The Central Nervous System The " Central Processing Unit "

• The central nervous system consists of the brain and the spinal cord

• The spinal cord serves two functions. The outer part of the cord transmits messages to and from the brain, whereas the inner part controls lifesaving reflexes such as the pain response

• Spinal cord reflexes involve afferent neuron interneurons, and efferent neurons, forming a simple reflex arc

• Great strides are being made in spinal cord repair and the growth of new neurons in the central nervous system

• Psychology in the News: Stem Cells: New Hope for Damaged Brains?

  • Research suggests that stem cells can be obtained from adult bone marrow, making the repair and replacement of damaged neurons more feasible

The Peripheral Nervous System- Nerves on the Edge

• The peripheral nervous system is all the neurons and nerves that are not part of the brain and spinal cord and that extend throughout the body

• There are two systems within the peripheral nervous system, the somatic nervous system and the autonomic nervous system

• The somatic nervous system contains the sensory pathway, or neurons carrying messages to the central nervous system, and the motor pathway, or neurons carrying messages from the central nervous system to the voluntary muscles

• The autonomic nervous system consists of the parasympathetic division and the sympathetic division. The sympathetic division is our fight-or-flight system, reacting to stress, whereas the parasympathetic division restores and maintains normal day-to-day functioning of the organ

  Peeking Inside the Brain

• We can study the brain by using deep lesioning to destroy certain areas of the brain in laboratory animals or by electrically stimulating those areas ( ESB )

• We can use case studies of human brain damage to learn about the brain's functions but cannot easily generalize from one case to another

• The EEG allows researchers to measure the electrical activity of the surface of the brain through the use of electrodes placed on the scalp

• CT scans are computer aided X - rays of the brain and show a great deal of brain structure

• MRI scans use a magnetic field and a computer to give researchers an even more detailed look at the structure of the brain. A related technique, fMRI, allows researchers to look at the activity of the brain

• PET scans use a radioactive sugar injected into the bloodstream to track the activity of brain cells, which is enhanced and color-coded by a computer

  From the Bottom Up : The Structures of the Brain

• The medulla is at the very bottom of the brain and top of the spinal column. It controls life - sustaining functions such as breathing and swallowing . The nerves from each side of the body also cross over in this structure to opposite sides

• The pons is above the medulla and acts as a bridge between the lower part of the brain and the upper part. It influences sleep , dreaming , arousal , and coordination of movement on the left and right sides of the body

• The reticular formation runs through the medulla and the pons and controls our wakefulness and arousal

• The cerebellum is found at the base and back of the brain and coordinates fine, rapid motor movement, learned reflexes, posture, and muscle tone .

• The thalamus is the relay station that sends sensory information to the proper areas of the cortex

• The hypothalamus controls hunger, thirst, sleep, sexual behavior , sleeping and waking , and emotions . It also controls the pituitary gland

• The limbic system consists of the thalamus hypothalamus, hippocampus, amygdala, and the fornix

• The hippocampus is the part of the brain responsible for storing memories and remembering the locations of objects

• The amygdala controls our fear responses and memory of fearful stimuli

• The cortex is the outer covering of the cerebrum and consists of a tightly packed layer of neurons about one-tenth of an inch in thickness. Its wrinkles, or verticalization , allow for the greater cortical area and are associated with greater intelligence

• The cortex is divided into two cerebral hemispheres connected by a thick band of neural fibers called the callosum corpus

• The occipital lobes at the back and base of each hemisphere process vision and contain the primary visual cortex

• The parietal lobes at the top and back of the cortex contain the somatosensory area, which processes our sense of touch, temperature

• The frontal lobes contain the motor cortex, which controls the voluntary muscles, and are also where all the higher mental functions occur, such as planning, language, complex decision making, and body position. Taste is also processed in this lobe

• Association areas of the cortex are found in all the lobes but particularly in the frontal lobes. These areas help people make sense of the information they receive from the lower areas of the brain

• An area called Broca's area in the left frontal lobe is responsible for producing fluent, understandable speech. If damaged, the person has Broca's aphasia in which words will be halting and pronounced incorrectly

• An area called Wernicke's area in the left temporal lobe is responsible for the understanding of language. If damaged, the person has Wernicke's aphasia in which speech is fluent but

nonsensical. The wrong words are used

• Classic Studies in Psychology: Through the Looking Glass: Spatial Neglect

  • Spatial neglect comes from damage to the association areas on one side of the cortex, usually the right side. A person with this condition will ignore information from the opposite side of the body or the opposite visual field

• Studies with split-brain patients’ in which the corpus callosum has been severed to correct epilepsy reveal that the left side of the brain seems to control language, writing, logical thought, analysis, and mathematical abilities. The left side also processes information sequentially

• The right side of the brain processes information globally and controls emotional expression, spatial perception, recognition of faces, patterns, melodies, and emotion

The Chemical Connection: The Endocrine Glands

• Endocrine glands secrete chemicals called hormones directly into the bloodstream, influencing the activity of the muscles and organs

