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Kin 256 2A
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Fuel for Brain
1. Glucose
2. Ketone bodies
Fuel for resting skeletal muscle
1. Fatty Acids
2. Ketone Bodies= Glucose
Fuel for liver
1. Fatty Acids
2. Ketone Bodies
3. Lactic acid= glucose
Fuel for heart
1. Fatty Acids
2. Glucose= Ketone bodies= Lactic acide
Paracrine
signal diffuses to nearby target cell
Autocrine
Signal substance effects secretory cell
synaptic
neuron's axon terminal secretes neurotransmitter, diffuses to postsynaptic cell (through the synapse)
Endocrine
endocrine glads secretes hormone into blood and reaches target cell through circulatory system
Electrical Forces
seperation of charged ions across a membrance cause this
Anions attract cations and vice versa
Where is Electrical signaling
in nerve and muscle tissue
These are called voltage-gated ion channels
When is the Activation gate in Voltage gated channel closed?
when the intracellular environment is negative mV
when is the gate open in voltage gated channel?
when the intracellular environment is positive mV
Example, sodium ion can enter the cell
Chemical Signaling
neurotransmitters bind to ligand-gated ion channels in nerve and muscle tissue
Ligand
signal triggering molecule
Ex. hormone, neurotransmitter or other
when is the ligand gated channel open?
When ligand is attached to receptor, movement occurs down the concentration gradient
Metabotropic receptors
act through a second messenger system and usually linked to a G protein
G Protein-linked receptors
extracellular ligand, binds to specific plasma membrane protein receptor > activates and intracellular G protein causing a signalling cascade.
Primary messenger
starts cascade
Secondary messenger
amplifies the signal by activating further enzymes in a pathway
Resting Membrane potential Ranges
-20 to -200 mV
Resting Neuron potential
-70 mV
Resting muscle potential
-95 mV
In resting Cell k and Na ion concentrations Inside cell
K+>> Na+
Ca++ concentration at resting membrane potential
Ca++ concentration outside the cell is much greater than inside the cell
Protein concentration
much greater inside the cell
Passive or leakage channels
Always open, relatively uncommon
Ion pump action
Sodium Potassium Pump
pumps 3 Na+ out of cell and 2 K+ in to regulate resting membrane potential
1 ATP used
Ca++ pumps
pump Ca++ out to regulate resting membrane potential
Polarized
negative mV at rest
How is Resting potential maintained?
active transport of ions against concentration gradient
Depolarization
positive change in mV> cell becomes activated
Neurons
transmit nerve impulse as action potentials
Flow of message on Neuron
Dendrite > cell body> axon
Glial Cells
support neurons
Schwann cells
Oligodendrocytes
Schwann cells
produce myelin sheath of PNS
Oligodendrocytes
form myelin sheath of of CNS
"white matter"
Author
souimet05
ID
201446
Card Set
Kin 256 2A
Description
Unit 2
Updated
2/18/2013, 5:36:57 PM
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