Chapter 4 Body and Behavior Section 1 The Nervous System: The Basic Structure • http://www.nytimes.com/2014 /02/25/science/the-brainsinner-language.html?_r=0 How the nervous system works • Central nervous system (CNS)- the brain and spinal cord • Spinal cord- nerves that run up and down the length of the back and transmit most messages between the body and brain • Peripheral nervous system (PNS)- nerves branching beyond the spinal cord into the body Neurons • The long, thin cells of nerve tissue along which messages travel to and from the brain • Transmission occurs whenever cells are stimulated past a minimum point and emit a signal. • Either fires or does not fire Parts of a neuron • Dendrites- short, thin fibers that protrude from the cell body – Receive impulses or messages and send them to the cell body • Axon- carries the impulses from the cell body to the axon terminals • Axon terminals- release neurotransmitters to stimulate dendrites of the next neuron Parts of a neuron • Myelin sheath- insulates and protects the axon for some neurons – speeds the transmission of impulses – In cases of multiple sclerosis, the myelin sheath is gone. The Neuron Connection • Synapse- the gap that exists between individual nerve cells • Neurotransmitters- the chemicals released by neurons which determine the rate at which other neurons fire • Examples of neurotransmitters – Norepinephrine- is involved with memory and learning – Endorphine- inhibits pain Neuron Activity • Intensity of neurons depends on how many other neurons are acting on it • Afferent neurons- sensory neurons that relay messages from the sense organs to the brain (eyes, ears, nose, skin) • Efferent neurons- motor neurons that send messages from the brain to the glands and muscles • Interneurons- process signals, connecting only to other neurons, not to sensors or muscles Voluntary and Involuntary activities • Somatic nervous system (SNS)- the part of the peripheral nervous system that controls voluntary movement of skeletal muscles • Autonomic nervous system (ANS)- the part of the peripheral nervous system that controls internal biological functions Autonomic Nervous System • Sympathetic nervous system – Prepares the body for dealing with emergencies or strenuous activity • Parasympathetic – Works to conserve energy and to enhance the body’s ability to recover from strenuous activity Section 2 Studying the Brain Three parts of the Brain • Hindbrain- a part of the brain located at the rear base of the skull that is involved in the basic processes of life. • Midbrain- a small part of the brain above the pons that arouses the brain, integrates sensory information, and relays it upward • Forebrain- a part of the brain that covers the brain’s central core, responsible for sensory and motor control and the processing of thinking and language Three parts of the Brain Hindbrain • Includes the following parts: • Cerebellum – Helps control posture, balance and voluntary movements • Medulla – Controls breathing, heart rate, and reflexes • Pons – Bridge between the spinal cord and brain – Produces chemicals the body needs for sleep Hindbrain Forebrain • Includes the following parts: • Thalamus – Integrates sensory input – “relay station” for all info that travels to and from the cortex • Hypothalamus – Controls functions of hunger, thirst, and sexual behavior – Controls the bodies reaction to temperature Forebrain • Includes the following parts: • Cerebral cortex – Outer layer of the forebrain • Cerebrum – Inner layer of the forebrain – Gives you the ability to learn and store complex and abstract information Forebrain Forebrain • Limbic system – Includes various structures that regulate our emotions and motivations – Amygdala- controls violent emotions like rage or fear – Hippocampus- is important for the formation of memories The Lobes of the Brain • Corpus callosum- a band of fibers that joins the two sides or hemispheres of the cerebrum • Lobes- are the different regions into which the cerebral cortex is divided Lobes of the Brain • Occipital lobe- visual signals are sent • Pariental lobe- concerned with various information from the senses • Temporal lobe- concerned with hearing, memory, emotion, and speaking • Frontal lobe- concerned with organization, planning, and creative thinking Lobes of the Brain Left and Right Hemispheres • Right and left sides of the brain complement each other • Left hemisphere of the brain controls the right side of the body – Mathematical ability, where speech is located • Right hemisphere of the brain controls the left side of the body – Controls visual and spatial relations – Perceptual tasks How Psychologists Study the Brain • Recording – Electroencephalograph (EEG)- is a machine used to record electrical activity of large portions of the brain – Overall electrical activity can be measured and the rhythms of the brain differ depending on whether a person is awake, drowsy, or asleep How Psychologists Study the Brain • Stimulation – Electrodes may be used to set off the firing of neurons as well as record it – Has been used with terminal cancer patients to relieve their pain – Used to control violent emotional behavior Images • Computerized axial tomography (CT) – An imaging technique used to study the brain to pinpoint injuries and brain deterioration – Radiation is absorbed depending on the density of the brain tissue – Computers measure the amount of radiation absorbed and then transformed into 3-D images Images • Positron Emission Tomography (PET) – Is an imaging technique used to see which brain areas are being activated while performing tasks – Injects radioactive solution into the blood and measuring the amount of radiation absorbed by the blood cells – Show activity in different areas of the brain when a person is thinking, speaking, or looking at objects Images • Magnetic Resonance Imaging (MRI) – A measuring technique used to study brain structure and activity – Combines the features of CT and PET scans • fMRI- observes both the functions of different structures of the brain and which structures participate in specific functions Section 3 The Endocrine System The Endocrine System https://www.youtube.com/watch?v=WVrlHH14q3o The Endocrine Glands • Endocrine system- a chemical communication system, using hormones, by which messages are sent through the bloodstream. • Hormones- chemical substances that carry messages through the body in blood The Endocrine Glands • Hormones have effects on your behavior • Hormones can also influence your moods and drives • Duct glands – Release their contents through small holes on the surface of the body • Sweat glands, tear glands, salivary glands Pituitary Gland • Is the center of control of the endocrine system that secretes a large number of hormones • Controls growth and reproduction including ovulation and lactation Thyroid Gland • Produces thyroxine • Stimulates certain chemical reactions that are important for all tissues of the body • Hyperthyroidism- too much thyroxine which causes overactivity • Hypothyroidism- too little thyroxine makes people feel lazy Adrenal Glands • Become active when angry or frightened • Release epinephrene and norepinephrine which cause heartbeat and breathing to increase • Secrete cortical steroids which help muscles develop Sex Glands • Testes – Testosterone (male sex hormone) • Important in physical development • Helps decide sex of the fetus • Ovaries – Produce estrogen and progesterone • Important in the development of female sex characteristics • Vary throughout the menstrual cycle Hormones v.s. Neurotransmitters • Both work to affect the nervous system • When a chemical is used as a neurotransmitter: – It is released right beside the cell that it is to excite or inhibit • When a chemical is used as a hormone: – It is released into the blood, which defuses into the body Section 4 Heredity and Environment Heredity and Environment • Heredity- the genetic transmission of characteristics from parents to their offspring • Inherited factors and environmental conditions always act together in different ways Nature versus Nurture • Nature refers to characteristics that a person inherits – Family, culture, education, individual experiences • Genes are the basic units of heredity – Can be reproduced and passed from generation to generation – For example, musical talent Twin Studies • Identical twins- twins who come from one fertilized egg; twins having the same heredity • Genes- the basic building blocks of heredity • Fraternal twins- twins who come from two different eggs fertilized by two different sperm Twin Studies • Twins growing up in the same house share the same environment as well as the same genes • Twins growing up in different environments have common behaviors despite different social, cultural, or economic backgrounds Twin Studies • Twin quiz • http://multiples.about.com/cs/polls/l/bltwint ype_quiz.htm Sources: • Kasschau, Richard, A. Understanding Psychology. McGraw-Hill, Glencoe, New York, New York, 2008.