When a pathogen comes in contact with your body, it has to breach the first line of defense to get inside. Your skin and mucus membranes are the main barrier here. Mucus traps the pathogens, and then is forced out of your body when you cough or blow your nose. Your skin also secretes chemicals that have antiviral properties, killing viruses on contact. If the pathogens get through that defense, the next line is non-specific immunity cells that patrol your tissues engulfing pathogens. There are other cells that do this, like macrophages, but the dendritic cells are most important for activating the third line of defense in your body.
Dendritic cells reside in your tissues, waiting for an invader to arrive. When they do find one, they engulf it and digest it. After they do this, they select pieces of the invader called antigens and put them on their surfaces. The dendritic cells migrate back to lymph nodes, key locations in your body filled with immune cells. There, they show the antigens, called antigen presentation, to two types of lymphocytes, T-cells and B-cells, activating them for a full immune response.
Answer:
A secondary pollutant
Explanation:
Pollutants can broadly be classified into two main categories based on their formation or synthesis. 1: Primary pollutants, 2: Secondary pollutants.
1: Primary pollutants
Primary pollutant can be considered as any environmental pollutant that is being directly emitted from a certain source like when we burn coal carbon di oxide is directly emitted into the atmosphere so CO2 is a primary pollutant.
Similarly sulfur di oxide or SO2 is also a primary pollutant that is emitted by the gas emissions of motor vehicles.
2: Secondary pollutants:
On the other hand, secondary pollutant is something that is not directly emitted on earth as an environmental pollutant but some how it is formed due to a reaction of primary pollutant.
Such as mentioned in the question that SO2 when oxidized in air in the presence of enzymes and water, it form H2SO4 or acid rain which directly falls on earth and incurs great amount of damage to not only living organisms but also non-living organisms such as marble buildings.
Therefore, acid rain is secondary pollutant. Please see picture for better understanding.
Hope it help!
Answer:
Muscles - skeletal, smooth, and cardiac.
Location
Skeletal - This is located between bones.
Smooth - walls of hollow visceral organs ( such as the liver, pancreas, and intestines.)
Cardiac - the heart.
Explanation:
This is my FAVORITE thing to learn about. but it's some people's challenges so I thought I could help them out.