• The pituitary gland is found in the brain just below the hypothalamus. It has two parts, the anterior and the posterior. It controls the levels of salt and water in the system and, in women, the onset of labor and lactation, as well as secreting growth hormone and influencing the activity of the other glands

• The pineal gland is also located in the brain. It secretes melatonin, a hormone that influences the sleep-wake cycle in humans and some animals in response to changes in light

• The thyroid gland is located inside the neck. It controls metabolism ( the burning of energy ) by secreting thyroxin

• The pancreas controls the level of sugar in the blood by secreting insulin and glucagon. Too much insulin produces hypoglycemia, whereas too little causes diabetes

• The gonads are the ovaries in women and testes in men. They secrete hormones to regulate sexual growth, activity, and reproduction

• The adrenal glands, one on top of each kidney, control the stress reaction through the adrenal medulla's secretion of epinephrine and norepinephrine. The adrenal cortex secretes over 30 different corticoids (hormones ) controlling salt intake, stress, and sexual development

Vocab:

• Nervous system: an extensive network of specialized cells that carries information to and from all parts of the body

• Neuroscience: a branch of the life sciences that deals with the structure and function of neurons, nerves, and nervous tissues

• Biological Psychology/Behavioral Neuroscience: branch of neuroscience that focuses on the biological bases of psychological processes, behavior, and learning

• Neuron: the basic cell that makes up the nervous system and that receives and sends messages within that system

• Dendrites: branchlike structures that receive messages from other neurons

• Soma: the cell body of the neuron responsible for maintaining the life of the cell

• Axon: tubelike structure that carries the neural messages to other cells

• Glial cells: cells that provide support for the neurons to grow on and around, deliver nutrients to the neurons, produce myelin to coat axons, clean up waste products and dead neurons, influence information processing, and, during prenatal development, influence the generation of new neurons

• Myelin: fatty substances produced by certain glial cells that coat the axons of neurons to insulate, protect, and speed up the neural impulse

• Nerves: bundles of axons coated in myelin that travel together through the body

• Resting potential: the state of the neuron when not firing a neural impulse

• Action potential: the release of the electrical charge within the axon

• The nervous system is a complex network of cells that carries information to and from the all parts of the body

• All-or-none: referring to the fact that a neuron either fires completely or does not fire at all

• Axon terminals: branches at the end of the axon

• Synaptic knob: rounded areas on the end of the axon terminals

• Synaptic vesicles: saclike structures found inside the synaptic knob containing chemicals

• Neurotransmitter: a chemical found in the synaptic vesicles that, when released, has an effect on the next call

• Synapse (synaptic gap): microscopic fluid-filled space between the synaptic knob of one cell and the dendrites or surface of the next cell

• Receptor sites: holes in the surface of the dendrites or certain cells of the muscles and glands, which are shaped to fit only certain neurotransmitters

• Excitatory synapse: synapse at which a neurotransmitter causes the receiving cell to fire

• Inhibitory synapse: synapse at which a neurotransmitter causes the receiving cell to stop firing

• Agonists: chemical substances that mimic or enhance the effects of a neurotransmitter on the receptor sites of the next cell, increasing or decreasing the activity of that cell

• Antagonists: chemical substances that block or reduce a cell’s response to the action of other chemicals or neurotransmitters

• Dopamine is removed from the synapse by reuptake sites. Cocaine acts by blocking dopamine reuptake sites, allowing dopamine to remain active in the synapse longer

• Reuptake: process by which neurotransmitters are taken back into the synaptic vesicles

• Central nervous system (CNS): part of the nervous system consisting of the brain and spinal cord

• Spinal cord: a long bundle of neurons that carries information from the senses to the central nervous system

• Afferent (sensory) neuron: a neuron that carries information from the senses to the central nervous system

• Efferent (motor) neuron: a neuron that carries messages from the central nervous system to the muscles of the body

• Interneuron: a neuron found in the center of the spinal cord that receives information from the afferent neurons and sends commands to the afferent neurons and sends commands to the muscles through the efferent neurons. Interneurons also make up the bulk of the neurons in the brain

• Reflex arc: the connection of the afferent neurons the interneurons to the interneurons tp the efferent neurons, resulting in a reflex action

• Neuroplasticity: the ability within the brain to constantly change both the structure and function of many cells in response to experience or trauma

• Stem cells: special cells found in all the tissues of the body that are capable of becoming other cell types when those cells need to be replaced due to damage or wear and tear

• Stem cells are basic cells that differentiate into specific types of cells, such as red blood cells, white blood cells and platelets. Stem cells can also become other types of cells, such as brain cells and nerve cells

• Peripheral nervous system (PNS): all nerves and neurons that are not contained in the brain and spinal cord but that run through the body itself

• Somatic nervous system: division of the PNS consisting of nerves that carry information from the senses to the CNS and from the CNS to the voluntary muscles of the body

• Autonomic nervous system (ANS): division of the PNS consisting of nerves that control; all of the involuntary muscles, organs, and glands

