ATI TEAS 7
ATI TEAS Science Practice Test
1. What is the bottom number in a blood pressure reading?
- A. Diastolic pressure
- B. Systolic pressure
- C. Pulse rate
- D. Mean arterial pressure
Correct answer: A
Rationale: The correct answer is A: Diastolic pressure. The bottom number in a blood pressure reading represents the diastolic pressure, which indicates the lowest pressure in the arteries when the heart is resting between beats. This value is important in understanding the overall health of the cardiovascular system. Choice B, Systolic pressure, is the top number in a blood pressure reading and represents the pressure in the arteries when the heart is contracting. Choice C, Pulse rate, refers to the number of times the heart beats in a minute. Choice D, Mean arterial pressure, is a calculated value using both systolic and diastolic pressures to provide an average pressure in the arteries during a cardiac cycle, but it is not the bottom number in a blood pressure reading.
2. Melanin, the pigment responsible for skin color, is produced by
- A. Keratinocytes (These cells produce keratin)
- B. Melanocytes
- C. Sebocytes (These cells produce sebum)
- D. Langerhans cells (These cells are part of the immune system)
Correct answer: B
Rationale: Melanocytes are the cells responsible for producing melanin, the pigment that determines skin color. Melanin gives skin its color and protects it from the harmful effects of UV radiation. Keratinocytes produce keratin, a tough protein that forms the outer layer of the skin, hair, and nails. Sebocytes produce sebum, an oily substance that helps moisturize and protect the skin. Langerhans cells are a type of immune cell found in the skin that play a role in protecting against infections and foreign substances but do not produce melanin.
3. What is the term for a genetic disorder caused by a mutation on the X chromosome?
- A. Autosomal dominant disorder
- B. Autosomal recessive disorder
- C. Sex-linked recessive disorder
- D. Sex-linked dominant disorder
Correct answer: C
Rationale: A genetic disorder caused by a mutation on the X chromosome is termed a sex-linked recessive disorder (Option C). This type of disorder is more commonly seen in males due to their single X chromosome, making them more vulnerable to X-linked mutations. Females have two X chromosomes, providing a protective effect against X-linked disorders.\n- Autosomal dominant disorders (Option A) result from a mutation in one copy of a gene on non-sex chromosomes (autosomes) and are not specifically related to the X chromosome.\n- Autosomal recessive disorders (Option B) occur due to mutations in both copies of a gene on autosomes, not on the X chromosome.\n- Sex-linked dominant disorders (Option D) are rare and lead to more severe symptoms in males as they only require one copy of the mutated gene on the X chromosome to express the disorder. However, this is not the term for a genetic disorder caused by an X chromosome mutation.
4. What is the primary mode of CO2 transport in the body?
- A. Bicarbonate
- B. Carbamino compounds
- C. None of these
- D. Plasma
Correct answer: A
Rationale: The correct answer is A: Bicarbonate. In the body, the primary mode of CO2 transport is as bicarbonate. Carbon dioxide is converted to bicarbonate in red blood cells as part of the bicarbonate buffer system, which helps maintain the pH balance in the blood. Bicarbonate is then transported in the plasma to the lungs where it is converted back to carbon dioxide for exhalation. While carbamino compounds also play a role in CO2 transport by binding to amino groups on proteins, bicarbonate is the main mode of transport for carbon dioxide in the body. Options B, C, and D are incorrect as they do not represent the primary mechanism of CO2 transport in the body.
5. Which component of the nervous system is responsible for controlling voluntary movements, such as the contraction of skeletal muscles?
- A. Autonomic nervous system
- B. Peripheral nervous system
- C. Somatic nervous system
- D. Sympathetic nervous system
Correct answer: C
Rationale: The correct answer is C: Somatic nervous system. The somatic nervous system is responsible for controlling voluntary movements, such as the contraction of skeletal muscles. This system consists of motor neurons that send signals from the central nervous system to the skeletal muscles, allowing for conscious control over movement. The autonomic nervous system (A) controls involuntary functions like heart rate and digestion, the peripheral nervous system (B) includes all nerves outside the central nervous system, and the sympathetic nervous system (D) is a division of the autonomic nervous system responsible for the fight-or-flight response. Therefore, choices A, B, and D are incorrect as they do not specifically regulate voluntary movements of skeletal muscles, which is a function of the somatic nervous system.
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