ATI TEAS 7
Chemistry
1. What does the term "solute" refer to in a solution?
- A. The substance present in the largest amount
- B. The substance that dissolves in the solvent
- C. The liquid portion of the solution
- D. The temperature at which the solution freezes
Correct answer: B
Rationale: The solute is the substance that dissolves in the solvent to form a solution. The other choices do not accurately describe the solute.
2. Action potentials, the all-or-nothing electrical signals traveling along neurons, are generated by the movement of:
- A. Glucose
- B. Sodium and potassium ions
- C. Neurotransmitters
- D. Myelin
Correct answer: B
Rationale: The correct answer is B: Sodium and potassium ions. Action potentials are generated by the movement of sodium and potassium ions across the neuronal membrane. During depolarization, sodium ions rush into the cell, causing a change in electrical charge. This influx of positive ions triggers the opening of voltage-gated potassium channels, allowing potassium ions to exit the cell during repolarization. Glucose is a source of energy for cells but does not directly generate action potentials. Neurotransmitters are chemical messengers released at synapses, while myelin is a fatty substance that insulates axons, speeding up the conduction of action potentials but not directly generating them.
3. The fluid-filled sacs that cushion the brain within the skull are called:
- A. Meninges
- B. Cerebrospinal fluid
- C. Dura mater
- D. Arachnoid mater
Correct answer: B
Rationale: The correct answer is B: Cerebrospinal fluid. Cerebrospinal fluid is a clear, colorless fluid that surrounds the brain and spinal cord, acting as a cushion to protect the central nervous system from injury. Meninges (Option A) are the protective membranes that cover the brain and spinal cord, while the dura mater (Option C) and arachnoid mater (Option D) are specific layers of the meninges. However, cerebrospinal fluid is the fluid-filled sac that directly cushions the brain within the skull, making it the most appropriate answer for this question.
4. Histamine, released during an allergic reaction, causes symptoms like:
- A. Fever and fatigue
- B. Runny nose and itchiness
- C. Muscle aches and joint pain
- D. Cough and shortness of breath
Correct answer: B
Rationale: The correct answer is B: 'Runny nose and itchiness.' Histamine is a chemical released by the body during an allergic reaction. It causes various symptoms such as itching, sneezing, runny nose, and watery eyes. These symptoms are commonly associated with allergic reactions like hay fever or hives. Fever and fatigue (option A) are not directly caused by histamine release. Muscle aches and joint pain (option C) are not typical symptoms of histamine release during an allergic reaction. Cough and shortness of breath (option D) are more commonly associated with asthma or respiratory allergies rather than histamine release.
5. The phrase "illuminates not only past events" suggests that history
- A. primarily serves as a nostalgic exercise in remembering old stories.
- B. offers valuable lessons beyond simply recalling occurrences from the past.
- C. is focused solely on factual accuracy and avoids drawing any interpretations.
- D. exists only as a static record of unchanging events with no relevance to our lives.
Correct answer: B
Rationale: The phrase highlights that history goes beyond mere chronology, offering valuable insights and lessons beyond the dates and facts.
6. Which part of the heart generates the QRS complex on an ECG?
- A. Sinoatrial node (SA node)
- B. Atrioventricular node (AV node)
- C. Bundle of His
- D. Ventricular muscle cells
Correct answer: D
Rationale: The correct answer is D, ventricular muscle cells. The QRS complex on an ECG represents the depolarization of the ventricles. This electrical activity is generated by the spread of impulses through the bundle branches and Purkinje fibers to the ventricular muscle cells. The SA node (option A) is responsible for initiating the electrical impulse in the heart, but it does not directly generate the QRS complex. The AV node (option B) delays the impulse to allow for proper coordination of atrial and ventricular contractions. The Bundle of His (option C) and its branches facilitate the conduction of the electrical signal from the AV node to the ventricles but do not generate the QRS complex directly.
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