Chapter 6 Body and Behavior
Section 1 The Nervous System: The Basic Structure
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
Essential Question: What behaviors do the hindbrain, midbrain, and forebrain control?
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
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
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
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
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 Forebrain
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
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 Corpus callosum carries messages back and forth between the two hemispheres Severe seizure patients sometimes have this severed to control & lessen seizures Right and left can no longer communicate [ball]
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 Tiny electric currents applied to temporal lobe
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 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
Sources: Kasschau, Richard, A. Understanding Psychology. McGraw-Hill, Glencoe, New York, New York, 2008.