Psych109 Flashcards
(39 cards)
Where do the neurotransmitters interact with a neuron?
In the synapse, after being secreted into the synaptic gap by the axon of the presynaptic neuron.
Neurotransmitters are released from the presynaptic neuron into the synaptic cleft and then diffuse across to the postsynaptic membranes where they bind to specific receptors.
Describe how the synapse occurs at the synaptic gap
The synaptic vesicles that are filled with neurotransmitters move to the presynaptic membrane during the action potential. They spill the neurotransmitters into the synaptic gap where they bind onto the reception site on the postsynaptic membrane of the receiving neuron.
Neurotransmitters will only affect the postsynaptic membrane if their shape fits into the synaptic receptors.
Explain the difference between depolarization and resting potential in the axon.
Resting potential is more negative (-80 mV) whilst depolarization is much more positive in response to the rapid influx of Na+ ions.
In resting potential, the inside of the axon is negative at about -80mV, while in depolarization it switches toward positive.
Explain the difference between the afferent and efferent nerves
Afferent nerves send signals from the sensors to the brain and CNS, while efferent nerves send signals from the brain (CNS) to the effectors or muscles in the body.
Afferent is sensory nerves and efferent is motor nerves.
Name the three types of neurons and their functions.
- Sensory neurons: start at the sense organ and send information to the brain via spinal cord.
- Motor neurons: start at the CNS and exit through the spinal cord for communication.
- Interneurons: interposed between other neurons, essential for computation in the brain.
Describe the role of a motor neuron in the nervous system.
Motor neurons begin in the CNS and attach to muscle fibers to control muscle movement.
What is the difference between myelinated and unmyelinated axons?
A myelinated axon is covered by a myelin sheath, which increases the speed of signal transmission, while an unmyelinated axon does not have this sheath and sends signals more slowly.
What is the composition of myelin and what is its function?
Myelin is made mostly of fat and some protein.
In the Thalamus, what do the neurons make correlations with?
The thalamus receives signals from sensory organs (eye, skin) and sends them to the cortex.
Briefly describe the process of synaptic reuptake and explain its role in the communication between neurons in the brain.
Synaptic reuptake is when neurotransmitters, after delivering the message across the synapse, are reabsorbed back into the presynaptic neuron that originally released them. This enables them to be recycled for future use.
What is the resting state of an axon?
-70 millivolts
When the protons inside the axon are negative at about -70mV.
What are the three different types of neurons?
Sensory neurons, motor neurons, and interneurons.
Name the different types of neurons and explain at least 1 difference.
Motoneurons, sensory neurons, and interneurons. All three neurons have different functions and occur at different locations.
What is the function of Motoneurons?
Motoneurons carry signals from CNS to PNS to signal muscle contractions and movement.
What are the 3 ways in which drugs can affect the synapse?
- By inhibiting neurotransmitter release.
- By blocking postsynaptic receptor molecules.
- By inhibiting reuptake of neurotransmitters.
Are myelinated or unmyelinated axons faster at sending signals to other neurons?
Myelinated axons are faster.
Explain the Lock and Key Model and explain what function it controls.
The key represents a chemical and the lock represents a brain receptor; only the right key fits into the lock, which then controls how messages are sent in the brain.
What is the definition of an action potential?
Action potential is the quick electric “pulse” a neuron fires to send a message
What is the primary function of myelin sheath on neurons?
The primary function of the myelin sheath on neurons is to insulate the axon and increase the speed of electrical signal (action potential) transmission along the nerve cell.
What would likely happen if the occipital lobe is damaged?
Damage to the occipital lobe can lead to visual problems such as partial or complete blindness, visual field cut offs, or difficulties recognizing objects.
What is the required size of a pulse to exceed the excitation threshold and cause an action potential?
Around -55 millivolts.
What are the components of the peripheral nervous system and what are their functions?
- Somatic nervous system: information from the sensory information in relation to afferent and the efferent system.
- Autonomic nervous system: regulation of the viscera such as the heart, lungs, blood vessels, digestion, and sex organs.
What is the primary function of the temporal lobe?
Processing auditory information and the encoding of memory.
