Nokea
Which chamber of the heart is the strongest and largest?
- A. Left atrium
- B. Right atrium
- C. Right ventricle
- D. Left ventricle
Correct Answer: D
Rationale: The left ventricle is the largest and most powerful chamber of the heart. It receives oxygenated blood from the left atrium and pumps it out to the body through the aorta, providing the body's tissues with vital oxygen and nutrients. The left atrium primarily acts as a receiving chamber for oxygenated blood from the lungs. The right atrium receives deoxygenated blood from the body, while the right ventricle pumps this blood to the lungs for oxygenation. Therefore, the correct answer is the left ventricle, as it is responsible for pumping oxygenated blood to the body.
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What is the function of white blood cells?
- A. To carry oxygen to the cells
- B. To fight infection
- C. To transport nutrients
- D. To clot blood
Correct Answer: B
Rationale: White blood cells are a vital part of the immune system. Their primary function is to fight infections by attacking bacteria, viruses, and other pathogens that enter the body. They play a crucial role in protecting the body against illnesses and maintaining overall health. Choice A is incorrect because the role of carrying oxygen to cells is primarily performed by red blood cells. Choice C is incorrect as the transportation of nutrients is mainly carried out by the bloodstream and specialized cells. Choice D is incorrect as the process of clotting blood is primarily mediated by platelets.
Which organ is responsible for the production of insulin?
- A. Thyroid gland
- B. Pituitary gland
- C. Pancreas
- D. Adrenal gland
Correct Answer: C
Rationale: The correct answer is C: Pancreas. The pancreas is responsible for producing insulin, a hormone that regulates blood glucose levels by facilitating the uptake of glucose into cells. Insulin is crucial for maintaining proper blood sugar levels and is produced by specialized cells within the pancreas known as beta cells. Choices A, B, and D are incorrect because the thyroid gland, pituitary gland, and adrenal gland do not produce insulin. The thyroid gland produces hormones that regulate metabolism, the pituitary gland releases various hormones that control other glands, and the adrenal gland produces hormones like cortisol and adrenaline.
What is the main component of the cell membrane?
- A. Proteins
- B. Carbohydrates
- C. Lipids
- D. Nucleic acids
Correct Answer: C
Rationale: The main component of the cell membrane is the phospholipid bilayer, which is primarily composed of lipids. Lipids form a barrier that separates the interior of the cell from the external environment, providing structural integrity and regulating the passage of substances in and out of the cell. Proteins are also essential components of the cell membrane, serving various functions such as transport, signaling, and cell recognition. Carbohydrates are present in the form of glycoproteins and glycolipids on the cell membrane surface, contributing to cell-cell recognition. Nucleic acids are not a primary component of the cell membrane.
Which hormone is released in response to low blood glucose levels?
- A. Insulin
- B. Glucagon
- C. Cortisol
- D. Adrenaline
Correct Answer: B
Rationale: Glucagon is the hormone released in response to low blood glucose levels. When blood glucose levels drop, the pancreas secretes glucagon to stimulate the liver to break down glycogen into glucose, increasing blood sugar levels. This helps to restore the body's glucose balance. Insulin, on the other hand, is released in response to high blood glucose levels to lower blood sugar by promoting glucose uptake by cells. Cortisol is a stress hormone, and adrenaline is released in response to stress or danger, not specifically to regulate blood glucose levels.
Which part of the brain controls involuntary actions such as breathing and heart rate?
- A. Cerebrum
- B. Cerebellum
- C. Medulla oblongata
- D. Hypothalamus
Correct Answer: C
Rationale: The medulla oblongata, located at the base of the brainstem, controls essential involuntary actions such as breathing, heart rate, and blood pressure. It plays a crucial role in maintaining vital functions necessary for survival. The cerebrum is responsible for voluntary actions, conscious thought, and sensory processing, making it an incorrect choice. The cerebellum primarily coordinates movement, balance, and posture, not involuntary actions like breathing and heart rate. The hypothalamus regulates body temperature, thirst, hunger, and controls the endocrine system, but it is not directly responsible for controlling breathing and heart rate.