muscle contractions that normally move food along the human digestive system are known as

HESI A2

Anatomy HESI A2

1. What are muscle contractions that normally move food along the human digestive system known as?

A. defecation
B. osmosis
C. peristalsis
D. circulation

Correct answer: C

Rationale: Muscle contractions that move food along the human digestive system are known as peristalsis. Peristalsis consists of a series of coordinated muscular contractions and relaxations that help propel food through the esophagus, stomach, and intestines, facilitating efficient digestion and nutrient absorption. Defecation refers to expelling waste from the body, osmosis is the movement of water across a membrane, and circulation relates to the movement of blood in the body's circulatory system, not directly involved in food transportation along the digestive tract.

2. Which of the following is not part of the axial skeletal system?

A. the skull
B. the ribs
C. the breastbone
D. the radius

Correct answer: D

Rationale: The correct answer is D, the radius. The axial skeleton comprises bones located along the central axis of the body. It includes the skull, ribs, breastbone (sternum), vertebrae, and sacrum. The radius, on the other hand, is a bone of the forearm, part of the appendicular skeleton. The appendicular skeleton consists of the bones of the limbs and their girdles, not the central axial bones.

3. What is the function of platelets in the blood?

A. Transporting oxygen
B. Clotting blood
C. Fighting infection
D. Transporting nutrients

Correct answer: B

Rationale: Platelets, also known as thrombocytes, are responsible for clotting blood. When there is an injury, platelets help form blood clots to prevent excessive bleeding. This function is crucial in maintaining hemostasis and preventing hemorrhage. Choices A, C, and D are incorrect. Platelets do not transport oxygen, fight infection, or transport nutrients in the blood.

4. Which muscle group is primarily responsible for extending the knee?

A. Hamstrings
B. Quadriceps
C. Calves
D. Glutes

Correct answer: B

Rationale: The quadriceps, a group of muscles located on the front of the thigh, are primarily responsible for extending the knee joint. When the quadriceps contract, they work to straighten the knee, allowing for actions like kicking or standing up from a seated position. The hamstrings (Choice A) are responsible for flexing the knee, the calves (Choice C) primarily work on plantar flexion at the ankle joint, and the glutes (Choice D) are mainly involved in hip extension.

5. What are the chemical messengers that control growth, differentiation, and metabolism of specific target cells called?

A. Hormones
B. Neurons
C. Glands
D. Second messengers

Correct answer: A

Rationale: Hormones are signaling molecules produced by glands in multicellular organisms. They travel through the bloodstream to specific target cells where they regulate various physiological processes, including growth, differentiation, and metabolism. Neurons (choice B) are nerve cells that transmit nerve impulses and are not responsible for controlling growth, differentiation, or metabolism. Glands (choice C) produce and release hormones but are not the chemical messengers themselves. Second messengers (choice D) are molecules involved in intracellular signal transduction, not the primary chemical messengers controlling growth, differentiation, and metabolism. Therefore, hormones (choice A) are the correct answer as they match the description provided in the question.