Ch 2

  1. The Nervous System
    Complex network of cells specialized to perform three basic functions:

    • 1. detection of sensory stimuli
    • 2. information processing (perception, analysis, memory storage and retrieval)
    • 3. generating responses and transmitting them to muscles, glands, and organs
  2. The Nervous System (cont.)
    Made up to two major branches:

    • 1. central nervous system (cns) - nerve tissue encased within the bony protection of the spine and skull
    • 2. peripheral nervous system (pns) - all the nerve tissues laying outside the cns
  3. Central Nervous System (CNS)
    Serves as the command center of the nervous system, made up of two major compnoents:

    • 1. spinal cord - main pathway connection the pns and the brain
    • 2. brain - evaluation and analysis of sensory input, decide on appropriate response, transmit responses

    Consists of several distinct parts: hindbrain, midbrain, and forebrain
  4. Terms
    Posterior (or caudal): "in back of"

    Superior (or dorsal): "above"

    Anterior (or vostral): "in front of"

    Interior (or ventral): "below"Lateral: "to the side"Medial: "toward the middle"
  5. Brain Stem and Cerebellum (Four Brains, #1)
    Brain Stem: two-way information highway; basic life support functions; key roles in consciousness and REM sleep

    Cerebellum: coordination of movement; balance and posture; integration of sensory and motor functions; certain memory and cognitive functions
  6. Limbic System, Basal Ganglia (Four Brains, #2)
    • Limbic System: generating emotions; learning and memory; sexual and social behavior; biological rhythms
    • --includes thalmus, hypothalmus, nucleus accumbens, amyfdala, septum, cingulate gyrus, hippocampus

    • Basal Ganglia: initiating and controlling movements
    • --includes caudate nucleus, putamen, globus pallidus, and several other structures deep inside the brain
  7. Lobes of the Neo Cortex (Four Brains, #3 & 4)
    Neo cortex = "thinking cap", responsible for all higher mental functions

    • Divided into two large hemispheres (left and right), which are further divided into four functions:
    • 1. occipital (back of brain) - visual processing
    • 2. parietal (top rear area) - processing body sensations
    • 3. temproal (lower side of each hemisphere) - hearing, emotions, language
    • 4. frontal (front of each hemisphere) - emotional control, all behavior
  8. Peripheral Nervous System (PNS)
    Sensory nerves: detect stimuli from outside the body and convey this information to CNS

    Motor nerves: convey commands from CNS to all muscles and organs of the body

    Spinal nerves: 31 nerves, receives sensory input (through back) or conveys motor output (through front) to a specific body part

    Cranial nerves: 12 nerves, enter brain directly, handle sensory and motor function in head and face
  9. Division of PNS
    Somatic nervous system: sensory nerves that detect internal and external stimulation and sends ingo to the CNS; mostly under voluntary control

    • Autonomic nervous system: nerves reach out to every part of the body to regulate ongoing activity of muscles, organs, and glands; mostly automatic
    • --includes sympathetic nervous system (fight or flight) and parasympathetic nervous system (rest responses)
  10. Neurons (Cells of the Nervous System)
    About 180 billion in the brain; responsible for everything you do

    Receive, process, and transmit info to each other

    When neurons die, new ones generally do not develop to replace them, except in the hippocampus; when we are born we have almost all the neurons we will ever have; brain compensates for lost neurons by creating more connections (synapses) between live neurons
  11. Connections (Cells of the Nervous System)
    Each neuron has one specific job; neurons with similar jobs form networks with each other to perform tasks (ex. memory, emotion); the possible number of interconnections exceeds the number of stars in the known universe!

    The vast processing capacity of the brain is only possible because of these complex networks
  12. Neuroglia ("glial cells")
    10x more than neurons!

