Which protein complex in the sarcomere is responsible for the thick filament?

Correct Answer: B

Rationale: Myosin is the protein complex responsible for the thick filament in the sarcomere. It interacts with actin, another protein in the sarcomere, to generate the sliding movement that results in muscle contraction. Actin is a thin filament protein that interacts with myosin to create the sliding filament mechanism. Tropomyosin and troponin are regulatory proteins that regulate muscle contraction by controlling the interaction between actin and myosin, rather than directly being responsible for the thick filament.

Correct Answer: C

Rationale: The gland located on top of the kidneys responsible for regulating blood pressure and electrolyte balance is the adrenal gland. The adrenal gland produces hormones such as cortisol and aldosterone, which play a crucial role in regulating blood pressure and electrolyte balance in the body. The other choices, thyroid gland (choice A), pituitary gland (choice B), and parathyroid gland (choice D), do not have a primary role in regulating blood pressure and electrolyte balance. The thyroid gland is responsible for regulating metabolism, the pituitary gland controls various endocrine functions, and the parathyroid gland regulates calcium levels in the body.

Correct Answer: B

Rationale: Blood pressure is the term for the pressure exerted by blood against the walls of blood vessels. It is measured in millimeters of mercury (mmHg) and consists of two numbers: systolic pressure (the top number) and diastolic pressure (the bottom number). Heart rate (A) is the number of times the heart beats per minute, cardiac output (C) is the volume of blood pumped by the heart per minute, and stroke volume (D) is the volume of blood pumped by the heart in one contraction. Understanding blood pressure is crucial in assessing cardiovascular health and the risk of various conditions like hypertension.

Correct Answer: C

Rationale: The correct answer is C: Buffering system. The buffering system is responsible for maintaining a relatively constant blood pH level by minimizing changes in pH when acids or bases are added to the blood. This system consists of chemical compounds that can donate or accept protons to help stabilize the pH. Choice A, Cellular respiration, and Choice B, Gas exchange, are processes involved in gas exchange within the body, not specifically related to maintaining blood pH. Choice D, Deoxygenation, refers to the removal of oxygen from a substance and is not directly related to the regulation of blood pH.

Correct Answer: B

Rationale: Bronchitis is the correct answer. It is the inflammation of the bronchi, which are the air passages in the lungs. Bronchitis typically presents with symptoms such as a persistent cough, mucus production, and sometimes difficulty breathing. Pneumonia, on the other hand, is an infection that causes inflammation in the air sacs of the lungs, not specifically the bronchi. Emphysema is a chronic lung condition characterized by the gradual destruction of the air sacs in the lungs, resulting in breathing difficulties. Pleurisy refers to inflammation of the pleura, the lining around the lungs and chest cavity, causing chest pain when breathing or coughing.