which type of muscle is found in the walls of hollow organs

HESI A2

HESI A2 Practice Test Anatomy and Physiology

1. Which type of muscle is found in the walls of hollow organs?

A. Skeletal muscle
B. Cardiac muscle
C. Smooth muscle
D. Striated muscle

Correct answer: C

Rationale: Smooth muscle tissue is found in the walls of hollow organs, such as the intestines, blood vessels, and bladder. It contracts involuntarily, allowing for movements like peristalsis in the intestines and regulation of blood flow in blood vessels. Skeletal muscle (Choice A) is attached to bones and helps in voluntary movements. Cardiac muscle (Choice B) is found in the heart and contracts involuntarily to pump blood. Striated muscle (Choice D) refers to both skeletal and cardiac muscles, which have a striped appearance due to the organization of their filaments. However, smooth muscle (Choice C) is specifically the type found in hollow organs.

2. Where does digestion begin in the digestive system?

A. Stomach
B. Mouth
C. Small intestine
D. Esophagus

Correct answer: B

Rationale: Digestion begins in the mouth. Mechanical digestion through chewing and chemical digestion through saliva initiate the breakdown of food. Enzymes in saliva start breaking down carbohydrates, marking the beginning of the digestive process. The stomach primarily functions in further breaking down food and mixing it with gastric juices. The small intestine is where most of the digestion and absorption of nutrients occur. The esophagus is a muscular tube that helps move food from the mouth to the stomach, but digestion does not begin there.

3. Which of the following organs is involved in the immune system?

A. Heart
B. Bronchi
C. Appendix
D. Esophagus

Correct answer: C

Rationale: The appendix is involved in the immune system as it is believed to play a role in maintaining and protecting beneficial gut bacteria, especially after gastrointestinal illnesses. This helps in restoring the balance of intestinal bacteria crucial for immune function. The heart (Choice A), bronchi (Choice B), and esophagus (Choice D) are not directly involved in the immune system's functions. The heart pumps blood, the bronchi are part of the respiratory system, and the esophagus is responsible for transporting food to the stomach.

4. Which structure in the ear is responsible for balance?

A. Cochlea
B. Semicircular canals
C. Ossicles
D. Eustachian tube

Correct answer: B

Rationale: The semicircular canals in the inner ear are responsible for maintaining balance by detecting changes in head position and movement. These structures contain fluid and hair cells that send signals to the brain regarding the body's orientation in space, helping us stay balanced and navigate our surroundings. The cochlea is responsible for hearing, the ossicles are involved in sound transmission, and the Eustachian tube helps equalize pressure in the middle ear, but they are not directly related to balance.

5. Where are B-lymphocytes produced?

A. Thymus
B. Red bone marrow
C. Lymph nodes
D. Spleen

Correct answer: B

Rationale: B-lymphocytes are produced in the red bone marrow. The red bone marrow is the primary site for B-cell development, where they mature before entering the circulation. The thymus is responsible for T-lymphocyte maturation, not B-lymphocytes. Lymph nodes and spleen play roles in immune responses but are not the primary sites for B-lymphocyte production.