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Chapter 2

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Department
Psychology
Course
PSYC 3140
Professor
Joel Goldberg
Semester
Winter

Description
Atheory is a set of ideas that provides a framework for asking questions about a phenomenon, and for gathering and interpreting information about that phenomenon. nature-nurture question: Is the cause of the disorder something in the nature, or biology, of the person or in the person's nurturing, or history of events to which the person was exposed? Many contemporary theorists recognize that many pathways can all lead to the same endthe development of a specific disorder Biological, psychological, and social approaches are being integrated to develop comprehensive models of the many factors that lead some people to develop a given mental disorder: vulnerability-stress models or or diathesis-stress models The vulnerability-stress model says that it takes both an existing vulnerability to a disorder and a trigger, or stress, to create the disorder. Only when the vulnerability and the stress come together in the same individual does the full- blown disorder emerge contemporary theories of abnormality recognize the feedback effects that biological and psychosocial factors have on each other, as feedback effects develop, changes in one factor result in changes in second factor,changes in second factor feed back to change first factor again integrative models of psychopathology suggest that biological, social, psychological factors all affect one another in feedback loops that maintain and enhance psychopathological processes. Phineas P. Gage 25-year-old construction foreman, victim of a bizarre accident momentary distraction let Gage begin tamping directly over the powder before assistant had a chance to cover it with sand. result was powerful explosion away from rock and toward Gage He remained as able-bodied and appeared to be as intelligent as before the accident intelligence. As a result of damage to his brain from the accident, Gage's basic personality seemed to change. He was transformed from a responsible, socially appropriate man to an impulsive, emotional, and socially inappropriate man Studies of people today who suffer damage to the same area of the brain as Gage's injury reveal they have trouble making rational decisions in personal and social matters and have trouble processing information about emotions basic intellectual functioning remains intact, but emotional control and judgment in personal and social matters are impaired Structural damage to the brain is one of three causes of abnormality on which biological approaches to abnormality often focus The other two are biochemical imbalances and genetic abnormalities Structural BrainAbnormalities people who suffer damage (sometimes referred to as lesions) to the brain or who have major abnormalities in the structure of the brain often show problems in psychological functioning cerebral cortex, an area of the brain involved in many of our most advanced thinking processes hypothalamus, which regulates eating, drinking, and sexual behaviour limbic system, is a collection of structures closely interconnected with the hypothalamus and appear to exert additional control over some of the instinctive behaviours regulated by the hypothalamus, such as eating, sexual behaviour, and reactions to stressful situations damage may result in chronic aggression and excessive passivity hippocampus: important in memory in schizophrenia it is believed the cerebral cortex does not function effectively or normally Biochemical causes ofAbnormality neurotransmitters, biochemicals that act as messengers, carrying impulses from one neuron, or nerve cell, to another in the brain and in other parts of the nervous system Each neuron has cell body and number of short branches, called dendrites. Dendrites and cell body receive impulses from adjacent neurons, impulse then travels down the length of tubelike extension called an axon, to small swellings at end of the axon, called synaptic terminals Aslight gap exists between the synaptic terminals and the adjacent neurons: synapse The neurotransmitter is released into the synapse. It then binds to receptors, which are molecules on the membranes of adjacent neurons Neurotransmitter Theories The amount of a neurotransmitter available in the synapse can be affected by two processes reuptake occurs when the initial neuron releasing the neurotransmitter into the synapse reabsorbs the neurotransmitter, decreasing the amount left in the synapse degradation, occurs when the receiving neuron releases an enzyme into the synapse that breaks down the neurotransmitter into other biochemicals Serotonin plays a particularly important role in mental health by regulating emotions and impulses. Serotonin travels through many key areas of brain, affecting function of those areas The serotonin 5-HT1Areceptor agonists and antagonists likely play a role in depression, anxiety, and stress-related disorders Dopamine is neurotransmitter prominent in areas of brain that regulate our experience of reinforcements or rewards, affected by substances, such as alcohol, also important to functioning of muscle systems, plays role in disorders involving control over muscles, such as Parkinson's disease. Evidence suggests that psychotic illnesses are related to dopamine activity schizophrenia is characterized by abnormally low dopamine activity in the mesocortex, which leads to cognitive deficits and negative symptoms; elevated dopamine transmission in subcortical regions is associated with positive symptoms norephinephrine(aka noradrenaline)is neurotransmitter produced mainly by neurons in brain stem. Cocaine/amphetamines, prolong action of norepinephrine by slowing reuptake process when too little norepinephrine reaches in the brain, the person's mood level is depressed gamma-aminobutyric acid, or GABA, inhibits action of other neurotransmitters. Certain drugs have tranquilizing effect because they increase the inhibitory activity of GABA. GABAis thought to play an important role in anxiety symptoms It is possible that neurotransmitters interact, particularly serotonin and dopamine. Dysfunction in one system would then have a cascading effect, leading to dysfunction in another neurotransmitter system and resulting in symptoms of psychopathology The Endocrine System endocrine system: system of glands produces many different chemicals called hormones, which are released directly into the blood hormone: carries messages throughout the body, potentially affecting a person's moods, levels of energy, and reactions to stress One of the major endocrine glands, the pituitary, called the master gland because it produces the largest number of different hormones and controls the secretion of other endocrine glands The relationship between the pituitary gland and the hypothalamus illustrates the complex interactions that take place between the endocrine system and the nervous system corticotropin-release factor (CRF) is carried from the hypothalamus to the pituitary through a channel-like structure. CRF stimulates the pituitary to release the body's major stress hormone: adrenocorticotropic hormone (ACTH) ACTH is carried by bloodstream to adrenal glands and various other organs of body, causingrelease of 30 hormones, each which plays role in body's adjustment to emergency situations some theories of anxiety and depression suggest that these disorders result from dysregulation of this relationship, called the hypothalamic-pituitary-adrenal axis (or HPA axis) People who have dysregulated HPAaxis may have abnormal physiological reactions to stress, making it more difficult to cope psychologically with the stress, resulting in symptoms of anxiety and depression Genetic factors inAbnormality Behaviour genetics, the study of the genetics of personality and abnormality At conception, the fertilized embryo has 46 chromosomes, 23 from the female egg and 23 from the male sperm, making up 23 pairs of chromosomes One of pairs is referred to as the sex chromosomes because it determines the sex of the embryo: The XX combination results in a female embryo, the XY combination results in a male embryo Down syndrome results when chromosome 21 is present in triplicate instead of as the usual pair Down syndrome is characterized by mental retardation, heart malformations Chromosomes contain individual genes, which are segments of long molecules of deoxy ribonucleic acid (DNA) Genes come in pairs, Half of the pair comes from the mother,half comes from the father. Abnormalities in genes that make up chromosomes are much more common than are major abnormalities in the structure or number of chromosomes most disorders are not the result of single faulty genes but of combinations of altered genes polygenic processit takes multiple genetic abnormalities coming together in one individual to create a disorder Anumber of physiological disorders, such as diabetes, coronary h
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