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:
The given statement is True.
Explanation:
Scala media has endolymph as its constituent and endolymph is rich in Potassium ions (K+)
whereas
Scala tympani and scala vestibuli has in its composition Perilymph and Perilymph has sodium ions as their major constituent ions.
Therefore, scala media is Potassium ion rich while scala tympani and vestibuli are sodium ion rich.
Answer:
Special properties of an oxygen-binding protein in the muscles of marine mammals, such as seals, whales and dolphins, are the reason these animals can hold their breath underwater for long periods of time, according to a new study. ... In fact, the amount was so high in the muscle that it almost looked black in color.
Explanation:
The statement which is true about a rhombus is that it <span>is a parallelogram that has all sides equal, opposite sides parallel, and diagonals bisect at right angles - so the second answer is the correct one.
Every rhombus has 4 equal sides, where the opposite ones are parallel. Its diagonals always bisect in the middle, creating a 90 degree angle. </span>
