What are the subdivisions of the dorsal cavity, located at the back of the human body?

Correct Answer: A

Rationale: The correct answer is A: Cranial and spinal. The dorsal cavity, situated at the back of the human body, is divided into the cranial cavity (housing the brain) and the spinal cavity (housing the spinal cord). Choices B, C, and D are incorrect as they do not represent the correct subdivisions of the dorsal cavity. Option B (Dorsal and ventral) is incorrect as it confuses the dorsal cavity with the dorsal and ventral body planes. Option C (Lateral and proximal) and option D (Inferior and superior) are incorrect as they refer to different anatomical terms that do not apply to the subdivisions of the dorsal cavity.

Correct Answer: C

Rationale: The correct order of formed elements in blood from smallest to largest cell size is thrombocytes (platelets), erythrocytes (red blood cells), and leukocytes (white blood cells), making choice C the correct answer. Thrombocytes are the smallest, followed by erythrocytes, and then leukocytes. Choices A, B, and D are incorrect because they do not follow the correct order of cell size in blood formed elements.

Correct Answer: B

Rationale: An electrocardiogram (ECG or EKG) is used to measure and display the heart's rate and rhythm. It provides valuable information about the electrical activity of the heart, allowing healthcare providers to assess the heart's health, detect abnormalities in the heart's rhythm, and diagnose various cardiac conditions. Choices A, C, and D are incorrect. Choice A is incorrect because an ECG does not indicate the rate of blood flow but rather focuses on the heart's electrical activity. Choice C is incorrect because identifying a person's blood group type is typically done through blood typing tests, not ECG. Choice D is incorrect because determining cell type in a blood sample is unrelated to the purpose of an ECG.

Correct Answer: C

Rationale: The correct order of airflow in the lungs starts with air entering through the trachea, moving into the bronchi, then proceeding to the bronchioles, and finally reaching the alveoli where gas exchange occurs. Therefore, the correct sequence is Trachea, Bronchi, Bronchioles, Alveoli, making choice C the accurate representation of the airflow in the lungs. Choices A, B, and D are incorrect because they do not follow the anatomical path of airflow in the lungs as air moves from the trachea to the bronchi, then bronchioles, and finally the alveoli for gas exchange.

Correct Answer: A

Rationale: The correct answer is 'Diffusion.' Diffusion is the process by which gases are exchanged between air in the alveoli and blood in the capillaries. Oxygen moves from the alveoli into the blood, while carbon dioxide moves from the blood into the alveoli through diffusion. Exhalation is the process of expelling air from the lungs, inspiration is the process of inhaling air into the lungs, and ventilation refers to the overall movement of air in and out of the lungs. While these processes are essential for the respiratory system to function, they are not directly responsible for the gas exchange between air and blood, which is primarily achieved through diffusion.