DPBioY2 - 2020 - 6.5 Neurones and synapses
DPBioY2 - 2020 - 6.5 Neurones and synapses
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DPBioY2 - 2020 - 9.3 Plant Growth
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1. What is different concerning the composition of sensory vs motor neurons?
ReplyDelete2. What parts of the brain controls stimulation of neurons?
3. What cytokines/proteins/hormones are released as stimuli to cause depolarization?
1. In regards to function,
Delete"The cell body of the motor neuron is located in the ventral root ganglion of the spinal cord and consists of dendrites. Cell body of the sensory neuron is situated in the dorsal root ganglion of the spinal cord and no dendrites are found in it. Motor neurons are multipolar whereas sensory neurons are unipolar. Motor neuron has efferent fiber whereas sensory neuron has afferent fiber. Motor neuron consists of many short dendrons whereas sensory neuron consists of one long dendron. Motor neurons do not have a receptor whereas sensory neurons have a receptor. Motor neurons consist of a long axon whereas sensory neuron consists of a short axon."
Efferent fiber is carrying impulses away from the CNS.
Afferent fiber is carrying impulses towards the CNS.
https://vivadifferences.com/structural-and-functional-difference-between-sensory-and-motor-neuron/#:~:text=Motor%20neurons%20do%20not%20have,but%20receive%20from%20sensory%20neurons.
To answer your 2nd question the frontal lobes hold various functions, one of them being motor skills. The specific area that is responsible for movement in parts of the body is mainly the motor cortex or precentral gyrus. The prefrontal cortex plays is important in memory, concentration, intelligence, temper, and personality. The premotor cortex guides eye and head movements and sense of orientation.
DeleteHere is a link with more information about other parts of the brain and what they control
https://www.aans.org/en/Patients/Neurosurgical-Conditions-and-Treatments/Anatomy-of-the-Brain#:~:text=The%20frontal%20lobes%20are%20the,motor%20cortex%20or%20precentral%20gyrus.
In regards to your third question, I couldn’t find information clearly regarding certain hormones. However, the stimulus itself can be any number of things: light, chemical, sensory, etc.
Delete1. What is saltatory conduction?
ReplyDelete2. Why does k+ leak out the axon membrane faster than Na+?
3. What is the refractive period?
4. How do neurons contact each other?
To answer your first question saltatory conduction describes how electrical impulses jump from node to node, down the axon, quickening the arrival of the impulse at the terminal of the nerve
Deletehttps://www.sciencedirect.com/topics/veterinary-science-and-veterinary-medicine/saltatory-conduction#:~:text=Saltatory%20conduction%20describes%20the%20way,spreading%20down%20an%20unmyelinated%20axon.
4. Neurons are cells which can contact other neurons or the target effector cells via a process known as Synapses. A synapse is a structure which permits the neuron to transmit electrical or chemical signalling to another neuron. The presynaptic region typically refers to the axon or the axial terminal while the post synpatic region refers to the dendrite or soma of the target effector cell. During Synapses, the presynaptic neuron comes into close contact with the membrane of the postynaptic cell. Both of these cells have complex machinary that link the two membranes together and undergo chemical/electrical signalling with various binding techniques. I'm sure we will cover the rest of this part in class, but this is just my understanding of it.
DeleteTo answer your third question,
DeleteThe refractory period is the stage that follows neuron re polarization. After the nueron is repolarized, the opening of the potassium pumps leads to a -80mV intracellular charge. This is not the appropriate concentration gradients that facilitate proper polarization As a result, the sodium potassium pump is activated and pushes 3 NA+ out and 2 K+ in to restore the concentration gradient of a -70mV intracellular charge. This effectively sets up the neuron back to its resting potential where it has the ability to fire again.
To answer your second question, the potassium leaks out of the cell membrane a lot faster because the cell membrane is more permeable to the K+ Ions.
DeleteHere is the source I used:
https://courses.lumenlearning.com/boundless-biology/chapter/how-neurons-communicate/#:~:text=The%20negative%20charge%20within%20the,%2B%20movement%20than%20Na%2B%20movement.&text=Therefore%2C%20potassium%20diffuses%20out%20of,rate%20than%20sodium%20leaks%20in.
1. Do all animals have myelinated nerve fibers?
ReplyDelete2. What equipment do scientist use to stimulate neurons? And how does it work?
3. What are the different types of neurons and how do they differ from one another?
4. What is the role of acetylcholine?
4. Acetylcholine is a neurotransmitter and is an effector of the automatic nervous system. ACH is released into the synaptic cleft between 2 neurons. It regulates long-term and working memory.
