Module 2 Chapter 2 General Psychology PDF

**MODULE 2** This module is concerned with the functions of the brain and its component neural systems, which provide the basis for all human behavior. Under the direction of the brain, the nervous and endocrine systems coordinate a variety of voluntary and involuntary behaviors and serve as the bo...

**MODULE 2** This module is concerned with the functions of the brain and its component neural systems, which provide the basis for all human behavior. Under the direction of the brain, the nervous and endocrine systems coordinate a variety of voluntary and involuntary behaviors and serve as the body's mechanisms for communication with the external environment. The brain consists of the brainstem, the thalamus, the cerebellum, the limbic system, and the cerebral cortex. Knowledge of the workings of the brain has increased with advances in neuroscientific methods. Studies of split-brain patients have also given researchers a great deal of information about the specialized functions of the brain's right and left hemispheres. Many students find the technical material in this chapter difficult to master. Not only are there many terms for you to remember, but you must also know the organization and function of the various divisions of the nervous system. Learning this material will require a great deal of rehearsal. Working the chapter review several times, drawing and labeling brain diagrams, and mentally reciting terms are all useful techniques for rehearsing this type of material. **CHAPTER 2** **THE BIOLOGY OF THE MIND** **NEURAL COMMUNICATION** **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. Sensory neurons carry incoming information from sense receptors to the brain and spinal cord, and motor neurons carry information from the brain and spinal cord out to the muscles and glands. Interneurons communicate within the brain and spinal cord and between sensory and motor neurons. A neuron sends signals through its axons, and receives signals through its branching dendrites. If the combined signals are strong enough, 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 absorbs the excess neurotransmitter molecules in the synaptic gap. The receiving neuron, if the signals from that neuron and others are strong enough, 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?** Each neurotransmitter travels a designated path in the brain and has a particular effect on behavior 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 communication at the synapse. Agonists excite by mimicking particular neurotransmitters or by blocking their reuptake. Antagonists inhibit a particular neurotransmitter's release or block its effect. *Neurotransmitter pathways Each of the brain's differing chemical messengers has designated pathways where it operates, as shown here for serotonin and dopamine (Carter, 1998).*  **THE NERVOUS SYSTEM** **What are the functions of the nervous system's main divisions?** One major division of the nervous system is the central nervous system (CNS), the brain and spinal cord. The other is the peripheral nervous system (PNS), which connects the CNS to the rest of the body by means of nerves. The peripheral nervous system has two main divisions. The somatic nervous system enables voluntary control of the skeletal muscles. The autonomic nervous system, through its sympathetic and parasympathetic divisions, controls involuntary muscles and glands. Neurons cluster into working networks. **THE ENDOCRINE SYSTEM** **How does the endocrine system---the body's slower information system---transmit its messages?** 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. Some hormones are chemically identical to neurotransmitters (those chemical messengers that diffuse across a synapse and excite or inhibit an adjacent neuron). The endocrine system and nervous system are therefore close relatives: Both produce molecules that act on receptors elsewhere. Like many relatives, they also differ. The speedy nervous system zips messages from eyes to brain to hand in a fraction of a second. Endocrine messages trudge along in the bloodstream, taking several seconds or more to travel from the gland to the target tissue. If the nervous system's communication delivers messages rather like e-mail, the endocrine system is the body's snail mail. But slow and steady sometimes wins the race. Endocrine messages tend to outlast the effects of neural messages. 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. **THE BRAIN** **How do neuroscientists study the brain's connections to behavior and mind?** Clinical observations and lesioning reveal the general effects of brain damage. MRI scans now reveal brain structures, and EEG, PET, and Fmri (functional MRI) recordings reveal brain activity. **What are the functions of important lower-level brain structures?** The brainstem is the oldest part of the brain and 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, the brain's sensory switchboard, sits above the brainstem. The cerebellum, attached to the rear of the brainstem, coordinates muscle movement and helps process sensory information. The limbic system is linked to emotions, memory, and drives. Its neural centers include 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 hormonal system). The pituitary (the "master gland") controls the hypothalamus by stimulating it to trigger the release of hormones. The hippocampus processes memory.  **What functions are served by the various cerebral cortex regions?** In each hemisphere the cerebral cortex 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 controls voluntary movements. The sensory cortex registers and processes body 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. **Areas of the cortex in four mammals** More intelligent animals have increased "uncommitted" or association areas of the cortex. These vast areas of the brain are responsible for integrating and acting on information received and processed by sensory areas. **To what extent can a damaged brain reorganize itself?