Lecture 6 Flashcards
What are the main parts of a neuron?
Soma, Nucleus, Membrane
These parts are common to all human cells.
What is the function of the soma in a neuron?
Acts like a factory where proteins and neurotransmitters are manufactured
Contains all of the organelles.
What does the nucleus of a neuron contain?
The genetic material of the cell.
What is the role of the membrane in a neuron?
Controls ion flow, signal reception, and cell communication for neuron function.
What specialized parts do neurons have that are not found in other cell types?
Axons, Dendrites, Myelin sheath, Axon terminals.
What is the function of dendrites?
Gather much of the information incoming from other cells.
What are dendritic spines?
Small, protruding structures on dendrites that act as a receiving point for chemicals released by other neurons.
What is an axon?
A long, slender, fiber-like extension of a neuron that conducts electrical impulses away from the cell body.
How many axons does each neuron have?
Each cell has only one axon.
What is the myelin sheath?
An insulating material that speeds up action potentials.
What cells produce myelin in the Central Nervous System?
Oligodendrocytes.
What cells produce myelin in the Peripheral Nervous System?
Schwann Cells.
What are nodes of Ranvier?
Regularly spaced gaps in the myelin sheath surrounding the axon of a neuron.
What disease is caused by the loss of myelin around neuronal axons?
Multiple Sclerosis.
What is resting potential?
The baseline electrical charge across a neuron’s membrane when at rest, about -70 millivolts.
What two features maintain resting potential?
- Ion Channels
- Sodium Potassium Pump.
What is an action potential?
A very brief shift in a neuron’s electrical charge that travels along an axon.
What happens to the electrical charge during an action potential?
Reverses from about -70mv to about +30mv, known as depolarization.
What is the all-or-none law in neurons?
Neurons either fire an action potential or they don’t.
What is the absolute refractory period?
The minimum length of time after an action potential during which another action potential cannot begin.
What is a synapse?
A specialized junction between two neurons that allows for the transfer of electrochemical signals.
What is the synaptic gap?
The small space between the axon terminal of a pre-synaptic neuron and the post-synaptic neuron.
What are neurotransmitters?
Chemical messengers that facilitate communication between neurons.
What are the eight key stages involved in neurotransmission?
- Synthesis
- Transportation and storage
- Release
- Binding
- Deactivation
- Autoreceptor activation
- Reuptake
- Degradation.
What is synthesis in neurotransmission?
The process by which the body produces neurotransmitters.
What are synaptic vesicles?
Small structures within a neuron that store neurotransmitters.
What triggers the release of neurotransmitters?
Action potentials.
What is exocytosis?
The process of moving molecules from within a cell to the exterior of the cell.
What occurs when neurotransmitters bind to receptors on the post-synaptic cell?
They can either excite or inhibit the neuron.
What is deactivation in neurotransmission?
The process of terminating or reducing the effects of a neurotransmitter in the synaptic cleft.
What are the three main processes by which neurotransmitters are eliminated from the synapse?
- Diffusion
- Reuptake
- Degradation.
What are autoreceptors?
Receptors on the releasing (pre-synaptic) neuron that help regulate neurotransmission.
What is reuptake?
The reabsorption of a neurotransmitter by the presynaptic neuron after it has been released.
What is enzymatic degradation?
When enzymes in the synaptic cleft break down neurotransmitter molecules into inactive byproducts.
What are the four common properties of neurotransmitters?
- Synthesized in the neuron
- Stored in the synaptic terminals
- Released during an action potential
- Deactivated/removed from the synapse after neurotransmission.
What is GABA?
The primary inhibitory neurotransmitter in the brain.
What is glutamate?
The primary excitatory neurotransmitter in the brain.
What are monoamines?
A group of neurotransmitters including dopamine, noradrenaline, and serotonin.
What role does dopamine play?
Involved in movement and reward.
What is the function of noradrenaline?
Mobilizes the brain and body for action, increases attention and vigilance.
What is serotonin involved in?
Many complex behaviors/cognitions including sleep, mood, and memory.
What happens when dopaminergic neurons become damaged?
It leads to Parkinson’s Disease.
What neurotransmitter is involved in movement and reward, released during eating and sex?
Dopamine
Dopamine plays a crucial role in pleasure and reward mechanisms in the brain.
What is the function of noradrenaline?
Mobilizes the brain and body for action, increases attention and vigilance
It is released during stress or fear as part of the fight-or-flight response.
Which neurotransmitter is involved in complex behaviors such as sleep, mood, and memory?
Serotonin
Serotonin plays a key role in regulating mood and cognitive functions.
What is Parkinson’s Disease characterized by?
Tremors, slowness of movement, muscle stiffness, and balance problems
Parkinson’s Disease results from damage to dopamine-secreting neurons.
What class of drugs targets serotonin and is used to treat depression?
Selective Serotonin Reuptake Inhibitors (SSRIs)
SSRIs work by blocking serotonin reuptake, increasing serotonin levels in the synaptic gap.
How is norepinephrine synthesized?
From dopamine
Norepinephrine acts as both a neurotransmitter and a hormone.
What types of drugs typically target norepinephrine?
Drugs for Attention Deficit Disorders
Examples include amphetamines, which increase norepinephrine levels in the brain.
What is the primary role of acetylcholine (ACh)?
Transmitter between motor neurons and voluntary muscles
ACh is essential for all voluntary movements, including walking and talking.
What system is acetylcholine the primary neurotransmitter for?
Parasympathetic nervous system
This system is responsible for rest, digestion, and slowing the heart rate.
What type of poisons block acetylcholine?
Some poisons, such as Atropa belladonna
Atropa belladonna is known as ‘deadly nightshade’ and can interfere with ACh signaling.
