Micro: Entry, Exit, Transmission

The urinogenital tract is a continuous system, meaning it is not divided into separate parts but is instead a single interconnected pathway. This allows microorganisms to easily move from one part of the tract to another, increasing the risk of infection or the spread of pathogens throughout the entire system.

Microorganisms can enter the host through various routes, including the respiratory tract, GI tract, and GU tract. However, blood vessels are not considered an area of entry for microorganisms. Microorganisms typically enter the bloodstream through other routes, such as wounds or injections.

In order for an infection to be established, the rate of growth in the keratin layer needs to be greater than the rate of shedding in the keratinous product. This means that the infection-causing organism is multiplying and spreading faster than the body can naturally get rid of it. Therefore, the statement is true.

B. pertussis is the bacteria that causes whooping cough. Whooping cough, also known as pertussis, is a highly contagious respiratory infection. It is caused by the bacterium Bordetella pertussis, which affects the respiratory system and causes severe coughing fits. The coughing fits are often followed by a whooping sound when the person tries to breathe in. B. pertussis is primarily transmitted through respiratory droplets when an infected person coughs or sneezes, making it important to vaccinate against this bacteria to prevent the spread of whooping cough.

Chlamydia is the correct answer because it is a bacteria that has efficient attachment mechanisms to the conjunctiva. Chlamydia trachomatis, specifically, is known to cause conjunctivitis by attaching to the conjunctival cells and causing inflammation. This bacterium is transmitted through direct contact with infected secretions and can easily attach to the conjunctiva, leading to infection and symptoms such as redness, discharge, and irritation.

Lactobacilli are part of the normal flora in the vagina and are responsible for maintaining a lower pH. They produce lactic acid, which helps to create an acidic environment that inhibits the growth of harmful bacteria and other microorganisms. This acidic pH is important for the overall health of the vagina and helps to prevent infections. Streptococci, Staphylococci, and Candida are not typically part of the normal vaginal flora and do not play a significant role in lowering the pH.

IgA is the correct answer because it is the antibody found in mucous secretions that aids in host defense. IgA is primarily found in areas such as the respiratory and gastrointestinal tracts, where it helps to prevent the entry of pathogens and neutralize toxins. It plays a crucial role in protecting the body's mucosal surfaces from infections. IgE is involved in allergic reactions, IgG is the most abundant antibody in the bloodstream, and IgM is the first antibody produced during an immune response.

There is no clear evidence to support the statement that bacterial infections are less common in uncircumcised males. The risk of bacterial infections can be influenced by various factors such as personal hygiene practices, sexual activity, and underlying health conditions. Therefore, it is incorrect to make a blanket statement that circumcised males are more prone to bacterial infections.

The conjunctiva is a thin, transparent membrane that covers the white part of the eye and lines the inside of the eyelids. It is not a part of the skin, but rather a specialized area that serves to protect and lubricate the eye. Therefore, the statement that the conjunctiva is a specialized area of the skin around the eye is false.

Dermatophytes are a type of fungi that infect the non-living keratinous structures of the skin. The stratum corneum is the outermost layer of the epidermis and is composed of dead skin cells that are rich in keratin. This layer acts as a protective barrier for the underlying layers of the skin. Since dermatophytes infect the non-living keratinous structures, it makes sense that they would primarily target the stratum corneum, as it is the layer where these structures are found.

Hepatitis B is not a burrowing microbe because it is a virus that primarily affects the liver. It is transmitted through blood and bodily fluids, rather than through burrowing or living in the soil or other environments. Schistosoma, Leptospira, and Ancylostoma are all examples of burrowing microbes, as they are parasitic worms that live in the bodies of their hosts, including humans.

Both Shigella and Salmonella are bacterial pathogens that can invade host cells and cause infection. One of the mechanisms they use to evade the host immune response is by inducing apoptosis, which is a programmed cell death. By triggering apoptosis, these bacteria can manipulate the host cell's signaling pathways and immune response to their advantage. Therefore, it is true that both Shigella and Salmonella produce apoptosis in their host cells.

Hair is not a protective barrier of the skin. The skin has multiple protective barriers, such as the acidic pH of 5.5, which helps to inhibit the growth of harmful bacteria. Langerhans cells are specialized immune cells in the skin that help to defend against pathogens. Normal flora refers to the beneficial bacteria that naturally reside on the skin and help to protect against harmful microorganisms. However, hair does not provide a protective barrier as it is primarily composed of dead cells and does not have any immune or antimicrobial properties.

H. pylori produces the enzyme urease in order to counteract the low pH in the stomach. Urease helps the bacteria survive in the acidic environment by breaking down urea into ammonia and carbon dioxide, which neutralizes the stomach acid. This allows H. pylori to colonize and infect the stomach lining.

Both Shigella and Salmonella invade M cells in the GI epithelium. M cells are specialized cells found in the mucosa-associated lymphoid tissue (MALT) of the gastrointestinal tract. These cells play a crucial role in the immune response by sampling antigens from the gut lumen and delivering them to underlying immune cells. Shigella and Salmonella exploit this mechanism to invade the host's cells and cause infection. By invading M cells, these pathogens can bypass the protective barrier of the GI epithelium and gain access to the underlying tissues, leading to gastrointestinal diseases.

Typhoid fever is a disease caused by the Salmonella bacteria, specifically Salmonella typhi. It is characterized by high fever, abdominal pain, headache, and diarrhea. The bacteria is usually contracted through contaminated food or water. If left untreated, it can lead to serious complications such as intestinal perforation or septicemia. Scarlet fever is caused by a different type of bacteria and is characterized by a rash, while septicemia is a condition where bacteria enters the bloodstream. Diarrhea can be a symptom of Salmonella infection, but typhoid fever specifically refers to the systemic illness caused by this bacteria.

E. coli is a common invader of the urinary tract causing cystitis.

Microbes that infect the respiratory system attach to or inhibit the lung epithelium. The lung epithelium is the layer of cells that line the respiratory tract, including the bronchioles and alveoli. When microbes enter the respiratory system, they can attach to the lung epithelium, causing infection and inflammation. This attachment allows the microbes to establish themselves in the respiratory system and potentially spread further. Inhibiting the lung epithelium can also disrupt the normal functioning of the respiratory system, leading to respiratory symptoms and complications.

Rarely are urogenital infections spread via urine.

A stye is an infection of a hair follicle on the eyelid. It is characterized by a red, painful lump that forms on the edge of the eyelid. Styes are typically caused by bacteria and can be quite uncomfortable. Treatment usually involves warm compresses and antibiotics, if necessary.