
B cells… antibodies…defense
What is the final step in the cell-mediated response to a viral infection?
a. Macrophages digest viral particles and display viral antigens on their cell surface.
b. Antibodies coat viral antigens.
c. Cytotoxic T cells punch holes in the membranes of infected host cells.
d. Helper T cells secrete chemicals that stimulate it to divide.
c. Cytotoxic T cells punch holes in the membranes of infected host cells.
This event causes infected host cells to burst and die and prevents the virus from spreading to other cells.
Which of the following types of cell can ingest pathogens?
a. cytotoxic T cells
b. helper T cells
c. macrophages
d. B cells
c. macrophages
Macrophages are phagocytic cells that can ingest pathogens; they can also present antigens to helper T cells.
What type(s) of cell(s) can helper T cells become?
a. MHC proteins
b. cytotoxic T cells
c. plasma cells
d. memory helper T cells and effector helper T cells
d. memory helper T cells and effector helper T cells
Helper T cells can develop into both memory helper T cells and effector helper T cells.
Structures that precipitate antigens, promote lysis, attract phagocytes, and neutralize toxins are called ________.
a. macrophages
b. cytotoxic T cells
c. antibodies
d. cytotoxic B cells
c. antibodies
Antibodies defend the system by precipitating antigens, promoting lysis, attracting phagocytes, and neutralizing toxins.
During which stage of HIV infection are viral levels in the blood at their lowest?
a. AIDS
b. initial disease symptoms
c. asymptomatic stage
d. initial infection
c. asymptomatic stage
During the asymptomatic stage, the immune system “controls” the infection and circulating virus levels drop; during this stage, the virus is “hiding out” in the lymph nodes and other lymphatic organs.
Which of the following conditions would NOT necessarily result in a diagnosis of AIDS in an HIV-infected individual?
a. swollen lymph nodes
b. wasting syndrome
c. Kaposi’s sarcoma
d. pneumonia, particularly if caused by the organism, Pneumocystis carinii
a. swollen lymph nodes
Swollen lymph nodes could appear during the asymptomatic stage or later as part of the initial disease symptoms. Both of these stages occur well before a diagnosis of AIDS.
A person is diagnosed as HIV positive. Why is the level of that person’s helper T cell level monitored?
a. Helper T cells stimulate B cells, which produce antibodies against the virus.
b. Helper T cells are the target of HIV.
c. Helper T cells stimulate the cytotoxic T cells, which can defend the body against the HIV infection.
d. All of the listed responses are correct.
d. All of the listed responses are correct.
The helper T cells are HIV’s target and it is the helper T cells that stimulate cytotoxic T cells as well as B cells.
What is the most likely reason an HIV-positive person might develop thrush and/or shingles?
a. A person with HIV is not eating properly, and these two diseases can occur in anyone who is not getting the correct nutrition.
b. The exact reason that HIV-positive persons are more susceptible to thrush and shingles is not known.
c. Thrush and shingles are caused by opportunistic organisms. An HIV-positive person has a compromised immune system and is vulnerable to infection by these and other organisms.
d. These two diseases are caused by organisms that are closely related to HIV.
c. Thrush and shingles are caused by opportunistic organisms. An HIV-positive person has a compromised immune system and is vulnerable to infection by these and other organisms.
Thrush and shingles are caused by opportunistic organisms and are thus able to cause disease in the immune-compromised HIV-positive person.
The urinary tract represents a portal of entry for E.coli, a normal inhabitant of the GI tract. Introduction of this opportunistic pathogen and its subsequent colonization is known as __________.
a. a symptom
b. an infection
c. a syndrome
d. a sign
b. an infection
Which of the following statements best describes the end result of bacterial conjugation?
a. One cell has lost a chromosome, while the other has gained one.
b. One cell has lost a plasmid, while the other cell has gained one.
c. One cell has given a copy of a plasmid to another cell and kept one copy for itself.
d. The two cells have had an equal exchange of plasmids.
c. One cell has given a copy of a plasmid to another cell and kept one copy for itself.
Both cells end up with a copy of the same plasmid.
From which cell does the sex pilus originate during bacterial conjugation?
a. Both the donor cell and the recipient cell
b. The donor cell
c. The recipient cell
b. The donor cell
The sex pilus originates from the donor cell.
True or False. During bacterial conjugation, the recipient cell receives a single-stranded loop of DNA
True.
One strand of the plasmid enters the recipient cell; this strand must be replicated in the recipient cell to produce a double-stranded plasmid that can replicate independently of the bacterial chromosome.
While exploring a local wooded area, you encounter what you believe to be a previously uncharacterized organism. Upon microscopic evaluation, you notice a single-celled organism about 1 micrometer, lacking a nucleus. What type of cell is this?
a. prokaryote
b. not enough information provided
c. eukaryote
d. nucelote
a. prokaryote
The lack of a nucleus is indicative of a prokaryotic cell.
