HESI A2 Anatomy and Physiology Quizlet

Correct Answer: C

Rationale: The correct answer is C: Mitochondria. Mitochondria are responsible for generating energy in the form of ATP through cellular respiration. This organelle contains enzymes needed for the process of oxidative phosphorylation. The other choices, A: Nucleus, B: Ribosome, and D: Golgi apparatus, do not directly participate in energy production. The nucleus houses genetic material, ribosomes are involved in protein synthesis, and the Golgi apparatus is responsible for processing and packaging proteins.

Correct Answer: C

Rationale: The correct answer is C: Medulla oblongata. The medulla oblongata is located in the brainstem and is responsible for controlling vital functions such as breathing, heart rate, and blood pressure. It contains important centers that regulate these involuntary actions, making it the correct choice. The cerebrum (A) is responsible for higher brain functions such as thinking and voluntary movement. The cerebellum (B) is involved in coordination and balance. The hypothalamus (D) regulates body temperature, hunger, and thirst, but does not directly control breathing and heart rate.

Correct Answer: B

Rationale: The correct answer is B: Pituitary gland. The pituitary gland is known as the 'master gland' because it controls the functions of other endocrine glands in the body. It secretes hormones that regulate various bodily functions, such as growth, metabolism, and reproduction. Other choices are incorrect because the thyroid gland mainly regulates metabolism, the adrenal gland is responsible for stress response and metabolism, and the pineal gland produces melatonin to regulate sleep-wake cycles. The pituitary gland stands out as the 'master gland' due to its control over other gland functions.

Correct Answer: A

Rationale: The correct answer is A: Parathyroid gland. During stress, the hypothalamus signals the pituitary gland to release ACTH, which then stimulates the adrenal cortex to release stress hormones like cortisol. The posterior pituitary releases oxytocin and vasopressin, not directly related to stress. The parathyroid gland regulates calcium levels, not involved in the stress response.

Correct Answer: B

Rationale: The correct answer is B: Adrenaline. The adrenal medulla is part of the adrenal glands and is responsible for producing adrenaline, also known as epinephrine. Adrenaline is a hormone that plays a crucial role in the body's fight or flight response, increasing heart rate, blood flow to muscles, and overall alertness in response to stress or danger. Insulin (A) is produced by the pancreas to regulate blood sugar levels, cortisol (C) is produced by the adrenal cortex to regulate stress response and metabolism, and melatonin (D) is produced by the pineal gland to regulate sleep-wake cycles.