Deletehttps://www.news-medical.net/health/What-is-Acetylcholine.aspx
3. There are 4 different types of neurons: neurons in the brain, sensory neurons, motor neurons, interneurons.
DeleteMotor neurons are multipolar, sensory neurons are unipolar, interneurons are multipolar. Motor neuron has efferent fiber whereas sensory neuron has afferent fiber. Motor neuron consists of many short dendrons whereas sensory neuron consists of one long dendron. Motor neurons do not have a receptors, sensory neurons do. Motor neurons consist of a long axon, sensory neurons consist of a short axon. Motor neurons either travel from spinal cord to muscle or brain to spinal cord. Sensory neurons respond to physical and chemical inputs, then interact with the central nervous system. Interneurons just connect spinal motor and sensory neurons.
https://qbi.uq.edu.au/brain/brain-anatomy/types-neurons
To try to answer your first question, The myelin sheath was a transformative vertebrate acquisition, enabling great increases in impulse propagation velocity along axons. Not all vertebrates possess myelinated axons, however, and when myelin first appeared in the vertebrate lineage is an important open question.
Delete2. Deep brain stimulation involves implanting an electrode deep within your brain. The amount of stimulation delivered by the electrode is controlled by a pacemaker-like device. it is placed on their chests A wire that travels under your skin connects the device to the electrode.
Deletehttps://www.mayoclinic.org/tests-procedures/deep-brain-stimulation/about/pac-20384562#:~:text=Deep%20brain%20stimulation%20involves%20implanting%20an%20electrode%20deep%20within%20your,the%20device%20to%20the%20electrode.
1) What connects sensory neurons to motor neurons?
ReplyDelete2) Can neurons regenerate? and How do you repair damaged neurons?
3) Why is Saltatory conduction faster than continuous conduction? and What is the benefit of Saltatory conduction?
To answer your 1st question sensory neurons and motor neurons are connected by interneurons, they are able to communicate with one another creating circuits of different complexity. They are also multipolar like motor neurons.
Deletehttps://qbi.uq.edu.au/brain/brain-anatomy/types-neurons
To answer your third question, the saltatory conduction is faster because the axon has the myelin wrapped around it so it is able to travel farther with the stable charge and concentration in the axon. However once it hits the Node of Ranvier, the concentrations and charges have to switch again. The benefit of the saltatory conduction is they can have nerve impulses faster and can travel more rapidly throughout the axon.
DeleteHere is a resource to help: https://faculty.washington.edu/chudler/salt.html#:~:text=Electrical%20signals%20travel%20faster%20in%20axons%20that%20are%20insulated%20with%20myelin.&text=Action%20potentials%20traveling%20down%20the,in%20an%20axon%20without%20myelin.
For your second question,
DeleteYes, in healthy adults, neurons can regenerate through the process of neurogenisis. However, as we age, the speed at which neurogenisis occurs begins to slow down. This is thought to be associated with many mental disorders such as Alzheimer, etc. Currently, researchers are identifying stimuli that could prevent this breakdown of neurogensis and lead to improved cognitive ability as we age.
1. Can some give and explain the definition of synapses?
ReplyDelete2. What happens to Neurons and synapses when someone has nerve damage?
3. Which part of the human body contains the most amount of nerves?
To answer your first question, In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell. .
Delete3. The lips, tongue, and fingertips contain the most nerve endings and are the most touch-sensitive in the body.
Deletehttps://pages.jh.edu/jhumag/495web/touch.html
In regards to your second question, nerve damage can make it difficult to control muscles and can cause weakness. Here is a resource I found regarding your question: https://medlineplus.gov/ency/article/000593.htm
DeleteTo answer your second question, An injury to a neuron can stop the signals transmitted to and from the brain, causing muscles to not work properly or a loss of feeling in an injured area. Nerve injuries can impact the brain, the spinal cord, and peripheral nerves.
ReplyDelete1. How are neurotransmitters broken down / reduced?
ReplyDelete2. What do vesicles form from inside of the axon?
3. What are some ways to increase calcium ion concentrations in the body?
4. When a nerve dies or the cycle reaches the ending of the body, what happens to the remaining energy?
To answer your second question, the vesicles in the axon hold the neurotransmitters and the vesicles form from the cell body where the Golgi apparatus is located. They then move to the pre-synaptic cell through the cytoplasm.
DeleteHere is the source I used: https://psych.athabascau.ca/html/Psych402/Biotutorials/11/a6.shtml#:~:text=Small%20vesicles%20are%20produced%20by,Small%20vesicles%20store%20neurotransmitters.&text=Calcium%20ions%20are%20also%20essential,neurotransmitters%20into%20the%20synaptic%20cleft.
to answer the first question, there are three ways: (1) destruction of the neurotransmitter by degradative enzymes; (2) diffusion of the neurotransmitter away from the post-synaptic receptors; and (3) reuptake of the neurotransmitter either by the pre-synaptic terminal or by other cells.
Deletehttps://www.sciencedirect.com/topics/medicine-and-dentistry/neurotransmitter#:~:text=7%2C%20there%20are%20three%20general,terminal%20or%20by%20other%20cells.
To answer your 4th question,
DeleteMacrophages eat dying neurons in order to clear the debris. I am assuming that the energy is just engulfed by the macrophages or dissolves in the synapse.
https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Life-and-Death-Neuron#Death
In regards to your third question, eat calcium and vitamin D rich food! Here is a resource explaining it more in depth: https://www.nursingtimes.net/roles/nurse-educators/maintaining-calcium-balance-physiology-and-implications-10-05-2005/
Delete1. What type of enzymes break down neurotransmitters?
