Video Transcript
Goblet cells, like the one shown in
the diagram, are mucus-secreting cells. They are present in mucous
membranes throughout the body and the mucus they release traps pathogens and other
foreign particles. Which organ does not contain goblet
cells? (A) Skin, (B) trachea, (C) stomach,
(D) nose, (E) vagina.
This question is asking us about
goblet cells and mucous membranes, which are featured as part of the innate immune
system. The immune system is a network of
cells and proteins that defend us against infection. It can be divided into innate, or
nonspecific, immunity, and adaptive, or specific, immunity. This question is asking us about
features of the innate immune system, so let’s describe that in some detail.
Innate immunity is the first line
of defense while the adaptive immune response develops. It is rapid and includes barriers,
like our skin, that can prevent pathogens from entering and causing infection. Innate immunity is nonspecific,
meaning it fights all pathogens in the same way. While our skin does a good job of
protecting our body from the outside, mucous membranes act to protect our body
cavities and internal surfaces.
Here’s what a typical mucous
membrane looks like: the cell in the center, and in the provided diagram on the
left, is a goblet cell. These cells have special vesicles
inside that contain mucus that they can secrete. The cells on either side are
ciliated epithelial cells. You can see the cilia on top of the
cells. Cilia are hairlike structures that
extend from the surface of the cells. Mucus can be secreted from the
goblet cell and can combine with the cilia. This can trap foreign particles
like pathogens, which can then be swept away by the cilia.
Mucous membranes can be found in a
number of places in the body. They’re found in openings, such as
the nose, mouth, and vagina, which can lead to the inside of the body. So we can eliminate these answer
choices. Mucous membranes are also found in
the trachea, which is the tube that connects the mouth to the lower respiratory
tract. Air from the environment is
breathed in through this tube, and mucus helps filter the air of pathogens before
entering the lungs. So we can eliminate answer choice
(B).
Mucous membranes can also be found
in the stomach to help lubricate the movement of food and to help protect it from
pathogens. So let’s eliminate answer choice
(C). The skin does not contain mucous
membranes because it has a tough surface that is difficult for pathogens to
enter.
Therefore, the organ that does not
contain goblet cells is given by answer choice (A), skin.
