which of the following neurotransmitters slows down the activity of neurons to prevent overexcitation

ATI TEAS 7

ATI TEAS 7 Science

1. Which of the following neurotransmitters slows down the activity of neurons to prevent overexcitation?

A. Acetylcholine
B. Dopamine
C. GABA
D. Serotonin

Correct answer: C

Rationale: The correct answer is C: GABA (gamma-aminobutyric acid). GABA is an inhibitory neurotransmitter that slows down neuronal activity, helping to prevent overexcitation in the brain. It counterbalances the effects of excitatory neurotransmitters like glutamate, playing a crucial role in maintaining the balance of neuronal activity in the brain. Acetylcholine (Choice A) is primarily an excitatory neurotransmitter involved in muscle movement and cognitive functions. Dopamine (Choice B) plays a role in reward-motivated behavior and motor control. Serotonin (Choice D) is involved in regulating mood, appetite, and sleep but is not primarily responsible for slowing down neuronal activity to prevent overexcitation.

2. Which organ of the body compensates when a person's intake of vitamins decreases?

A. Appendix
B. Liver
C. Pancreas
D. Stomach

Correct answer: B

Rationale: The liver is the organ that compensates when a person's intake of vitamins decreases. It stores certain vitamins, such as vitamins A, D, E, K, and B12, and releases them when dietary intake decreases. This helps maintain the body's vitamin levels and functions. The other organs listed - Appendix, Pancreas, and Stomach - do not primarily play a role in compensating for a decrease in vitamin intake. The liver is crucial in maintaining vitamin balance, making it the correct choice in this context.

3. Which form of energy is associated with the motion of an object?

A. Kinetic energy
B. Potential energy
C. Thermal energy
D. Electrical energy

Correct answer: A

Rationale: Kinetic energy is the form of energy associated with the motion of an object. When an object is in motion, it possesses kinetic energy due to its movement. Potential energy, on the other hand, is stored energy that an object has due to its position or condition. Thermal energy is related to heat, while electrical energy is associated with the flow of electric charge. In this case, the correct answer is kinetic energy as it directly correlates with the motion of an object.

4. What is the normal (complete) flow of blood through the heart?

A. Right atrium â†’ lungs â†’ left atrium â†’ body
B. Left atrium â†’ left ventricle â†’ body â†’ right atrium
C. Right atrium â†’ right ventricle â†’ lungs â†’ left atrium â†’ left ventricle â†’ aorta â†’ body
D. Right ventricle â†’ left ventricle â†’ body

Correct answer: C

Rationale: The correct flow of blood through the heart starts with the right atrium receiving deoxygenated blood from the body, followed by the right ventricle pumping blood to the lungs for oxygenation. Oxygenated blood then returns to the heart through the left atrium, then passes to the left ventricle which pumps it out to the body through the aorta. This flow ensures that blood is properly oxygenated before circulating through the body. Choice A is incorrect as the blood does not go directly from the left atrium to the body, skipping the left ventricle. Choice B is incorrect as it does not follow the correct flow sequence in the heart. Choice D is incorrect as it does not include the full pathway of blood through the heart.

5. Which type of cells make up the myelin sheaths?

A. Glial cells.
B. Dendrites.
C. Melanocytes.
D. Squamous cells.

Correct answer: A

Rationale: The correct answer is A: Glial cells. Glial cells are responsible for producing the myelin sheaths that surround and insulate nerve cells in the central and peripheral nervous systems. Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system are types of glial cells that form the myelin sheaths. Choice B, dendrites, are not involved in forming myelin sheaths; they are extensions of neurons that receive signals. Choice C, melanocytes, are cells responsible for producing melanin, not myelin. Choice D, squamous cells, are flat epithelial cells found in various tissues but are not involved in myelin sheath formation.