Fundamental Elements of the Nervous System 1: The Neuron chapter 3

• neurons
• they are communication machines
• they are morphologically and biochemically designed for the purpose of serving the role as info couriers

• one portion designed to receive and process info
• second portion designed to move info rapidly
• third portion designed to deliver info to another neuron

somewhat central, expanded body region

numerous projections or processes that extend out from the soma

• a neuronal process that extends toward an anatomic or physiologic target
• can communicate with muscle, dendrite and neuron
• splits into many terminal branches as it approaches its target structure

• the cytoplasm of axons
• type of protective fluid

• mechanism responsible for the movement of protein substances from the soma, pulsatile/ratchet-like movement along the microtubular skeleton of the axon
• this is efferent away from

• mechanism responsible for transporting substances to the soma that enter through the terminal of the axon
• afferent toward something

additional process that extends from the soma, usually more than one present on a neuron, and each may be highly branched

• in their proximal portions dendrites have nissl substance in their cytoplasm which is called dendroplasm
• dendrites also have the ability to produce protein substances
• collective consisting of rough endoplasmic reticulum and ribosomes
• distributed throughout the neuroplasm of the soma with the exception of the axon hillock

• plasma membrane and is semipermeable (filter) that encloses the entire neuron
• selectively regulates the movement of certain substances and ions into and out of the neuron (central to it's ability to process and move info)

• the cytoplasm of the neuron found in the plasmalemma
• contains the organelles necessary for synthesizing proteins

• nucleus
• nucleolus
• golgi apparatus
• rough endoplasmic reticulum (sheets of membrane)
• ribosomes

axon's origin

some of the synthetic products of the organells, chemical messengers released by one neuron to communicate with another neuron

• 1. those that form ion channels gated by the neurtransmitter
• 2. those that are coupled to g-proteins such that neurotransmitter binding initiates a series of chemical reactions in the cell to produce an effect

one of the 1st neurotransmitters to be identified, and is the major neurotransmitter used in the pns

neurotransmitter check pg 56

additional neurotransmitter with an inhibitory role, distinctly localized in different parts of the brainstem

• epinephrine
• norepinephrine
• dopamine
• all serve as neurotransmitters in both the brain and pns

adrenaline and fatigue

most excitatory transmission in the brain is probably mediated by glutamate, or a related excitatory amino acid

ampa, kainate, nmda, and metabotropic

larger molecules than the fast neurotransmitters and are made up of amino acids strung together with peptide bonds

• balance
• as life has certain requirements, we have a narrow range of body temps and blood compositions. the hypothalamus regulates these levels in response to a changing external environment. homeostasis is the name of this regulatory process

• brain receives its blood supply through two main arterial groups:
• internal carotid arteries
• basilar artery

arterial circle at the base of the brain that connects carotid and vertebrobasilar system, the major anastomotic (the union of parts or branches) point in the brain

• cerebrospinal fluid
• circulates around the brain and spinal cord tissues, and is important in protecting and sustaining the cns

• greek for covering
• with csf protect the cns by suspension and cushioning of the brain and spinal cord with in the skull cavity and vertebral column

dura mater, arachnoid (greek for spider), and pia mater

bacterial meningitis or hydrocephalus

• acts as a physicla and enzymatic shield to help maintain homeostasis in the cns
• specialization of the walls of the brain capillaries that limits the movement of bloodborne substances into the extracellular fluid of the brain (inhibit, or block)

line the walls of the blood vessels and restrict the movement of: ions, proteins, nutrients in and out of the vessel

astrocytes, pericytes and basal lamina provide further restrictive defenses