Question

For each multiple choice, what is the answer and why?

5. Myelin A) is only found in the peripheral nervous system B) is secreted from the axon terminals of autonomic neurons. C) is a carbohydrate within the membranes of some neuroglia. D) is a chemical present in the plasma membrane of neurons. E) influences the rate of conduction of an electrical signal down an axon. 6. Which of the following organs/structures is (are) innervated by somatic motor nerves? (only ONE correct answer) A) the biceps brachii muscle B) the kidney C) the iris D) the heart E) the lungs 7. sounds cause vibration of the basilar membrane at a point the oval window. A) Loud / far from B) Loud / close to C) Low frequency / far from D) Soft / close to E) High frequency / far from 8. If the concentration of ATP were depleted in a typical nerve cell, the A) resting membrane potential would decrease (become less negative) B) resting membrane potential would eventually reach a positive value, inside with respect to outside. C) concentration gradient for Nat would remain the same. D) resting membrane potential would increase (become more negative). 9. Interneurons with only two processes attached to the neuron's soma are common in the retina of the eye and around other sensory organs. These are called_ neurons because of their appearance. A) unipolar B) bipolar C) motor D) efferent E) multipolar 10. Adaptation in sensory receptors A) is when receptors become more responsive to continuing stimuli. B) refers to the process by which the the eye uses the lens to focus on objects. C) occurs to the same extent in all types of receptors. D) refers to the decrease or cessation of receptor potentials from receptors despite a continuing stimulus. E) Both (A) and (B) are correct. 11. Which of the following statements can be TRUE of both action potentials and graded potentials? A) They have a threshold potential. B) They can depolarize a neuron C) They are capable of summation D) They fade decrementally. E) They occur along axons. 12. In off-pathway bipolar cells, A) Cyclic GMP (CGMP) hyperpolarizes the bipolar cell membrane. B) glutamate stimulates nonspecific cation channels to open, causing depolarization C) nonspecific cation channels open when the eye is exposed to light. D) Cyclic GMP (GMP) triggers depolarization when light strikes the eye. E) glutamate stimulates bipolar cell depolarization in an all-or-none fashion

Answer 1

5. E) influences the rate of conduction of an electric signal down an axon.

Myelin is an insulating layer that is formed by oligodendrocytes in central nervous system and by Schwann cells in peripheral nervous system .Myelin is lipid ( fatty) rich substance and also made up of proteins.The main function of myelin is to increase the rate of conduction of electric impulses across the nerve cells ( axon) .

6. A) the biceps brachii muscle

Somatic nervous system innervate structures like skeletal muscle ( efferent innervation ) and also provide innervation to skin, muscles and joints ( afferent innervation ).