Answer:
Kupffer cells, also known as stellate macrophages due to their particular structure while viewed under a microscope, were first identified by scientist Karl Wilhelm von Kupffer, after whom the cells were named, in 1876.
These cells, whose origin is in the yolk sack during fetal development, later on move to the liver where they will stay and further differentiate into their mature versions.
These cells are part of the liver cells, and are found particularly on the walls of the sinusoids, where they perform their two most important tasks. First, these cells are part of the immune system, as they are essentially macrophages. However, their role is pretty unique, as they are responsible not just for phagocytosis of invading bacteria, and other pathogens, and initiating immune responses, but also, this cell plays a role in decomposing red blood cells who are dying, and taking up the hemoglobin from them to further break that into reusable globin, and the heme group, from which iron is further extracted to be re-used and also to create bilirrubin, a part of bile.
Finally, these cells have been found to be connected to hepatic cirrhosis, as in their process of detoxifying ethanol, they produce toxins that force the liver cells to produce collagen, and thus to become fibrous.
Answer:
Pectoralis minor
Explanation:
Pecoralis minor is a thin, triangular muscle lies beneath the pectoralis major muscle. This muscle arises from the third ribs, fourth and fifth ribs.
The pectoralis muscles fans out from the shoulder upper ribs area. This muscle is involved in the coracoid process of scapula. The pectoralis muscle helps in the depression point of the shoulder.
Thus, the correct answer is option (D).
Answer:
Gastrulation.
Explanation:
The embryonic development occurs through the different developmental stages like cleavage, morula, blastula and so on. The formation of the germ layers occur in the gastrulation period.
The primitive streak is the structure that develops during the early stages of the gastrulation. As the embryo becomes asymmetric., the cells moves from their initial position and leads to the formation of primitive streak in the gastrulation phase.
Thus, the correct answer is option (C).
