what is the myelin sheath and what does it do
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Nursing Elites

ATI TEAS 7

ATI TEAS 7 science review

1. What is the myelin sheath and what does it do?

Correct answer: B

Rationale: The myelin sheath is a fatty substance that insulates some nerve fibers. It is made up of specialized cells that wrap around the axons of neurons, providing insulation and speeding up the transmission of nerve impulses. Choice A is incorrect as the myelin sheath is not a group of nerve cells but rather a substance that surrounds nerve fibers. Choice C is incorrect as the myelin sheath is not a fluid-filled cavity within the brain. Choice D is incorrect as the myelin sheath is not the junction between two neurons.

2. Which of the following is NOT a primary producer in an ecosystem?

Correct answer: B

Rationale: - A) Grass: Grass is a primary producer because it can photosynthesize and convert sunlight into energy, making it the base of the food chain. - B) Deer: Deer are consumers that feed on primary producers like grass, so they are not primary producers themselves. - C) Algae: Algae are primary producers that can photosynthesize and produce energy from sunlight. - D) Mushroom: Mushrooms are decomposers that break down organic matter, so they are not primary producers.

3. Which of the following statements is not true about the relationship between the gastrointestinal system and the endocrine system?

Correct answer: D

Rationale: The gastrointestinal system and the endocrine system are closely interconnected. Hormones released by the endocrine system play a crucial role in signaling hunger or fullness, regulating blood glucose levels, and stimulating digestive processes like enzyme secretion and peristalsis for efficient food digestion. Option D, stating 'All of the above are true,' is incorrect in the context of the question because there is a need to identify the statement that is not true about the relationship between the gastrointestinal system and the endocrine system. Choices A, B, and C are all correct statements that reflect the close relationship and interactions between the gastrointestinal and endocrine systems.

4. What is the fatty sheath that insulates some nerve fibers and speeds up signal transmission called?

Correct answer: A

Rationale: The correct answer is A: Myelin sheath. The myelin sheath is a fatty layer that surrounds and insulates some nerve fibers, facilitating the rapid transmission of signals along the nerve fibers. Choices B, C, and D (Dura mater, Pia mater, and Arachnoid mater) are layers of the meninges, protective membranes that surround the brain and spinal cord. The primary function of the meninges is to protect and support the central nervous system, not to insulate nerve fibers for signal transmission.

5. Which of the following is NOT a type of vaccine?

Correct answer: D

Rationale: A) Live attenuated vaccine: This type of vaccine contains a weakened form of the virus or bacteria that causes the disease. When administered, it stimulates an immune response without causing the disease itself. B) Toxoid vaccine: Toxoid vaccines are made from toxins produced by bacteria that have been inactivated. They stimulate the immune system to produce antibodies against the toxin, providing immunity against the disease. C) Conjugate vaccine: Conjugate vaccines are made by combining a weak antigen with a strong antigen to enhance the immune response. They are commonly used to protect against bacterial infections. D) Antibiotic: Antibiotics are medications used to treat bacterial infections by killing or inhibiting the growth of bacteria. They are not a type of vaccine but rather a class of antimicrobial drugs. Therefore, the correct answer is D) Antibiotic, as it is not a type of vaccine.

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