HESI A2 Anatomy and Physiology Quizlet

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.

Correct Answer: B

Rationale: The correct answer is B: Mitochondria. Mitochondria are known as the powerhouse of the cell because they are responsible for energy production through the process of cellular respiration. They produce ATP, the main energy currency of the cell. The other choices are incorrect because the nucleus is responsible for storing genetic material, ribosomes are involved in protein synthesis, and the Golgi apparatus is responsible for packaging and transporting proteins. Therefore, only the mitochondria play a direct role in energy production within the cell.

Correct Answer: B

Rationale: The correct answer is B: Quadriceps. The quadriceps muscle group, specifically the rectus femoris, is primarily responsible for extending the knee. This muscle group is located on the front of the thigh and contracts to straighten the knee joint. The other choices are incorrect because: A: Hamstrings primarily flex the knee. C: Calves primarily assist in ankle plantar flexion. D: Glutes primarily extend the hip, not the knee.

Correct Answer: C

Rationale: The main component of the cell membrane is lipids, specifically phospholipids. They form a lipid bilayer that provides structure and acts as a barrier to regulate what enters and exits the cell. Proteins are also important in the cell membrane for various functions, but they are not the main component. Carbohydrates are found on the surface of the cell membrane for cell recognition and communication, not as the main component. Nucleic acids are not found in the cell membrane, as they are responsible for genetic information storage and protein synthesis inside the cell.

Correct Answer: B

Rationale: The correct answer is B: Pivot joint. Pivot joints allow for rotational movement around a single axis. This type of joint is found in the neck, allowing the head to rotate side to side. Hinge joints (choice A) allow movement in one plane like the elbow. Ball and socket joints (choice C) allow for a wide range of movement in multiple directions like the hip and shoulder. Saddle joints (choice D) allow for movement in two axes like the thumb. Therefore, the correct answer is pivot joint as it specifically allows for rotational movement around a single axis.