Ch. 2 Flashcards
define biological perspective
concerned with the links between biology and behavior. Includes psychologists working in neuroscience, behavior genetics, and evolutionary psychology
nerve cells ____ ____.
conduct electricity
how do nerve cells “talk” to each other?
by sending chemical messages across a tiny gap that separates them
specific brain systems serve specific _____.
functions
What do phrenology and psychology’s biological perspective have in common?
They share a focus on the links between the brain and behavior. Phrenology faded because it had no scientific basis—skull bumps don’t reveal mental traits and abilities.
what are the names which psychologists who are working on the biological perspective of psychology referred to as?
behavioral neuroscientists neuropsychologists behavior geneticists physiological psychologists biopsychologists
define dendrites
a neuron’s bushy, branching extensions that receive messages and conduct impulses toward the cell body
define axon
the neuron extension that passes messages through its branches to other neurons or to muscles or glands.
how long can axon be?
several feet
define myelin sheath
a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next
define glial cells (glia)
cells in the nervous system that support, nourish, and protect neurons; they may also play a role in learning, thinking, and memory
define action potential
a neural impulse; a brief electrical charge that travels down an axon
define refractory period
(1) a period of inactivity after a neuron has fired. (2) a resting period after orgasm, during which a man cannot achieve another orgasm
define threshold
the level of stimulation required to trigger a neural impulse
define all or none response
a neuron’s reaction of either firing (with a full-strength response) or not firing
When a neuron fires an action potential, the information travels through the axon, the dendrites, and the cell body, but not in that order. Place these three structures in the correct order.
dendrites, cell body, axon
How does our nervous system allow us to experience the difference between a slap and a tap on the back?
Stronger stimuli (the slap) cause more neurons to fire and to fire more frequently than happens with weaker stimuli (the tap)
define neurotransmitters
chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse
define synapse
he 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
define reuptake
a neurotransmitter’s reabsorption by the sending neuron
What happens in the synaptic gap?
Neurons send neurotransmitters (chemical messengers) across this tiny space between one neuron’s terminal branch and the next neuron’s dendrite or cell body.
What is reuptake? What two other things can happen to excess neurotransmitters after a neuron reacts?
Reuptake occurs when excess neurotransmitters are reabsorbed by the sending neuron. (They can also drift away or be broken down by enzymes.)
Serotonin, dopamine, and endorphins are all chemical messengers called ______________.
neurotransmitters
define agonist
a molecule that increases a neurotransmitter’s action
define antagonist
a molecule that inhibits or blocks a neurotransmitter’s action
Curare poisoning paralyzes its victims by blocking ACh receptors involved in muscle movements. Morphine mimics endorphin actions. Which is an agonist, and which is an antagonist?
Morphine is an agonist; curare is an antagonist.
define nervous system
the body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems
define Central nervous system (CNS)
the brain and spinal cord
define Peripheral nervous system (PNS)
the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body
define nerves
bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sense organs
define Sensory (afferent) neurons
neurons that carry incoming information from the sensory receptors to the brain and spinal cord
define Motor (efferent) neurons
neurons that carry outgoing information from the brain and spinal cord to the muscles and glands
define interneurons
neurons within the brain and spinal cord; communicate internally and process information between the sensory inputs and motor outputs
define somatic nervous system
the division of the peripheral nervous system that controls the body’s skeletal muscles. Also called the skeletal nervous system
define autonomic nervous system (ANS)
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
define sympathetic nervous system
the division of the autonomic nervous system that arouses the body, mobilizing its energy
define Parasympathetic nervous system
the division of the autonomic nervous system that calms the body, conserving its energy
What bodily changes does your ANS direct before and after you give an important speech?
Responding to this challenge, your ANS sympathetic division will arouse you. It accelerates your heartbeat, raises your blood pressure and blood sugar, slows your digestion, and cools you with perspiration. After you give the speech, your ANS parasympathetic division will reverse these effects.
define reflexes
a simple, automatic response to a sensory stimulus, such as the knee-jerk response
define endocrine system
the body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream
define hormones
chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissue
define adrenal glands
a pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress
define pituitary gland
the endocrine system’s most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands
Why is the pituitary gland called the “master gland”?
Responding to signals from the hypothalamus, the pituitary releases hormones that trigger other endocrine glands to secrete hormones, which in turn influence brain and behavior.
How are the nervous and endocrine systems alike, and how do they differ?
Both of these communication systems produce chemical molecules that act on the body’s receptors to influence our behavior and emotions. The endocrine system, which secretes hormones into the bloodstream, delivers its messages much more slowly than the speedy nervous system, and the effects of the endocrine system’s messages tend to linger much longer than those of the nervous system.
Why are psychologists concerned with human biology?
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.
What are neurons, and how do they transmit information?
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. Glial cells provide myelin, and they support, nourish, and protect neurons; they may also play a role in learning and thinking.
If the combined signals received by a neuron 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.
how do nerve cells communicate with other nerve cells?
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.
How do neurotransmitters influence behavior, and how do drugs and other chemicals affect neurotransmission?
