Chapter 2

Question 1

neuron

Answer 1

a nerve cell; the basic building block of the nervous system

Question 2

sensory neurons

Answer 2

neurons that carry incoming information from the sensory receptors to the brain and spinal cord.

Question 3

motor neurons

Answer 3

neurons that carry outgoing information from the brain and spinal cord to the muscles and glands.

Question 4

interneurons

Answer 4

neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs.

Question 5

dendrite

Answer 5

the bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body.

Question 6

axon

Answer 6

the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands.

Question 7

myelin sheath

Answer 7

a layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next.

Question 8

action potential

Answer 8

a neural impulse; a brief electrical charge that travels down an axon.

Question 9

threshold

Answer 9

the level of stimulation required to trigger a neural impulse.

Question 10

synapse

Answer 10

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or synaptic cleft.

Question 11

neurotransmitters

Answer 11

chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, they travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse.

Question 12

reuptake

Answer 12

a neurotransmitter’s reabsorption by the sending neuron.

Question 13

nervous system

Answer 13

the body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems.

Question 14

central nervous system (CNS)

Answer 14

the brain and spinal cord.

Question 15

peripheral nervous system (PNS)

Answer 15

the sensory and motor neurons that connect the central nervous system to the rest of the body.

Question 16

nerves

Answer 16

bundled axons that form neural “cables” connecting the central nervous system with muscles, glands, and sense organs.

Question 17

somatic nervous system

Answer 17

the division of the peripheral nervous system that controls the body’s skeletal muscles. Also called the skeletal nervous system.

Question 18

autonomic nervous system

Answer 18

the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.

Question 19

sympathetic nervous system

Answer 19

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations.

Question 20

parasympathetic nervous system

Answer 20

the division of the autonomic nervous system that calms the body, conserving its energy.

Question 21

reflex

Answer 21

a simple, automatic response to sensory stimulus, such as the knee-jerk response.

Question 22

endocrine system

Answer 22

the body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream.

Question 23

hormones

Answer 23

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues.

Question 24

adrenal glands

Answer 24

a pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrene) that help arouse the body in times of stress.

Question 25

pituitary glands

Answer 25

the endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.

Question 26

lesion

Answer 26

tissue destruction. It is natural or experimentally-caused destruction of brain tissue.

Question 27

electroencephalogram (EEG)

Answer 27

an amplified recording of the waves of electrical activity that sweep across the brain's surface. These waves are measured by electrodes placed on the scalp.

Question 28

PET (positron emission tomography)

Answer 28

scan a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task

Question 29

MRI (magnetic resonance imaging)

Answer 29

a technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. These scans show brain anatomy.

Question 30

fMRI (functional MRI)

Answer 30

a technique for revealing bloodflow and, therefore, brain activity by comparing successive MRI scans. These scans show brain function.

Question 31

brainstem

Answer 31

the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; it is responsible for automatic survival functions.

Question 32

medulla

Answer 32

the base of the brainstem; controls heartbeat and breathing.

Question 33

reticular formation

Answer 33

a nerve network in the brainstem that plays an important role in controlling arousal; leads up to the thalamus; enables alertness

Question 34

thalamus

Answer 34

the brain's sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla.

Question 35

cerebellum

Answer 35

the "little brain" at the rear of the brainstem; functions include processing sensory input (nonverbal learning and memory) and coordinating voluntary movement output and balance.

Question 36

limbic system

Answer 36

neural system (including the hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives.

Question 37

amygdala

Answer 37

two lima bean-sized neural clusters in the limbic system; linked to emotion.

Question 38

hypothalamus

Answer 38

a neural structure lying below (hypo) the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.

Question 39

cerebral cortex

Answer 39

the intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body's ultimate control and information-processing center.

Question 40

glial cells (glia)

Answer 40

cells in the nervous system that support, nourish, and protect neurons.

Question 41

frontal lobes

Answer 41

portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgments.

Question 42

parietal lobes

Answer 42

portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position.

Question 43

occipital lobes

Answer 43

portion of the cerebral cortex lying at the back of the head; includes areas that receive information from the visual fields from the opposite visual field

Question 44

temporal lobes

Answer 44

portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each receiving information primarily from the opposite ear; auditory processing areas

Question 45

motor cortex

Answer 45

an area at the rear of the frontal lobes that controls voluntary movements.

Question 46

sensory cortex

Answer 46

area at the front of the parietal lobes that registers and processes body touch and movement sensations.

Question 47

association areas

Answer 47

areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking.

Question 48

plasticity

Answer 48

the brain's ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience.

Question 49

neurogenesis

Answer 49

the formation of new neurons.

Question 50

corpus callosum

Answer 50

the large band of neural fibers connecting the two brain hemispheres and carrying messages between them.

Question 51

split brain

Answer 51

a condition resulting from surgery that isolates the brain's two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them.

Question 52

Biological Pyschology

Answer 52

a branch of psychology that is concerned with the links between biology and behavior. Also known as behavioral neuroscientists, neuropsychologists, behavior geneticists, physiological psychologists, or biopsychologists.

Question 53

endorphins

Answer 53

"morphine within" - natural, opiatelike neurotransmitters linked to pain control and to pleasure

Question 54

functions of brainstem and cerebellum

Answer 54

coordinates the body

Question 55

limbic (border) system functions

Answer 55

manages emotions, and connects thought to the body

Question 56

cortex (outer covering) function

Answer 56

integrates all of the information coming in

Question 57

what part of the brain makes humans unique from lower organisms?

Answer 57

the cortex

Question 58

pons

Answer 58

unconscious movements (swallowing, blinking)

Question 59

hippocampus

Answer 59

makes conscious memory; works with the amygdala for emotionally charged memories

Question 60

building blocks of the mind

Answer 60

neurons

Question 61

Why are psychologists concerned with human biology?

