Biological Flashcards
1) What are the parts of a neuron?
1) Dendrite Nucleus Axon Myelin sheath Node of Ranvier Schwann Cell Axon Terminal
1) What is Action Potential?
1) The method by which the electrical impulse passes down the axon of the neuron to stimulate the release of neurotransmitters (chemical messengers) to another neuron.
1) What are the three types of neurons?
1)
Sensory Neurons - Carry messages along PNS to CNS. They have long dendrites and short axons.
Motor Neurons - Carry messages from the CNS, along nerves in the PNS to effectors in the body. They have short dendrites and long axons.
Relay Neurons - Connect sensory and motor neurons together, and also connect to other relay neurons, only found in CNS. Short dendrites and short axons.
1) What are Excitatory Neurotransmitters?
2) What’s an example?
1) Excitatory neurotransmitters cause the axon to become less negative. Therefore, excitatory neurotransmitters increase the likelihood of an action potential firing.
2) Dopamine
1) What are Inhibitory Neurotransmitters?
2) What’s an example?
1) Inhibitory neurotransmitters cause the axon to become more negative. Therefore, inhibitory neurotransmitters decrease the likelihood of an action potential firing.
2) Serotonin
1) Communication within a neuron is ______?
2) Communication between neurons is ______?
1) Electrical
2) Chemical
1) What is Synaptic Transmission?
1) When an action potential reaches the presynaptic terminal, it causes the vesicles to fuse with the presynaptic membrane and release their contents (neurotransmitters) into the synaptic cleft.
Once the neurotransmitters are in the synaptic cleft they diffuse across and bind to the receptors on the postsynaptic neuron. The chemical signal is converted back into an electrical signal in the postsynaptic neuron, which may fire another AP.
1) What happens to neurotransmitters that remain in the synaptic cleft?
1) They are either reabsorbed into the presynaptic neuron by an uptake pump, this is a process called reuptake and means the neurotransmitters can be used again.
Or enzymes break down the neurotransmitters within the synaptic cleft.
1) What does the neurotransmitter Serotonin do?
1) Associated with mood control in the limbic system of the brain. Involved in feelings of hunger and pain.
1) What does the neurotransmitter Dopamine do?
1) Emotional and cognitive functioning. Reinforcement in learning and addiction.
1) What does the neurotransmitter Acetylcholine do?
1) Involved in muscle contractions so is key to motor functioning. Also important for cognitive functions such as attention, memory and learning.
1) What does the neurotransmitter Noradrenaline do?
1) Emotion and mood control- as well as sleeping.
1) Explain the reward pathway
1)The brain contains a reward pathway which causes us to experience a pleasant and rewarding feeling.
Behaviour + nice feeling = continued/repeated behaviour
The reward pathway has evolved – it is adaptive for us to feel good after eating high-calorie food for example, as it ensures we store enough fat on our bodies in preparation for periods of famine.
Drugs hijack this reward system and produce pleasurable feelings without any adaptive functioning, e.g. cocaine floods the synapses with excess levels of dopamine as it blocks the molecules on presynaptic neuron involved in its reuptake.
1) Explain the effects of Cocaine
1)Increases the activity in the dopamine pathway by blocking the reuptake of dopamine, it mimics the structure of dopamine binding to the uptake pumps on the presynaptic neuron.
As a result the synapse is flooded with excess quantities of dopamine, available for binding with postsynaptic receptors. Excess of dopamine creates the euphoric “high” that the person feels when taking cocaine.
1) Explain the effects of Nicotine
1)Targets aspects of the dopamine pathway increasing the amount and transmission of dopamine by blocking the enzyme that breaks it down. It also mimics acetylcholine and binds to nicotinic receptors stimulating them.
1)Explain the effects of Alcohol
1) Has a depressant effect on the nervous system; it acts to inhibit neural transmission by increasing the action of GABA (inhibitory neurotransmitter), this makes memory less efficient (slows down neural communication). But does increase serotonin which makes individuals feel happier.
1) Your brain controls/processes your body _________
2) Which means…
1) Contralaterally
2) The right side of your brain is responsible for controlling the left side of your body and vice versa.
