Chapter 3 - Neurons and Neurotransmitters Flashcards
What is the function of neurons?
use electrical impulses and chemical signals to transmit information between different areas of the brain, and between the brain and the rest of the nervous system
How do neurotransmitters function?
Chemical messengers that cross the synaptic gaps between neurons. Neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse.
What are the main parts of a neuron?
dendrites axon soma nucleus presynaptic terminals
What is in the process of synaptic transmission?
synapse - > dendrites - > soma - > axon - > synaptic terminal
What are the synaptic parts needed for synaptic transmission?
1. Pre-synaptic neuron (sender) Terminal button - Synaptic vesicles (sacs) - Pre-synaptic membrane 2. Synaptic cleft (space) - Release of neurotransmitters 3. Post- synaptic neuron (receptor) - revives neurotransmitters and electrical impulse is stimulated
What do excitatory synapse enable?
Firing by the release of a neurotransmitter that excites the postsynaptic neuron leading to its action potential.
Excitatory vs. Inhibitory synapse
Excitatory = increases the amount of firing of the axon of the presynaptic neuron, to Glutamate (more likely)
Inhibitory synapse = inhibits firing leading to GABA (less likely)
Types of Neurotransmitters
Acetylcholine Epinephrine (adrenaline) Norepinephrine Dopamine Serotonin
Function of acetylcholine
Stimulates muscle contractions, learning, memory, and controls REM sleep.
Controls breathing, digestion and cardiovascular system
Function of Epinephrine
hormone + neurotransmitter, secreted by adrenal glands
fight vs flight, increase heartrate, blood pressure
Function of Norepinephrine
Increases alertness and arousal, speed up reaction times, regulates mood + concentration
Function of Dopamine
thoughts, feelings, motivation, behaviour, Controls reward and pleasure centres
Function of Serotonin
mood, social behaviour, appetite, digestion, sleep memory, sexual functioning
A change in neurotransmitters can be caused by?
- Neurons producing too much or not enough neurotransmitters
- Deactivation of a neurotransmitter by enzymes
- Neurotransmitters being reabsorbed too quickly
Parkinson’s disease is caused from the degeneration of?
dopamine-producing neurons in the substantia nigra
Function of substantia nigra
reward, addiction, movement and coordination
Symptoms of Parkinson’s disease
slow movement
rigid and involuntary movement of appendages, jaw, head
difficulty in controlling movement
Symptoms of Alzheimer’s disease
gradual memory loss commencing with declarative memory, confusion, impaired attention, disordered thinking and depression
Amnesia Types
Anterograde
Retrograde
Anterograde amnesia
impaired capacity for new learning
Retrograde amnesia
loss of information that was acquired before the onset of amnesia
Alzheimer’s due to loss of neurotransmitters shares?
o Decrease in acetylcholine in the CNS = sign of Alzheimer’s and other progressive dementias
o Cholinergic neuron (cognitive & motor functions) release acetylcholine
o Acetylcholine latches on to neighboring neuron receptors allowing signals to pass from cell to cell
o When acetylcholine functioning is impaired, or levels are depleted the neural pathways used in memory and leering start to deteriorate
What is inside presynaptic neurons?
Neurotransmitters
What is the process called?
Action Potential
What part of the brain is effected in Alzheimer’s?
Hippocampus
Neurotransmission
An action potential travels down the axon of a neuron, causing vesicles containing neurotransmitters to be released across the synapse. These attach to receptors on the receiving dendrite, creating action potential in the next neuron.
How does Parkinson’s disease occur?
Neurons producing dopamine and norepinephrine die
How does Alzheimer’s disease occur?
Levels of acetylcholine decline
