which of the following describes saltatory conduction

ATI TEAS 7

ATI TEAS 7 Science

1. Which of the following accurately describes saltatory conduction?

A. It is faster than normal nerve conduction
B. It occurs from one node of Ranvier to the next
C. It only occurs in myelinated neurons
D. All of the above

Correct answer: D

Rationale: The correct answer is D, 'All of the above.' Saltatory conduction is faster than normal nerve conduction, occurs from one node of Ranvier to the next, and is exclusive to myelinated neurons. This form of conduction allows for the rapid transmission of nerve impulses by the action potential jumping between the nodes of Ranvier in myelinated neurons, enhancing the efficiency of signal propagation along the axon. Choice A is correct as saltatory conduction is indeed faster than normal conduction. Choice B is accurate as it describes the mechanism of conduction 'jumping' from one node of Ranvier to the next. Choice C is correct because saltatory conduction occurs specifically in myelinated neurons where the myelin sheath insulates the axon except at the nodes of Ranvier, facilitating faster transmission of nerve impulses.

2. Which blood component is responsible for the production of antibodies?

A. Platelets
B. Red blood cells
C. White blood cells
D. Plasma cells

Correct answer: C

Rationale: White blood cells, specifically B lymphocytes or B cells, are responsible for producing antibodies as part of the immune response. When the body encounters foreign substances (antigens), B cells are activated to differentiate into plasma cells, which then produce antibodies to target and neutralize the antigens. Platelets are involved in blood clotting and not in antibody production. Red blood cells are primarily responsible for carrying oxygen in the blood and do not produce antibodies. Plasma cells are actually differentiated B cells that produce antibodies, but the question asks for the blood component responsible for the production of antibodies, which is the white blood cells.

3. Which of the following are the abdominal quadrants?

A. RUQ, RLQ, LLQ, LUQ
B. RUQ, LUQ, RLQ, LLQ
C. LUQ, RUQ, LLQ, RLQ
D. LLQ, LUQ, RUQ, RLQ

Correct answer: B

Rationale: The correct answer is B: RUQ, LUQ, RLQ, LLQ. The four abdominal quadrants are named as follows: Right Upper Quadrant (RUQ), Left Upper Quadrant (LUQ), Right Lower Quadrant (RLQ), and Left Lower Quadrant (LLQ). These quadrants are used in healthcare to describe specific areas of the abdomen during assessments and discussions related to abdominal anatomy and pathology. Choices A, C, and D are incorrect because they do not follow the standard order of the abdominal quadrants.

4. Which hormone is responsible for lowering blood sugar levels?

A. Glucagon
B. Insulin
C. Adrenaline
D. Cortisol

Correct answer: B

Rationale: Insulin is the hormone responsible for lowering blood sugar levels. It is produced by the pancreas and facilitates the entry of glucose into cells, thereby reducing blood sugar levels. Glucagon, adrenaline, and cortisol have roles in increasing blood sugar levels through various mechanisms. Glucagon raises blood sugar levels by stimulating the liver to release stored glucose, adrenaline increases blood sugar in fight-or-flight responses, and cortisol raises blood sugar levels as part of the stress response. Therefore, in the context of lowering blood sugar levels, insulin is the correct answer.

5. At which of the following ages would ossification most likely take place to replace cartilage at the growth plate?

A. 5
B. 18
C. 42
D. 91

Correct answer: B

Rationale: Ossification, the process where cartilage is replaced by bone, typically occurs during adolescence, around the age of 18. This is when the growth plates in the bones close, and the bones stop growing in length, leading to the replacement of cartilage with bone tissue. Choice A (5) is incorrect because ossification primarily occurs during adolescence, not early childhood. Choice C (42) is incorrect as ossification is completed well before this age, usually during the late teens or early twenties. Choice D (91) is incorrect as ossification is a process that occurs earlier in life, typically during adolescence, and is not a process that occurs in advanced age.