Gen Psyc. Study Guide - Chapter 2

Excitatory & Inhibitory Messages

A neurotransmitter communicates either an excitatory or an inhibitory message to a postsynaptic neuron. An excitatory message increases the likelihood that the postsynaptic neuron will activate and generate an action potential. Conversely, an inhibitory message decreases the likelihood that the postsynaptic neuron will activate. If a postsynaptic neuron receives an excitatory and an inhibitory message simultaneously, the two messages cancel each other out.

Identify and Explain the Effects of the following Neurotransmitters on Behavior: Acetycholine Dopamine Endorphin GABA Norepinephrine Serotonin

Acetylcholine: is found in all motor neurons. It stimulates muscle to contract. It is important in memory, learning, and general intellectual functioning. It's associated disorder is Alzheimer's disease. Dopamine: is involved in movement, attention, thought processes, learning, and pleasurable or rewarding sensations. Associated diseases include: Parkinson's disease, Schizophrenia, Addiction, and Drug Abuse. Endorphins: are released in response to stress or trauma and they reduce the perception of pain. It also leads to an increase in positive emotions. It's associated disorder is Opiate Addiction. GABA: is found primarily in the brain. GABA usually communicates an inhibitory message to other neurons, helping to balance and offset excitatory messages. It regulates excitation in the brain. Too much GABA impairs learning, motivation, and movement, but too little GABA can lead to seizures and anxiety disorders. Norepinephrine: is implicated in the activation of neurons throughout the brain (physical arousal) and helps the body gear up in the face of danger or threat. It also plays a key role in the regulation of sleep, learning, and memory retrieval. Associated diseases include: Stress & Major Depressive Disorder. Serotonin: is involved in sleep, sensory perceptions, moods, and emotional states, including depressive symptoms. It's associated disorder is Major Depressive Disorder.

Explain the terms Agonist & Antagonist

An agonist is a drug or other chemical substance that binds to a receptor site and triggers a response in the cell. They are chemically similar to a specific neurotransmitter and produce the same effect. An antagonist is a drug or other chemical substance that blocks a receptor site and inhibits or prevents a response in the receiving cell. It blocks the effect of neurotransmitters.

Identify & Describe the Structure of the Limbic System & their Functions

Beneath the cerebral cortex are a group of forebrain structures that form a border around the brainstem also called the Limbic System. Its structures form complex neural circuits that play critical roles in learning, memory, motivation, and emotional control. The hippocampus plays an important role in learning & your ability to form new memories of events and information. The thalamus processes motor & sensory information for all senses, except smell, and distributes it to the cerebral cortex. It is also thought to be involved in regulating levels of awareness, attention, motivation, and emotional aspects of sensations. The hypothalamus is a peanut-sized structure located below the thalamus that regulates both divisions of the autonomic nervous system, increasing and decreasing such functions as heart rate and blood pressure. It also helps regulate a variety of behaviors related to survival, such as eating, drinking, frequency of sexual activity, fear, and aggression. The hypothalamus exerts considerable control over the secretion of endocrine hormones by directly influencing the pituitary gland which is directly below it. The hypothalamus produces both neurotransmitters and hormones that directly affect the pituitary gland. The amygdala is an almond-shaped cluster of neurons involved in memory and emotional responses, especially fear.

Explain Broca & Wernicke Contribution to our understanding of Lateralization of Brain (speech & language functioning)

Broca & Wernicke provided the first compelling clinical evidence that language and speech functions are performed primarily by the left cerebral hemisphere. If similar brain damage occurs in the exact same locations on the right hemisphere, these severe disruptions in language and speech are usually not seen. Speech and language functions are lateralized on the left hemisphere.

How is information communicated via function of hormones, glands and gonads?