Neurotransmitters travel designated pathways in the brain and may influence specific behaviors and emotions. Acetylcholine (ACh) 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 increase a neurotransmitter’s action, and may do so in various ways. Antagonists decrease a neurotransmitter’s action by blocking production or release.
What are the functions of the nervous system’s main divisions, and what are the three main types of neurons?
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 (afferent) neurons carry incoming information from sensory receptors to the brain and spinal cord. (2) Motor (efferent) 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.
How does the endocrine system transmit information and interact with the nervous system?
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, including the adrenal 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.
define lesion
tissue destruction. A brain lesion is a naturally or experimentally caused destruction of brain tissue
define electroencephalograph
an amplified recording of the waves of electrical activity sweeping across the brain’s surface. These waves are measured by electrodes placed on the scalp
define PET (positron emission tomography) scan
a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task
define MRI (magnetic resonance imaging)
a technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. MRI scans show brain anatomy.
define FMRI (functional MRI)
a technique for revealing bloodflow and, therefore, brain activity by comparing successive MRI scans. fMRI scans show brain function as well as structure
define brainstem
the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival functions
define medulla
the base of the brainstem; controls heartbeat and breathing
Nerves from the left side of the brain are mostly linked to the ______________ side of the body, and vice versa.
right
define thalamus
the brain’s sensory control center, 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
define reticular formation
a nerve network that travels through the brainstem into the thalamus and plays an important role in controlling arousal.
define cerebellum
the “little brain” at the rear of the brainstem; functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory
In what brain region would damage be most likely to (1) disrupt your ability to skip rope? (2) disrupt your ability to hear and taste? (3) perhaps leave you in a coma? (4) cut off the very breath and heartbeat of life?
- cerebellum, 2. thalamus, 3. reticular formation, 4. medulla
define limbic system
neural system (including the hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives
define hippocampus
neural center located in the limbic system; helps process explicit memories for storage
define amygdala
two lima-bean-sized neural clusters in the limbic system; linked to emotion
Electrical stimulation of a cat’s amygdala provokes angry reactions. Which autonomic nervous system division is activated by such stimulation?
The sympathetic nervous system
define hypothalamus
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
What are the three key structures of the limbic system, and what functions do they serve?
(1) The amygdala is involved in aggression and fear responses. (2) The hypothalamus is involved in bodily maintenance, pleasurable rewards, and control of the hormonal systems. (3) The hippocampus processes conscious memory.
How do neuroscientists study the brain’s connections to behavior and mind?
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.
What structures make up the brainstem, and what are the functions of the brainstem, thalamus, reticular formation, and cerebellum?
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 control center. The cerebellum, attached to the rear of the brainstem, coordinates muscle movement and balance and also helps process sensory information.
What are the limbic system’s structures and functions?
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 hypothalamus controls the pituitary (the “master gland”) by stimulating it to trigger the release of hormones.
define cerebral cortex
the intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body’s ultimate control and information-processing center
Which area of the human brain is most similar to that of less complex animals? Which part of the human brain distinguishes us most from less complex animals?
The brainstem; the cerebral cortex
define frontal lobes
portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgments
define parietal lobes
portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position
define occipital lobes
portion of the cerebral cortex lying at the back of the head; includes areas that receive information from the visual fields
define temporal lobes
portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each receiving information primarily from the opposite ear
define motor cortex
an area at the rear of the frontal lobes that controls voluntary movements
define somatosensory cortex
area at the front of the parietal lobes that registers and processes body touch and movement sensations
Our brain’s ______________ cortex registers and processes body touch and movement sensations. The ______________ cortex controls our voluntary movements.
somatosensory; motor
Why are association areas important?
Association areas are involved in higher mental functions—interpreting, integrating, and acting on information processed in other areas.
define association areas
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
define plasticity
the brain’s ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience
define neurogenesis
he formation of new neurons
define corpus callosum
the large band of neural fibers connecting the two brain hemispheres and carrying messages between them
define split brain
a condition resulting from surgery that isolates the brain’s two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them
(1) If we flash a red light to the right hemisphere of a person with a split brain, and flash a green light to the left hemisphere, will each observe its own color? (2) Will the person be aware that the colors differ? (3) What will the person verbally report seeing?
- yes, 2. no, 3. green
Almost all right-handers process speech in the ______________ hemisphere; most left-handers process speech in the ______________ hemisphere.
left; left—the other 30 percent vary, processing speech in the right hemisphere or in both hemispheres
What are the functions of the various cerebral cortex regions?
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 somatosensory 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 somatosensory 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.
To what extent can a damaged brain reorganize itself, and what is neurogenesis?
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.
What do split brains reveal about the functions of our two brain hemispheres?
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.
What does research tell us about being left-handed? Is it advantageous to be right-handed?
Some 10 percent of us (somewhat more among males, somewhat less among females) are left-handed. Handedness appears to be influenced by genetic or prenatal factors. Most left-handers process speech in the left hemisphere, as right-handers do, but some do so in the right hemisphere or use both hemispheres. Left-handers are more likely to be among those with reading disabilities, allergies, and migraine headaches, but sometimes do better academically. Left-handedness is also more common among musicians, mathematicians, architects, artists, and in professional baseball and cricket players. The pros and cons of being left-handed seem roughly equal.
