A&P Exam 4

Which of the following is not a motor cranial nerve?

vestibulocochlear nerve (VIII)

"Somatosensory" does not refer to sensory signals from __________.

viscera

The __________ division carries signals to the smooth muscle in the large intestine.

visceral motor

What is the most common inhibitory neurotransmitter in the brain?

γ-aminobutyric acid (GABA)

The vision association area resides primarily in the temporal lobe

False it resides in the occipital lobe

Which of the following accurately describes the reflex pictured here?

Polysynaptic

What is happening during the point on the grap labeled 1

The local current arrives at the axon hillock

Why is the membrane hyperpolarized at the point on the graph labeled 6

The membrane is more temporarily more permeable to potassium than to sodium.

Which cranial nerve innervates most of the viscera in the thoracic and abdominopelvic cavities?

vagus nerve (X)

Sensory stimuli enter the spinal cord via

afferent axons

Local potentials are ______, meaning they vary in magnitude according to the strength of the stimulus

graded

This figure shows the three main functional classes of neurons. Which option below correctly matches the types of neuron to the numeric labels on the figure?

1-afferent neuron, 2- interneuron, 3- efferent neuron

Which of the following is true regarding unmyelinated nerve fibers in the PNS?

A Schwann cell folds its plasma membrane around several fibers .

A neuron receives a stimulus. Which of the following events happens next?

A local potential develops

A myelin sheath is composed primarily of __________.

lipids

The sensitivity of the muscle spindle is maintained by

Alpha motor neurons

Which of the following will cause the plasma membrane to hyperpolarize when at its RMP?

An inflow of chloride

Nonfluent aphasia, due to a lesion in the __________, results in slow speech, difficulty in choosing words, or use of words that only approximate the correct word.

Broca area

Place the following events in synaptic transmission at a cholinergic synapse in order: A-a postsynaptic potential is produced. B- voltage gated calcium channels open and calcium enters the cell. C- ACh is released and diffuses across the axon terminal. D- A nerve signal arrives at an axon terminal. E- ligand gated sodium channels open and sodium enters the cell

D, B, C, E, A

What would be the best explanation for why myelinated fibers conduct signals faster than unmyelinated fibers?

Electrical signals spread faster through insulated (myelinated) regions of axon.

What type of cell is labeled 2

Ependymal cell

A nerve fiber is enclosed in its own fibrous sleeve called perineurium.

FALSE

Most nerves are motor nerves.

FALSE Most nerves are "mixed nerves" - mix of sensory (afferent fibers) and motor (efferent fibers)

Somatic reflexes are responses of skeletal, smooth, and cardiac muscles

FALSE Somatic reflexes are unlearned skeletal muscle reflexes that are mediated by the brainstem and spinal cord.

A typical reflex contains a sensory neuron attached directly to an effector.

False

Acetylcholine triggers the synthesis of the second messenger cAMP only in neurons of the PNS.

False

In a myelinated fiber, only the initial segment in the trigger zone has voltage regulated channels

False

In the brain, neurons are more abundant than neuroglia

False

Neurons move material away from the neurosoma by retrograde transport.

False

Oligodendrocytes serve the same purpose in the CNS that satellite cells do in the PNS

False

The nervous system employs exclusively electrical means to send messages, whereas the endocrine system communicates by means of chemical messages

False

The stretch reflex is the tendency of a muscle to stretch when it is over contracted

False

Voluntary motor signals typically begin in an upper motor neuron in the thalamus

False

When a neuron is stimulated, Na+ gates open and allow Na+ to exit the cell

False

In an action potential, which event directly follows repolarization?

Hyperpolarization of the membrane

An inhibitory local potential causes which of the following?

Hyperpolarization of the plasma membrane

In PNS nerve fiber regeneration, how is a growing axon directed to its original destination?

It grows within a regeneration tube.

Which of the following is true regarding the tendon reflex?

It prevents overcontraction of a muscle.

If the potassium leak channels were suddenly blocked in a resting neuron, what would happen to its resting membrane potential?

It would become more positive

What type of cell labeled 5?

Microglia

Why does the voltage peak at the point on the graph labeled 4?

Voltage-gated sodium channels innactivate.

A _______ is a cordlike organ composed of numerous________

Nerve; axons

What type of cell is 3?

Neuron

Name the part of the axon labeled 4

Node of Ranvier

What type of cell is labeled 4?

Oligodendrocyte

Where are unmyelinated nerve fibers surrounded by Schwann cells?

PNS

flexor reflex (withdrawal reflex) employs a ________ which maintains a sustained contraction

Parallel after-discharge circuit

Which of the following ions has the greatest influence on the resting membrane potential?

Potassium

What causes hyperpolarization of a neuronal membrane?

