Chapter 13 - Neuronal Communication Flashcards
What is a synapse?
A synapse is the junction between 2 neurones.
The synapse is made from 3 parts, what are these parts?
The presynaptic neurone, the synaptic cleft and the postsynaptic neurone.
Explain how action potentials can cross the synaptic cleft.
Action potentials cannot bridge the gap between the pre and postsynaptic neurones.
The action potential instead triggers the depolarisation of the presynaptic knob. This opens up calcium ion channels. The calcium then guide and diffuse neurotransmitters across the membrane into the synaptic cleft. Neurotransmitters then attach to receptors on the postsynaptic knob opening up the sodium ion channels which depolarise the postsynaptic neurone, once it hits 40v a new action potential starts.
Explain how and why it’s important for neurotransmitters to be disabled after a new action potential has been made.
Hydrolytic enzymes break down any lingering neurotransmitters into ethanoic acid and choline, which diffuse back into the presynaptic neurone to be recycled. This stops the transmission of signals so the postsynaptic neurone does not continue to create action potentials.
State the difference between the peripheral nervous system (PNS) and the central nervous system (CNS)
The CNS controls the brain and spinal cord whereas the PNS controls all the neurones (senators and motor).
The peripheral nervous system can be broken into the SNS and ANS, state the difference between the somatic nervous system (SNS)and the autonomic nervous system (ANS)
The SNS is under conscious control whereas the ANS is under subconscious control (e.g a heartbeat)
The autonomic nervous system can be further broken down into the sympathetic and parasympathetic pathways. State the difference between them.
The sympathetic pathway is where the outcome increases activity (heartbeat increases during exercise) whereas the parasympathetic pathway is where the outcome decreases (heartbeat decreases after exercise).
State and explain one reason why many autonomic functions can also be controlled by the somatic nervous system.
Many aspects of the autonomic nervous system can come under conscious control, such as holding your breath or sealing rapidly. When organisms do not choose to control these functions the autonomic nervous systems takes control which frees up the conscious areas of the brain.
State how the presynaptic neurones are adapted to their function.
The presynaptic neurones have mitochondria which produce ATP in for the SER to create vesicles and neurotransmitters. It also has calcium ion channels that allow neurotransmitters to diffuse across the membrane.
Name a neurotransmitter.
Acetylcholine
Is a synapse used acetylcholine as a neurotransmitter, the synapse is called…
Cholinergic synapse
Why are synapses important?
1) Ensure impulses flow in one direction as receptors are only present on the postsynaptic neurone.
2) Can allow impulses from one neurone to travel to many other neurones.
What is summation?
Summation refers to when the amount of neurotransmitters have to build up before an action potential can be created.
State the difference between spatial summation and temporal summation.
Spatial summation refers to when multiple presynaptic neurone release many neurotransmitters to one postsynaptic neurone, whereas temporal summation refers to when 1 presynaptic neurone releases neurotrophic to 1 postsynaptic neurone.
What is the location and function of the hypothalamus?
Its found just beneath the middle part of the brain. It maintains the body temperature and produces hormones that control the pituitary gland.
