Nokea
Which part of the nervous system is responsible for the "fight-or-flight" response?
- A. Somatic nervous system
- B. Parasympathetic nervous system
- C. Sympathetic nervous system
- D. Enteric nervous system
Correct Answer: C
Rationale: The sympathetic nervous system is responsible for the 'fight-or-flight' response, triggering the body's automatic response to a perceived threat or danger. This system initiates physiological changes like increased heart rate, dilated pupils, and the release of adrenaline, preparing the body to confront or escape the threat. The somatic nervous system (Choice A) controls voluntary movements, the parasympathetic nervous system (Choice B) is responsible for the 'rest and digest' response to promote relaxation and digestion, and the enteric nervous system (Choice D) regulates the gastrointestinal system. Therefore, they are not associated with the 'fight-or-flight' response.
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Which part of the heart is responsible for generating the QRS complex on an ECG?
- A. Sinoatrial node (SA node)
- B. Atrioventricular node (AV node)
- C. Bundle of His
- D. Ventricular muscle cells
Correct Answer: D
Rationale: The QRS complex on an ECG represents ventricular depolarization. This electrical activity is generated by the ventricular muscle cells. While the SA node generates the P wave, the AV node delays the impulse, and the Bundle of His and Purkinje fibers assist in rapidly conducting the impulse through the ventricles, it is the ventricular muscle cells that specifically create the QRS complex. Therefore, choice D, Ventricular muscle cells, is the correct answer. Choices A, B, and C are incorrect as they are primarily involved in initiating and coordinating the electrical impulses in the heart but do not directly generate the QRS complex on an ECG.
Which of the following structures in the male reproductive system produces the fluid that carries sperm?
- A. Testes
- B. Scrotum
- C. Prostate gland
- D. Seminal vesicles
Correct Answer: D
Rationale: The seminal vesicles in the male reproductive system are responsible for producing the fluid that carries sperm. These glands contribute a significant portion of the semen's volume, providing nutrients and protection for the sperm, which helps in their motility and survival. The testes are responsible for producing sperm cells, not the fluid that carries them. The scrotum is the external sac that holds the testes and helps regulate their temperature but does not produce the fluid. The prostate gland produces a milky fluid that helps nourish and protect sperm but is not the main structure responsible for producing the fluid that carries sperm.
What property of a substance remains constant regardless of changes in its location in the universe?
- A. Mass
- B. Weight
- C. Density
- D. Volume
Correct Answer: A
Rationale: Mass is the amount of matter in an object and remains constant regardless of its location in the universe. Weight, on the other hand, is the force of gravity acting on an object and can vary depending on the gravitational pull at different locations. Density and volume can change based on the conditions the substance is in, so they are not constant properties. Therefore, the correct answer is mass as it does not change with changes in location.
What is the measure of the total amount of space occupied by an object?
- A. Mass
- B. Density
- C. Weight
- D. Volume
Correct Answer: D
Rationale: Volume is the measure of the total amount of space occupied by an object. Mass refers to the amount of matter in an object, density is the mass per unit volume, and weight is the force of gravity acting on an object. When determining the space occupied by an object, volume is the appropriate measurement to consider. Therefore, the correct answer is D. Choices A, B, and C are incorrect as they do not directly indicate the total amount of space occupied by an object. Mass, density, and weight are relevant in different contexts and measurements compared to volume.
What is the primary composition of the stratum corneum, the outermost layer of the epidermis?
- A. Keratinized dead cells
- B. Melanocytes
- C. Langerhans cells
- D. Merkel cells
Correct Answer: A
Rationale: The stratum corneum, the outermost layer of the epidermis, is primarily composed of keratinized dead cells. These cells are flattened, fully keratinized, and lack nuclei, serving a protective function for the skin. Melanocytes are responsible for producing melanin, providing skin pigmentation. Langerhans cells are involved in the immune response within the skin. Merkel cells are associated with sensory functions in the skin, particularly in touch sensations. Therefore, the correct answer is A as it accurately reflects the main constituent of the stratum corneum, which acts as a barrier against external factors.