** If one hemisphere is damaged early in life, the other will pick up many of its functions. This plasticity diminishes later in life. Some brain areas are capable of neurogenesis (forming new neurons). ***Example**: Brain plasticity If surgery or an injury destroys one part of a child's brain or, as in the case of this 6-year-old, even an entire hemisphere (removed to eliminate seizures), the brain will compensate by putting other areas to work. One Johns Hopkins medical team reflected on the child hemispherectomies they had performed. Although use of the opposite hand is compromised, they reported being "awed" by how well children retain their memory, personality, and humor after removal of either brain hemisphere (Vining et al., 1997). The younger the child, the greater the chance that the remaining hemisphere can take over the functions of the one that was surgically removed (Choi, 2008).*  **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. ***Example:** In an early experiment, Gazzaniga (1967) asked these patients to stare at a dot as he flashed, HE·ART on a screen. Thus, HE appeared in their left visual field (which transmits to the right hemisphere) and ART in the right field (which transmits to the left hemisphere). When he then asked what they had seen, the patients said they had seen ART. But when asked to point to the word, they were startled when their left hand (controlled by the right hemisphere) pointed to HE. Given an opportunity to express itself, each hemisphere reported what it had seen. The right hemisphere (controlling the left hand) intuitively knew what it could not verbally report* **FUN FACT!!** Which one is happier? Look at the center of one face, then the other. Does one appear happier? Most people say the right face does. Some researchers think this is because the right hemisphere, which is skilled in emotion processing, receives information from the left half of each face (when looking at its center) **\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_** **How does handedness relate to brain organization?** About 10 percent of us are left-handed. Almost all righthanders process speech in the left hemisphere, as do more than half of all left-handers. **TERMS AND CONCEPTS TO REMEMBER** - **neuron** is a nerve cell; the basic building block of the nervous system. - **sensory neurons** are neurons that carry incoming information from the sensory receptors to the brain and spinal cord. - **motor neurons** are neurons that carry outgoing information from the brain and spinal cord to the muscles and glands. - **interneurons neurons** are within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs. - **dendrite** the bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body. - **axon** the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands. - **myelin** \[MY-uh-lin\] sheath 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. - **action potential** a neural impulse; a brief electrical charge that travels down an axon. - **threshold** the level of stimulation required to trigger a neural impulse. - **synapse** \[SIN-aps\] 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. - **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. - **reuptake** a neurotransmitter's reabsorption by the sending neuron. - **endorphins** \[en-DOR-fins\] "morphine within"---natural, opiatelike neurotransmitters linked to pain control and to pleasure. - **nervous system** the body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems. - **central nervous system (CNS)** the brain and spinal cord. - **peripheral nervous system (PNS)** the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body. - **nerves** bundled axons that form neural "cables" connecting the central nervous system with muscles, glands, and sense organs. - **somatic nervous system** the division of the peripheral nervous system that controls the body's skeletal muscles. Also called the skeletal nervous system. - **autonomic** **\[aw-tuh-NAHM-ik\] nervous system** 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. - **sympathetic nervous system** the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations. - **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. - **MRI (magnetic resonance imaging)** a technique that uses magnetic fields and radio waves to produce computergenerated images of soft tissue. MRI scans show brain anatomy. - **Fmri (functional MRI)** a technique for revealing bloodflow and, therefore, brain activity by comparing successive MRI scans. Fmri scans show brain function. - **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. - **medulla \[muh-DUL-uh\]** the base of the brainstem; controls heartbeat and breathing. - **reticular formation** a nerve network in the brainstem that plays an important role in controlling arousal. - **thalamus \[THAL-uh-muss\]** 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. - **cerebellum \[sehr-uh-BELL-um\]** the "little brain" at the rear of the brainstem; functions include processing sensory input and coordinating movement output and balance - **limbic system** neural system (including the hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives. - **amygdala \[uh-MIG-duh-la\]** two lima bean--sized neural clusters in the limbic system; linked to emotion. - **hypothalamus \[hi-po-THAL-uh-muss\]** 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. - **cerebral \[I-REE-bruhl\]** cortex the intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body's ultimate control and information-processing center. - **glial cells (glia)** cells in the