Where does primary peristalsis occur?
- A. Esophagus
- B. Stomach
- C. Nervous system
- D. Small intestine
Correct Answer: A
Rationale: Primary peristalsis occurs in the esophagus. Peristalsis is the coordinated muscular contractions that propel food through the digestive tract. In the esophagus, primary peristalsis is the involuntary wave-like contractions that push food from the mouth to the stomach. It is the natural and automatic process that occurs to facilitate the movement of food during digestion. The stomach (choice B), nervous system (choice C), and small intestine (choice D) are not the primary sites where peristalsis occurs in the digestive system.
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Which of the following is true about skeletal muscle?
- A. Skeletal muscle makes up 40% of the body's weight.
- B. Skeletal muscle attaches to bones by tendons.
- C. Muscle contraction is not involved in temperature regulation.
- D. Skeletal muscles contract only when in use.
Correct Answer: B
Rationale: The correct statement is that skeletal muscle attaches to bones through tendons, enabling movement. Tendons connect muscles to bones and allow the force generated by muscle contraction to be transmitted to the bones, facilitating voluntary movements. Choice A is incorrect because skeletal muscle typically makes up around 40-50% of an individual's body weight, not a fixed 40%. Choice C is incorrect as muscle contraction plays a vital role in temperature regulation by generating heat. Choice D is incorrect as skeletal muscles may have constant low-level contractions even at rest, known as muscle tone.
Which is another name for thiamine?
- A. Vitamin B1
- B. Vitamin B2
- C. Vitamin B6
- D. Vitamin D
Correct Answer: A
Rationale: Thiamine is another name for Vitamin B1. It is an essential vitamin that plays a crucial role in energy metabolism and is important for the proper functioning of the nervous system. Vitamin B2 is riboflavin, not thiamine. Vitamin B6 is pyridoxine, not thiamine. Vitamin D is a different vitamin responsible for calcium absorption and bone health, not thiamine. Therefore, the correct answer is Vitamin B1.
To which system do the retinas belong?
- A. skeletal system
- B. nervous system
- C. lymphatic system
- D. circulatory system
Correct Answer: B
Rationale: The retinas belong to the nervous system. The retina is a layer of tissue at the back of the eye responsible for detecting light and sending visual information to the brain through the optic nerve. This process is essential for vision, which is controlled by the nervous system. Choices A, C, and D are incorrect because the retinas have no association with the skeletal, lymphatic, or circulatory systems.
What does trypsin break down in the body?
- A. Fat
- B. Starch
- C. Proteins
- D. Nucleic acids
Correct Answer: C
Rationale: Trypsin is an enzyme that specifically breaks down proteins into smaller peptides by hydrolyzing peptide bonds. It is a key enzyme involved in the digestion of proteins in the body, particularly in the small intestine where it helps in the final stages of protein digestion. Choices A, B, and D are incorrect because trypsin does not break down fats, starch, or nucleic acids; its primary function is the digestion of proteins.
The sebaceous glands are part of which system?
- A. Endocrine system
- B. Digestive system
- C. Respiratory system
- D. Integumentary system
Correct Answer: D
Rationale: The sebaceous glands are a component of the integumentary system, which includes the skin, hair, nails, and associated structures. Sebaceous glands are typically found throughout the skin and are responsible for producing an oily substance called sebum, which helps keep the skin and hair lubricated and moisturized. The endocrine system (Choice A) consists of glands that produce hormones, the digestive system (Choice B) is responsible for processing food, and the respiratory system (Choice C) is involved in breathing and gas exchange.