Describe the production of an Action Potential in a post-synaptic neuron and its production of an AP in a neuron. Compare the propagation of these AP's (from the trigger zone to the axon terminal) in myelinated and unmyelinated axon.

Answers

Answer 1

Answer and Explanation:

The function of neurons is to transmit nerve impulses. The transmission depends on the unequal distribution of ions in the interior and the exterior of the cell.

The cell interior has many negative ions –anions- and k+ ions that cannot get out of the cell, while the extracellular space has many Na+ and Cl- ions.  

The charge difference between the interior and the cell exterior is named resting potential difference, representing a non-exited state.  

When the neuron is stimulated, many changes in channel proteins occur that let the ions move through the membrane altering the resting-potential difference.

The central nervous system generates an action potential that travels to the target activating the calcium channels. Calcium triggers vesicles fusion to the presynaptic membrane releasing a neurotransmitter into the synaptic space. Once there, the molecule binds to its receptors on the postsynaptic membrane, causing ion channels to open. The activation of different receptors will cause a change in the postsynaptic membrane modifying the cell activity.  

Two types of receptors can be found the in te postsynaptic membrane:

Ion channel receptors -or ionotropic- that produce a fast change in the membrane potential when opening. But when the neurotransmitter disappears, the response does it too.   Metabotropic receptors that trigger a slow change in the membrane potential. They produce a slower response, but it lasts longer.  

Depending on the ion flow through the membrane channel receptors, the postsynaptic potential may be depolarizing - excitatory postsynaptic potential, EPP-, or hyperpolarizing - inhibitory postsynaptic potential, IPP-. For instance, the entrance of Na+ ion depolarizes de cell. But if K+ gets out of the cell, it produces hyperpolarization.  

Depolarizations or hyperpolarizations can be taken to other regions of the cell. The depolarizing or hyperpolarizing effect will gradually fade as it increases the distance from the potential change origin.  

Under physiological conditions, when the axon is stimulated occurs a depolarization. If the stimulus exceeds a threshold level, many sodium gates open simultaneously, and the action potential occurs, responsible for the nerve impulse transmission. Once Na+ channels get closed, K+ channels open. Ions traffic consists of the pass of sodium to the interior of the cell and potassium to the exterior. K+ follows a concentration gradient, while Na+ follows an electrochemical gradient.  

When the electrical stimulus is applied to the membrane of the axon it produces depolarization by activating the sodium voltage-dependent channels all along the axon. Depolarization propagates to inactivated regions adjacent to the membrane opening more sodium channels.  

There is a directly proportional relationship between the fiber diameter and the conduction velocity. The greater the diameter is, the faster the conduction is. Most axons contain a myelin sheath formed by the envelopment of the axon by glial cells. Myelin is fatty and isolates the axon, so in myelinic regions, there is no ion exchange. So to conduct the impulse, there must be regions without myelin. These regions are the Ranvier nodes, which have channels for ion interchange.  

The conduction speed increases in myelinated fibers because of the high concentrations of sodium channels in the Ranvier nodes. Mielinized fibers are thick, and their conduction velocities are very fast.


Related Questions

Questions for Activity 3: Making Molecular Models of Aerobic and Anaerobic Respiration

Text BoxDraw what you think the models of aerobic and anaerobic respiration would look like if you constructed them using models like in figures 3-6

Answers

kaka ddjzomssomx dmdxjsomdmsxk

Irineu vc não sabe nem eu

sksosmmsos!s s s s s. s sim cofmc. kc c. ocmc c. ximc.

heheheheheheheheheheeheheheeheh

sou toxic

toma trou xa deu mtos pontos atoa kakakakakaja

Explain osmosis using this image

Answers

Answer:

A liquid moving from an area of low concentration, to an area of high concentration through a semi-permiable membrane.

Explanation:

Hope this helps :)

The meaning of the term ionic bond

Answers

It is a type of bond that takes place between positively and negatively charged ions. Example on that is sodium chloride

Answer:

A type of Chemical Bonding that includes electrostatic attraction between opposite ions.

Explanation:

Ionic bonds are the attraction of two opposite ions.

An ion is an atom that has a net electric charge.

Equilibrium is when the concentration is the same throughout an entire system. Explain how a cell reaches equilibrium in all three types of solutions (hypertonic, hypotonic, and isotonic).

Answers

It is pertinent to understand what hypertonic, hypotonic, and isotonic solution means before setting out to explain how a cell reaches equilibrium in each type of solution.

