Which of the following functions does the myelin sheath perform for a nerve cell?
A. Insulation
B. Regeneration
C. Sensory perception
D. Nutrition
This question was extracted from the actual TEAS 7 Exam. Get access to the actual TEAS 7 Exams (past and recent) on ExamGates.
The myelin sheath is a protective membrane that wraps around parts of certain nerve cells.
Its fatty-protein coating provides protective insulation for your nerve cell like the plastic insulation covering that encases the wires of an electrical cord ².
This allows the electrical impulses to travel quickly and efficiently between one nerve cell and the next. The other options are incorrect because they do not describe the functions of the myelin sheath.
Regeneration, sensory perception, and nutrition are not functions performed by the myelin sheath for a nerve cell.
Therefore, the Correct Answer is A.
More Questions on TEAS 7 Science Exam 3
Question 1:
Genetic information describing the characteristics of an organism is found in which of the following?
A. Nuclei
B. Membranes
C. Cilia
D. Ribosomes
The Correct Answer is A.The correct answer is a. Nuclei. Genetic information describing the characteristics of an organism is found in the nuclei of its cells. The nucleus contains the organism's DNA, which carries the genetic information that determines its traits.
b. Membranes are structures that surround and enclose cells and organelles, but they do not contain genetic information.
c. Cilia are hair-like structures that protrude from the surface of some cells and are involved in movement, but they do not contain genetic information.
d. Ribosomes are organelles that are involved in protein synthesis, but they do not contain genetic information.
Question 2:
Which of the following is a component of the integumentary system that secretes pheromones?
A. Fossa ovalis
B. Seminiferous tubule
C. Dermal papilla
D. Apocrine gland
The Correct Answer is D.The apocrine gland is a component of the integumentary system that secretes pheromones. Pheromones are chemical signals that are released by an individual and can affect the behavior or physiology of other individuals of the same species.
The other options are not components of the integumentary system that secrete pheromones. The fossa ovalis is a depression in the interatrial septum of the heart, the seminiferous tubule is a structure in the testes where sperm are produced, and the dermal papilla is a structure at the base of a hair follicle that provides nutrients to the hair.
Question 3:
A patient goes to the doctor with a cold and sore throat and asks for antibiotics. The doctor refuses to prescribe antibiotics to the patient because the illness is caused by which of the following pathogens?
A. Fungus
B. Virus
C. Protist
D. Bacteria
The Correct Answer is B.The doctor refuses to prescribe antibiotics to the patient because the illness is caused by a virus. The common cold is a viral infection of the upper respiratory tract. Antibiotics are not effective against viral infections and are only used to treat bacterial infections.
The other options are not correct because they do not accurately describe the cause of the common cold and sore throat. Fungus, protist, and bacteria are not the pathogens responsible for causing the common cold.
Question 4:
Which of the following structures is present in both prokaryotic and eukaryotic cells?
A. Endoplasmic reticulum
B. Cell membrane
C. Chloroplast
D. Golgi apparatus
The Correct Answer is B.The structure that is present in both prokaryotic and eukaryotic cells is the cell membrane ². The cell membrane is a thin layer that surrounds the cell and separates its internal environment from the external environment ². It is composed of a lipid bilayer and proteins and regulates the movement of substances into and out of the cell ².
The other options are not correct because they are not present in both prokaryotic and eukaryotic cells. The endoplasmic reticulum, chloroplast, and Golgi apparatus are organelles that are only found in eukaryotic cells ².
Question 5:
Emphysema caused by damage to alveoli from toxins and pollutants is likely to result in the body having difficulty performing which of the following actions?
A. Releasing histamine and acetylcholine
B. Exchanging oxygen and carbon dioxide
C. Absorbing food
D. Producing enzymes
The Correct Answer is B.Emphysema is a lung condition that is caused by damage to the alveoli, the tiny air sacs in the lungs where gas exchange occurs. When the alveoli are damaged, the body has difficulty exchanging oxygen and carbon dioxide. This can lead to shortness of breath and other respiratory problems. The other options are not directly related to the function of the alveoli or the effects of emphysema.
