Anatomy HESI A2 Practice Test

Correct Answer: C

Rationale: The correct answer is C: To store urine. The urinary bladder is a muscular organ that serves as a reservoir for urine produced by the kidneys. It temporarily stores urine until it is ready to be excreted from the body. Filtering blood (A) is the function of the kidneys, storing and concentrating bile (B) is the function of the gallbladder, and absorbing nutrients (D) mostly occurs in the small intestine. Therefore, the main function of the urinary bladder is to store urine before it is eliminated from the body.

Correct Answer: A

Rationale: The correct answer is A: They secrete chemicals into the blood. Endocrine glands are ductless glands that secrete hormones directly into the bloodstream. This allows the hormones to travel throughout the body to target organs and tissues. Choices B, C, and D are incorrect because endocrine glands do not secrete enzymes into ducts (B), produce sweat (C), or produce saliva (D). These functions are typically associated with exocrine glands that have ducts for secretion.

Correct Answer: B

Rationale: The correct answer is B: Energy production. Mitochondria are known as the powerhouse of the cell due to their role in producing energy in the form of ATP through cellular respiration. This process involves the breakdown of glucose to generate ATP, which is the main energy currency of the cell. Mitochondria have their own DNA and ribosomes, allowing them to produce some of their proteins, but they are not primarily responsible for protein synthesis (Choice A). Breaking down waste (Choice C) is mainly carried out by lysosomes. Cell division (Choice D) involves processes such as DNA replication and mitosis, which are not directly linked to the function of mitochondria.

Correct Answer: B

Rationale: The correct answer is B: Medulla oblongata. This brain part is located in the brainstem and controls vital functions such as heart rate and blood pressure. It contains the cardiovascular center which regulates these functions through autonomic nervous system pathways. The other choices (A: Cerebellum, C: Hypothalamus, D: Pons) do not have direct control over heart rate and blood pressure regulation. The cerebellum is mainly responsible for motor coordination, the hypothalamus regulates body temperature, hunger, and thirst, and the pons is involved in sleep and arousal. Thus, the medulla oblongata is the correct choice for regulating heart rate and blood pressure.

Correct Answer: A

Rationale: The correct answer is A: To filter blood and remove old red blood cells. The spleen is an important organ in the lymphatic system responsible for filtering blood, removing old or damaged red blood cells, and storing platelets. It also plays a role in immune function by producing antibodies and storing lymphocytes. Choices B, C, and D are incorrect as the spleen's main functions are related to blood filtration and immune response, not lymphocyte production, vitamin storage, or temperature regulation.