the patella commonly known as the kneecap is an example of a

ATI TEAS 7

TEAS version 7 quizlet science

1. The patella, commonly known as the kneecap, is an example of a:

A. Sesamoid bone
B. Long bone
C. Short bone
D. Irregular bone

Correct answer: A

Rationale: The patella, also known as the kneecap, is an example of a sesamoid bone. Sesamoid bones develop within tendons, such as the patellar tendon in this case. The patella is embedded in the tendon of the quadriceps muscle, enhancing the mechanical advantage of the muscle and protecting the knee joint. Long bones, like the femur, are characterized by their elongated shape with growth plates at the ends. Short bones, such as those in the wrist and ankle, are cube-shaped bones. Irregular bones, like vertebrae, do not fit into the other bone shape categories due to their unique shapes and functions.

2. How is work defined in terms of force and displacement?

A. Work is the product of force and displacement in any direction
B. Work is done only when the displacement is vertical
C. Work is done only when the force and displacement are perpendicular
D. Work is the product of force and displacement in the direction of the force

Correct answer: D

Rationale: Work is defined as the product of the force applied on an object and the displacement of the object in the direction of the force. This means that work is only done when the force and displacement are in the same direction. If the force and displacement are not in the same direction, only the component of the force in the direction of the displacement contributes to the work done. Therefore, choice D correctly defines work in terms of force and displacement. Choices A, B, and C are incorrect because work is specifically calculated based on the force and displacement in the direction of the force, not in any direction, only when the displacement is vertical, or when the force and displacement are perpendicular.

3. Which of the following hormones is produced by the adrenal medulla and prepares the body for a stressful situation?

A. Testosterone
B. Cortisol
C. Epinephrine (adrenaline)
D. Growth hormone

Correct answer: C

Rationale: The correct answer is C: Epinephrine (adrenaline). Epinephrine is produced by the adrenal medulla and is responsible for preparing the body for a stressful situation. It increases heart rate, dilates airways, and mobilizes energy stores to help the body respond to a fight-or-flight scenario. Testosterone (Choice A) is a sex hormone produced by the testes in males and in smaller amounts by the ovaries in females, not by the adrenal medulla. Cortisol (Choice B) is a stress hormone produced by the adrenal cortex, not the adrenal medulla. Growth hormone (Choice D) is produced by the pituitary gland and is involved in growth, metabolism, and various bodily functions, not by the adrenal medulla.

4. What is the primary purpose of control rods within a nuclear reactor?

A. Reflecting neutrons back into the core
B. Absorbing excess neutrons to control criticality
C. Moderating the velocity of neutrons
D. All of the above

Correct answer: B

Rationale: The primary purpose of control rods in a nuclear reactor is to absorb excess neutrons to control criticality. When inserted into the reactor core, control rods absorb neutrons, reducing the number available for sustaining the fission chain reaction. This action allows operators to manage the reactor power levels and prevent overheating or runaway reactions. Reflecting neutrons back into the core and moderating neutron velocity are not the primary functions of control rods in a nuclear reactor. Choice A is incorrect because control rods do not reflect neutrons back into the core but absorb them. Choice C is incorrect as the moderation of neutron velocity is typically achieved by other materials like a moderator (e.g., water, graphite) rather than control rods. Choice D is incorrect as control rods do not reflect neutrons or moderate neutron velocity, making it an incorrect option.

5. What is the pH of a solution with a hydrogen ion concentration of (1x10^{-9}) M?

A. 5
B. 7
C. 9
D. 11

Correct answer: C

Rationale: The pH of a solution can be calculated using the formula: pH = -log[H+]. Given that the hydrogen ion concentration is $1 \times 10^{-9}$ M, the pH can be calculated as pH = -log(1 x 10^-9) = 9. Therefore, the correct answer is C) 9.