Which structure is located where the esophagus penetrates the diaphragm?

A. esophageal hiatus

B. cardiac orifice

C. upper esophageal sphincter

D. lower esophageal sphincter

Answer Explanation:

a) esophageal hiatus

- Correct: The structure located where the esophagus penetrates the diaphragm is called the esophageal hiatus. The esophagus passes through an opening in the diaphragm known as the esophageal hiatus as it descends from the thoracic cavity into the abdominal cavity. This hiatus allows the esophagus to connect the pharynx to the stomach.

b) cardiac orifice

- Incorrect: The cardiac orifice is the opening of the stomach into the esophagus. It is located at the superior portion of the stomach and is surrounded by the lower esophageal sphincter. It is not located where the esophagus penetrates the diaphragm.

c) upper esophageal sphincter

- Incorrect: The upper esophageal sphincter is a muscular ring located at the upper end of the esophagus, where it meets the pharynx. It controls the passage of food from the pharynx into the esophagus but is not located where the esophagus penetrates the diaphragm.

d) lower esophageal sphincter

- Incorrect: The lower esophageal sphincter (LES), also known as the cardiac sphincter, is a muscular ring located at the lower end of the esophagus, where it meets the stomach. It controls the passage of food from the esophagus into the stomach but is not located where the esophagus penetrates the diaphragm.

Therefore, the Correct Answer is A.

Q #1: Where does the chemical digestion of starch begin?

A. mouth

B. esophagus

C. stomach

D. small intestine

Answer Explanation

a) mouth

- Correct: The chemical digestion of starch begins in the mouth. Salivary amylase, an enzyme secreted by the salivary glands, initiates the breakdown of starch molecules into maltose and other smaller carbohydrate molecules. This process begins as soon as food enters the mouth and continues as it is mixed with saliva during chewing and swallowing.

b) esophagus

- Incorrect: The esophagus is not directly involved in the chemical digestion of starch. It serves primarily as a conduit for the passage of food from the mouth to the stomach via peristaltic contractions.

c) stomach

- Incorrect: While some minor digestion may occur in the stomach due to the presence of salivary amylase from swallowed saliva, the stomach is not the primary site of starch digestion. Its acidic environment inhibits the activity of salivary amylase, so significant starch digestion does not occur there.

d) small intestine

- Incorrect: Starch digestion continues in the small intestine, primarily in the duodenum, but it does not begin there. Enzymes such as pancreatic amylase and brush border enzymes further break down starch into simpler sugars in the small intestine.
Q #2: Most of the nutrient absorption along the alimentary canal occurs in the

A. ascending colon

B. stomach

C. jejunum

D. ileum

Answer Explanation

C. jejunum

- Correct: Most of the nutrient absorption along the alimentary canal occurs in the jejunum, which is the middle segment of the small intestine. The jejunum has a highly folded inner surface covered with finger-like projections called villi and even smaller microvilli. These structures greatly increase the surface area available for absorption. The epithelial cells lining the villi contain numerous transport proteins and enzymes responsible for absorbing nutrients such as carbohydrates, proteins, fats, vitamins, and minerals into the bloodstream for distribution to the body's cells.

A. ascending colon

- Incorrect: The ascending colon is part of the large intestine (colon) where water and electrolytes are primarily absorbed, but it is not a major site of nutrient absorption.

B. stomach

- Incorrect: While some substances, such as water, electrolytes, alcohol, and certain drugs, can be absorbed in small amounts in the stomach, the stomach is not a major site of nutrient absorption. Its main function is to begin the digestion of proteins and store food temporarily.

D. ileum

- Incorrect: The ileum is the final segment of the small intestine, and while it does participate in nutrient absorption, the majority of nutrient absorption occurs in the jejunum, which precedes the ileum along the alimentary canal. The ileum primarily absorbs bile salts, vitamin B12, and some remaining nutrients not absorbed in the jejunum.
Q #3: Which part of the large intestine attaches to the appendix?

A. cecum

B. ascending colon

C. transverse colon

D. descending colon

Answer Explanation

Cecum attaches to the appendix

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Which structure is located where the esophagus penetrates the diaphragm?

More Questions on TEAS 7 Science

Q #1: Where does the chemical digestion of starch begin?

Answer Explanation

Q #2: Most of the nutrient absorption along the alimentary canal occurs in the

Answer Explanation

Q #3: Which part of the large intestine attaches to the appendix?

Answer Explanation

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