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90 Cards in this Set
- Front
- Back
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What are the two componets of the CNS?
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Brain and spinal cord
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What are the components of the PNS?
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Cranial nerves arising from the brain and spinal nerves arising from the spinal cord
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Describe neurons
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Basic structural and functional components of the nervous system, respond to physical and chemical stimuli, conduct electrochemical impulses, release chemical regulators
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Describe Supporting cells
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5x more abundant than neurons, they can divide miotically
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What is another name for supporting cells?
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neuroglia or glial cells
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What are the three components of a neuron?
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Cell body, dendrites, axon
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Describe the cell body of a neuron
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Enlarged portion, nutritional center, macromolecules produced, contains rough ER, known as Nissl bodies and these are not found on dendrites or axon
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What are clusters of cell bodies called in the CNS and in the PNS?
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CNS-nuclei
PNS-ganglia |
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Describe dendrites
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Thin, branched processes that extend from cytoplasm of cell body, provide receptive area that transmits electrical impulses to cell body
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Describe Axons
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Longer processes that conducts impulses away from cell body
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What is sensory input?
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monitoring stimuli both internally and externally
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What is integration?
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interpretation of sensory input, and makes a decision on how to proceed
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What is motor output?
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response to stimuli by activing effector cells
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What is the function of sensory afferent fibers?
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Carry impulses skin, skeletal muscles, joints to the brain
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What is the function of visceral afferent fibers?
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Carry impulses from organs to the brain
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What is the function of motor (efferent) divison?
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From CNS to effector organs
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What is the function of interneurons?
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Located entirely within CNS, serve associative or integrative functions of system
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What are the two types of motor neurons?
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Somatic motor and Autonomic motor
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What is the function of somatic motor neurons?
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Responsible for both reflex and volentary movement
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What is the function of autonomic neurons?
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Sympathetic and parasympathetic function
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What is the function of the somatic system?
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concious control of skeletal muscles (volentary)
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What is the function of the autonomic system?
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regulates smooth muscles, cardiac muscle, and glands (involentary), divisions (parasympathetic and sympathetic)
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What is the general function of the parasympathetic system?
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house-keeping duties of the body functions during rest, conserves energy
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What is the general function of the sympathetic system?
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mobilizes body systems during activity
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What is the differences between pseudounipolar neurons, bipolar neurons, multipolar neurons?
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Pseudo- have single short processes that branch like a T
bipolar- have two processes on at either end (retina) multipolar- most common, have several dendrites and one axon extending from cell body, motor neurons are good example of this type |
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What is a good definition of a nerve?
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Bundle of axons located outside the CNS
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What are the two types of supporting cells in the PNS?
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Schwann cells
Satellite Cells/ Ganglionic gliocytes |
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What are the four types of supporting cells known as neuroglia or glial cells in the CNS?
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Oligodendrocytes
Microglia Astrocytes Ependymal cells |
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What is the function of Schwann cells in the PNS?
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Form myelin sheaths around peripheal axons
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What is the function of satellite cells or Ganglionic gliocytes in the PNS?
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Supports neuron cell bodies within the ganglia of the PNS
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What is the function of Oligodendrocytes in the CNS?
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For myelin sheaths around axons of the CNS
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What is the function of microglia in the CNS?
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Migrate through CNS and phagocytize degenerated material
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What is the function of Astrocytes in the CNS?
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Help to regulate the external environment of neurons in the CNS
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What is the function of Ependymal cells in the CNS?
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Line ventricles (cavities) of brain and the central canal of spinal cord
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All axons in PNS are surrounds by ____________
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living sheath of schwann cells and known as neurilemma
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In the CNS axons surrounded by sheath are formed by ________
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Oligodendrocytes
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True or false, unlike neurons, glial cells can undergo mitosis and regenerate
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true
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Which neuroglia (supporting cell) in the CNS is likely to take up glucose from blood, metabolize blood and support and brace neurons
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Astrocytes
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What neurotransmitters do astrocytes release and are they inhibitory or excitatory?
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ATP (inhibitory)
Glutamate (stimulatory) |
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What would be considered the only immune system of the brain?
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microglia
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What are the gaps left uncovered by myelin sheath called?
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Nodes of Ranvier
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Leaving these nodes of ranvier exposed is to produce ______
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nerve impulses
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Schwann cells create myelin sheath by wrapping ________ axon at a time
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one
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Oligodendrocytes create myelin sheath by wrapping ______ axon at a time
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many
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A high conc of white color when referring to Oligodendrocytes means_______ (finish sentence)
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Lots of axons with myelin sheath
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What is the significance of the cell body having no centrioles?
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Amiotic nature
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What part of the nerve cell is the focal point for outgrowth during embryonic development?
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Cell body
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What are process called in the CNS and what are they called in the PNS?
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CNS-Tracts
PNS-Nerves Theses are bundles of neuron processes (axons and dendrites) |
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What is another name for axon terminal?
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Boutons
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What is the meaning of Anterograde?
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Toward axon terminal
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What is the meaning of Retrograde?
