Nokea
Which of the following is responsible for maintaining the body's circadian rhythm?
- A. Thyroid gland
- B. Pineal gland
- C. Pancreas
- D. Hypothalamus
Correct Answer: B
Rationale: The pineal gland is responsible for maintaining the body's circadian rhythm by producing melatonin. Melatonin is a hormone that helps regulate the sleep-wake cycle and is essential in controlling the body's internal clock. The thyroid gland, although important for metabolism, is not directly involved in regulating circadian rhythms. The pancreas plays a role in blood sugar regulation through insulin production, not in controlling circadian rhythms. The hypothalamus is involved in regulating various bodily functions, but the pineal gland is specifically responsible for the circadian rhythm.
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Which type of bond is exemplified by KCl?
- A. Ionic bond
- B. Covalent bond
- C. Hydrogen bond
- D. Polar covalent bond
Correct Answer: A
Rationale: KCl exemplifies an ionic bond. In an ionic bond, electrons are transferred between atoms, resulting in the formation of ions. In the case of KCl, potassium (K) donates an electron to chlorine (Cl), leading to the creation of K+ and Cl- ions, which are held together by electrostatic forces of attraction. Choice B, covalent bond, is incorrect because covalent bonds involve the sharing of electrons between atoms, not the transfer of electrons as seen in KCl. Choice C, hydrogen bond, is incorrect as hydrogen bonds are a type of intermolecular force, not a bond formed by the transfer or sharing of electrons between atoms. Choice D, polar covalent bond, is also incorrect because although it involves the sharing of electrons with an unequal distribution of charge, KCl is a clear example of ionic bonding where electrons are completely transferred.
Which cavity is primarily lined by the peritoneum?
- A. Abdominal
- B. Dorsal
- C. Ventral
- D. Thoracic
Correct Answer: A
Rationale: The correct answer is 'Abdominal.' The peritoneum primarily lines the abdominal cavity, providing support and protection to abdominal organs. It is a serous membrane that covers the abdominal organs and the abdominal wall, aiding in their function and protection. Choice B, 'Dorsal,' is incorrect because the peritoneum does not primarily line the dorsal cavity. Choice C, 'Ventral,' is incorrect as the peritoneum is not primarily associated with the ventral cavity. Choice D, 'Thoracic,' is incorrect because the peritoneum primarily lines the abdominal cavity and is not primarily found in the thoracic cavity.
Which of the following best defines the anatomical term medial?
- A. Being face down
- B. On the front of the body or limb
- C. Near to the midline of the body
- D. Above or on top of the lungs
Correct Answer: C
Rationale: The correct definition of the anatomical term 'medial' is being close or near to the midline of the body. This term describes a position closer to the center or midline of the body, opposite to 'lateral' which refers to a position further away from the midline. Choice A, 'Being face down,' is incorrect as it describes the anatomical term 'prone.' Choice B, 'On the front of the body or limb,' is incorrect as it describes the anatomical term 'anterior.' Choice D, 'Above or on top of the lungs,' is incorrect as it does not relate to the term 'medial.'
What is the primary mode of CO2 transport in the body?
- A. Bicarbonate
- B. Carbamino compounds
- C. None of these
- D. Plasma
Correct Answer: A
Rationale: The correct answer is A: Bicarbonate. In the body, the primary mode of CO2 transport is as bicarbonate. Carbon dioxide is converted to bicarbonate in red blood cells as part of the bicarbonate buffer system, which helps maintain the pH balance in the blood. Bicarbonate is then transported in the plasma to the lungs where it is converted back to carbon dioxide for exhalation. While carbamino compounds also play a role in CO2 transport by binding to amino groups on proteins, bicarbonate is the main mode of transport for carbon dioxide in the body. Options B, C, and D are incorrect as they do not represent the primary mechanism of CO2 transport in the body.
Which of the following is a function of the skeletal system?
- A. To produce red blood cells
- B. To provide structural support
- C. To transport nutrients
- D. To store fat
Correct Answer: B
Rationale: The correct answer is B: To provide structural support. The skeletal system is primarily responsible for supporting the body's structure, protecting internal organs, facilitating movement, and storing minerals. While bones do play a role in producing red blood cells (hematopoiesis) in the bone marrow, the main function related to the question is providing structural support. Choices C and D are incorrect as the skeletal system is not involved in transporting nutrients or storing fat. The main functions of the skeletal system are related to support, protection, movement facilitation, mineral storage, and hematopoiesis.