Which would be present in an animal with a nerve net?
What is the difference between a neuron and a nerve?
They consist of different numbers of cells.
A cluster of nerve cell bodies outside the central nervous system is referred to as a(n) _____.
A neuron that transmits an impulse to the central nervous system after the neuron is stimulated by the environment is called a(n) _____.
sensory neuron ( Sensory neurons communicate information between sensory receptors and the central nervous system about the external and internal environments.)
Which of the following is specifically a part or a function of the central nervous system?
Effectors include _____.
endocrine glands ( Effector cells are muscles or gland cells that carry out the body's response to stimuli.)
Which of the following describes a withdrawal reflex response?
The first two answers are correct ( It requires a sensory neuron, an interneuron, and motor nerves; It results in the limb moving toward the midline of the body.)
The part of a neuron that carries nerve impulses toward the cell body is called _____.
Schwann cells make up the _____.
Cells that provide metabolic and structural support to the neurons include _____.
astrocytes, oligodendrocytes, and Schwann cells
Which one of the following statements is NOT true about the resting potential?
The concentration of sodium is much higher inside the cell than outside.
The sodium-potassium pump _____.
expels sodium from the cell ( The sodium-potassium pump is a channel protein that expels sodium from the cell, exchanging it for potassium.)
A drug that causes potassium to leak out of a neuron, increasing the positive charge on the outside, would _____.
inhibit transmission of nerve signals by the neuron
Threshold depolarization is of great significance in the physiology of neurons because if threshold depolarization is not reached, _____.
positive-feedback depolarization will not occur
An action potential is _____.
a traveling wave of depolarization in the neuron membrane ( An action potential is an all-or-none change in membrane potential that travels along the neuron.)
The period in which an axon membrane cannot act is called _____.
the refractory period ( A membrane cannot act during the refractory period because its gates will not open.)
"Saltatory conduction" means that the membrane potential changes _____.
only at the nodes of Ranvier
Action potentials are generated along a neuron because _____.
depolarization of the membrane at one point causes an increase of permeability to sodium at the next point
How are neurons structurally adapted to chemically transmit impulses to neighboring neurons?
Axon terminals contain neurotransmitter substances within synaptic vesicles. ( Numerous sacs, called synaptic vesicles, located in the cytoplasm at the tip of the presynaptic axon release molecules of a neurotransmitter across the synaptic cleft, which bind to receptors imbedded in the membrane of the postsynaptic cell.)
Which one of the following statements about the transmission across a typical chemical synapse is NOT true?
Vesicles containing neurotransmitter molecules diffuse to the receiving cell's plasma membrane.
Acetylcholinesterase is the enzyme that degrades acetylcholine. What effect on nerve transmission would occur following the administration of a chemical that inhibited acetylcholinesterase?
Extra excitatory postsynaptic potentials would occur in the postsynaptic neuron.
In humans, making more serotonin available to brain cells typically _____.
produces an effect on mood
A natural pain reliever is _____.
Which of the following includes all the others?
peripheral nervous system (PNS)
Which of the following parts of the nervous system would allow you to discover the qualities of a mouthful of black pepper?
Which one of the following structures is (are) included in the peripheral nervous system?
The gray matter of the cerebral cortex, where most higher-level thinking occurs, is composed mostly of _____.
dendrites, unmyelinated axons, and nuclei ( The gray matter is involved in relaying incoming sensory information and outgoing motor commands. It processes this information and develops the appropriate response, an activity sometimes called thinking.)
Which of the following structures constitute(s) the mammalian forebrain?
thalamus, epithalamus, hypothalamus, and cerebrum
Alex becomes so dehydrated while playing tennis that his blood pressure starts to drop. His _____ detects the drop in pressure and sends signals via _____ to speed up the heart to compensate.
medulla oblongata ... sympathetic neurons
A physician friend of yours tells you about a patient with a head injury who suddenly stopped breathing during the examination. What portion of the brain was probably injured?
medulla oblongata ( The medulla oblongata contains centers that control several visceral functions, such as breathing, heart and blood vessel activity, swallowing, vomiting, and digestion.)
As you start to pick up your biology book, you suddenly realize that it is much heavier than you expected. Which of the following brain regions is responsible for the rapid adjustment of muscle force that allows you to pick up the book smoothly?
Monitoring blood CO2 levels as well as triggering breathing at the appropriate times are functions of the _____.
The relay center for sensory messages is the _____.
thalamus ( The thalamus is a relay center for motor and sensory messages, except those from olfactory receptors, in all vertebrate classes.)
A man is admitted to the hospital suffering from an abnormally low body temperature, a loss of appetite, and extreme thirst. A brain scan shows a tumor located in the _____.
hypothalamus ( Each of the problems experienced by the patient is associated with specific functions of the hypothalamus and its role in maintaining homeostasis.)
In mammals, the part of the brain that increases in size and complexity most significantly is derived from the embryonic _____.
forebrain ( The cerebral cortex develops from the telencephalon, an outgrowth of the forebrain.)
The corpus callosum connects the _____.
right and left cerebral hemispheres
An important concept in biology is that evolution is a process that builds on present body plans. This means that embryonic development sequences often display evidence of evolutionary relationships. Such evidence would indicate that which part of the brain was most prominent in early vertebrates?
the hindbrain ( The hindbrain maintains homeostasis, necessary for all animals, and makes up a significant portion of the brain of a one-month-old embryo.)
Damage to the occipital lobe would be most likely expressed as _____.
The hearing centers are located in the _____.
temporal lobes of the cerebral cortex ( Hearing centers are located in the temporal lobes of the cerebral cortex.)
Which of the following is NOT regulated by the association areas in the cerebral cortex?
balance ( With the exception of balance, which is controlled by the cerebellum, all the other listed functions occur in the cerebral cortex.)
After a stroke, Bill can feel his left leg but is unable to move it. His neurologists suspect damage to the _____.
right frontal lobe ( Voluntary motor control originates in the frontal lobe. Because the organization of the cerebral cortex is contralateral, the right cortex controls the left side of the body.)
The limbic system is involved in _____.
emotion and memory ( Mostly associated with emotion, the limbic system also includes two regions, the amygdala and hippocampus, which function in memory.)
Which ancestral region of the brain is responsible for modern humans' speech and ability to do algebra?
forebrain ( This part of the brain developed into the cerebral cortex, which makes these activities possible.)
Which of the following contributes to learning and memory storage in the brain?
excitatory neurotransmitters sent from neurons into synapses
Which part of the brain's limbic system ties an event to a scent, making it possible for a long-term memory to be triggered by a smell?
Damage to the nervous system presents particular challenges for physicians. Which of these is NOT a new development likely to translate into new therapies for damaged nervous system components?
It has been discovered that the removal of certain parts of the brain may cause personality changes.