Anatomy - Chapter 12 Fundamentals of the Nervous System

Which of the following is not a characteristic of neurons?

ability to survive without oxygen

In axon terminals, mitochondria are __________.

abundant because the release of neurotransmitters requires a great deal of ATP

**The typical and most common type of synapse is__________.

axodendritic

**The peripheral process and central process of a sensory neuron together are both part of the __________.

axon

This neuronal region transmits electrical impulses away from the cell body.

axon

This tends to be the longest cytoplasmic projection from a neuron.

axon

The ________ of a presynaptic neuron associates with the dendrite of a postsynaptic neuron.

axon terminal

These regions of a neuron are also referred to as terminal boutons.

axon terminal

Most synapses transmit communicating signals using

chemical signaling molecules-neurotransmitters

**__________neurons are rare neurons, but are located in the retina and in the olfactory mucosa.

bipolar

An axosomatic synapse occurs between the axon terminals of one neuron and the ________ of another neuron.

cell body

What important function could be diminished if the cilia on ependymal cells were absent?

circulation of cerebrospinal fluid (CSF)

Nonmyelinated axons

conduct impulses more slowly than myelinated axons

**The basic components of the peripheral nervous system are __________ and __________.

cranial nerves; spinal nerves

These regions of the neuron direct electrical currents toward the cell body.

dendrite

**The processes that branch from the cell body of a neuron and receive signals from other neurons are__________.

dendrites

Ciliated neuroglial cells that form an epithelium and play an active role in forming and moving cerebrospinal fluid are

ependymal cells

The entire nerve is surrounded by a tough fibrous sheath called the

epineurium

A neuron is a collection of nerve fibers in the PNS.

false

All of the neuron's organelles are localized to the cell body.

false

Oligodendrocytes and Schwann cells myelinate neurons within the peripheral nervous system.

false

The somatic motor subdivision of the peripheral nervous system is considered to be an involuntary nervous system.

false

**Motor neurons __________.

form junctions with effector cells, stimulating muscles to contract or glands to secrete

In which direction does the nerve signal pass at the synapse illustrated here?

from presynaptic axon terminal to postsynaptic dendrite

The peripheral nerve fibers that measure the degree of stretch in the biceps brachii muscle and its tendons are classified as

general somatic sensory

The peripheral nerve fibers that speed up the movement of the digestive tract are classified as

general visceral motor (efferent)

**The somatic sensory division of the PNS __________.

includes general senses of pressure, pain, vibration, and temperature in body wall and limbs

**__________matter is a mixture of neuronal cell bodies, dendrites, unmyelinated axons, and neuroglia.

gray

How are gray matter and white matter arranged in the CNS?

gray matter is deep to the superficial white matter in the spinal cord

Which of the following statements describes interneurons?

interneurons are multipolar neurons that are confined to the CNS and are linked together in chains that form complex neuronal pathways

A node of Ranvier (myelin sheath gap)

is a bare region of axonal membrane in myelinated axons only

**Which factors contribute to increasing the speed of nerve impulse transmission?

larger diameter of axon and the presence of myelin sheath

Which part or parts of the neuron are found in the white matter of the central nervous system?

long axonal processes

Which cells are the macrophages of the CNS?

microglial cells

A somatic motor neuron carries

motor commands to the skeletal musculature

The majority of neurons in the body are

multipolar

A nerve cell is the same as a

neuron

**Glial cells that provide the myelin sheath in the CNS are __________.

oligodendrocytes

Interneurons are found

only in the CNS

Which of the following is not considered a special somatic sense?

pain

**Nerve fascicles are bound into bundles by a wrapping of connective tissue called __________.

perineurium

Reflex arc path:

receptor --> sensory neuron --> integration center --> motor neuron --> effector

The visceral motor division of the PNS __________.

regulates the contraction of smooth and cardiac muscle and regulates secretion by the body's many glands

The difference between myelinated and unmyelinated axons is that

schwann cells wrap around myelinated axons in concentric layers

Myelin on axons functions to

speed the rate of impulse conduction and insulate neighboring axons from one another

**What is the function of synaptic vesicles inside axon terminals?

store and release neurotransmitters

This is the site of communication between neurons.

synapse

**Why must axons receive proteins from the cell body of the neuron?

the RER and ribosomes and other organelles involved in protein synthesis are absent from the axon

The complexity of the CNS can be attributed to

the large number of interneurons in the CNS

Which of the following statements about neurotransmitters is false?

they are waves of positive charges that travel down axons

**Within the white matter of the CNS, axons traveling to similar destinations are bundled together in __________.

tracts

Any long axon is called a nerve fiber.

true

Most neurons in the body are multipolar neurons.

true

Special somatic senses have receptors that are located mostly in the head, including hearing and balance and vision.

true