A hypertonic solution is one whose solute concentration is higher than that of the sap of a cell that is immersed in it.A hypotonic solution is one with the same solute concentration as that of the sap of the cell immersed in it.An isotonic solution has a lower solute concentration than that of the sap of the cell immersed in it.

In biological systems, water molecules move by osmosis from the region of higher water potential or lower concentration of solutes to the region of lower water potential or higher concentration of solute. An equilibrium is reached when there is no net movement of water between two sides. Hence;

A cell placed in a hypertonic solution will lose water to the surrounding solution until an equilibrium is reached. This means that such a cell will end up shrinking (wilting) or even dying due to loss of water from the cell sap.A cell placed in a hypotonic solution will gain water from the surrounding solution until there is no net movement of water anymore. Such a cell might become turgid or even burst out its cell content.A cell placed in an isotonic solution will neither gain nor lose water because the cell sap and the surrounding solution have equal solute concentrations.

More about osmosis here: https://brainly.in/question/1213189

Answer:

A cell placed in a hypertonic solution will lose water to the surrounding solution until an equilibrium is reached. This means that such a cell will end up shrinking (wilting) or even dying due to loss of water from the cell sap.

A cell placed in a hypotonic solution will gain water from the surrounding solution until there is no net movement of water anymore. Such a cell might become turgid or even burst out its cell content.

A cell placed in an isotonic solution will neither gain nor lose water because the cell sap and the surrounding solution have equal solute concentrations.

Explain why your model improves upon the student’s original model. How would your model help someone who was learning about photosynthesis for the first time? Plato question

Answers

Answer:

Due to inclusion of more steps of photosynthesis.

Explanation:

My model is more advance than the student's original model which provides more information about the process of photosynthesis to the learners by explaining various parts of photosynthesis. My model presents the various steps of photosynthesis in a very efficient way with the help of including some extra parts. The student's original model is not more advance so it can't provides more information about the process of photosynthesis so that's why my model provides more information about photosynthesis.

Answer:

This model shows all the major molecules involved in the Calvin cycle and how they change at each stage of the process. This added detail would clarify that the Calvin cycle is a series of complex steps. The student’s original model didn’t show this breakdown at all, and it shows only the final products. This model also shows the number of each molecule created, which the original model doesn’t do.

When calcium carbonate is heated, it
decomposes into calcium oxide and carbon
dioxide. If 100 g of calcium carbonate are
decomposed, 56 g of calcium oxide is produced.
What would be the mass of the carbon dioxide
given off by the decomposition?
A. 448
B. 110 g
C. 156 g

Answers

Answer:

A. 44 g

Explanation:

First, you need to write a balanced equation:

CaCO₃ -> CaO + CO₂

Then, you need to find the molar mass of CaCO₃:

Ca = 40.078 amu

C = 12.0107 amu

3O = 47.9982 amu

_________________

100.0869 amu

Then, you calculate the moles of CaCO₃:

100 g ÷ 100.0869 amu = 0.9991 moles

In the balanced equation, we can see that the molar ratio of CaCO₃ and CO₂ is 1 : 1, so moles of CaCO₃ = moles of CO₂.

Now you need to find the molar mass of CO₂:

C = 12.0107 amu

2O = 31.9988 amu

________________

44.0095 amu

Finally, you can calculate the mass of CO₂ produced:

0.9991 moles * 44.0095 amu = 43.9698 g = 44 g

If eukaryotes all came about due to endosymbiosis, what would result from that?

Answers

your question isnt clear. but endosymbiosis means earlier bigger prokaryotes engulfed prokaryotes that carried out aerobic respiration(later became mitochondria) and other prokaryotes that carried out photosynthesis(later became chloroplasts). these “now” mitochondria and chloroplasts “realised” that they couldnt survive without the bigger prokaryotes that engulfed them hence they remained part of the larger prokaryotes. hope that explains it.

Endosymbiosis occurs when larger prokaryotes envelop prokaryotes that perform aerobic metabolism (later known as mitochondria) and prokaryotic cells that do photosynthesis.

These "now" mitochondrion's "came to realise" that they really can not live without the bigger prokaryotes that swallowed them, and therefore they stayed with them. 

