The nervous system | Practice Problems, Examples & Solutions

Neuron Structure and Function

Essential Cell Biology

Through the exchange of small metabolites and ions, gap junctions provide metabolic and electrical coupling between cells. Why, then, do you suppose that neurons communicate primarily through chemical synapses (as shown in Figure $12-40$ ) rather than through gap junctions?

Cell Communities: Tissues, Stem Cells, and Cancer

04:39

Essential Cell Biology

The ion channels that are regulated by binding of neurotransmitters, such as acetylcholine, glutamate, GABA, or glycine, have a similar overall structure. Yet each class of these channels consists of a very diverse set of subtypes with different transmitter affinities, different channel conductances, and different rates of opening and closing. Do you suppose that such extreme diversity is a good or a bad thing from the standpoint of the pharmaceutical industry?

Transport Across Cell Membranes

05:00

Essential Cell Biology

The neurotransmitter acetylcholine is made in the cytosol and then transported into synaptic vesicles, where its concentration is more than 100 -fold higher than in the cytosol. When synaptic vesicles are isolated from neurons, they can take up additional acetylcholine added to the solution in which they are suspended, but only when ATP is present. $\mathrm{Na}^{+}$ ions are not required for the uptake, but, curiously, raising the $\mathrm{pH}$ of the solution in which the synaptic vesicles are suspended increases the rate of uptake. Furthermore, transport is inhibited when drugs are added that make the membrane permeable to $\mathrm{H}^{+}$ ions. Suggest a mechanism that is consistent with all of these observations.

Transport Across Cell Membranes

Resting Neuron Potential

26 Practice Problems

00:59

Molecular Cell Biology

Why is the cell unable to initiate another action potential if stimulated during the refractory period?

Cells of the Nervous System

07:50

Molecular Biology of the Cell

Acetylcholine-gated cation channels at the neuromuscular junction open in response to acetylcholine released by the nerve terminal and allow Na' ions to enter the muscle cell, which causes membrane depolarization and ultimately leads to muscle contraction.
A. Patch-clamp measurements show that young rat muscles have cation channels that respond to acetylcholine (Figure $Q 11-4$ ). How many kinds of channel are there? How can you tell?
B. For each kind of channel, calculate the number of ions that enter in one millisecond. (One ampere is a current of one coulomb per second; one pA equals $10^{-12}$ ampere. An ion with a single charge such as $\mathrm{Na}^{+}$ carries a charge of $1.6 \times 10^{-19}$ coulomb.

Membrane Transport of Small Molecules and the Electrical Properties of Membranes

00:29

Molecular Biology of the Cell

Which statements are true? Explain why or why not.
The membrane potential arises from movements of charge that leave ion concentrations practically unaffected, causing only a very slight discrepancy in the number of positive and negative ions on the two sides of the membrane.

Membrane Transport of Small Molecules and the Electrical Properties of Membranes

Action Potential Generation and Propogation

47 Practice Problems

00:23

Biology of Humans: Concepts, Applications, and Issues

Repolarization
a. establishes the threshold voltage.
b. is due to movement of potassium ions out of the axon.
c. is due to movement of sodium ions into the axon.
d. occurs as the sodium-potassium pump moves potassium out of the axon.

Neurons: The Matter of the Mind

00:38

Biology of Humans: Concepts, Applications, and Issues

Choose the incorrect statement:
a. Neurotransmitters diffuse across the myelin sheath.
b. In an inhibitory synapse, the neurotransmitter makes it less likely that an action potential will be generated in the postsynaptic (after the synapse) neuron.
c. Neurotransmitters are stored in synaptic vesicles.
d. Most interneurons are found in the central nervous system.

Neurons: The Matter of the Mind

02:21

Biology: Concepts and Investigations

Use the following activity to visualize the ion movements of an action potential: If you're in a classroom with several other students, label half of them as sodium ions and half as potassium ions. Find an object to represent a membrane (e.g., a line in the floor); label four mats or pieces of paper to represent different membrane proteins, and lay them across the line. Choose which side will be the inside of the cell. Act out how the ions move before, during, and after an action potential. Alternatively, if you are working alone or in a small group, use 20 coins of two different types to represent $10 \mathrm{Na}^{+}$ and $10 \mathrm{K}^{+}$ ions. Draw a line on a piece of paper to serve as a membrane, add four types of proteins, and label the inside and outside of the cell. Position the ions before, during, and after an action potential. Then, write a sentence or two about your activity.

The Nervous System

Neurotransmitters

54 Practice Problems

00:33

Molecular Cell Biology

What is the role of glial cells in the brain and other parts of the nervous system?

Cells of the Nervous System

05:03

Introduction to General, Organic and Biochemistry

(a) Identify two monoamine neurotransmitters in Table $24-1$
(b) Explain how they act.
(c) Which medication controls the diseases caused by a lack of monoamine neurotransmitters?

