Which of the following statements concerning myelination is true?
A. Unmyelinated axons rest in invaginations of Schwann cells or oligodendrocytes.
B. The myelin sheath inhibits the flow of electrical charges at nodes.
C. Myelination will not influence the speed of conduction of action potentials.
D. The myelin sheath does not electrically insulate the axons from one another.
E. The myelin sheath is a protein wrapping.
Answer: A
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Which is the best description for the function of the cranial bones?
A) allowing introduction of food into the digestive system B) house the special sense organs C) protection of the brain D) providing passageways for respiratory gases to move into and out of the body
Answer the following statements true (T) or false (F)
1. In expiration, the size of the chest cavity is reduced. 2. In the lung, diffusion moves oxygen from the alveoli to the blood. 3. In the lung, hemoglobin becomes oxyhemoglobin. 4. Most of the carbon dioxide in the blood is carried as carbaminohemoglobin. 5. In order for external respiration to take place, the alveoli must have a higher oxygen concentration and a lower carbon dioxide concentration than the blood in the lung capillaries.
The expansion of the lungs during inspiration generates a pressure gradient causing air to flow into the lungs. This is an example of Boyle's law.
Answer the following statement true (T) or false (F)
The first capillary bed associated with the nephron
A) reverses the flow of blood. B) reabsorbs nutrients. C) adjusts pH. D) filters.