Chapter 3 Biopsychology

Biopsychology 3.1 Human Genetics                Psychological researchers study genetics in order to better understand the biological basis that contributes to certain behaviors. Our parts are each expressed in a wide variety of behaviors, thoughts, and reactions. Charles Darwin describes the theory of evolution by natural selection. Organisms that are better suited for their environment will survive and reproduce, while those that are poorly suited for their environment will die off. 2 fields that study the interaction of genes and the environment: o Evolutionary psychology  Focuses on how universal patterns of behavior and cognitive processes have evolved over time. (fear response, food preferences, mate selection) o Behavioral genetics  Study how individual differences arise, in the present, through the interaction of genes and the environment. The egg and the sperm each contain 23 chromosomes (23 pairs total) Chromosomes are long strings of genetic material known as deoxyribonucleic acid (DNA). Made up of nucleotide base pairs. In each chromosome, sequences of DNA make up genes that control of partially control a number of visible characteristics, known as traits. A single gene may have multiple possible variations, or alleles. An allele is a specific version of a gene that will affect which hair color an individual has, if its on a gene for hair color. A person’s genotype is the genetic makeup of that individual. Phenotype refers to the individual’s inherited physical characteristics. o Cleft chin is a dominant trait o Sickle cell anemia is a recessive trait When someone has a combination of alleles for a given gene, they are said to be heterozygous. When someone has two copies of the same allele, they are said to be homozygous for that allele. Most traits are polygenic: controlled by more than one gene. Ex. Height, skin color, weight A mutation is a sudden, permanent change in a gene. Our environment is important in determining when and how our genes express themselves and in what combination. (range of reaction—our genes set the boundaries within which we can operate & our environment interacts with genes to determine where we will fall—FIXED AND LIMITED)   Genetic environmental correlation our genes influence our environment and our environment influences the expression of our genes. the field of epigenetics looks beyond the genotype itself and studies how the same genotype can be expressed in different ways. *NOT FIXED AND LIMITED 3.2 Cells of the Nervous System   composed of 2 basic cell types: glial cells and neurons o glial cells provide scaffolding on which the nervous system is built, help neurons line up closely with each other to allow neuronal communication, provide insulation to neurons, transport nutrients and waste products, and mediate immune responses.  Can form a fatty substance known as the myelin sheath o Neurons serve as interconnected information processors that are essential for all of the tasks of the nervous system. Psychotropic medications are drugs that treat psychiatric symptoms by restoring neurotransmitter balance. 3.3 Parts of the Nervous System 2 major subdivisions: the central nervous system (CNS) and the peripheral nervous system (PNS) CNS brain and spinal cord PNS connects the CNS to rest of the body - Made up of nerves Somatic nervous system and autonomic nervous system Somatic nervous system conscious activities; voluntary Autonomic nervous system  controls our internal organs and glands; involuntary o Sympathetic nervous system: involved in preparing the body for stress-related activities (fight or flight response) o Parasympathetic nervous system: associated with returning the body to routine, day-to-day operations. (relaxed state) 3.4 The Brain and Spinal Cord - Spinal cord has its own system of automatic processes called reflexes Brain stem controls the basic processes of life such as breathing and digestion - Brain o Has 2 hemispheres o Surface of the brain is known as the cerebral cortex. Has many fold or bumps known as gyri and grooves, known as sulci.  Most prominent sulcus is known as the longitudinal fissure that separates the brain into two halves or hemispheres: the left hemisphere and the right hemisphere o Corpus callosum connects the two hemispheres of the brain o Lobes of the brain:  Frontal lobe- in front of brain and extends back to the central sulcus; involved in reasoning, motor control, emotion and language.  Prefrontal cortex- is responsible for higher-level cognitive functioning  Broca’s area- is essential for language production; difficulty producing language of any form  Parietal lobe- located behind frontal lobe; involved in processing information from the body’s senses.  Contains somatosensory cortex- essential for processing sensory information from across the body  Temporal lobe- located on the side of the head; associated with hearing, memory, emotion, and some aspects of language.  Auditory cortex-main area responsible for processing auditory information  Wernicke’s area- important for speech comprehension.  Occipital lobes- located at back of brain; contains primary visual cortex— responsible for interpreting incoming visual information o Thalamus sensory relay for the brain o Limbic system involved in processing both emotion and memory  Hippocampus  Amygdala  Hypothalamus o Reticular formation—important in regulating the sleep/wake cycle, arousal, alertness, and motor activity o Medulla- controls the automatic processes of the autonomic nervous system, such as breathing, blood pressure, and heart rate. o Pons- serves to connect the brain and spinal cord; involved in regulating brain activity during sleep o Cerebellum- receives messages from muscles, tendons, joints, and structures in our ear to control balance, coordination, movement, and motor skills o A computerized tomography (CT) scan—involves taking a number of x-rays of a particular section of a person’s body or brain. o Positron emission tomography (PET) scans—create pictures of the living, active brain  Injected with a mildly radioactive substance called a trace  Requires that the brain be exposed to radiation o In magnetic resonance imaging (MRI)- a person is placed in a machine that generates a strong magnetic field. Causes hydrogen atoms in body cells to move. o Functional magnetic resonance imaging (fMRI)- operates on the same principles, but it shows changes in brain activity over time by tracking blood flow and oxygen levels. Better accuracy. o Electroencephalography (EEG)- provides a measure of a brain’s electrical activity 3.5 The Endocrine System - consists of a series of glands that produce chemical substances known as hormones - secreted into bloodstream and travel throughout the body, affecting any cells that contain receptors for them. - widespread effect and longer lasting - The pituitary gland descends from the hypothalamus at the base of the brain, and acts in close association with it. Mostly carries out instructions from the hypothalamus. The thyroid gland releases hormones that regulate growth, metabolism, and appetite. The adrenal gland sits atop our kidneys and secretes hormones involved in stress response, such as epinephrine and norepinephrine. The pancreas is an internal organ that secretes hormones that regulate blood sugar levels: insulin and glucagon The gonads secrete sexual hormones; females= ovaries and males=testis