Chapter 5 Pt.1 Flashcards
What marked the beginning of research into how chemicals carry information from one neuron to another in the nervous system
Otto Loewi’s successful heartbeat experiment
Loewi was the first person to isolate a chemical messenger, what is this messenger called and what does it do
The chemical messenger is acetylcholine (ACh) , and it actives the skeletal muscles, but in the heartbeat experiment, ACh acts to inhibit the heartbeat (slow it down)
What does ach do to skeletal muscles?
It excites the skeletal muscles in the somatic nervous system, causing them to contract
How does ach both excite or inhibit various internal organs in the autonomic system?
The ion channel and its associated receptor determine whether the messenger will be excitatory or inhibitory.
What is epinephrine (adrenaline)?
A substance produced by the adrenal glands that acts as a neurotransmitter and hormone that mobilizes the body for fight or flight
What are neurotransmitters?
A chemical with an excitatory or inhibitory effect when released by a neuron onto a target.
The results of Loews experiments showed that __________ from the vagus nerve inhibits heartbeat, whereas __________ from the accelerator nerve excites it
Acetylcholine, epinephrine
In mammals, the chemical that accelerates heart rate is called ______________.?
Norepinephrine
Neurons that secrete acetylcholine are called ________ neurons, those that secrete epinephrine are known as _________ adrenergic neurons, and those that secrete norepinephrine are called _________ (NA neurons)
Cholinergic, adrenergic, and noragrenergic neutrons.
What releases hormones into the bloodstream to excite or inhibit targets?
The pituitary gland, controlled by the hypothalamus
What is an example of how neurotransmitters and hormones can be chemically identical?
When epinephrine is synthesized by a neutron and influences another neuron, its called a neurotransmitter, but when its synthesized by the adrenal gland and increases heart rate, its called a hormone.
How can you tell the difference between neurotransmitters and hormones
From the distance they travel From their release point to the receptor
How many neurotransmitters are there?
60
Where are neurotransmitters located?
The axon terminal (packaged into vesicles)
What are synaptic vesicles?
A compartment in the neuron that contains neurotransmitter molecules
What is the small space that separates the terminal and the dendrite?
The synaptic cleft, neurotransmitter chemicals must bridge this gap to carry a message From one neuron to the next
What is the function of a mitochondrion?
It provides the cell with energy
What is the function of a postsynaptic receptor?
The area where a neurotransmitter molecule binds
What is a chemical synapse?
Where messenger molecules are released when stimulated by an action potential
What is a synapse?
The places where nurons connect and communicate with each other
What is an astrocyte?
A large star shaped cell that holds nerve cells in place
Astrocytes contribute to chemical neurotransmissions in what 3 ways?
They supply building blocks for neurotransmitter synthesis, confine movement of neurotransmitters to the synapse, and mop up excess neurotransmitter molecules.
What is the difference between the presynaptic and postsynaptic neuron
The presynaptic membrane forms the axon terminal, and the postsynaptic membrane forms the dendritic spine
The integration and physical proximity of the presynaptic membrane, postsynaptic membrane, and their association with surrounding astrocytes make up what’s known as the ___________ __________.
Tripartite synapse
What is the Anterograde synaptic transmission 5-step process?
Its a process of transmitting information across a chemical synapse from the presynaptic side to the postsynaptic neuron
