The most likely localization of the toxin would be to the ovaries, since this is where gamete production begins for females. For males, gametes are produced in the testes. The incorrect answers are all parts of the female reproductive system. The oviduct is where fertilization takes place. The endometrium (the lining of the uterus) is where the embryo will eventually implant.

The sympathetic (fight or flight) and the parasympathetic (rest and digest) systems control bodily processes that are involuntary, or autonomic. Somatic refers to voluntary actions, which are not controlled by either the sympathetic or parasympathetic systems.

The gastrointestinal, or digestive, system is primarily designed to break down (catabolize) nutrients and absorb them into the blood for use by the body. Digestion of nutrients by stomach and pancreatic enzymes allows for their absorption in the small intestine. The large intestine is responsible for water absorption.

Filtration occurs in three primary areas in the body: the kidney, the liver, and the spleen/lymph nodes. The kidney is part of the excretory system, in which fluids are filtered from the blood to remove solute waste from the body. The liver filters the blood in circulation, and is responsible for removing toxins that may have been absorbed during digestion. It is not, however, part of the gastrointestinal tract. The spleen and lymph nodes filter the interstitial fluid to screen for antigens and pathogens.

The sympathetic (fight or flight) and the parasympathetic (rest and digest) systems control bodily processes that are involuntary, or autonomic. Somatic refers to voluntary actions, which are not controlled by either the sympathetic or parasympathetic systems.

In order to stimulate digestion in the stomach G cells secrete gastrin, which stimulates parietal cells. Pepsinogen is released by chief cells. The parietal cells release hydrochloric acid into the stomach lumen. The lowered acidity cleaves pepsinogen and creates pepsin, which begins to degrade proteins.

Mucous cells have the nondigestive role of lubricating the stomach lumen and protecting the stomach epithelium from degradation by the highly acidic gastric juices.

The large intestine is the last organ in the digestive tract. The food mass exits the stomach as chyme and enters the small intestine, where 90% of chemical digestion occurs. The digested chyme is transported to the large intestine where most of the water and undigested nutrients in the chyme are reabsorbed; therefore, the majority of the digestion occurs in the small intestine, while the majority of water reabsorption occurs in the large intestine. This makes statement I false.

The large intestine also contains E. coli, a bacterial species that thrives in the anaerobic environment of the large intestine. Presence of E. coli is beneficial to humans because the bacteria synthesize vital vitamins such as vitamin B12. This makes statement II true.

Recall that the stomach is characterized by its highly acidic environment. This means that the lumen of the stomach contains a low pH and, therefore, a high concentration of hydrogen ions. Other organs involved in digestion, such as the large intestine, do not contain a highly acidic environment. The pH of the large intestine is higher than that of the stomach and, consequently, it has a lower concentration of hydrogen ions than stomach. This makes statements III true.

Skeletal muscle is under voluntary control, and are innervated by the somatic nervous system. Skeletal muscle is responsible for skeletal movement, such as swinging the arms or lifting the legs.

Cardiac and smooth muscle are under the control of the autonomic nervous system. Cardiac muscle contracts the heart autonomously, without additional neuronal input.

The role of a plasma cell in the immune system is to produce antibodies. These antibodies are effective in binding to extracellular pathogens. Antibodies produced by plasma cells would not be effective in binding to intracellular pathogens, such as M. tuberculosis and intracellular HIV. Only one answer choice specifies an extracellular pathogen.

Plasma cells are developed from B-lymphocyte precursors in response to the presence of a specific antigen, and are part of the adaptive immune response. As such, they would be relatively ineffective at fighting a newly-evolved microbe to which the body has never been exposed before.

The most likely localization of the toxin would be to the ovaries, since this is where gamete production begins for females. For males, gametes are produced in the testes. The incorrect answers are all parts of the female reproductive system. The oviduct is where fertilization takes place. The endometrium (the lining of the uterus) is where the embryo will eventually implant.

The defect in clearance of apoptotic cells in SLE is mainly attributed to macrophages, which serve integral roles in phagocytosis of dead cells and debris. An inability to clear these apoptotic cells over time leads to secondary necrosis, which results in the production and release of several DAMPS or damage-associated molecular pattern molecules which are potent inducers of the immune response.