Endocrine glands communicate information from one part of the body to another by secreting messenger chemicals called hormones into the bloodstream. The hormones circulate throughout the bloodstream until they reach specific hormone receptors on target organs or tissue. Metabolism, growth rate, digestion, blood pressure, and sexual development and reproduction are just some of the processes that are regulated by the endocrine hormones. Hormones are also involved in emotional response and your response to stress. Hormones rely on the circulation of the blood to deliver their chemical messages to target organs. The signals that trigger the secretion of hormones are regulated by the brain, primarily by a structure called the hypothalamus. The hypothalamus serves as the main link between the endocrine system and the nervous system. The hypothalamus directly regulates the release of hormones by the pituitary gland (body's master gland), a pea-sized gland just under the brain. The pituitary's hormones, in turn, regulate the production of other hormones by many of the glands in the endocrine system.

What is the difference between functional & structural plasticity?

Functional plasticity refers to the brain's ability to shift functions from damaged to undamaged brain areas. While structural plasticity refers to the brain's ability to physically change its structure in response to learning, active practice, or environmental stimulation.

What is meant by the concept of "the brain functions as an integrated system?"

It is meant that although we will identify the functions that seem to be associated with particular brain regions, it's important to remember that specific functions seldom correspond neatly to a single, specific brain site. Most psychological processes, especially complex ones, involve multiple brain structures and regions. Even seemingly simple tasks involve the smoothly coordinated synthesis of information among many different areas of your brain.

What is the function of the nervous system?

It is the primary internal communication network of the body; divided into the central nervous system and the peripheral nervous system.

Explain "Runner's High"

It is the rush of euphoria that many people experience after sustained exercise, especially running or cycling. It's thought to be caused by endorphins.

Define Biological Psychology

It is the scientific study of the biological bases of behavior and mental processes.

How do drugs affect the function of certain neurotransmitters?

Many drugs, especially those that affect moods or behavior, work by interfering with the normal functioning of neurotransmitters in the synapse. Some drugs increase or decrease the amount of neurotransmitter released by neurons. Drugs may also affect the length of time the neurotransmitter remains in the synaptic gap, either increasing or decreasing the amount available to the postsynaptic receptor. One way in which drugs can prolong the effects of the neurotransmitter is by blocking the reuptake of the neurotransmitter by the sending neuron. Drugs can also mimic specific neurotransmitters.

What is Spinal Reflex and why is it an important automatic behavior?

Most behaviors are controlled by your brain. However, the spinal cord produces spinal reflexes—simple, automatic behaviors that occur without any brain involvement. Spinal reflexes are crucial to your survival. The additional few seconds that it would take you to consciously process sensations and decide how to react could result in serious injury (Ex. moving your hand before burning or shocking yourself). Spinal reflexes are also important as indicators that the neural pathways in your spinal cord are working correctly.

What is the importance of neural pathways?

Neural pathways link different brain structures. Neural pathways are formed by groups of neuron cell bodies in one area of the brain that project their axons to other brain areas. These neural pathways form communication networks and circuits that link different brain areas.

Define the Concept of Neurogenesis

Neurogenesis is the development of new neurons after birth. It has been proven that the brain has the capacity to generate new neurons through the lifespan in the hippocampus, involved in learning and memory, and the olfactory bulb, responsible for odor perception. And, it appears that these new neurons are incorporated into the existing neural networks in the adult brain.

What is a neuron and what are the three basic components of a neuron?

Neurons are cells that are highly specialized to receive and transmit information from one part of the body to another. The three basic components of a neuron are a axon, cell body, and dendrites. The cell body, also called the soma, contains structures that manufacture proteins and process nutrients, providing energy to the neuron. It also contains the nucleus, which in turn contains twisted strands of DNA called chromosomes. Dendrites are short fibers that extend from the cell body that receive messages from other neurons or specialized cells. The axon is a single, elongated tube that extends from the cell body that can carry information from the neuron to other cells in the body.

What is the difference between neurons and nerves?

Neurons are the most important transmitter of messages in the central nervous system. In the peripheral nervous system, communication occurs along nerves. Nerves and neurons are not the same thing. Nerves are made up of large bundles of neuron axons while a neuron is the basic cell of the nervous system and is made of the cell body, dendrites, and an axon.