nervous system that support, nourish, and protect neurons. - **frontal lobes** portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgments. - **parietal \[puh-RYE-uh-tuhl\] 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. - **occipital \[ahk-SIP-uh-tuhl\] lobes** portion of the cerebral cortex lying at the back of the head; includes areas that receive information from the visual fields. - **temporal lobes** portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each receiving information primarily from the opposite ear. - **motor cortex** an area at the rear of the frontal lobes that controls voluntary movements. - **sensory cortex** area at the front of the parietal lobes that registers and processes body touch and movement sensations. - **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. - **plasticity** the brain's ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience.**neurogenesis** the formation of new neurons. - **corpus callosum \[KOR-pus kah-LOWsum\]** the large band of neural fibers connecting the two brain hemispheres and carrying messages between them. - **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. **ACTIVITY 4** **ESSAY** Why is pituitary gland called "master gland"? Answer should not exceed the box provided below. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ **ACTIVITY 5** **IDENTIFICATION** A. Identify the major parts of the neuron diagrammed below: a. b. B. In the diagrams to the right, the numbers refer to the brain locations that have been damaged. Match each location with its probable effect on behavior. Write the letter of your choice from the Column B to the Column A +-----------------------------------+-----------------------------------+ | **Column A** | **Column B** | | | | | **LOCATION** | **BEHAVIORAL EFFECT** | +===================================+===================================+ | 1. | a\. vision disorder | +-----------------------------------+-----------------------------------+ | 2. | b\. insensitivity to touch | +-----------------------------------+-----------------------------------+ | 3. | c\. motor paralysis | +-----------------------------------+-----------------------------------+ | 4. | d\. hearing problem | +-----------------------------------+-----------------------------------+ | 5. | e\. lack of coordination | +-----------------------------------+-----------------------------------+ | 6. | f\. abnormal hunger | +-----------------------------------+-----------------------------------+ | 7. | g\. split brain | +-----------------------------------+-----------------------------------+ | 8. | h\. sleep/arousal disorder | +-----------------------------------+-----------------------------------+ | 9. | i\. altered personality | +-----------------------------------+-----------------------------------+ **ACTIVITY 6** ESSAY Discuss how the endocrine and nervous systems become involved when you feel stress---such as that associated with an upcoming final exam. (Use the space below to list the points you want to make, and organize them. Then write the essay in the box provided below) ACTIVITY **7** **CROSS CHECK** ACROSS 3\. The division of the nervous system that connects the brain and spinal cord to the body's sense receptors, muscles and glands. 6\. Located on the side of the brain, these lobes contain the auditory areas, which receive information from the ears. 7\. Located at the back of the frontal lobe, the part of the cortex that controls voluntary movement 9\. Located just behind the forehead, these lobes are involved in speaking and muscle movements and in making plans and judgements 12\. Glands that produce the hormones epinephrine and norepinephrine 14\. Located in the brainstem, this structure controls breathing and heartbeat 15\. the thin outer covering of the cerebral hemispheres 16\. Junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. 17\. Amplified recording of the waves of electrical activity of the brain. 19\. Destruction of tissue 20\. Technique that uses magnetic fields and radio waves to produce computer-generated images of brain structures. 22\. Located at the back and base of the brain, these lobes contain the visual cortex, which receives information from the eyes. 23\. The part of the limbic system involved in regulation of the emotions of fear and range. 26\. Situated between the frontal and occipital lobes, these lobes contain the sensory cortex DOWN 1\. Limbic system structure that regulates hunger, thirst, and body temperature and contains the so-called reward centers of the brains 2\. Large band of neural fibers that links the right and left hemispheres, 3\. Technique that measures the levels of activity of different areas of the brain by tracing their consumption of a radioactive form of glucose. 4\. Neural impulse generated by the movement of positively charged atoms in and out of channels in the axon\'s membrane. 5\. Neurotransmitter that triggers muscle contractions, 8, Simple, automatic, inborn response to a sensory stimulus. 10\. Doughnut-shaped neural system that plays an important role in the regulation of emotions and basic physiological drives. 11 Natural opiatelike neurotransmitters linked to pain control and to pleasure. Division of the peripheral nervous system that controls the glands and the muscles of internal organs. 17\. The body\'s slower chemical communication system, consisting of glands that secrete hormones into the bloodstream, 18\. The brain and spinal cord, collectively, are the nervous system. 21\. An impairment of language as a result of damage to any of several cortical areas. 24\. More numerous than cortical neurons, these cells of the brain guide neural connections and provide nutrients and insulating myelin. 25\. Extension of a neuron that sends impulses to other nerve cells or to muscles or glands.