Nokea
Which part of the brainstem controls heart rate and breathing?
- A. Medulla oblongata
- B. Pons
- C. Midbrain
- D. Thalamus
Correct Answer: A
Rationale: The medulla oblongata is a critical part of the brainstem responsible for regulating essential functions such as heart rate, breathing, and blood pressure. It houses centers that oversee these involuntary processes, making it the correct answer. The pons, midbrain, and thalamus do not primarily control heart rate and breathing, thus making them incorrect choices for this question.
You may also like to solve these questions
What is the main function of the epiglottis, a small flap of cartilage located above the larynx?
- A. To warm and humidify inhaled air
- B. To control the passage of food and air
- C. To produce sound vibrations for speech
- D. To sense the presence of foreign objects
Correct Answer: B
Rationale: The main function of the epiglottis is to control the passage of food and air. It acts as a cover for the trachea during swallowing to prevent food from entering the airway. This mechanism ensures that food safely travels down the esophagus to the stomach, while air simultaneously enters the trachea and moves into the lungs for respiration. Choice A is incorrect as the warming and humidifying of inhaled air primarily occur in the nasal cavity. Choice C is incorrect because sound production for speech involves structures like the vocal cords rather than the epiglottis. Choice D is incorrect as sensing foreign objects is not a primary function of the epiglottis; instead, this role is typically associated with sensory receptors in the respiratory tract.
What is the involuntary muscle tissue found in the walls of blood vessels and organs like the stomach and intestines?
- A. Skeletal muscle
- B. Cardiac muscle
- C. Smooth muscle
- D. Striated muscle
Correct Answer: C
Rationale: Smooth muscle is the correct answer. It is the involuntary muscle tissue found in the walls of blood vessels and organs like the stomach and intestines. Smooth muscle is responsible for various involuntary movements in the body, such as peristalsis in the digestive system and regulating blood flow in blood vessels. Skeletal muscle is voluntary and attached to bones for movement. Cardiac muscle is specific to the heart and not found in blood vessel walls or organs like the stomach and intestines. Striated muscle refers to both skeletal and cardiac muscle due to their striped appearance under a microscope, but it does not specifically describe the involuntary muscle tissue in the walls of blood vessels and organs as asked in the question.
What type of lens is thinner at the center than at the edges and causes light rays to diverge?
- A. Convex lens
- B. Concave lens
- C. Diverging lens
- D. Plano-convex lens
Correct Answer: B
Rationale: A concave lens is thinner at the center than at the edges, causing light rays to diverge when passing through it. This type of lens is also known as a diverging lens because it causes light rays to spread out. Concave lenses are used in various optical devices to correct vision problems and in scientific instruments to diverge light rays for specific purposes. The other choices are incorrect. A convex lens is thicker at the center and converges light rays, while a plano-convex lens has one flat surface and one convex surface, converging light. Diverging lens is a general term that can refer to concave or plano-concave lenses, but in this context, the specific type being referred to is a concave lens.
What is the relationship between force and acceleration according to Newton's second law?
- A. Force is directly proportional to acceleration
- B. Force is inversely proportional to acceleration
- C. Force has no relation to acceleration
- D. Force causes deceleration, not acceleration
Correct Answer: A
Rationale: According to Newton's second law of motion, the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. This relationship is mathematically expressed as F = ma, where F represents force, m represents mass, and a represents acceleration. Therefore, an increase in force will result in a proportional increase in acceleration, supporting the statement that force is directly proportional to acceleration. Choice B is incorrect as it suggests an inverse relationship, which is not consistent with Newton's second law. Choice C is incorrect because force and acceleration are indeed related as per Newton's second law. Choice D is incorrect as force can cause acceleration or deceleration depending on the direction of the force relative to the motion of the object, but it does not exclusively cause deceleration.
What is the name for the change in enthalpy (heat) associated with a chemical reaction at constant pressure?
- A. Entropy
- B. Enthalpy
- C. Gibbs free energy
- D. Heat of reaction
Correct Answer: D
Rationale: The correct answer is D, Heat of reaction. The heat of reaction, also known as the enthalpy change, is the amount of heat absorbed or released during a chemical reaction at constant pressure. Entropy (A) is a measure of the disorder or randomness of a system and is not specifically related to heat changes in a chemical reaction. Enthalpy (B) is the total heat content of a system and not just the change associated with a reaction. Gibbs free energy (C) is a measure of the energy available to do work in a system at constant temperature and pressure, but it is not the specific term for the heat change in a chemical reaction.