Name: Jada Cumberbatch
ID#: 816010507
Course Code: BIOL 2867
Assignment 3
2). Explain why gaps are needed in nerves?
They are intercellular channels that directly connect the cytoplasm amid adjacent cells. In the
CNS numerous types of cells are joined via gap junctions, which play an imperative role in
preserving normal function. Neuronal gap junctions are involved in electrical coupling and may
also contribute to the recovery of function after cell injury. If absent gap, the death of one neuron
would likely be carried over to the next. It ensures that the two neurons have autonomous actions
resulting in the neurons to come and go as well as reconnect and reorganize. The gaps are called
synapses. Synapses are the junctions between neurons in the nervous system. A neurotransmitter
is released there, a chemical that permits one neuron to talk to the next neuron and continue
transfer the impulse (Qura, 2016).
Gaps ensures that the flow of impulses is in one direction only. This is as a result of the vesicles
comprising of the transmitter which only in the presynaptic membrane and the receptor
molecules are only on the postsynaptic membrane.
Integration would not occur, in this process an impulse travelling down a neurone may reach a
synapse which has several post synaptic neurones, all going to different locations. The impulse
can thus be dispersed. This can also work in reverse, where several impulses can converge at a
synapse (Qura, 2017).
It permits ‘summation’ to occur as synapses require the release of enough transmitter into the
cleft for enough of the transmitter to bind to the postsynaptic receptors and the impulse to be
created in the postsynaptic neurone. In spatial summation, several presynaptic neurones converge
at a synapse with a single post synaptic neurone. In temporal summation there is only one
presynaptic and one postsynaptic neurone but the frequency of impulses reaching the synapse is
important. Both types of summation allow for ‘grading’ of nervous response if the stimulation
affects too few presynaptic neurones or the frequency of stimulation is too low, the impulse is
not transmitted across the cleft (Qura, 2017).
They allow the ‘filtering out’ of continual unnecessary or unimportant background stimuli. If a
neurone is constantly stimulated (e.g. clothes touching the skin) the synapse will not be able to
renew its supply of transmitter fast enough to continue passing the impulse across the cleft. This
‘fatigue’ places un upper limit on the frequency of depolarisation.
Nodes of ranvier allow for action potential to quickly travel down the axon. Without these breaks
of myelin sheath, the action potential would not travel as quickly. These node of ranvier allow
electricity to be conducted within the cell's environment and the electrical signal will be
propagated down the axon (ScienceDirect, 2017).
References:
2020. https://www.quora.com/What-are-synapses-and-why-are-they-important.
2020. Study.Com. https://study.com/academy/answer/describe-what-is-happening-in-the-axonal-
membrane-as-an-action-potential-propagates-along-the-axon-relate-this-explanation-to-the-
graph-what-is-the-refractory-period-and-why-is-it-so-important-image.html.
2020. https://www.quora.com/What-are-synapses-and-why-are-they-important.
Lodish, Harvey, Arnold Berk, S Zipursky, Paul Matsudaira, David Baltimore, and James
Darnell. 2020. "Neurotransmitters, Synapses, And Impulse
Transmission". Ncbi.Nlm.Nih.Gov.
https://www.ncbi.nlm.nih.gov/books/NBK21521/#A6188.
Lodish, Harvey, Arnold Berk, S Zipursky, Paul Matsudaira, David Baltimore, and James
Darnell. 2020. "The Action Potential And Conduction Of Electric
Impulses". Ncbi.Nlm.Nih.Gov. https://www.ncbi.nlm.nih.gov/books/NBK21668/.