Answer 61

Psychologists working from a biological perspective study the links between biology and behavior. We are biopsychosocial systems, in which biological, psychological, and social-cultural factors interact to influence behavior.

Question 62

What are neurons, and how do they transmit information?

Answer 62

Neurons are the elementary components of the nervous system, the body’s speedy electrochemical information system. A neuron receives signals through its branching dendrites, and sends signals through its axons. Some axons are encased in a myelin sheath, which enables faster transmission. If the combined received signals exceed a minimum threshold, the neuron fires, transmitting an electrical impulse (the action potential) down its axon by means of a chemistry-to-electricity process. The neuron’s reaction is an all-or-none process.

Question 63

How do nerve cells communicate with other nerve cells?

Answer 63

When action potentials reach the end of an axon (the axon terminals), they stimulate the release of neurotransmitters. These chemical messengers carry a message from the sending neuron across a synapse to receptor sites on a receiving neuron. The sending neuron, in a process called reuptake, then normally reabsorbs the excess neurotransmitter molecules in the synaptic gap. If incoming signals are strong enough, the receiving neuron generates its own action potential and relays the message to other cells.

Question 64

How do neurotransmitters influence behavior, and how do drugs and other chemicals affect neurotransmission?

Answer 64

Neurotransmitters travel designated pathways in the brain and may influence specific behaviors and emotions. Acetylcholine affects muscle action, learning, and memory. Endorphins are natural opiates released in response to pain and exercise. Drugs and other chemicals affect brain chemistry at synapses. Agonists excite by mimicking particular neurotransmitters or by blocking their reuptake. Antagonists inhibit a particular neurotransmitter’s release or block its effect.

Question 65

What are the functions of the nervous system’s main divisions, and what are the three main types of neurons?

Answer 65

The central nervous system (CNS)—the brain and the spinal cord—is the nervous system’s decision maker. The peripheral nervous system (PNS), which connects the CNS to the rest of the body by means of nerves, gathers information and transmits CNS decisions to the rest of the body. The two main PNS divisions are the somatic nervous system (which enables voluntary control of the skeletal muscles) and the autonomic nervous system (which controls involuntary muscles and glands by means of its sympathetic and parasympathetic divisions). Neurons cluster into working networks. There are three types of neurons: (1) Sensory neurons carry incoming information from sense receptors to the brain and spinal cord. (2) Motor neurons carry information from the brain and spinal cord out to the muscles and glands. (3) Interneurons communicate within the brain and spinal cord and between sensory and motor neurons. In addition, glial cells support, nourish, and protect neurons and may also play a role in learning and thinking.

Question 66

How does the endocrine system transmit information and interact with the nervous system?

Answer 66

The endocrine system is a set of glands that secrete hormones into the bloodstream, where they travel through the body and affect other tissues, including the brain. The endocrine system’s master gland, the pituitary, influences hormone release by other glands. In an intricate feedback system, the brain’s hypothalamus influences the pituitary gland, which influences other glands, which release hormones, which in turn influence the brain.

Question 67

How do neuroscientists study the brain’s connections to behavior and mind?

Answer 67

Clinical observations and lesioning reveal the general effects of brain damage. Electrical, chemical, or magnetic stimulation can also reveal aspects of information processing in the brain. MRI scans show anatomy. EEG, PET, and fMRI (functional MRI) recordings reveal brain function.

Question 68

What structures make up the brainstem, and what are the functions of the brainstem, thalamus, and cerebellum?

Answer 68

The brainstem, the oldest part of the brain, is responsible for automatic survival functions. Its components are the medulla (which controls heartbeat and breathing), the pons (which helps coordinate movements), and the reticular formation (which affects arousal). The thalamus, sitting above the brainstem, acts as the brain’s sensory switchboard. The cerebellum, attached to the rear of the brainstem, coordinates muscle movement and balance and also helps process sensory information.

Question 69

What are the limbic system’s structures and functions?

Answer 69

The limbic system is linked to emotions, memory, and drives. Its neural centers include the hippocampus (which processes conscious memories); the amygdala (involved in responses of aggression and fear); and the hypothalamus (involved in various bodily maintenance functions, pleasurable rewards, and the control of the endocrine system). The pituitary (the “master gland”) controls the hypothalamus by stimulating it to trigger the release of hormones.

Question 70

What are the functions of the various cerebral cortex regions?

Answer 70

The cerebral cortex has two hemispheres, and each hemisphere has four lobes: the frontal, parietal, occipital, and temporal. Each lobe performs many functions and interacts with other areas of the cortex. The motor cortex, at the rear of the frontal lobes, controls voluntary movements. The sensory cortex, at the front of the parietal lobes, registers and processes body touch and movement sensations. Body parts requiring precise control (in the motor cortex) or those that are especially sensitive (in the sensory cortex) occupy the greatest amount of space. Most of the brain’s cortex—the major portion of each of the four lobes—is devoted to uncommitted association areas, which integrate information involved in learning, remembering, thinking, and other higher-level functions. Our mental experiences arise from coordinated brain activity.

Question 71

To what extent can a damaged brain reorganize itself, and what is neurogenesis?

Answer 71

If one hemisphere is damaged early in life, the other will pick up many of its functions by reorganizing or building new pathways. This plasticity diminishes later in life. The brain sometimes mends itself by forming new neurons, a process known as neurogenesis.

Question 72

What do split brains reveal about the functions of our two brain hemispheres?

Answer 72

Split-brain research (experiments on people with a severed corpus callosum) has confirmed that in most people, the left hemisphere is the more verbal, and that the right hemisphere excels in visual perception and the recognition of emotion. Studies of healthy people with intact brains confirm that each hemisphere makes unique contributions to the integrated functioning of the brain.