Biochemistry of Neurotransmission and Neurotransmitters Flashcards
The neuron is the basic functional unit of _______.
CNS
How many synaptic connections from input fibers are there?
2.Few hundred to 200, 000
The brain is composed of how many neurons?
3.100 Billion neurons
How many connections between neurons are there?
10 raised to the 16
What are the 2 types of signal messengers?
- Internal and External messengers
The signaling mechanism is regulated by what?
6.The amount of action potential that can progress or dampen
Signals are received from the ________.
dendrites
The output from the signals are discharged via the _____.
axon
The main function of this neuron is to initiate the activity of transmitting the information from the receptors to the CNS through the peripheral nerves.
Sensory Neurons
The main function of this neuron is to relay the signals of the CNS to the effectors.
Motor neurons
The skin and glands are actual structures that perform functions dictated by the nerve signals. Collectively, they are called the _______.
Effectors
The myelinated nerves are composed of cells that lay down myelin or sphingomyelin. These cells are also excellent electrical insulators. What are these cells?
Schwann cells
Schwann cells (increase or decrease) ion flow through the membrane?
Decrease.
Between the schwann cells are uninsulated area called the ______.
Nodes of Ranvier.
True or False. Nodes of Ranvier lets ions pass through the membrane with ease.
TRUE
True or False. Nodes of Ranvier wastes energy.
- False, they conserve energy.
What is the speed of the increased transmission velocity brought by the Nodes of Ranvier?
100 m/sec.
True or False. In the processing of information, unimportant sensory information is also processed.
False.
In the channeling of information, information is directed to proper regions of brain (unidirectionally, bidirectionally).
Unidirectionally.
What is the integrative function of the CNS?
20.Important sensory information is channeled into proper integrative and motor regions of the brain to cause desired responses.
Depolarization of the end terminal opens voltage-gated (Calcium, Sodium, Potassium) channels which triggers the release of neurotansmitter.
Calcium
Once neurotransmitter is released, it will bind to the receptor to transiently open (Calcium, Sodium, Potassium) channels.
Sodium
The local depolarization brought by the opening of sodium channels further result to opening of voltage-gated (Calcium, Sodium, Potassium) channels to cause widespread depolarization.
Sodium.
The widespread depolarization brought by the voltage-gated sodium channels opens voltage-gated (Calcium, Sodium, Potassium) channels.
Calcium.
Calcium enters to what type of receptors in the SR membrane?
Ryanodine receptors.
Once calcium attaches to the ryanodine receptors, they open ________________ in the SR membrane to start muscle contraction.
Ligand-gated Calcium channels.
Specialized structure or a junction point that transfers info between neurons
Synapse
Who coined the term synapse?
28.Sir Charles Scott Sherrington and colleagues.
What are the 2 roles of synapse?
- to determine the direction of spread of signal. 2. to serve as point of control of synaptic transmission.
True or False. Synapses have different capacity to transmit signals.
True.
What are the two types of synapses?
Electrical and Chemical Synapses.
The mediator in an electrical synapse are the _________ while the mediator in a chemical synapse are the ______.
Connexons in gap junctions; Neurotransmitters
Nature of Electrical Synapse?
Direct open fluid channels that conduct electricity
Nature of Chemical Synapse?
Presence of vesicles that fuse with the presynaptic vesicles.
The communication in an electrical synapse depends on 2 factors:
35.1. gap junctions 2. transmission of signals in either direction
The communication in a chemical synapse depends on 3 factors:
36.1. nature of the chemical messenger 2. type of post-synaptic receptor 3. mechanism that couples receptors to effector systems
What are the three main components of a synapse?
37.1. presynaptic terminal 2. synaptic cleft 3. postsynaptic neuron
How many presynaptic terminals are there and their composition?
10, 000 to 200, 000 where 80-95% on dendrites while 5-20% on soma.
True or False. Most of the presynaptic terminals are inhibitory.
False, most are excitatory.
An autoreceptor is located in the __________.
presynaptic terminal.
Width of the synaptic cleft.
200-300 A width
The cholinesterase in synpatic cleft is in the ____________.
- proteoglycan reticulum
What are the 2 types of receptor proteins in a postsynaptic neuron?
43.1. binding compartment 2. ionophore.
This protrudes outward from the membrane into the synaptic cleft.
Binding compartment.
This passes all the way through postsynaptic membrane.
- Ionophore.
What are the 2 types of ionophore.
- ion channel 2. second messenger activator
The ion channel allows passage of 2 specified types of ions: __________ and __________.
47.cation channel (allow sodium ions to pass; excitatory transmitters) and anion channel (allow chloride ions to pass; inhibitory transmitters).
The _________ activates a second neuron by releasing G protein.
48.Secondary messenger activator
The G protein is regulated by what pathway?
Receptor-tyrosine kinase pathway.
What are the four subsequent possible effects of G protein.
50.1. Opening specific ion channels through the postsynaptic cell membrane 2. Activation of cyclic adenosine monophosphate (cAMP) or cyclic guanosine monophosphate (cGMP) in the neuronal cell. 3. Activation of one or more intracellular enzymes directly activate one or moreintracellular enzymes. In turn the enzymes can cause any one of many specific chemical functions in the cell. 4. Activation of gene transcription- can cause formation of new proteins within the neuron, thereby changing its metabolic machinery or its structure
What are the other secondary messengers?
Cyclic AMP, Calcium, Diacylglycerol, Nitric Oxide
If you repetitively stimulate an excitatory synapse at a rapid rate, it will result to _______.
Fatigue of synaptic transmission.
True or False. Stored neurotransmitters can be exhausted.
True.