• Sensory pathway: nerves coming from the sensory organs to the CNS consisting of afferent neurons'

• Motor pathway: nerves coming from CNS to the voluntary muscles, consisting of efferent neurons

• Sympathetic division (flight-or-flight): part of the ANS that is responsible for reacting to the stressful events and bodily arousal

• Parasympathetic division: part of the ANS that restores the body to the normal functioning after the arousal and is responsible for the day-to-day functioning of the organs

• Deep lesioning: insertion of a thin, insulated wire into the brain through which an electric current is sent that destroys the brain cells at the top of the wave

• Electroencephalograph (EEG): equipment designed to record the brain wave patterns produced by electrical activity of the surface of the brain

• Computed tomography (CT): brain imaging method using computer-controlled X-rays of the brain

• Magnetic resonance imaging (MRI): brain imaging method using radio waves and magnetic field of the body to produce detailed images of the brain

• Positron emission tomography (PET): brain imaging method in which a radioactive sugar is injected into the subject and a computer compiles a color coded image of the activity of the brain, with lighter colors indicating more activity

• Medulla: the first large swelling at the top of the spinal cord, forming the lowest part of the brain, which is responsible for life-sustaining functions such as breathing, swallowing, and heart rate

• Pons: the larger swelling above the medulla that connects the top of the brain to the bottom and thar plays a part in sleep, and arousal

• Reticular formation (RF): an area of neurons running through the middle of the medulla and the pons and slightly beyond that play a role in general arousal, alertness, and sleep

• Cerebellum: part of the lower brain located behind the pons that controls and coordinates involuntary rapid, fine motor movement

• Limbic system: a group of several brain structures located under the cortex and involved learning, emotion, memory, and motivation

• Thalamus:  part of the limbic system located in the center of the brain, this structure relays sensory information from the lower part of the brain to the proper areas of the cortex and processes some sensory information before sending it to its proper area

• Olfactory bulbs:  two projections just under the front of the brain that receive information from the receptors in the nose located just below

• Hypothalamus: small structure in the brain located below the thalamus and directly above the pituitary gland, responsible for Mortar Behavior such as sleep, hunger, thirst, and sex

• Hippocampus: curved structure located within each temporal lobe, responsible for the information of long-term memories and the storage of memory for location of objects

• Amygdala: brain structure located near the hippocampus, responsible for fear responses and memory of fear

• cerebral hemispheres:  the two sections of the cortex on the left and right sides of the brain

• Corpus callosum: thick band of neurons that connects the right and left cerebral hemispheres

• Occipital lobe:  section of the brain located at the rear and bottom of each cerebral hemisphere containing the visual centers of the brain

• Parietal lobes: Sections of the brain located at the top and bottom of each cerebral hemisphere containing the centers for touch, taste, and temperature

• Somatosensory cortex: area of neurons running down the front of the parietal lobes responsible for processing information from the skin and internal body receptors for touch, temperature, body position, and possibly taste

• Temporal lobe: ever use of the cortex located just behind the Temple's containing the neurons responsible for the sense of hearing and meaningful speech

• Frontal lobes: areas of the cortex located in the front and top of the brain, responsible for higher mental processes and decision-making as well as the production of fluent speech

• Motor cortex: Section of the frontal lobe located at the back, responsible for sending motor commands to the muscles of the somatic nervous system

• Association areas: areas within each lobe of the cortex responsible for the coordination and interpretation of information, as well as higher mental processes

• Broca's aphasia: a condition resulting from damage to Broca's area, causing the affected person to be unable to speak fluently, to mispronounced words, and speak haltingly

• Wernicke's aphasia: a condition resulting from damage to Warnock's area, causing the affected person to be unable to understand or produce meaningful language

• Spatial neglect: Condition produced by damage to the association areas of the right hemisphere resulting in an inability to recognize objects or body parts in the last visual field

• Cerebellum: the upper part of the brain consisting of the two hemispheres and the structures that connect them

• Roger Sperry created The Split-Brain Experiment to demonstrate the specialization of the left and right hemispheres of the brain

• Endocrine glands: glands that secrete chemicals called hormones directly into the bloodstream

• Hormones: chemicals released into the bloodstream by endocrine glands

Pituitary gland: gland located in the brain that secretes growth hormone and influences all other hormone-secreting glands ( also known as the master gland)

• Pineal gland: Endocrine gland located near the base of the cerebellum; secretes melatonin

• Thyroid gland: endocrine gland found in the neck; regulates metabolism

• Pancreas: endocrine gland; controls the levels of sugar in the blood

• Gonads: sex glands; decrease hormones that regulate sexual development and behavior as well as reproduction

• Ovaries: the female gonads

• Testes: the male gonads

• Adrenal glands: endocrine glands located on the top of each kidney that secrete over 30 different hormones to deal with stress, regulate salt intake, and provide a secondary source of sex hormones affecting the sexual changes that occur during adolescence

• Mirror neurons: Neurons that fire when an animal or person performs an action and also when an animal or person observes the same action being performed by another