Exam 2 Flashcards
(57 cards)
What are the 2 primary ligands
Hormones , Neurotransmitters
Hormones are secreted by?
- endocrine glands
- can travel long distances
- considered metabotrophic
Neurotransmitters are secreted by?
axon terminal knobs into a synaptic cleft.
- considered ionotropic (directly)
- considered metabotropic if binding to a receptor results in changing its target cells metabolism (indirectlyO
Receptors can be found on?
Surface of the cell membrane or in the cytosol of a cell.
Ion channel linked receptors and G protein linked receptors or intracellular.
What are the 2 kinds of Surface receptors
- ion channel-linked receptors
- G protein-linked receptors
Where is leakage channels located?
located all over the surface of aneuron
Two main types of ion channels
- Leakage
- Gated channels
1. Ligand gated
(open with binding of a specific chemical )
2 . voltage gate
(open and close in response to changes in membrane potential)
Resting membrane potential?
-70mV
At what voltage does action potential get triggered
- 55mV
Sodium Na+ fuse down concentraiton gradient T/F
T
Which is more permeable? K+ channel or Na+?
K+ .
K+ diffuses out of cell down gradient
More K+ diffuses out than sodium diffuses in –> inside of cell is more negative
Graded potential moves __ distances
short
Depolarization ?
decrease in membrane potential
- inside of membrane becomes less negative than resting membrane potential.
Action potential moves ____ distance
long signals of axons
Hyperpolarization?
increase in membrane potential
- inside of membrane becomes more negative than resting membrane potential
Action potential only occurs in?
muscle cell and axons of nuerons
Which potential decays over distance?
Graded potential
What is saltatory conduction
Action potentials can only be generated at the Nodes of Ranvier
The action potential jumps from node to node
Because of saltatory conduction the speed of impulse transmission is much faster on myelinated process
(The synapse) : Electrical synapse?
when an action potential spreads from one cell to another through a gap junction
- associated with smooth and cardiac muscle
Chemical synapse?
- a junction between 2 neurons
- include the axon terminal of presynaptic neuron and the dendrite, cell body or axon hillock of post synaptic neuron
- neurotransmitter is released int othe synaptic cleft by terminal knobs
What is the process of chemical synapse?
Excitatory neurotransmitters?
cause depolarization of a postsynaptic neuron by opening chemically gated Na+ ion channels.
- ACH
- is the most common neurotransmitter in the whole body
- comes in both ionotropic and metabotropic - Glutamate
- is the most common neurotransmitter in the brain.
Inhibitory neurotransmitters
cause hyperpolarization of a postsynaptic neuron by opening chemically gated K+/Cl- ion channels.
- harder to reach threshold and initiate action potential
- GABA is the most common inhibitor in the brain.
GABA
- inhibitory
- most common n the brain
- opens chloride ion channels
-the brain relies heavily on inhibition through GABA to prevent too many stimuli - is enhanced by valium