Choose the best answer.

1			One role of astrocytes is to __________________.
			A)	produce cerebrospinal fluid
			B)	phagocytize tissue debris
			C)	promote neuron growth
			D)	form myelin in the CNS
2			The reason that damaged nerve fibers in the CNS are not able to regenerate is that they lack __________________.
			A)	the axolemma and neurilemma
			B)	the neurilemma and endoneurium
			C)	the myelin sheath and neurilemma
			D)	Schwann cells and nodes of Ranvier
3			Failure of the rostral end of the neural tube to close is called __________________.
			A)	anencephaly
			B)	spina bifida
			C)	microcephaly
			D)	rostrational clef
4			When one or more of the vertebra fail to enclose the spinal cord, this is called __________________________.
			A)	anencephaly
			B)	spina bifida
			C)	microcephaly
			D)	rostrational clef
5			The forebrain divides into the diencephalon and the _______________________.
			A)	metencephalon
			B)	myelencephalon
			C)	mesencephalon
			D)	telencephalon
6			The sympathetic neurons, Schwann cells and adrenal medulla arise from these cells. What are they called?
			A)	Cephalic cells
			B)	Neural plate cells
			C)	Neural crest cells
			D)	Oligodendrocytes
7			In a neuronal pool of A-B-C- and D, if C excites D as well as A, this is called a ___________________________ circuit.
			A)	parallel after-discharge
			B)	converging
			C)	reverberating
			D)	diverging
8			In a chemical synapse the swelling found at the end of the presynaptic neuron is called the _______________________.
			A)	knob
			B)	cleft
			C)	hillock
			D)	vesicles
9			The structures in the terminal end of the presynaptic neuron that release neurotransmitter into the cleft are called ________________.
			A)	mitochondria
			B)	vesicles
			C)	receptors
			D)	gap junctions
10			Single-unit smooth muscle cells and cardiac cells use this type of synapse.
			A)	Electrical
			B)	Neuronal
			C)	Chemical
			D)	Mechanical
11			The sudden ionic movement across a nerve's membrane is called a/n ____________________________.
			A)	synapse
			B)	neuromuscular junction
			C)	action potential
			D)	resting membrane potential
12			The speed of neuronal conduction is based upon the _____________________.
			A)	amount of myelin
			B)	size of the axon
			C)	length of the axon
			D)	All of the above answers are correct.
			E)	None of the above answers are correct.