Nokea
Electroencephalography (EEG) measures electrical activity in the brain, primarily reflecting the activity of:
- A. Neurons
- B. Astrocytes
- C. Oligodendrocytes
- D. Microglia
Correct Answer: A
Rationale: EEG measures electrical activity in the brain, primarily reflecting the activity of neurons. Neurons are the primary cells responsible for generating electrical impulses and transmitting information in the brain. Astrocytes, oligodendrocytes, and microglia are other types of cells in the brain that have different functions and are not primarily involved in generating the electrical activity measured by EEG. Astrocytes support neuronal function, oligodendrocytes produce myelin to insulate axons, and microglia are involved in immune responses and maintaining brain health, but they do not generate the electrical impulses detected by EEG.
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Photons, the basic unit of light, are:
- A. Charged particles
- B. Packets of energy with wave-particle duality
- C. Electromagnetic waves only
- D. Always absorbed by matter
Correct Answer: B
Rationale: Photons are not charged particles; they are packets of energy that exhibit wave-particle duality, meaning they can behave as both particles and waves. While photons are part of the electromagnetic spectrum, they are not electromagnetic waves themselves but rather discrete energy packets. They are not always absorbed by matter; they can be reflected, transmitted, or scattered.
Which of the following is NOT a function of the muscular system?
- A. Movement
- B. Maintaining posture
- C. Generating heat
- D. Regulating blood sugar levels
Correct Answer: D
Rationale: The muscular system is responsible for movement, maintaining posture, and generating heat. Regulating blood sugar levels is not a function of the muscular system. This function is primarily carried out by the endocrine system, specifically the pancreas and its production of insulin and glucagon. Choices A, B, and C are all correct functions of the muscular system as they involve the contraction and relaxation of muscles to produce movement, support the body's structure, and generate heat as a byproduct of muscle activity.
Tissues are groups of cells with similar:
- A. Appearance only
- B. Function and structure
- C. Location only
- D. Age only
Correct Answer: B
Rationale: Tissues are groups of cells that work together to perform a specific function. They have similar structures that enable them to carry out their specialized functions effectively. Therefore, tissues are defined by both their function and structure, making option B the correct choice. Choices A, C, and D are incorrect because tissues are not solely defined by their appearance, location, or age, but rather by the shared function and structure of the cells within them.
Myelin sheath is a fatty substance that insulates and protects the long extensions of some nerve cells. It is produced by:
- A. Schwann cells
- B. Astrocytes
- C. Neurons
- D. Oligodendrocytes
Correct Answer: A
Rationale: Schwann cells are indeed responsible for producing the myelin sheath in the peripheral nervous system. These cells wrap around axons to form the myelin sheath, which enhances the speed of nerve impulse conduction. In the central nervous system, oligodendrocytes are responsible for producing the myelin sheath. Astrocytes provide support and maintenance functions for neurons, while neurons are the nerve cells themselves and do not produce myelin. Therefore, the correct answer is Schwann cells as they are specifically involved in myelin production in the peripheral nervous system.
What is the name of a condition where the immune system mistakenly attacks healthy body tissues?
- A. Allergy
- B. Autoimmune disease
- C. Immunodeficiency
- D. Sepsis
Correct Answer: B
Rationale: Autoimmune diseases occur when the immune system mistakenly targets and attacks healthy body tissues, leading to inflammation and damage. This results in conditions such as rheumatoid arthritis, lupus, and type 1 diabetes. Allergies, on the other hand, involve an exaggerated immune response to harmless substances like pollen or certain foods. Immunodeficiency refers to a weakened immune system, making individuals more susceptible to infections. Sepsis is a severe systemic response to an infection, leading to organ dysfunction and potentially life-threatening complications.