The flashcards below were created by user
souimet05
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Fuel for Brain
- 1. Glucose
- 2. Ketone bodies
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Fuel for resting skeletal muscle
- 1. Fatty Acids
- 2. Ketone Bodies= Glucose
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Fuel for liver
- 1. Fatty Acids
- 2. Ketone Bodies
- 3. Lactic acid= glucose
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Fuel for heart
- 1. Fatty Acids
- 2. Glucose= Ketone bodies= Lactic acide
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Paracrine
signal diffuses to nearby target cell
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Autocrine
Signal substance effects secretory cell
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synaptic
neuron's axon terminal secretes neurotransmitter, diffuses to postsynaptic cell (through the synapse)
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Endocrine
endocrine glads secretes hormone into blood and reaches target cell through circulatory system
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Electrical Forces
seperation of charged ions across a membrance cause this
Anions attract cations and vice versa
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Where is Electrical signaling
in nerve and muscle tissue
These are called voltage-gated ion channels
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When is the Activation gate in Voltage gated channel closed?
when the intracellular environment is negative mV
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when is the gate open in voltage gated channel?
when the intracellular environment is positive mV
Example, sodium ion can enter the cell
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Chemical Signaling
neurotransmitters bind to ligand-gated ion channels in nerve and muscle tissue
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Ligand
signal triggering molecule
Ex. hormone, neurotransmitter or other
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when is the ligand gated channel open?
When ligand is attached to receptor, movement occurs down the concentration gradient
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Metabotropic receptors
act through a second messenger system and usually linked to a G protein
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G Protein-linked receptors
extracellular ligand, binds to specific plasma membrane protein receptor > activates and intracellular G protein causing a signalling cascade.
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Primary messenger
starts cascade
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Secondary messenger
amplifies the signal by activating further enzymes in a pathway
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Resting Membrane potential Ranges
-20 to -200 mV
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Resting Neuron potential
-70 mV
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Resting muscle potential
-95 mV
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In resting Cell k and Na ion concentrations Inside cell
K+>> Na+
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Ca++ concentration at resting membrane potential
Ca++ concentration outside the cell is much greater than inside the cell
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Protein concentration
much greater inside the cell
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Passive or leakage channels
Always open, relatively uncommon
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Ion pump action
Sodium Potassium Pump
pumps 3 Na+ out of cell and 2 K+ in to regulate resting membrane potential
1 ATP used
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Ca++ pumps
pump Ca++ out to regulate resting membrane potential
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Polarized
negative mV at rest
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How is Resting potential maintained?
active transport of ions against concentration gradient
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Depolarization
positive change in mV> cell becomes activated
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Neurons
transmit nerve impulse as action potentials
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Flow of message on Neuron
Dendrite > cell body> axon
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Glial Cells
- support neurons
- Schwann cells
- Oligodendrocytes
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Schwann cells
produce myelin sheath of PNS
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Oligodendrocytes
- form myelin sheath of of CNS
- "white matter"
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