ReplyDelete2. How many nerves are in the body and which are the most sensitive?
3. why does neurogenisis slow down and cause Alzheimers? which part of the brain is affected the most/quickest?
To answer your 1st question,
Deleteenzyme acetylcholinesterase breaks down neurotransmitters.
http://charlesfrye.github.io/FoundationalNeuroscience//28/#:~:text=Neurotransmitters%20can%20also%20be%20broken,the%20enzyme%20acetylcholinesterase%20(AChE).
For your second question,
DeleteThere are more than seven trillion nerves and the most sensitive in the context of pain is the trigeminal nerve which is located in the cranial nerve system.
https://www.northeastspineandsports.com/important-nerves-in-the-body-and-what-they-do/
https://www.theguardian.com/lifeandstyle/2011/oct/17/mapping-the-body-trigeminal-nerve
1. What exactly ~is~ a neurotransmitter?
ReplyDelete2. How are neurotransmitters created from action potential?
3. Can nerve damage be fixed/reversed and how?
For your first question,
DeleteNeurotransmitters are a molecule known as a "chemical messenger". They are typically in the amine group in the context of amino acids or peptides.
https://qbi.uq.edu.au/brain/brain-physiology/what-are-neurotransmitters
For your second question,
DeleteFrom what I can understand, neurotransmitters aren't made from action potential, but actually they instead cause action potential. The neurons make a neurotransmitter and when stimulated, they release the neurotransmitters down the axon and thus they begin the depolarization process which creates action potential.
https://faculty.washington.edu/chudler/chnt1.html
What about calcium makes synapses possible?
ReplyDeleteWhat is a full summary of the process of a nerve impulse journey?
How were neurons discovered?
To answer your 3rd question,
Delete"When the leading anatomists of the 19th century examined fragile nervous tissue with the best microscopes available to them, they identified cell bodies that sprouted many tangled projections. German histologist Joseph Gerlach's observations convinced him that the fibers emerging from different cell bodies fused to form a continuous network, a seamless web known as the "reticulum." His ideas were popular. Many researchers accepted that, unlike the heart or liver, the brain and nervous system could not be split up into distinct structural units."
"In 1873, Italian physician Camillo Golgi discovered a chemical reaction that allowed him to examine nervous tissue in much greater detail than ever before. For some reason, hardening a piece of brain in potassium dichromate, and subsequently dousing it with silver nitrate, dyed only a few cell bodies and their respective projections in the tissue sample, revealing their complete structures and exact arrangement within the unstained tissue. If the reaction had stained all the neurons in a sample, Golgi would have been left with an unfathomable black blotch, as though someone had spilled a bottle of ink. Instead, his technique yielded neat black silhouettes against a translucent yellow background."
"Golgi's "black reaction," combined with the painstaking work of Karl Deiters and others, clearly distinguished two kinds of projections from cell bodies in nervous tissue: a long slender cable that did not seem to branch much and a cluster of shorter branching fibers."
"Fourteen years later, in 1887, Spanish neuroanatomist Santiago Ramón y Cajal learned about Golgi's black reaction from psychiatrist Luis Simarro Lacabra, who had managed to improve Golgi's original technique. Cajal, who was already obsessed with studying the structures of living tissues in minute detail, immediately recognized the black reaction as the most sophisticated way to investigate the nervous system and puzzled at why so few scientists apart from Golgi himself had tried out the staining procedure. Cajal further improved the black reaction and applied the technique to all kinds of nervous tissue from different animals and from people, producing beautiful and detailed sketches of what he saw under the microscope—drawings that scientists and educators still rely on today."
https://blogs.scientificamerican.com/brainwaves/know-your-neurons-the-discovery-and-naming-of-the-neuron/#:~:text=In%201891%20German%20anatomist%20Wilhelm,discrete%20cells%2C%20which%20Waldeyer%20dubbed
1. What factors would compromise the health of a neuron?
ReplyDelete2. What happens when someone is potassium deficient, in terms of neuron function?
3. What initiates the electrical signal which activates depolarization?
3. the stimulus of a neuron occurs when ion channels embedded in the membrane open and close. The opening of channels let positive ions flow into the cell which can start depolarization.
Deletehttps://www.khanacademy.org/science/biology/human-biology/neuron-nervous-system/a/depolarization-hyperpolarization-and-action-potentials#:~:text=Depolarization%20and%20hyperpolarization%20occur%20when,enter%20or%20exit%20the%20cell.&text=into%20the%20cell.-,The%20opening%20of%20channels%20that%20let%20positive%20ions,the%20cell%20can%20cause%20depolarization.
2. In a person with low potassium, the potassium channels stay open a bit longer than usual to allow positive ions to exit through the neuron. This will then cause the cell to temporarily hyperpolarize meaning that it gets even more negative than at its resting state.
Deletehttps://www.khanacademy.org/test-prep/mcat/organ-systems/neuron-membrane-potentials/a/neuron-action-potentials-the-creation-of-a-brain-signal