ch 12 nervous system

The cranial nerves are part of which of the following portions of the nervous system?

peripheral nervous system

The spinal nerves that branch off the spinal cord are part of which portion of the nervous system?

peripheral

Which of the following portions of the nervous system are involved in increasing the heart rate?

sympathetic

Which of the following portions of the nervous system are involved in controlling the activities of glands?

autonomic

A single axon is classified as a __________.

nerve fiber

The myelinated axons in the spinal cord are called __________

nerve tracts

The brain and spinal cord have noticeable areas of gray and white. Which of the following constitutes the white matter?

myelinated axons

The best way to see the corpus callosum of the brain is by looking at a(n) __________ view

sagittal

The thalamus and fornix are located within the __________ ventricle

third

The axons of some neurons in the CNS are protected by glial cells that form a myelin sheath around the axons. These glial cells are called _________

oligodendrocytes

What is the name of the glial cells that act as phagocytes to aid in protecting CNS neurons?

microglia

There are two types of glial cells found in the peripheral nervous system. Which of the following is found in the peripheral nervous system?

neurolemmocytes (Schwann cells)

The myelin sheath (formed by neurolemmocytes) wrap around the __________ of a neuron to provide protection and insulation

axon

The neurofibril nodes are areas of the axon that _________

are not covered by the neurolemmocytes

If a neurolemmocyte makes 10 wraps around an axon, the nucleus of the neurolemmocyte can be found in wrap number ________

10

Which part of the neuron is involved in sending an impulse to the synapse area or to an effector?

axon

Impulses that are going toward the CNS are called __________ and impulses going away from the CNS are called ________

afferent; efferent

When a neuron is depolarized, the gated channels of the membrane open to allow __________ to enter the neuron. A neuron becomes hyperpolarized when the gated channels of the membrane open thus allowing __________ to exit the neuron

Na+; K+

A resting membrane is measured at __________ while a depolarized membrane will measure at _________

\-70 mV; +30mV

When the sodium channels open to let sodium ions into the neuron, other gated channels open to allow __________ to exit the neuron

potassium ions

In order to maintain an ionic charge balance across a neuron's membrane after depolarization, what ion is moved to the outside of the membrane to maintain the ionic charge?

potassium

Depolarization is the term used to describe the movement of __________ ions to the inside of a neuron while repolarization is the term used to describe the movement of __________ ions to the outside of a neuron

sodium potassium

__________ is the term used to describe the movement of potassium ions to the outside of a neuron, and __________ is the term used to describe excess potassium ions moving to the outside of a neuron

repolarization; hyperpolarization

During repolarization, the sodium channels are closed. How does this affect a neuron?

the neuron cannot respond to new stimuli

When a neuron is hyperpolarized, it _________

cannot respond to new stimuli

Which of the following can cause the gated channels to open?

stimulus

Once the gated channels are open and positive ions begin to enter the neuron, we have the start of a(n) _________

impulse

Which of the following correctly depicts the voltage value going from a resting neuron to a depolarized neuron?

\-70mV to 0mV

A graded potential arises in all of the following EXCEPT ________

axons

Which of the following ions cause the presynaptic vesicles to fuse with the presynaptic membrane and release a neurotransmitter into the synaptic area?

calcium

When calcium ions enter and cause the release of a neurotransmitter, the neurotransmitter will bind to the receptors on the _________

postsynaptic membrane

In order for an impulse to be transmitted from one neuron to the next or from a neuron to its destination, a neurotransmitter must be released from ________

the terminal end of the axon

dilution into surrounding tissue

diffusion

cleaves acetate off of acetylcholine

enzymatic degradation

reuptake by the secreting cells, or absorption by surrounding glial cells

uptake by cells

initiates membrane depolarization (allows sodium or calcium to flow into cell)

excitatory postsynaptic potential

hyperpolarizes the membrane (Cl- into cell or K+ flow out of cell)

inhibitory postsynaptic potential

3 to 40 amino acids in length

neuropeptides

spinal cord and brain; enhances pain perception

substance p

involved in pain suppression

enkephalins, endorphins, dynorphins

drugs that mimic the action of a neurotransmitter or hormone by binding to the receptor and causing the same action

agonists

drugs that bind to neurotransmitter or hormone receptors but do not activate the action of the nuerotransmitter or hormone

antagonists

blocks postsynaptic glycine receptors (inhibitory or hyperpolarizing) causing excessive motor neuron firings, skeletal muscles and diaphragm remain continuously contracted

strychnine

blocks release of acetylcholine in somatic motor neurons

botulinum toxin (BoTox)