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Away from the axon terminal
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Dendrites are always________
myelinated/unmyelinated |
unmyelinated
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Which transmits electrical impulses faster myelinated or unmyelinated?
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myelinated
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What is saltatory conduction?
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impulse jumping (not literally) from node of ranvier to node of ranvier
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Sensory neurons are likely to be unipolar/bipolar/mulitpolar?
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bipolar and unipolar
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Motor neurons are more likely to be unipolar/bipolar/multipolar?
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multipolar
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Interneurons are more likely to be unipolar/bipolar/multipolar?
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multipolar
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What are neutrophins and why are they important?
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Chemicals that promote neuron growth in fetal brain, nerve growth factor (NGF), NGF is also important maintainence of sympathetic ganglia, required for mature sensory neurons to regenerate after injury
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What supporting cell is likely to keep the proper ionic environment for neurons?
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Astrocytes
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Describe the blood-brain-barrier
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Capillaries in the brain do not have pores like other organs, instead endothelial cells are joined by tight junctions, therefore the brain cannot obtain molecules from blood plasma by nonspecific filtering process
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How are substances passed within the blood-brain-barrier?
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Molecules in the brain capillaries must be moved through by diffusion, active transport and endo/exocytosis
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What are some common substances that pass through the blood-brain-barrier?
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Nonpolar molecules (O2,CO2), some organics, alcohol, and barbituates, Ionic and polar require carrier proteins
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What is the carrier protein that is used to move glucose through the Blood-brain-barrier?
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GLUT1
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What is depolarization?
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The inside of the cell membrane becomes more positive (less negative)
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What is repolarization?
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The membrane returns to its resting membrane potential (-70mV)
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What is hyperpolarization?
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The inside of the cell membrane becomes mroe negative than the resting potential
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Depolarization is __________ and hyperpolarization is ___________ when reffering to the effects on the nerve impulses (inhibitory or excitatory
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depolarization-excitatory
hyperpolarization-inhibitory |
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What are the neutrophic factors NGF, BDNF, GDNF
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NGF- Nerve growth factor
BDNF-brain-derived neurotrophic factor GDNF-Glial cell-lined neurotrophic factor There is also Neutrophin-3 |
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What are some importances of neutrophic factors?
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Promote neuronal growth and differentiation,mostly active in fetal growth and childhood development, may play a role in neurodegenative diseases in adults, they are mostly proteins that are synthesized in the CNS
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Where are two areas that the blood-brain-barrier is absent?
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vomitting center and hypothalamus, allowing these areas to monitor the chemical composition of blood
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When do voltage-gated ion channels open and close?
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When the membrane potential changes
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What are some difference between graded and action potentials?
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action- all-or-none maintained throughout axon, long distance,can be local or saltatory, only on depolarizations
Graded- short lived localized changes in membrane potential,magnitude varies directly with strength of stimulus,local current flow, can result from hyperpolarizations and depolarizations |
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What is the absolute refractory period?
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Prevents the neuron from generating AP, ensures that APs are separate, enforces one way transmission of nerve impulses, membrane is uneffected by all other stimulus
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What is relative refractory period?
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repolarization is occuring, interval period between absolute refractory period na gates are closed and k are open, threshold is elevated so only very strong stimulus can create APs
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What is the importance of axon diameter?
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The larger the diameter (thicker the neuron) the faster the impulse
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What are some key examples of electrical synapses?
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Important in CNS, arousal from sleep, mental alertness, emotions and memory, ion and water homeostasis
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Describe chemical synapses
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Axonal terminal-presynaptic vesicles releasing NTs to Dendrites or soma-postsynaptic neuron
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Describe the synaptic cleft
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fluid filled space separting pre and postsynaptic neurons, prevents nerve impulses from directly passing one nerve to the other
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Example of excitatory NT
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glutamate
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Two examples of inhibitory NTs
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Glycine, GABA
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What are the three catecholamines?
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dopamine, norepinephrine, epinephrine
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What are the two indolamines?
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histamine, serotonin
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What does GABA stand for?
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Gamma Aminobutyric Acid
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GABA and glycine cause______
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hyperpolarizations
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Glutamate causes __________
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depolarizations
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What are three polypeptides that act as NTs and what is their function?
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Beta-Endorphin, Enkephalins,Dynorphin, these are produced by brain and pituitary gland, when activated by stressors can block transmission of pain, same receptors as opiates and morphine
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What is Substance P?
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Polypeptide NT mediator of pain signals
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What are Endocannibinoids and their function?
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Retrograde NTs, effect appetite, decrease anxiety, bind to same receptors as THC
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What is the significance of synaptic plasticity?
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Repetition of synaptic transmission enhances the transmission, involved in memory and learning, Long term potentiation-long lasting enhancement of communications
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What does EPSP and IPSP stand for and are they graded or action potentials?
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EPSP-Excitatory postsynaptic potential
IPSP-Inhibitory postsynaptic potential, they are graded meaning they have no refractory period, depolarization doesnt get over 0mV, more ACh released more depolarization |