How is information communicated between neurons? Include: Action Potential, Stimulus Threshold, Resting Potential, All or None Law, Important of the Synapse & Synaptic Gap, and Reuptake in Neural Communication.

Neurons communicate information by sending electrical signals throughout the body. It is an electrochemical process. Also, communication between neurons take place at the synapse, the junction between two adjoining neurons. It is a chemical process. In general, messages are gathered by the dendrites and cell body and then transmitted along the axon in the form of a brief electrical impulse called an action potential. The action potential is produced by the movement of electrically charged particles, called ions, across the membrane of the axon. Some ions are negatively charged, others positively charged. Each neuron requires a minimum level of stimulation from other neurons or sensory receptors to activate it. This minimum level of stimulation is called the neuron's stimulus threshold. While waiting for sufficient stimulation to activate it, the neuron is said to be polarized. This means that there is a difference in the electrical charge between the inside and the outside of the axon. More specifically, there is a greater concentration of negative ions inside the neuron. Thus, the axon's interior is more negatively charged than is the exterior fluid surrounding the axon. The negative electrical charge is about -70 millivolts (thousandths of a volt). The -70 millivolts is referred to as the neuron's resting potential. In this polarized, negative-inside/positive-outside condition, there are different concentrations of two particular ions: sodium and potassium. While the neuron is in resting potential, the fluid surrounding the axon contains a larger concentration of sodium ions than does the fluid within the axon. The fluid within the axon contains a larger concentration of potassium ions than is found in the fluid outside the axon. When sufficiently stimulated by other neurons or sensory receptors, the neuron depolarizes, beginning the action potential. At each successive axon segment, sodium ion channels open for. The sodium ions rush to the axon interior from the surrounding fluid, and then the sodium ion channels close. Right after, the potassium ion channels open, allowing potassium to flow out of the axon and into the fluid surrounding it, and then the channel closes. As this ion exchange occurs, the relative balance of positive and negative ions separated by the axon membrane changes. The electrical charge on the inside of the axon momentarily changes to a positive electrical charge. The result is a brief positive electrical impulse that progressively occurs at each segment down the axon—the action potential. Once the action potential is started, it is self-sustaining and continues to the end of the axon. In other words, there is no such thing as a partial action potential. Either the neuron is sufficiently stimulated and an action potential occurs, or the neuron is not sufficiently stimulated and an action potential does not occur. This principle is referred to as the all-or-none law. Following the action potential, a refractory period occurs during which the neuron is unable to fire. During the refractory period, the neuron repolarizes and reestablishes the negative-inside/positive-outside condition. The point of communication between two neurons is called the synapse. At this communication junction, the message-sending neuron is referred to as the presynaptic neuron. The message-receiving neuron is called the postsynaptic neuron. Neurons do not touch each other. The presynaptic and postsynaptic neurons are separated by a tiny, fluid-filled space, called the synaptic gap. In general terms, chemical communication occurs when the presynaptic neuron creates a chemical substance that diffuses across the synaptic gap and is detected by the postsynaptic neuron. When the presynaptic neuron is activated, it generates an action potential that travels to the end of the axon. At the end of the axon are several small branches called axon terminals. Floating in the interior fluid of the axon terminals are tiny sacs called synaptic vesicles. The synaptic vesicles hold special chemical messengers manufactured by the neuron, called neurotransmitters. When the action potential reaches the axon terminals, some of the synaptic vesicles "dock" on the axon terminal membrane, then release their neurotransmitters into the synaptic gap. The nuerotransmitters cross the synaptic gap and attach to receptor sites on the dendrites and other surfaces of the surrounding neurons. The entire process of transmitting information at the synapse is called synaptic transmission. What happens to the neurotransmitter molecules after they've attached to the receptor sites of the postsynaptic neuron? Most often, they detach from the receptor and are reabsorbed by the presynaptic neuron so they can be recycled and used again. This process is called reuptake. Reuptake also occurs with many of the neurotransmitters that failed to attach to a receptor and were left floating in the synaptic gap. Neurotransmitter molecules that are not reabsorbed or that remain attached to the receptor site are broken down or destroyed by enzymes.

