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88 Cards in this Set
- Front
- Back
Nerves
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a bundle of nerve fibers (axons) wrapped in fibrous connective tissue
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Ganglia
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a knotlike swelling in a nerve where neuron cell bodies are concentrated
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What are the two major subdivisions of the nervous system?
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1. Central Nervous System (CNS)
2. Peripheral Nervous System (PNS) |
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What are the two major subdivisions of the Peripheral Nervous System (PNS)?
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1. Sensory Division (afferent)
2. Motor Division (efferent) |
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sensory division
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carries sensory signals from various receptors to the CNS
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carries signals from the CNS to the effector organs
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motor division
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autonomic nervous system (visceral motor division)
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involuntary, and responses of this system and its receptors are visceral reflexes
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What are the 2 subdivisions of the Visceral Motor Division (autonomic nervous system)?
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1. Sympathetic Division
2. Parasympathetic Division |
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Which division of the autonomic nervous system has this function: arouse body for action, accelerates heart and respiration rate
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Sympathetic
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Which division of the autonomic nervous system has this function: calming effect, slows heart rate and breathing
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Parasympathetic
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What are the 3 functional properties of Neurons?
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1. Excitability
2. Conductivity 3. Secretion |
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ability to respond to environmental changes (stimuli)
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Excitability
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ability to transmit electrical signals
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conductivity
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release of a chemical neurotransmitter which crosses the physical gap between cells and stimulates the next cell
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secretion
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What are the 3 classes of Neurons?
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1. Sensory neurons (afferent)
2. Interneurons (association neurons) 3. Motor Neuron (efferent) |
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Which class of Neurons:
1. are Specialized to detect stimuli 2. Transmit information about them to the CNS |
sensory neurons
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Which class of Neurons:
1. lie entirely within the CNS 2. receive signals from many neurons and carry out the integrative function "making decisions" |
interneurons
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Which class of Neurons:
1. send signals out to muscles and glands (the effectors) |
motor neurons
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the body control center of the neuron
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soma
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branches coming from soma; primary site for receiving signals from other neurons
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dendrites
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specialized for rapid conduction of nerve signals away from dendrites and soma
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axon
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wraps axon; speeds rate of electrical conduction; formed by Schwann cells in PNS and oligodendrocytes in CNS
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myelin sheath
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Diseases of myelin sheath:
- myelin sheaths in the CNS deteriorate and are replaced by scar tissue - nerve conduction disrupted (double vision, tremors, numbness, speech defects) |
multiple sclerosis
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swelling that forms a synapse between other cells
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axon terminal
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- support and protect the neurons
- bind neurons together and form framework for nervous tissue |
neuroglia or glial cells
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cellular mechanisms for producing electrical potentials and currents; basis for neural communication and muscle contraction
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electrophysiology
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a difference in the concentration of charged particles between two points
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electrical potential (voltage)
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a flow of charged particles
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electrical current
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voltage across the membrane; about -70mV in a neuron
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resting membrane potential (RMP)
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Which ions have the greatest influence on resting membrane potential (RMP)?
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potassium ions
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What is concentrated in the ICF (inside cell)?
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potassium ions
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What is concentrated in the ECF (outside cell)?
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sodium ions
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Na+/K+ pumped out ___ Na+ for every ___ K+ it brings in
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3, 2
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dramatic change in voltage produced by voltage-regulated ion gates in the plasma membrane; a rapid up-and-down shift in the membrane voltage
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action potential
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when threshold is reached, neuron "fires" and produces an _____ _______.
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action potential
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Na+ and K+ switch places across the membrane during an ______ ______.
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action potential
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which type of membrane potential follows an "all or none law"?
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action potential
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the period of resistance to stimulation
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refractory period
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used to communicate across synaptic cleft
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neurotransmitters
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what are the 4 major categories of neurotransmitters?
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1. Acetylcholine (ACh)
2. Amino Acids 3. Monoamines 4. Neuropeptides |
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the first neuron has a soma in the brainstem or spinal cord
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presynaptic neuron
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has relatively short preganglionic and long postganglionic fibers
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sympathetic division
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small myelinated fibers that travel from spinal nerve to the ganglion by the way of the white communicating ramus (myelinated)
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preganglionic fibers
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leave the ganglion by way of the gray communicating ramus (unmyelinated)
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postganglionic fibers
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each ______ cell branches and synapses on 10 to 20 ____ cells.
