The Neurotransmitter Quiz

Neurons and Their Functions

• Sensory neurons transmit information from sensory cells to the brain.
• The estimated range of neurons in the human brain is approximately 86 billion.
• Interneurons connect other neurons with one another.
• On average, a neuron transmits information to about 1,000 other neurons.
• Motor neurons transmit commands from interneurons to the glands and muscles of the body.

Neurotransmitters and Their Roles

• Acetylcholine is involved in learning, attention, sleeping, memory, and muscle contraction.
• Dopamine is linked to oversupply associated with schizophrenia and undersupply associated with Parkinson's disease.
• Endorphins play a role in pain perception and contribute to positive emotions.
• Serotonin is associated with low levels leading to depression and high levels linked to agitated, manic states.

Neuron Structure and Activity

• Dendrites are responsible for receiving signals from other neurons.
• The myelin sheath is primarily composed of fatty insulating material that speeds up neuronal transmission.
• Terminal buttons release neurotransmitters into the synaptic cleft to communicate with adjacent neurons.

Neuronal Signaling

• Action potentials are brief electrical impulses that occur when a neuron is activated.
• The resting potential of a neuron is typically around -70 mV, which maintains neuronal stability.
• The main difference between action potentials and graded potentials is that action potentials are all-or-nothing events, while graded potentials vary in amplitude.
• During neurotransmitter release, neurotransmitters are expelled from vesicles into the synaptic cleft in response to an action potential.

Neurotransmitter Receptors and Modulation

• Receptors in the postsynaptic membrane that receive neurotransmitter messages are referred to as neurotransmitter receptors.
• Modulatory neurotransmitters influence overall neuronal activity rather than creating direct effects; they modify the efficacy of other neurotransmitters.
• Some neurotransmitters can either increase (excitatory) or decrease (inhibitory) neural firing depending on the receptor type they bind to.

Emotional and Behavioral Impacts

• Neurotransmitters like norepinephrine are implicated in emotional arousal, anxiety, and fear.
• The resting potential of a neuron remains stable until the neuron is depolarized (an increase in internal charge).
• A graded potential refers to a change in the membrane potential that is proportionate to the strength of the stimulus.

Neurotransmitters Linked to Pleasure and Addiction

• Dopamine is linked to pleasurable activities such as listening to music and eating favorite foods; it plays a significant role in positive affect expression.
• Dopamine is also implicated in addictions due to its role in reward pathways.
• The degeneration of dopamine-releasing neurons in the substantia nigra results in Parkinson's disease, a condition characterized by motor symptoms.