A&p HESI Study Booklet

Flagella are the small, tail-like projections from the cellular membrane that are used for locomotion. They are found in various types of cells, including bacteria and sperm cells. Flagella are composed of proteins and are responsible for the movement of the cell by propelling it through a whip-like motion. They are essential for the cell's ability to navigate its environment and are an important feature of many organisms.

Calcium is responsible for muscle contraction because it plays a crucial role in the process. When a muscle receives a signal to contract, calcium ions are released from storage sites in the muscle cells. These calcium ions bind to proteins within the muscle fibers, causing them to slide past each other and generate force, resulting in muscle contraction. Without sufficient calcium, the muscle cannot contract properly. Therefore, calcium is essential for muscle contraction.

Aldosterone is a hormone produced by the adrenal glands that plays a crucial role in regulating the body's electrolyte balance. Its main function is to conserve sodium in the body by increasing its reabsorption in the kidneys. This helps to maintain proper fluid balance and blood pressure. Therefore, the correct answer is that aldosterone conserves sodium in the body.

Parathyroid hormone regulates the levels of calcium in the body. It acts to increase the levels of calcium in the blood by stimulating the release of calcium from bones, increasing the absorption of calcium from the intestines, and reducing the excretion of calcium by the kidneys. This hormone plays a crucial role in maintaining calcium homeostasis and is essential for various physiological processes such as bone formation, nerve function, and muscle contraction.

Bile is a digestive fluid produced by the liver and stored in the gallbladder. It is then released into the small intestine to aid in the digestion and absorption of fats. The small intestine is the primary site for the digestion and absorption of nutrients, and the presence of bile helps break down fats into smaller molecules that can be easily absorbed by the body. Therefore, the correct answer is Small Intestine.

The phalanx is a bone. Phalanx refers to the bones in the fingers and toes, specifically the long bones that make up the digits. These bones are responsible for providing structure and support to the fingers and toes, allowing for movement and dexterity.

Baroreceptors are specialized sensory receptors located in the walls of blood vessels and the heart. They detect changes in blood pressure and send signals to the brain to regulate it. When blood pressure increases, baroreceptors signal the brain to decrease heart rate, leading to a decrease in blood pressure. Therefore, the function of baroreceptors is to decrease heart rate in response to high blood pressure.

Glucagon and epinephrine (adrenaline) must be present for the decomposition of glycogen to glucose in liver cells. Glucagon stimulates the breakdown of glycogen into glucose, while epinephrine enhances this process by increasing the release of glucose from the liver. These hormones work together to regulate blood sugar levels during times of low blood glucose, such as fasting or exercise.

The pulmonary veins are responsible for carrying oxygenated blood from the lungs back to the heart. This oxygenated blood is then pumped into the left atrium of the heart, where it is further circulated to the rest of the body.

The dermis is classified as an organ because it is a complex structure that is composed of different tissues working together to perform specific functions. The dermis contains blood vessels, nerves, sweat glands, hair follicles, and connective tissues, all of which work together to provide support, nourishment, and protection to the skin. This organization and coordination of different tissues make the dermis an organ.

Norepinephrine is the primary sympathetic neurohormone. It is released by the sympathetic nervous system during stress or danger, preparing the body for a fight-or-flight response. Norepinephrine increases heart rate, constricts blood vessels, and raises blood pressure, helping to mobilize the body's resources for immediate action. It also plays a role in regulating mood and attention.

Crossing over occurs during Prophase I of meiosis. This is the phase where homologous chromosomes pair up and exchange genetic material through a process called recombination. This exchange of genetic material between non-sister chromatids leads to genetic diversity among the resulting gametes. Prophase II, Metaphase I, and Metaphase II do not involve crossing over.

The expected pH of the stomach is .90 to 1.50. This is because the stomach contains hydrochloric acid, which helps in the digestion of food. The pH scale ranges from 0 to 14, with 0 being the most acidic and 14 being the most alkaline. A pH of .90 to 1.50 indicates a highly acidic environment, which is necessary for the breakdown of proteins and activation of digestive enzymes in the stomach.

The oculomotor nerve is responsible for regulating the amount of light entering the eye. This nerve controls the constriction and dilation of the pupil, which in turn regulates the amount of light that enters the eye. When the oculomotor nerve is functioning properly, it allows the pupil to constrict in bright light and dilate in dim light, ensuring that the appropriate amount of light reaches the retina for optimal vision.

The pulmonary vein is responsible for carrying oxygenated blood from the lungs back to the heart, specifically to the left atrium. This oxygen-rich blood is then pumped to the rest of the body to deliver oxygen to the tissues.