Learn more:

https://brainly.com/question/15829977?referrer=searchResults

Question 4
What happens to the host cell at the end of the lytic cycle?
the cell breaks open and releases the new viruses
viral DNA combines with host DNA
the host cell divides normally and reproduces viral DNA along with it's own
new viruses are made inside the bacterial cell

Answers

Answer:

In the lytic cycle, a phage acts like a typical virus: it hijacks its host cell and uses the cell's resources to make lots of new phages, causing the cell to lyse (burst) and die in the process.

Explanation:

Hope this helps.

three types of transpiration​

Answers

Answer:

1) Stomatal Transpiration

2) Lenticular Transpiration

3) Cuticular Transpiration

OAmalOHopeO

hello anyone online

answer me​

Answers

No definitely not online

During starch test why is leaf boiled in ethanol?
A) to kill its Protoplasm
B) to soften it
C) to extract its chlorophyll
D) to retain its starch

Answers

Answer:

think its C cause when you boil it almost loses all its colour

Sometimes the most practical way to do an experiment is not to perform it in an animal, but to look at cell responses in culture. Cells from mice, humans, and other mammals have been used to establish cell culture lines that have been very important for research. You are studying a novel water-soluble mouse hormone. You know cell culture can be a practical model to reveal protein function, so you apply the hormone to yeast cells, but nothing happens. What is a likely explanation for why nothing happened in your experiment

Answers

Answer:

Yeast cells likely do not have receptors that bind to this specific water-soluble mouse hormone

Explanation:

Receptors are molecules capable of binding specific signaling molecules (i.e., ligands). For example, steroid receptors can only bind to specific steroid hormones (e.g. estrogen, progesterone). Plasma membrane receptors are protein receptors that bind to water-soluble ligands. These receptors are embedded in the cell plasma membrane and usually contain several transmembrane domains. Examples of cell membrane receptors include G protein-coupled receptors (GPCRs), enzyme-linked protein receptors and ion channel receptors.

Question 8 of 10
A biologist measures the allele frequencies of pea plants in a very controlled
environment. The plants can either have a dominant tall allele (7) or a
recessive short allele (t). Which of the following would be a reason that this
population is not at Hardy-Weinberg equilibrium?
O A. There are no mutations in the alleles for height.
B. Tall plants are more likely to survive.
O c. All of the pea plants reproduce exactly once.
O D. The pea flowers are pollinated at random.

Answers

Answer:

 C. Tall plants are more likely to survive (

Explanation:

Water pollution is an environmental factor due to rapid population growth.(True or False)?​

Answers

Answer:

False

Explanation:

Water pollution is caused by factory workers

Why is the sequence of amino acids important to the properties of a protein?

It provides structural support; the structure determines the function.
It retains and transmits important biological information.
It stores energy and provides covering to avoid water loss.
It stores energy and provides structural support for cells.

Answers

Answer:

it provides structural support, the structure determines the function

Answer:

it provides structural support, the structure determines the function

Explanation:

took the test and I got it right :) happy learning everyone

trong chương trình lớp 7 các em đã học các ngành động vật nào?

Answers

Answer:

what's this can u explain me in hindi pls

how is the cell membrane adapted to it's function

Answers

Cell membrane is made up of Lipid Bilayer which are fluid in nature , means they move continuosly , due to this fluid nature they are selectively permeable to compounds.

Which of the following statements is correct with respect to the photosynthetic pathway of grass or a cactus?

Answers

Answer:

Where are statement

Explanation:

Please tell

A child is suffering from fever but the doctor cannot immediately pinpoint the ailment on the basis of this one symptom. Explain why. Also mention another two such general symptoms.​

Answers

the child can also have sore and or maybe stomach problems. it can be indigestion

so there are various conditions one can go through and this may take time for a doctor to discover or bring to light the medical condition that the person I'd goin thru

Explanation:

please notify me if I'm incorrect

Does anyone know the answer for the question four?

Answers

Answer:

I think it's A

Explanation:

it is because the populations of trees are decreasing as deforestation continues, so there is less resistance to greenhouse gases. please correct me if I'm wrong

what is the term for female reproductive cell ?

Answers

Answer:

female reproductive call are called ova

Egg is the term for a female reproductive cell.

What is fermentation

Answers

Answer:

Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes.......I am sure this is helpful for you....And have you a great future.....study well plz....first you read your book.....