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preganglionic; postganglionic
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secretes steroid hormones
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adrenal cortex
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-secretes a mixture of hormones into bloodstream
- essentially a sympathetic ganglion - also function as neurotransmitters -consists of modified postganglionic neurons without dendrites or axons |
adrenal medulla
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the nervous system of the digestive tract
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enteric nervous system
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is secreted by ALL preganglionic neurons in both divisions and the postganglionic parasympathetic neurons
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acetylcholine (ACh)
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what are the 2 types of cholinergic receptors?
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1. Muscarinic
2. Nicotinic |
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all cardiac muscle, smooth muscle, and gland cells have _____ ______.
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muscarinic receptors
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on all ANS postganglionic neurons, in the adrenal medulla, and at neuromuscular junctions of skeletal muscle
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nicotinic receptors
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-adrenergic receptors
-usually excitatory |
alpha
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-adrenergic receptors
- usually inhibitory |
beta
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- increased blood flow
- increased secretion |
vasodilation
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- decreased blood flow
- dcreased secretion |
vasoconstriction
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- neuron cell bodies
- site of information processing, synaptic integration - unmyelinated |
gray matter
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- myelinated axons
- transmits signals from one part of the CNS to another |
White matter
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neurons that stimulate muscle cells
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motor neurons
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motor neurons travels from CNS and synapse with muscle cells at the _________.
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neuromuscular junction (NMJ)
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Which type of neurons always release ACh?
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Preganglionic neurons
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What are the 2 classes of chemical synapses?`
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1. Cholinergic
2. Adrenergic |
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preganglion neuron secretes acetylcholine (ACh)
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cholinergic
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preganglion neuron secretes norepinephrine
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adrenergic
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embedded in membrane and are usually involved in transport or act as chemical messengers
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integral proteins
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diffusion in which a substance requires a carrier molecule or moves through a water filled protein channel
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facilitated diffusion
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moves solutes against their concentration gradient, requires energy (ATP) and carrier proteins
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active transport
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energy source is ATP
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primary active transport
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energy course is ion gradient, derived from ATP
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secondary active transport
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maintains the resting membrane potential
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sodium potassium pump
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- site of aerobic respiration
- where majority of ATP is produced - "power plant" of cell |
mitochondria
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modifies, concentrates, and packages proteins and lipids; "traffic director"
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Golgi apparatus
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- dispose of bacteria and debris
- "demolition crew" |
lysosomes
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- all preganglionic neurons are _______
- secrete Ach |
cholinergic
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- all postganglionic neurons are _____
- always excited by Ach |
nicotinic
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- contractile unit of myofibril
- "functional unit of muscle" - striations of muscle cell are evident by the arrangement of myofilaments |
sarcomere
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each filament conists of many myosin molecules whose heads protrude at opposite ends of the filament
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thick myofilaments (myosin)
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consists of two strands of actin subunits twisted into a helix plus two types of regulatory proteins (troponin and tropomyosin)
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thin myofilaments (actin)
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have active sites that bind with the globular head of myosin; each filament has 2 of these that are intertwined
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actin
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- plasma membrane of muscle cell
- contains T-Tubules (tube-like structures that protrude into muscle cells) allow impulses to reach inside of cell |
saraclemma
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-cytoplasm of muscle cell
-contains large amount of stored glycogen (ATP source) -contains large amount of myoglobin (oxygen storage; required for ATP production) |
sarcoplasm
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axon from nerve branches and forms communication with muscle fiber
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neuromuscular junction (NMJ)
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stimulation of muscle by motor neuron
generation of action potential facilitated by T-Tubule |
excitation
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development of tension in muscle which may result in shortening; "sliding filament theory"
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contraction
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return of muscle to resting state and length (muscle twitch)
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relaxation/repolarization
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involuntary branch of the PNS that helps maintain homeostasis and optimal body function; we do not control it consciously
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autonomic nervous system
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- the ability of an external solution (ECF) to have an effect on the volume and pressure of the fluid inside the cell (ICF)
- comparing concentrations |
tonicity
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-70mV
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in resting membrane potential, the result ICF has a voltage of ____.
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