    Do not transmit info and are constantly replaced

    Four types...
  13. Astrocytes
    Starlike shape, largest, most numerous

    Help form scar tissue; wrap themselves around capilaries to protect them; remove waste and dead cells by digesting them; help regulate levels of certain chemicals; may help communication between neurons
  14. Ogliodendroglia/Schwann cells
    Form myelin

    Ogliodendroglia - CNS

    Schwann cells - PNS
  15. Ependymal cells
    Found in ventricles (tissue that lines fluid-filled cavities in the brain)

    Form and secrete cerebrospinal fluid (CSF)
  16. Microglia
    5-20% of glial cells, distributed throughout CNS

    Believed to destroy foreign organisms, remove toxic substances, and promote tissue repair by secreting nerve growth factor (NGF)
  17. Cell Membrane (Structure of Neurons)
    Separates neurons from each other

    Allows necessary substances to enter (from surrounding extracellular fluid) and exit
  18. Cell Body (Structure of Neurons)

    Contrains cell's nucleus (DNA/RNA) and other organelles (mitochondria, Golgi appartus, ribosomes)

    Uses protien to work
  19. Dendrites (Structure of Neurons)
    Tiny, multiple busy "branches" that extend from the cell body

    Collectively called the dendrite tree; vary greatly in size, shape, and configuration depending on the type of neuron; account for 90% of the neurons total surface area
  20. Axon (Structure of Neurons)
    Long, wire-like fiber that sends messages; 1 per neuron

    1. Axon hillock - where long fiber starts

    2. Axon fibers - carries messages at up to 200mph (depending on size of axon and myelin content); may split into axon collaterals

    3. Axon terminals - bulbous, found at the end of the axon collaterals
  21. The Synapse
    Junction between neuron and dendite of another neuron

    Messages cannot cross the synaptic gap, so they are helped by neurotransmitters from the synaptic vesicles that "jump" the gap and bind with the receptors on the dendrites of the other neuron
  22. Myelin
    Cream-colored fatty substance that serves as "insulation" for axons

    Plays essential roles in transmitting signals: the thicker the myelin sheath, the faster signals are transmitted; icreaces the "fuel efficiency" of neurons by decreasing the metabolic demands involved in transmitting messages
  23. Types of Neurons: Sensory Neurons
    "Afferent" neurons

    Receive input from sensory receptors and convey info to CNS and brain
  24. Types of Neurons: Motor Neurons
    "Efferent" neurons

    Largest in the nerve system; have very long axons and extensive dendrites

    Convey commands from brain and spinal cord to muscle fibers or glands
  25. Types of Neurons: Interneurons
    "Association" neurons

    More than 97% of the neurons in the brain

    Receive and process input from other neurons and convey signals to other neurons
  26. Grey Matter
    Refers to brain tissue composed of closely packed groups of neuron cell bodies and their dendrites; found in several areas of the brain, within the inner core of spinal cord, and parts of the PNS

    Primary role = information processing
  27. Cortical Grey Matter
    Brain issue found in the cerebral cortex

    Responsible for the brain's highest levels of mental processing, ex. speech, language, cognition, personality
  28. Nucleus (Nuclei)
    Within the CNS

    Formed by closely packed clusters of neuron cell bodies and their dendrites

    Function as specialized "processing plans" which form sub-cortical structures, ex. thalmus, hypothalmus
  29. Ganglion (Ganglia)
    Within the PNS

    Composed of neurons with similar specializations and tasks to perform
  30. White Matter
    Most of the brain's interior; composed of large numbers of myelinated axons arranged in near-parallel formations called fiber tracts

    Function as information "superhighways"
  31. Fiber Tracts
    Carry signals from neuron to neuron; three types

    • 1. projection tracts: fan out from one brain region to another, up and down
    • 2. association tracts: link different parts of the same side of the brain, front to back
    • 3. commisures: carries signals to the left and right side of the brain
  32. Commisures
    1. Corpus Callasum: largest (200 million axons), major information "superhighway" between left/right halves of the brain

    2. Anterior Commissure: just below front of the CC, major "superhighway" between left/right temporal lobes

    3. Massa Intermedia: connects the left/right halves of the thalamus
Card Set
Ch 2
Ch 2, Psyc 4, Quiz 1