A&P1 exam 4

The resting potential of a neuron is ________.

-70 mV

Pulling away from a painful stimulus is an example of the ________ reflex.

withdrawal

The cranial nerves whose primary function is special sensory are

I, II, VIII olfactory, optic, vestibucochlear

Which cranial nerve is responsible for the motor innervation of pharyngeal muscles and parotid salivary glands?

IX Glossopharyngeal

Which of the following is the most sensitive body region?

face

In adults, the spinal cord usually extends to which level?

first or second lumbar vertebra

Changes in the membrane potential that cannot spread far from the site of stimulation are called ________.

graded potentials

Axons that cross from one side of the spinal cord to the other are found in the ________.

gray commissures

The projections of gray matter extending through the white matter toward the outer surface of the spinal cord are called

horns

Most neurons in the brain are

multipolar

Neurons that have two or more dendrites and a single axon extending away from the soma are called

multipolar

The myelin sheaths that surround the axons of some of the neurons in the CNS are formed by

oligodendrocytes

All of the nervous tissue outside of the central nervous system comprises the ________ nervous system.

peripheral

Which nerve innervates the diaphragm?

phrenic nerve

The ________ is the layer of the meninges that is in direct contact with the surface of the brain.

pia mater

Compound nerve trunks containing axons derived from several spinal nerves travel through

plexuses

ascending pathways

carry sensory information to the brain.

The brain and spinal cord comprise the

central nervous system

Enlargements of the spinal cord occur

cervical and lumbar regions

The phrenic nerves arise from the

cervical plexuses

Branches that sometimes occur along the length of an axon are called

collaterals

Which of the following is a descending pathway of the spinal cord?

corticospinal

Voluntary control of skeletal muscles is provided by the

corticospinal pathway

Which of the following is a descending pathway of the spinal cord?

corticospinal tract

Opening of voltage-gated sodium channels in the membrane of a neuron results in

depolarization

Which nerve from the brachial plexus innervates the extensor muscles of the arm and forearm?

radial

Which of the following lists the parts of a reflex arc in the correct order?

receptor, sensory neuron, interneuron, motor neuron, effector

Which of the following is a function of the efferent division of the nervous system?

sending signals to muscles

The posterior horns of the spinal cord contain

sensory nuclei

Spinal nerves from the brachial plexus innervate the

shoulder girdle and upper limb

The specialized membranes that protect the spinal cord are termed

spinal meninges

Head injuries that damage cerebral blood vessels are serious conditions because

these spaces compress and distort the relatively soft tissues of the brain

Bundles of CNS axons that share a common origin, destination, and function are called

tracts

Which spinal cord structure(s) contains the axons of CNS motor neurons that control muscles and glands?

ventral roots

The entire spinal cord is divided into ________ segments.

31

Identify the correct sequence of steps in the generation of an action potential.

1. Activation of sodium channels and rapid depolarization 2. Inactivation of sodium channels and activation of potassium channels 3. Depolarization to threshold 4. Closing of potassium channels 3,1,2,4

There are ________ pairs of spinal nerves.

31

Which of the following is the correct order of events that occur at a cholinergic synapse?

4. Axon terminal depolarizes. 1. Extracellular calcium enters the axon terminal, triggering the exocytosis of acetylcholine. 3. Acetylcholine binds to receptors and depolarizes the postsynaptic membrane. 2. Acetylcholine is removed by acetylcholinesterase.

Neurons that have one axon and one dendrite with the soma (cell body) between them are called

Bipolar

Which ion is needed to trigger the release of acetylcholine, via exocytosis, into the synaptic cleft?

Calcium

Clusters of rough endoplasmic reticulum and free ribosomes are known as

Nissl bodies

When a neuron is at rest, which ion passes through its membrane most easily?

Potassium

The neurilemma of axons in the peripheral nervous system is the outer layer of

Schwann cells

The cranial nerve that has three branches is the

Trigeminal

Which cranial nerve is responsible for the sensory innervation of the anterior two-thirds of the tongue?

VII

Motor innervation of the muscles of facial expression is transmitted through which cranial nerve?

VII facial

Which of the following neurotransmitters usually depolarizes postsynaptic neurons?

acetylcholine

The ________ nervous system provides involuntary regulation of smooth muscle, cardiac muscle, and glandular activity.

autonomic

The ________ division of the nervous system brings sensory information to the central nervous system.

afferent

The part of the peripheral nervous system that brings information to the central nervous system is the

afferent division

The all-or-none principle states that

all stimuli great enough to bring the membrane to threshold will produce identical action potentials

Monosynaptic reflexes

are exemplified by the stretch reflex.

Which of the following are responsible for reciprocal inhibition?

interneurons in the spinal cord

In general, the nervous system

is fast acting

saltatory conduction

is faster than conduction on an unmyelinated axon.

Another name for the patellar reflex is the

knee jerk reflex

Which of the following pairs is not properly matched?

lumbar spinal nerves: 4

Small phagocytic glial cells, which are derived from white blood cells, are called

microglia

Which of the following is abnormal in the adult?

Babinski sign

muscle spindles

are bundles of small, specialized skeletal muscle fibers.

Interneurons

are found only in the central nervous system.

The branching structures that, together with the cell body, are sensitive to chemical, mechanical, or electrical stimulation are called

dendrites

A stimulus that opens gated potassium ion channels, taking the membrane potential away from 0 mV, results in which of the following?

hyperpolarization

The spinal pathway(s) that carries/carry highly localized sensory information concerning fine touch and pressure is/are the

posterior column

If the dorsal root of a spinal nerve is severed,

incoming sensory information would be disrupted

Effects produced by the parasympathetic branch of the autonomic nervous system include

increased secretion by digestive glands

Which of the following delivers poorly localized sensations of touch, pressure, pain, and temperature to the primary sensory cortex?

spinothalamic pathway

Which of the following contains a delicate network of collagen and elastin fibers through which cerebrospinal fluid circulates?

subarachnoid space