What is the meaning of exocytosis?

Correct Answer: B

Rationale: Exocytosis is the process by which a cell releases substances to the outside by fusing with the plasma membrane. During exocytosis, vesicles containing molecules fuse with the cell membrane, allowing the release of the contents outside the cell. This process is crucial for the secretion of various substances such as hormones, enzymes, and neurotransmitters. Choices A, C, and D are incorrect as they describe processes different from exocytosis. Choice A describes endocytosis, where the cell engulfs substances to bring them into the cell. Choice C is more aligned with pinocytosis, the process of engulfing liquid material. Choice D refers to phagocytosis, which is the uptake of solid particles by the cell.

Correct Answer: C

Rationale: The lateral side of the right knee is the side that is farthest from the left knee when looking at the knee joint from the front. The term 'lateral' refers to the side of the body that is farther away from the midline or center of the body. In this case, the lateral side of the right knee is on the outer side of the knee joint, away from the other knee. Choice A is incorrect as the kneecap is located at the front of the knee. Choice B is incorrect as it describes the medial side, not the lateral side. Choice D is incorrect as it refers to the underside, which is not related to the lateral aspect of the knee.

Correct Answer: D

Rationale: Nearly all gaseous exchanges between air and blood take place in the alveoli of the lungs. The walls of the alveoli are thin and surrounded by an extensive network of tiny blood vessels called capillaries. Oxygen from the air diffuses through the alveoli walls and into the bloodstream, while carbon dioxide, a waste product, diffuses from the blood into the alveoli to be exhaled out of the body. This process is essential for respiration and providing oxygen to the body's cells. Choices A, B, and C are incorrect. Pleura is the membrane surrounding the lungs, trachea is the windpipe that carries air to the lungs, and bronchioles are the smaller air passages in the lungs. However, the primary site for gaseous exchange is the alveoli due to their structure and function.

Correct Answer: C

Rationale: The intercostal muscles located between the ribs play a crucial role in respiration by aiding in the enlargement and reduction of the space in the thorax. During inspiration, these muscles contract, lifting the rib cage, which increases the volume of the thoracic cavity and allows the lungs to expand and fill with air. This process directly relates to the expansion of the thorax rather than protecting bronchioles and alveoli (Choice A), signaling intra-alveolar pressure changes (Choice B), or maintaining the separation between pleurae (Choice D). Therefore, the correct answer is C.

Correct Answer: D

Rationale: The correct answer is D, Esophagus. Muscles push food into the stomach via peristalsis in the esophagus. Peristalsis is a coordinated muscular contraction that helps move food from the mouth to the stomach through the esophagus. The rhythmic contractions of the esophageal muscles create a wave-like motion that propels food downward toward the stomach for digestion. Choices A, B, and C are incorrect because the mouth is where digestion begins but does not push food into the stomach, the small intestine is mainly responsible for absorbing nutrients, and the epiglottis is a flap that prevents food from entering the trachea during swallowing, not involved in pushing food into the stomach.