what are the two layers of the spinal cord

ATI TEAS 7

ATI TEAS Science Practice Test

1. What are the two layers of the spinal cord?

A. White matter and grey matter
B. Epithelial and connective tissue
C. Adipose and muscular tissue
D. Dermis and hypodermis

Correct answer: A

Rationale: The correct answer is A: White matter and grey matter. The spinal cord is composed of an exterior layer of white matter, which surrounds an interior core of grey matter. White matter consists mainly of myelinated axons, while grey matter contains cell bodies, dendrites, and unmyelinated axons. White matter is responsible for transmitting nerve signals up and down the spinal cord, while grey matter processes sensory information and initiates motor commands. The other choices (B, C, D) are incorrect as they do not represent the anatomical layers of the spinal cord. Epithelial and connective tissue, adipose and muscular tissue, dermis, and hypodermis are not the layers of the spinal cord but are found in other parts of the body such as skin and organs.

2. What is the pathway of oxygenated blood from the lungs?

A. Lungs to the left atrium, through the mitral valve into the left ventricle, pumped into the aorta upon contraction, then dispersed to tissues via a network of arteries and capillaries
B. Lungs to the right atrium, through the mitral valve into the right ventricle, pumped into the aorta upon contraction, then dispersed to tissues via a network of arteries and veins
C. Lungs to the left atrium, directly to the right aorta, then dispersed to tissues via a network of arteries and capillaries
D. Lungs to the left atrium, through the septal valve, stored in the left ventricles, then dispersed to tissues via a network of arteries and capillaries

Correct answer: A

Rationale: The correct pathway of oxygenated blood from the lungs is as follows: Oxygenated blood travels from the lungs to the left atrium, then passes through the mitral valve into the left ventricle. From there, it is pumped into the aorta upon contraction of the heart and is then dispersed to various tissues throughout the body via a network of arteries and capillaries. Choice B is incorrect as it incorrectly mentions the right atrium and ventricle, which are associated with deoxygenated blood. Choice C is incorrect as it mentions a direct connection to the right aorta, which does not exist in the circulatory system. Choice D is incorrect as it refers to the septal valve (which is not anatomically correct) and storing blood in the left ventricle, which does not occur in the normal circulation of blood.

3. What is the unit of measurement for momentum?

A. Newton-second (N·s)
B. Kilogram-meter (kg·m)
C. Joule (J)
D. Meter per second (m/s)

Correct answer: A

Rationale: The correct unit of measurement for momentum is Newton-second (N·s). Momentum is calculated as the product of an object's mass and its velocity. The unit of mass is kilograms (kg) and the unit of velocity is meters per second (m/s). Therefore, the unit of momentum is kilogram-meter per second (kg·m/s). By Newton's second law of motion (F = ma), force is measured in Newtons (N), which is equivalent to kg·m/s². Multiplying the unit of force (N) by the unit of time (s) gives the unit of momentum as Newton-second (N·s). Choice B, Kilogram-meter (kg·m), is incorrect because it represents the unit of work or energy, not momentum. Choice C, Joule (J), is incorrect as it is a unit of energy. Choice D, Meter per second (m/s), is incorrect as it represents velocity alone, not momentum which is a vector quantity involving mass and velocity.

4. Which of the following is a characteristic of an interneuron?

A. Forms neural circuits
B. Interacts with effectors
C. Sends impulses to the CNS
D. Functions as an efferent nerve cell

Correct answer: A

Rationale: The correct characteristic of an interneuron is that it forms neural circuits, connecting sensory and motor neurons within the central nervous system. Interneurons facilitate communication between different neurons in the central nervous system, helping in the processing and integration of signals. Choice B is incorrect as interneurons primarily interact with other neurons, not effectors. Choice C is incorrect as interneurons typically do not send impulses to the CNS; they operate within the CNS. Choice D is incorrect as interneurons are not efferent nerve cells; they are mainly involved in processing signals within the CNS rather than transmitting signals to effectors.

5. After water absorption in the large intestine, what waste product remains and is eventually eliminated from the body?

A. Chyme
B. Bolus
C. Glucose
D. Feces

Correct answer: D

Rationale: The correct answer is D: Feces. After the large intestine absorbs water and electrolytes from digested food material, the waste product that remains is feces. Feces consist of undigested food material, bacteria, and waste products that were not absorbed by the body. Choice A, Chyme, is incorrect as chyme is a semi-fluid mass of partially digested food that moves from the stomach to the small intestine. Choice B, Bolus, is incorrect as bolus refers to a rounded mass of food that is swallowed. Choice C, Glucose, is incorrect as glucose is a simple sugar that serves as a vital energy source for the body and is not a waste product in this context.