Potassium leave the cell.

What type of cell is shown here?

Schwann cell

Which glial cell is found wrapped around nerve fibers in the PNS?

Schwann cells

Name the part of the neuron labeled 2

Soma

Which one of the following best describes the order of somatic reflex?

Somatic receptor->afferent nerve fiber->interneuron->efferent nerve fiber->skeletal muscle.

What is the primary site on a neuron for receiving signals for other neurons?

The dendrites

Looking at the muscles at B and G, which are being stimulated to contract and which are being inhibited from contracting?

The muscles at B are being stimulated to contract; the muscles at G are being inhibited from contracting.

A stretch reflex is often accompanied by reciprocal inhibition

True

In most neurons, action potentials occur in the axon

True

Most neurons have multiple dendrites.

True

Norepinephrine is a monoamine

True

The Wernicke area recognizes spoken and written language

True

The crossed extension reflex is the contraction of the extensors on one side of the body when the flexors are contracted on the other side

True

The tendon reflex is the inhibition of a muscles contraction that occurs when it's tendon is excessively stretched

True

Unipolar neurons have only a single process leading away from neurosoma

True

ependymal cells line the inner cavities of the CNS

True

Which neurotransmitter excites skeletal muscle and inhibits cardiac muscle?

acetylcholine

Some __________ neurons are specialized to detect stimuli, whereas __________ neurons send signals to the effectors of the nervous system.

afferent and efferent

What type of cell is labeled 1 in this figure?

astrocyte

What is labeled 1 on this figure?

axon of presynaptic neuron

Tendon organs are __________. A. chemoreceptors B. visceral receptors C. proprioceptors D. pain receptors E. nociceptors

c. proprioceptors

In the patellar tendon reflex arc, the patellar ligament is stretched, which stretches the quadriceps femoris muscle of the thigh. This reflex will cause the quadriceps femoris to ______ and the hamstrings to ________

contract and relax

A reflex in which the sensory input and motor output are on opposite sides of the spinal cord, is called a(n) _________ reflex arc.

contralateral

In which part of a neuron is the postsynaptic membrane usually found?

dendrite

Name the part of the neuron labeled 1

dendrites

Where do most local potentials form in a neuron?

dendrites

In a neuron, the opening of sodium gates typically leads to _______

depolarization of the plasma membrane

Motor commands are carried by __________ from the brain along the spinal cord.

descending tracts

From superficial to deep, the meninges occur in which order?

dura mater, arachnoid, pia mater

What property of neurons allows them to respond to changes in the environment?

excitability

A nurse pricks your finger to type your blood. You flinch at the pain, pulling your hand back. This is called the __________ reflex.

flexor (withdrawal)

Planning, motivation, and social judgment are functions of the brain associated with which part of the cerebrum?

frontal lobe

Local potentials are _______, whereas action potentials are ________

graded; all or none

About 90% of the neurons in the nervous system are __________ neurons.

inter

Name the parts of the axon labeled 5

internodes

If a bee sting on the right thigh causes a quick involuntary reaction of the right arm, this would be an example of a(n) __________ reflex.

intersegmental

Reflex arcs that only use two neurons are called ____________ reflex arcs.

monosynaptic

Which of the following are effectors?

muscles and glands

A traveling wave of excitation is known as a(n) __________.

nerve signal

During the absolute refractory period which of the following is true?

no stimulus of any strength will trigger a new action potential

Name the part of the neuron labeled 3

nucleus

Which cells form myelin in the spinal cord?

oligodendrocytes

Which of the following is most likely to cause a rapid depolarization?

opening of sodium channels

The ___________ association area is responsible for perceiving and attending to stimuli, and the ________ association area is responsible for identifying them

parietal and temporal

Which reflex is pictured here?

patellar tendon

When the voltage of a plasma membrane shifts from +35 mV toward 0 mV, the cell is

repolarizing

If a neuron is prevented from sending a neurotransmitter across a synapse to another cell, which neuron property is being inhibited?

secretion

You go to the movies after a long day and you begin to nod off as soon as the movie starts. Your head starts to lower a little, but a reflex causes your head to rise. This is called the __________ reflex.

stretch (myotatic)

The ____ division tends to prepare the body for action

sympathetic

What is labeled 5 on this figure?

synaptic cleft

What is labeled 2 on this figure?

synaptic vesicle

Which reflex shows the least synaptic delay?

tendon reflex

All of the following are typical characteristics of neurotransmitters except ________

they are released into the bloodstream before reaching the postsynaptic cell

What is the largest of the cranial nerves and most important sensory nerve of the face?

trigeminal nerve

Which cranial nerve pathway would be used to look cross-eyed at the tip of your nose?

trochlear nerve (IV)