Harry is doing a research project on the movement of plants from the ocean to land. He leaned that plants evolved
vascular tissues, which enabled them to pull water from the ground and survive on land. Which is most likely
another adaptation that contributed to the success of land plants?

cell walls?
chloroplasts
waxy cuticle
gametes

Answers

Answer:

Waxy Cuticle

Explanation:

Waxy Cuticle retains water. It's the closest in terms of surviving on land. For instance, the plants living in water do not need waxy Cuticle to retain or maintain water. The plants on land requires waxy Cuticle because the temperature is hotter than in the water and they are at higher risk of loosing water during hot seasons and climate. waxy Cuticle aids in their water retention allowing them to adapt to live on land.

b) Describe two measures each to conserve natural vegetation and wildlife, Class 8 - Geography - Unit 1 betwen 90to100 words​

Answers

Answer:

Afforestation and national sanctuaries are two measures each to conserve natural vegetation and wildlife.

Explanation:

The natural vegetation and wildlife restoration is one of the main concerns that are essential for the development and growth of a country's biodiversity. Due to human land-use changes and migration of people, from one place to another with their cattle, lands are becoming deserted and grassland and forest land are declining.  

So, we need to plant more trees that act as the natural habitat for the wildlife and preserve and conserve them in parks and sanctuaries which will help reduce the impacts of global warming and climate change. We should not kill any animal.We should decrease the use of plastics.

diffrences between pine tree and mango tree​

Answers

well ones a pine tree, and ones a mango tree

Answer:

A:pine tree is also know as Christmas tree

Explanation:

B:mango tree is broad andextremly big

how does a classification key help identify an organism , help me please

Answers

Answer:

Classification keys are tools that provide a means to correctly identify different organisms, based on observable traits. A dichotomous key is a listing of specific characteristics, such as structure and behavior, in such a way that an organism can be identified through a process of elimination.

A _____ country has high population density.

A: Densley populated country
B: Sparsely populated country
C: Open country
D: Overpopulated country

Answers

Answer:

A. A Densley populated country.

Explanation:

The vertebrate digestive system consists of a two-way tube with
A. a separate mouth and anus and accessory organs.
B. a one-way tube with a separate mouth and anus and accessory organs.
C. a two-way tube with a separate mouth and anus.
D. a tube with a single opening that serves as mouth and anus.
E. a one-way tube with a separate mouth and anus and no accessory organs.

Answers

[tex]Hello![/tex]

It's option B.

I'm sure about that.

The vertebrate digestive system consists of a two-way tube with...[tex]ANSWER:[/tex]

B. A one-way tube with a separate mouth and anus and accessory organs.

Sheets composed of two layers of amphipathic molecules arranged with the hydrophilic groups on the surface and the hydrophobic groups buried in the center that form in water are called A) micelles. B) liposomes. C) vacuoles. D) bilayer membranes. E) none of the above

Answers

Answer:

D) bilayer membranes

Explanation:

Two lipidic bilayers compose the cell membrane. There are also proteins and glucans incrusted in between. Lipids are amphipathic molecules with hydrophilic heads -negatively charged phosphate group- and hydrophobic tails. Lipids are arranged with their hydrophilic polar heads facing the exterior and the interior of the cells, while their hydrophobic tails are against each other, constituting the internal part of the membrane. Membranes are fluid, which means that the composing molecules can move through them.

Lipids can easily change places with other neighboring lipids by lateral diffusion in the same layer. This is passive diffusion, which means that it does not need energy to happen.

Lipids can also diffuse transversally to the other layer but not as easily as lateral diffusion. Jumps between monolayers are infrequent as the lipidic polar heads meet the fatty acid barrier.

There are also other lipidic movements as rotational diffusion that imply the rotation of the molecule.  

Which of the following represents a tragedy of the commons?
Plastic trash in the neighborhood park
Two hospitals for the town's residents Trash pile in a person's backyard
Not enough fruit at a local market​

Answers

Tragedy is when a person feels distress due to some event or something. There can be various tragedies a person might face in his life.

In a persons life tragedy might represent an event which causes an unhappy feeling or emotional distress.

This also represent a situation which every one wants to avoid, no one welcomes a tragic event with happiness or joy.

The most annoying tragedy is a trash pile which is stinking in the backyard. A person will have to remove the pile so that the there is less pollution.

The correct answer is Trash pile in a person's backyard.

Learn more at https://brainly.com/question/24384533

Answer:

it is Plastic trash in the neighborhood park

Explanation:

tragity of the colloms means a problem in which every individual has an incentive to consume a shared resource, but at the expense of every other individual, depleting or spoiling the shared resource by their collective actions. SOO YEA SORRY ABT THAT OTHER GUY >:)

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