Chemical Communications: Neurotransmitters and Hormones

01:26

Essential Cell Biology

Cell Communities: Tissues, Stem Cells, and Cancer

Vertebrate Nervous System Organization

108 Practice Problems

01:43

Nester's Microbiology: A Human Perspective

Which of these statements concerning poliomyelitis is false?
a) The sensory nerves are usually involved.
b) It can be caused by any of three specific polioviruses.
c) Only a small fraction of those infected will develop the disease.
d) The disease is transmitted via the fecal-oral route.
e) A post-polio syndrome can develop years after recovery from the original illness.

Nervous System Infections

01:18

Microbiology with Diseases by Body System

The layer of the meninges lying closest to the spinal cord is the ____.
a. arachnoid mater
b. pia mater
c. dura mater
d. cauda equina

Microbial Diseases of the Nervous System and Eyes

00:16

Biology of Humans: Concepts, Applications, and Issues

Belinda was riding a bicycle without a helmet and was struck by a car. She hit the back of her head very hard in the fall. The physician is quite concerned because the medulla is located at the base of the skull. She explains to Belinda's parents that injury to the medulla could result in
a. the loss of coordination, such that the child may never regain the motor skills needed to ride a bicycle.
b. the loss of speech.
c. amnesia (the loss of memory).
d. death, because many life-support systems are controlled here.

The Nervous System

The Peripheral Nervous System

31 Practice Problems

03:40

Biology: Concepts and Investigations

A male moth uses his antennae to detect the concentration of a pheromone on each side of his body, allowing him to fly toward the female that is producing the pheromone. Explain how sensory receptors, peripheral nerves, and the central nervous system interact to allow moths to compare pheromone concentrations in the air surrounding each antenna.

The Senses

00:24

Biology: Concepts and Investigations

How does the endocrine system interact with the nervous system? The circulatory system?

The Endocrine System

00:40

Biology Concepts and Applications

When something frightens you, ________neurons increase their output.
a. sympathetic
b. parasympathetic

Neural Control

Regional Specialization in the Vertebrate Brain

26 Practice Problems

00:38

Biology: Concepts and Investigations

Neuroglia outnumber neurons in the nervous system by about 10 to 1. In addition, neuroglia retain the ability to divide, unlike neurons. How do these two observations relate to the fact that most brain cancers begin in glial cells?

The Nervous System

00:36

Biology Concepts and Applications

The medulla oblongata
a. produces hemoglobin
b. is in the forebrain
c. regulates breathing rate
d. detects carbon monoxide

Respiration

03:07

Biology: The Unity and Diversity of Life

Match each item with its description.
a. start of brain, spinal cord
b. connects the hemispheres
c. protects brain and spinal cord from some toxins
d. type of signaling molecule
e. support team for neurons
f. stretch-sensitive receptor
g. roles in emotion, memory
h. most complex integration
i. myelinated axons of neurons
muscle spindle
neurotransmitter
Limbic system
orpus callosum
cerebral cortex
neural tube
neuroglia
white matter
blood-brain
barrier

Neural Control

Cerebral Cortex and Cognitive Function

26 Practice Problems

00:36

Biology of Humans: Concepts, Applications, and Issues

The autonomic nervous system
a. cannot be affected by emotional states.
b. controls conscious body movements.
c. is entirely contained within the central nervous system.
d. automatically adjusts the functioning of internal organs to suit conditions.

The Nervous System

02:20

Biology: Concepts and Investigations

In a rare condition called synesthesia, stimulation of one sense causes stimulation of another sense. For example, people with synesthesia have reported seeing bursts of color when stimulated with loud noises. Would you expect synesthesia to be a problem with sensory receptors, peripheral nerves, or the central nervous system? Explain.

The Senses

00:47

Biology: Concepts and Investigations

Compare and contrast the endocrine and nervous systems.

The Endocrine System

Memory and Learning

6 Practice Problems

04:33

Biology: Concepts and Investigations

Classify each of the following descriptions as either a proximate or an ultimate cause of behavior. For all proximate causes, speculate about a possible ultimate cause of the behavior.
a. A surge of epinephrine initiates a flight response in a gazelle.
b. Turtles use Earth's magnetic field lines as guides during migration.
c. $A$ small mammal ignores low-energy food sources that are difficult to obtain, maximizing energy gain from foraging.
d. $A$ bird distracts a predator near its nest, increasing the nestlings' chance of survival.

Animal Behavior

00:48

Human Biology

Memories are stored in the sensory association areas of the
a. cerebral cortex.
b. spinal cord
c. brain stem.
d. hypothalamus.

Nervous System

01:43

Anatomy & Physiology

Memory, emotional, language, and sensorimotor deficits together are most likely the result of what kind of damage?
a. stroke
b. developmental disorder
c. whiplash
d. gunshot wound

The Neurological Exam

Nervous System Disorders from a Molecular Standpoint

13 Practice Problems

02:36

Biology: Concepts and Investigations

In a disorder called macular degeneration, photoreceptors at the center of the retina die. How does macular degeneration impair vision? Why is peripheral vision unaffected?

The Senses

00:52

Biology: Concepts and Investigations

In what ways does an action potential resemble "the wave" in a football stadium? In what ways does a graded potential resemble a cheerleader's attempts to get "the wave" started?

The Nervous System

02:32

Biology: The Essentials

What are the two main cell types in nervous tissue?

Animal Tissues and Organ Systems