ATI TEAS 7
TEAS 7 science quizlet
1. Which hormone, produced by the pancreas, is released in response to low blood sugar levels and stimulates the release of glucose into the bloodstream?
- A. Insulin
- B. Glucagon
- C. Cortisol
- D. Thyroxine
Correct answer: B
Rationale: Glucagon is the hormone produced by the pancreas that is released in response to low blood sugar levels. It acts to stimulate the release of glucose into the bloodstream by promoting the breakdown of glycogen in the liver. Insulin, conversely, is released in response to high blood sugar levels and promotes the uptake of glucose by cells. Cortisol is a steroid hormone produced by the adrenal glands that regulates metabolism and the immune response. Thyroxine is a hormone produced by the thyroid gland that regulates metabolism but is not involved in responding to low blood sugar levels.
2. A pediatrician notes that an infant's cartilage is disappearing and being replaced by bone. What process has the doctor observed?
- A. Mineralization
- B. Ossification
- C. Osteoporosis
- D. Calcification
Correct answer: B
Rationale: The doctor has observed the process of ossification. Ossification is the natural process where cartilage in the body is replaced by bone. This process takes place during fetal development, growth, and bone fracture healing. Ossification involves the formation of bone tissue by depositing minerals like calcium and phosphorus within the cartilage matrix, leading to the development of a bone structure. Choice A, mineralization, refers to the process of forming mineral deposits in tissues, but it does not involve the replacement of cartilage by bone. Choice C, osteoporosis, is a condition characterized by bone density loss and increased fragility, not the natural process of cartilage replacement by bone. Choice D, calcification, is the process of deposition of calcium salts in various tissues, but it does not specifically involve the replacement of cartilage by bone as in ossification.
3. What is the primary function of lymph nodes, small, bean-shaped structures found along lymphatic vessels?
- A. To store excess lymph fluid
- B. To produce red blood cells
- C. To filter lymph and fight infection
- D. To transport lymph to the heart
Correct answer: C
Rationale: Lymph nodes primarily function to filter lymph and fight infection. They contain immune cells that help to remove pathogens and foreign particles from the lymph fluid as it passes through the nodes. This process helps to activate the immune response and defend the body against infections. Choice A is incorrect as lymph nodes do not store excess lymph fluid; they filter lymph. Choice B is incorrect as the production of red blood cells primarily occurs in the bone marrow, not in lymph nodes. Choice D is incorrect as lymph nodes do not transport lymph to the heart; they filter and process lymph to remove impurities and activate the immune response.
4. Which cells myelinate neurons in the PNS?
- A. Oligodendrocytes
- B. Astrocytes
- C. Schwann cells
- D. Microglia
Correct answer: C
Rationale: Schwann cells are the glial cells responsible for myelinating neurons in the peripheral nervous system (PNS). They form the myelin sheath around axons, which helps in the conduction of electrical impulses. Oligodendrocytes, on the other hand, myelinate neurons in the central nervous system (CNS). Astrocytes primarily provide support for neuronal function by regulating the chemical environment around neurons and maintaining the blood-brain barrier. Microglia are part of the immune response in the CNS, where they act as the resident macrophages, playing a role in immune surveillance and response to injury or disease. Therefore, the correct answer is Schwann cells (Choice C) as they specifically myelinate neurons in the PNS, differentiating them from the other cell types mentioned in the choices.
5. Which type of blood cell is primarily responsible for fighting infections?
- A. Red blood cell
- B. White blood cell
- C. Platelet
- D. Plasma
Correct answer: B
Rationale: The correct answer is B: White blood cell. White blood cells are the primary cells responsible for fighting infections and foreign invaders in the body. Red blood cells carry oxygen to tissues, platelets help in blood clotting to prevent excessive bleeding, and plasma is the liquid component of blood that carries cells and nutrients. White blood cells, also known as leukocytes, play a crucial role in the immune system by identifying and destroying pathogens, such as bacteria, viruses, and other harmful substances. Therefore, they are the key players in the body's defense against infections, making them the correct answer in this scenario. While red blood cells, platelets, and plasma have essential functions in the body, they are not primarily responsible for combating infections like white blood cells.
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