Identify & Describe the Structures of the Brainstem (Hindbrain & Midbrain)

The brainstem includes the hindbrain and midbrain, located at the base of the brain. The hindbrain connects the spinal cord with the rest of the brain. Its functions include coordinating movement and posture, regulating alertness, and maintaining vital life functions. Three structures make up the hindbrain—the medulla, the pons, and the cerebellum. The medulla is situated at the base of the brain directly above the spinal cord. The medulla plays a critical role in basic life-sustaining functions. It contains centers that control such vital autonomic functions as breathing, heart rate, and blood pressure. The medulla also controls a number of vital reflexes, including swallowing, coughing, vomiting, and sneezing. Above the medulla is a swelling of tissue called the pons. The pons connects the medulla to the two sides of the cerebellum; helps coordinate and integrate movements on each side of the body acting as a "bridge." It also helps regular breathing. Bulging out behind the pons is the large cerebellum. The cerebellum functions in the control of balance, muscle tone, and coordinated muscle movements. It is also involved in the learning of habitual or automatic movements and motor skills. At the core of the medulla and the pons is a network of neurons called the reticular formation, or the reticular activating system, which is composed of many groups of specialized neurons that project up to higher brain regions and down to the spinal cord. The reticular formation plays an important role in regulating attention, arousal and sleep. The midbrain is the middle and smallest brain region, involved in processing auditory and visual sensory information. A midbrain area called the substantia nigra is involved in motor control and contains a large concentration of dopamine-producing neurons. Translated it means "dark substance," and as the name suggests, this area is darkly pigmented.

Identify & Explain the Parts/Function of the Central Nervous System

The central nervous system (CNS) includes the brain and the spinal cord. It is central to all your behaviors and mental processes. And it is the central processing center—every action, thought, feeling, and sensation you experience is processed through the central nervous system. The most important element of the central nervous system is, of course, the brain, which acts as the command center. The spinal cord handles both incoming and outgoing messages. Sensory receptors send messages along sensory nerves to the spinal cord, then up to the brain. To activate muscles, the brain sends signals down the spinal cord, which are relayed out along motor nerves to the muscles.

Explain the function of the Endocrine System

The endocrine system is made up of glands that are located throughout the body. It involves the use of chemical messengers to transmit information from one part of the body to another. Although the endocrine system is not part of the nervous system, it interacts with the nervous system in some important ways.

Identify & Describe the Structures & Functions of the Cerebral Cortex, Its 4 Hemispheric Lobes, & Explain the Importance of the Corpus Callosum

The forebrain is the largest and most complex brain region, which contains centers for complex behaviors and mental processes; also called the cerebrum. The outer portion of the forebrain, the cerebral cortex, is divided into two cerebral hemispheres. The cerebral cortex is the outer covering of the forebrain. A thick bundle of axons, called the corpus callosum, connects the two cerebral hemispheres and serves as the primary communication link between the left & right cerebral hemispheres. Each cerebral hemisphere can be roughly divided into four regions, or lobes: the temporal, occipital, parietal, and frontal lobes. Each lobe is associated with distinct functions. Located near your temples, the temporal lobe contains the primary auditory cortex, which receives auditory information. At the very back of the brain is the occipital lobe. The occipital lobe includes the primary visual cortex, where visual information is received. The parietal lobe is involved in processing bodily, or somatosensory, information, including touch, temperature, pressure, and information from receptors in the muscles and joints. The frontal lobe is the largest lobe of the cerebral cortex, and damage to this area of the brain can affect many different functions. It is involved in planning, initiating, and executing voluntary movements.

