Chapter 2 Flashcards
What is the cell membrane of a neuron at resting potential like?
- Selectively permeable: Allows ions in and out
- ⬆️ (+) ions on the 🏰 Outside and ⬆️ (-) ions on the 🥀 Inside: This is called being polarized caused by the electrochemical potential
What is the cell membrane like when it has action potential? And where does it occur?
Depolarization occurs:
- The area on the inside becomes less (-)
- Gates open
- Sodium (+) ions enter inside
- –> This depolarizes the next gate
What is the function of the mylin sheath?
The mylin sheath speeds up a reaction -> It’s only found on some reactions
What is the refracting period?
The period during which the neuron is repolarized
How do neurons communicate?
Neuron terminals release neuro-transmitters across the synaptic gap
What do the dendrites/receptor sites do?
They accept neurotransmitters from the neuron before.
What are 2 types of neurotransmitters that can be accepted by the next neuron’s dendrites?
- Excitatory signal: Causes something to happen therefore depolarization occurs
- Inhibitions signal: Stops things from happening therefore hyperpolarization occurs
Sometimes a combination of excitatory signals and inhibitory signals are released at once, what situations cause action potential and what cause resting potential?
If Excitatory signal > Inhibitory signal : Action potential and depolarization
If Excitatory signal < Inhibitory signal : Resting potential and hyperpolarization
How does a nerve impulse carry through?
- Electrical impulse goes down the neuron’s axon till it reaches the synapse
- When this action potential reaches the synapse it triggers the release of certain neurotransmitters which cross the synapse and bind to the receptor sites on the dendrites of a receiving neuron cell thus allowing the electrical charge to enter the receiving neuron cell»_space; inhibits or excites new action potential
- Excess neurotransmitters are reabsorbed (uptook), broken down by enzymes or drift away
What is the purpose of the neurotransmitter acetylcholine? (ACh) What are the consequences of less of it?
Triggers muscle action, learning and memory. Consequences of break down of neurons producing acytl choline is Alzheimer’s disease.
What is the purpose of the neurotransmitter dopamine? What are the consequences of a oversupply or undersupply?
Dopamine effects movement, learning, emotion, and attention. Oversupply can lead to schizophrenia. Undersupply can lead to Parkinson’s disease.
What does the neurotransmitter serotonin effect? What are the consequences of having an undersupply of serotonin?
Serotonin effects appetite, mood, sleep, and arousal. Having an undersupply of serotonin can lead to depression.
What does the neurotransmitter Norepinephrine effect? What are the consequences of an undersupply?
Norepinephrine effects alertness and arousal. An undersupply of norepinephrine can depress mood
What is does the neurotransmitter GABA act as? What are the consequences of undersupply?
GABA acts as a inhibitory neurotransmitter. Undersupply of GABA can lead to insomnia, seizures and tremors.
What does the neurotransmitter glutamate act as? What are consequences of a oversupply of glutamate?
Glutamate acts as a excitatory neurotransmitter, part in memory. Oversupply of glutamate can lead to migranes or seizures (perhaps from MSG containing food)
What are endorphins?
Endorphins are natural opioid like neurotransmitters that are linked to pain control and pleasure
What is the difference between Agonists and Antagonists?
Agonists work to amplify a neurotransmitters action. Antagonists work to decrease a neurotransmitters actions by stoping either production or release.
How do antagonists work?
Antagonists work by being similar enough to the neurotransmitter that it can attach to receptor sites but not similar enough that it can trigger an action potential
Define the peripheral nervous system?
Made up of the sensory and motor neurons responsible for connecting the central nervous system to the rest of the body
Explain how the sensory neurons, motor neurons, and interneurons are related to each other?
The sensory neurons carry information from the body tissues to the brain, from there the interneurons (billions) carry the information through the necessary parts of the brain and spinal cord and to the motor neurons which carry information from the central nervous system to the rest of the body tissues
What are the 2 components of the peripheral nervous system and what do they do?
Somatic nervous system: Voluntary control of skeletal muscles
Autonomic nervous system: Involuntary control of our glands and internal organ muscles
Explain the breakdown of the nervous system starting from the peripheral nervous system and central nervous system (brain & spinal cord).
Nervous system is made of 2 main components: Peripheral nervous system (carries decisions from CNS to the rest of the body) and Central nervous system (decision maker)
Peripheral nervous system has 2 main components: Somatic (voluntary skeletal muscle movement), Autonomic (self regulated movement of glands and organ muscles)
Autonomic nervous system has 2 main components: Parasympathetic (calms and lowers heart rate, sweat production), Sympathetic (excites, increases heart rate)
Somatic nervous system has 2 main components: Sensory input, Motor output
How is a reflex reaction so much faster than a normal reaction?
A reflex reaction is carried by sensory nerves only up to the spinal cord rather than all the way to the brain allowing for a rapid response to pain or fear. This could have been a evolutionary advantage. This also means however that our reactions may not always be required or best suited when the brain has time to access the situation but it could stop immediate danger to body tissues, that may have otherwise taken too long to reach the brain.
