Chapter 5 exam Flashcards
What are the two big categories of synapse? What are the important parts of them?
There are two types of synapses. An electrical synapse (gap junctions) is a channel between a presynaptic neuron and a postsynaptic neuron. Channels are formed by pores in each membrane for ions and small molecules to flow. It is very fast transmission and tissues that want firing patterns want electrical synapses such as the heart. A chemical synapse is neurotransmitters passing through and motor neurons connecting nervous system to muscles for example the neuromuscular junction (NMJ) which is a fast transmission and one axon contacts one muscle fiber “end plate”.
What type of synapse works fastest?
Electrical synapse
Compare and contrast g-protein coupled receptors to ligand-gated ion channels
The ion channel (ionotropic) is fast and has less selectivity it allows both Na+ and K+ through. G-protein-coupled receptors (metabotropic) is slower and has very broad range of outcomes.
What are common synaptic arrangements?
Axon to dendrite, axon to soma, dendrite to dendrite
How might you tell if a synapse is excitatory or inhibitory? What neurotransmitters are commonly found at
each type? What sort of ion channel is likely to be affiliated with them?
Grays Type I Excitatory (asymmetric) synapses typically display a post-synaptic density (PSD). In contrast, the PSD in Grays type II inhibitory (symmetric) synapses looks similar to the presynaptic membrane, showing no obvious differences in membrane specialization. For example: Glutamate (excitatory, CNS), Gamma-aminobutyric acid (GABA) (inhibitory, CNS), Glycine (inhibitory brainstem, spinal cord).
What is the neural code?
information-processing channels that take incoming information, integrate it, and produce a signal that contains information encoded in the neuronal electrical activity pattern.
How can a neuron process incoming signals (e.g., how are multiple inputs counted?)
They receive incoming signals from other neurons and transfer them to the cell body, where the signals are integrated, and a response will be initiated. Multiple synaptic potentials combine within one postsynaptic neuron.
What’s the difference between an IPSP and an EPSP?
Type I synapse “EPSP” has a large active zone, wider cleft, dense material on membranes, and round vesicles. A brief graded potential that increases the chance a neuron will fire. Also, depolarizes neurons and opens NA+ channels. However, Type II synapse Inhibitory “IPSP” has a small active zone, narrow cleft, sparse material on membranes, and flat vesicles. A brief graded potential that decreases the chance a neuron will fire. Also, hyperpolarizes neurons and K+ leaves the cell (efflux) or Cl- enters the cell (influx).
What are agonists and antagonists? What are some examples?
An agonist is a molecule capable of binding to and functionally activating a target. The target is typically an ionotropic receptor. For example: opioid receptor agonists (morphine). An antagonist is a molecule that binds to a target and prevents other molecules (e.g., agonists) from binding. Antagonists have no effect on receptor activity. For example: opioid receptor antagonists (naloxone).
What are the neurotransmitter types?
Amino acids, amines, peptides
What makes the neuromuscular junction such a special synapse?
The neuromuscular junction (NMJ) is a synaptic connection between the terminal end of a motor nerve and a muscle. The site for the transmission of action potential from the nerve to the muscle.
What is the role of myelin in the nervous system?
Myelin is an insulating layer, or sheath that forms around nerves. This myelin sheath allows electrical impulses to transmit quickly and efficiently along the nerve cells.
What is exocytosis?
A process by which vesicles release their contents
What is the role of snares?
Snares penetrate and hang onto the pre-synaptic membrane.
What is the role of botox?
It degrades the snare protein and prevents ACh release at the terminal.