Define the Concept of Contralateral Organization

The left hemisphere controls the right side of the body, and the right hemisphere controls the left side of the body.

Why is the myelin sheath important?

The myelin sheath is made of two types of glial cells. It is a white fatty covering that is wrapped around the axons of some neurons that increases their communication speed.

Identify & Explain the Parts/Functions [divisions/subdivisons] of the Peripheral Nervous System

The peripheral nervous system comprises all the nerves outside the central nervous system that extend to the outermost borders of your body, including your skin. The communication functions of the peripheral nervous system are handled by its two subdivisions: the somatic nervous system and the autonomic nervous system. The somatic nervous system communicates sensory information to the central nervous system and carries motor messages from the central nervous system to the muscles. The autonomic nervous system regulates involuntary functions, such as heartbeat, blood pressure, breathing, and digestion. The involuntary functions regulated by the autonomic nervous system are controlled by two different branches: the sympathetic and parasympathetic nervous systems. These two systems control many of the same organs in your body but cause them to respond in opposite ways. The sympathetic nervous system arouses the body to expend energy, and the parasympathetic nervous system helps the body conserve energy. The sympathetic nervous system is the body's emergency system, rapidly activating bodily systems to meet threats or emergencies. The parasympathetic nervous system conserves and maintains your physical resources. It calms you down after an emergency.

Define Neuroscience

The scientific study of the nervous system, especially the brain.

Explain Sperry's Split-Brain Operation and what it tells about differences in function/abilities of the two hemispheres

The split-brain operation is a surgery that involves cutting the corpus collosum, the thick band of axons that connects the two hemispheres, to stop or reduce recurring seizures in severe cases of epilepsy that can't be treated in any other way. An epileptic seizure typically occurs when neurons begin firing in a disorganized fashion in one region of the brain. The disorganized neuronal firing quickly spreads from one hemisphere to the other via the corpus callosum. If the corpus callosum is cut, seizures should be contained in just one hemisphere, reducing their severity or eliminating them altogether. Sperry's experiments wanted to see the effect that cutting the corpus callosum had on the two hemispheres. It reconfirmed the specialized language abilities of the left hemisphere that Broca and Wernicke had discovered. Also, even though the split-brain subject's right hemisphere could not express itself verbally, it still processed information and expressed itself nonverbally. Researchers have concluded that—in most people—the left hemisphere is superior in language abilities, speech, reading, and writing. In contrast, the right hemisphere is more involved in nonverbal emotional expression and visual-spatial tasks. Also, the right hemisphere excels in recognizing faces and emotional facial cues, reading maps, copying designs, and drawing.

What are the three basic types of neurons?

The three basic types of neurons are sensory, motor, and interneurons. Sensory neurons communicate information from the environment to the central nervous system. They also carry information from the skin and internal organs to the brain. Motor neurons communicate information to the muscles and glands of the body from the central nervous system. Interneurons communicate information between neurons.

Why are glial cells important?

They not only provide structural support for neurons, nutrition, and removal of cell wastes throughout the nervous system but they are also involved in brain development and help communicate information between neurons.

Explain Concussions & Traumatic Brain Injury. How are they related to chronic traumatic encephalopathy (CTE)? What is CTE (Causes & Symptoms)?

When an event disrupts normal brain functioning, a traumatic brain injury (or TBI) may be diagnosed. A concussion is the most common, and mildest, type of TBI. Most people recover from concussions without complications. However, repeated concussions can lead to a serious brain disease called chronic traumatic encephalopathy, or CTE. CTE is a progressive, degenerative brain disease that can only be diagnosed after death. Symptoms include depression and anxiety, poor judgment and lack of impulse control, and problems with memory, concentration, and attention. Ultimately, CTE leads to major neurocognitive disorder and death.

What is the importance of neurotransmitters?

Your ability to perceive, feel, think, move, act, and react depends on the delicate balance of neurotransmitters in your nervous system. Too much or too little of a given neurotransmitter can have devastating effects.