Week 9: Definitions

Chapter 14 - Innate Immunity

1) Innate Immunity - Resistance to pathogens conferred by barriers, chemicals, cells, and processes that remain unchanged upon subsequent infections with the same pathogens.

2) Leukocyte - White blood cell.

3) Plasma Cells - B cells that are actively fighting against exogenous antigens and secreting antibodies.

4) Phagocytes - Cells, often leukocytes, that are capable of phagocytosis (type of endocytosis in which solids are moved into the cell).

5) Differential White Blood Cell Count - Lab technique that indicates the relative numbers of leukocytes.


*red blood cells surrounding a white blood cell

Week 8: Reflection

Last week when I was studying for my microbiology exam, I took a break and went to a restaurant with my cousins for dinner. Our waiter seated us close to the kitchen door and we were able to see to food being prepared. Along with the stoves and ovens, we were able to see huge sinks and faucets that were filled with dirty dishes, utensils, and cooking pans.

Comparing the cleaning process of dishes and utensils at a restaurant and the cleaning process at home is different. In a public area, such as a restaurant, the process of killing germs and microbes is known as sanitization. In a general area, such as a sink inside your kitchen, the process of killing germs and microbes is known as disinfection.

Sanitization kills 99.9% of bacteria in under 30 seconds and must pass the Official Detergent Sanitizer Test. Disinfection kills bacteria in under 10 minutes.

Week 7: Investigation

At my internship in a pediatrician's office at Washington Adventist University, I stood in and watched the doctor perform a throat culture on a young boy. The procedure was done with a swab (a larger version of a q-tip).

The procedure is quite simple: the patient opens his or her mouth and the doctor uses a tongue depressor so that he or she can have a better view of the back of the throat. Next, the doctor takes a swab and rubs it along the back of the patient's throat for a few seconds. After the swabbing is completed, the swab is concealed in a bag and is sent to the laboratory for testing.

The purpose of swabbing is to gather the secretions created by the throat and mouth that may have bacteria or foreign pathogens. The laboratory bag serves the purpose of blocking off foreign particles that might come in contact (via direct, liquid, or air) and prevents contamination. Once the swab is sent to the lab, the technicians use the same swab and rubs it in a petri-dish to be incubated. After the incubation period, the growth in the dish will determine if there were any foreign pathogens present and if so, what type of pathogen it was.

Typical diseases that can be diagnosed by a throat swab include strep throat, tonsillitis, and pneumonia.

Week 6: Observation

These past few lab periods, we placed different antimicrobial agents in a bacteria medium. After incubating them for two weeks, the bacteria grew and was visible. The places where the antimicrobial agents were placed each had a clear circle surrounding them. Each of the agents were different and had circles of different circumferences. The size of the circumference of the circle showed which agent was the most effective in stopping bacterial growth.

Although it was clear to see no growth around the microbial agents, one must go into further detail with the antimicrobial agent to determine if it was bacteriostatic or bactericidal. Bacteriostatic refers to bacteria-inhibiting and bactericidal refers to bacteria-killing. If it was bacteriostatic, no growth would've occurred because the microbial agent inhibited growth from the beginning. If it was bactericidal, bacteria would've grown like the rest of the plate but the agent would've killed whatever was surrounding it.