Nokea
What is the term for the small air sacs in the lungs where gas exchange (oxygen and carbon dioxide) takes place?
- A. Bronchi
- B. Alveoli
- C. Trachea
- D. Bronchioles
Correct Answer: B
Rationale: The correct answer is B: Alveoli. The alveoli are the small air sacs in the lungs where gas exchange occurs. Oxygen from the air we breathe passes into the bloodstream through the alveoli, while carbon dioxide from the bloodstream passes out of the body through the alveoli. Choice A, Bronchi, are the main airways in the lungs and not the site of gas exchange. Choice C, Trachea, refers to the windpipe, which is a different structure than the alveoli. Choice D, Bronchioles, are smaller airways branching off from the bronchi and are not where gas exchange primarily occurs.
You may also like to solve these questions
What term describes the functional unit of a skeletal muscle responsible for muscle contraction?
- A. Myofibril
- B. Sarcomere
- C. Tendon
- D. Myoglobin
Correct Answer: B
Rationale: The correct answer is B, 'Sarcomere.' The sarcomere is indeed the functional unit of a skeletal muscle responsible for muscle contraction. It is composed of actin and myosin filaments that interact to generate muscle contraction. Choice A, 'Myofibril,' is incorrect as myofibrils are composed of sarcomeres, not the functional units themselves. Choice C, 'Tendon,' is incorrect as tendons connect muscles to bones and do not directly participate in muscle contraction. Choice D, 'Myoglobin,' is incorrect as myoglobin is a protein that stores oxygen in muscle cells and is not directly involved in muscle contraction.
What is the primary hormone released by the parathyroid glands?
- A. Insulin
- B. Calcitonin
- C. Parathyroid hormone (PTH)
- D. Thyroxine
Correct Answer: C
Rationale: The primary hormone released by the parathyroid glands is parathyroid hormone (PTH). PTH plays a crucial role in regulating calcium and phosphorus levels in the body by increasing calcium levels in the blood through various mechanisms, such as promoting calcium release from bones and increasing calcium absorption in the intestines. Insulin is produced by the pancreas and regulates blood sugar levels, calcitonin is produced by the thyroid gland and helps lower blood calcium levels, and thyroxine is a hormone produced by the thyroid gland that regulates metabolism. Therefore, choices A, B, and D are incorrect as they are not the primary hormone released by the parathyroid glands.
What is the formula for calculating density?
- A. Density = Volume / Mass
- B. Density = Mass Volume
- C. Density = Mass / Volume
- D. Density = Volume - Mass
Correct Answer: A
Rationale: Density is defined as the amount of mass in a given volume. The formula for calculating density is Density = Mass / Volume. This means that you divide the mass of an object by its volume to determine its density. Therefore, the correct formula for calculating density is Density = Volume / Mass. Choice A is correct because density is calculated by dividing the volume by the mass. Choices B, C, and D are incorrect because they do not represent the correct relationship between mass and volume in calculating density.
Which property of a substance refers to its ability to be stretched into thin wires without breaking?
- A. Conductivity
- B. Viscosity
- C. Ductility
- D. Malleability
Correct Answer: C
Rationale: Ductility is the property of a substance that allows it to be stretched into thin wires without breaking. This property is distinct from the other options provided. Conductivity refers to the ability to conduct electricity or heat, viscosity refers to a liquid's resistance to flow, and malleability refers to the ability of a substance to be hammered or rolled into thin sheets. Therefore, the correct answer is 'Ductility.'
Memory B cells and memory T cells are crucial for immunological memory. How does immunological memory enhance the immune response upon re-exposure to a pathogen?
- A. It increases the production of the same ineffective antibodies.
- B. It allows for a quicker and more robust immune response.
- C. It suppresses the immune system to prevent overreaction.
- D. It triggers a completely different immune response.
Correct Answer: B
Rationale: Immunological memory enhances the immune response upon re-exposure to a pathogen by allowing for a quicker and more robust immune response. Memory B cells and memory T cells are primed to recognize the pathogen quickly and mount a faster and more effective response, leading to a more efficient clearance of the pathogen. Choice A is incorrect because immunological memory does not increase the production of ineffective antibodies but rather promotes the production of specific antibodies that are effective against the pathogen. Choice C is incorrect as immunological memory does not suppress the immune system; instead, it enhances the response. Choice D is incorrect because immunological memory leads to a recall of the specific immune response mounted during the initial exposure, not a completely different response.