Discussion Post 1

Glial cells take care of neurons. Review the different types of glial cells by matching each description with the appropriate cell. You may use answers more than once. 1. Wrap around axons in the CNS:                                                                                              2. Wrap around axons in the PNS:   3. Regulate exchange of substances with capillaries and control interstitial space:   4. Surround, regulate, and protect cell bodies of neurons in the PNS:   5. Tiny macrophages that engulf unwanted substances and keep the CNS "clean":   6. Provide a supportive network:   7. Help produce cerebrospinal fluid at choroid plexus:

Match the neuron structure with its correct function or description. 1. Structure that receives stimuli and carries impulses to the cell body Grey matter 2. Part of the neuron that releases a chemical transmitter across the synapse + Myelin sheath 3. Cells that protect, nourish, and defend neurons + White matter 4. Structure that contains the neuron's nucleus and is the site of the neuron's cell metabolism : Synapse 5. The gap between two myelin sheaths that allows faster conduction of action potential 6. Lipid, fatty insulating layer around some axons that protects the neurons and speeds the impulses along the neuron + Dendrite 7. Unmyelinated neurons in the CNS + Axon 8. Structure that transmits impulses away from the cell body to another neuron, the muscles, or glands Axon terminal 9. Myelinated neurons in the CNS Cell body 10. The gap or junction between two neurons or between a neuron and a muscle Node of Ranvier * Glial cell

119 B. THE NEURON 1. The following roots and suffixes are used to name the various structures of the neuron. Match each root or suffix with its meaning: Dendrite → Axon-> • Body • Soma -> peel (covering) axis (line) Lemma -> • branch (like that of a tree) 2. Structure of a multipolar neuron. Label the following figure with the terms in the box below. Soma Nucleus axon hillock (trigger zone)

16. Neurons that process similar kinds of information are organized into what are called “neuron or neuronal pools.”Different ways of processing information occurs in these pools, depending on their function, and how they are organized. What are the two types of processing of information described below?___________________________________One neuron stimulates the next, which stimulates the next, and so on; the most clear cut example of this type of processing would be innate reflexes.___________________________________ This type of process can activate many pathways simultaneously, and is essential for high-level processes such as complex thinking and problem solving.

_5.Fill in interval.  Neurons in the ____________ in the _____________ respond best to the form and shape of complex images as opposed to single lines or dots.m

14) Review the process by which an action potential is conducted across a synapse. Suppose that in the future you become a researcher that is trying to cure a new neurological disorder. This disorder causes some post-synaptic neurons to fire action potentials to intrequently in response to the excitatory neurotransmitter dopamine. You want to design a medication that will target the cellular mechanisms that are causing this to happen at the synapse. List (no explanation required) four different things that vour medication could do at the synapse to increase the rate of firing of action potentials, *(Note that each different thing you list should produce an effect by targeting a different part of the process by which conduction of an action potential across a synapse is regulated).

3. List and describe the four types of neuroglial cells including function: 4. Describe the organization of a nerve including connective tissue coverings: 5. Describe continuous nerve conduction: 6. Describe saltatory nerve conduction: 7. Describe two events that occur at a synapse: 8. Define the following terms: a. resting membrane potential b. depolarization c. threshold d. action potential Laboratory 12 | Nervous System: Overview 281

5. all three parts are either: -55mV, +55mV, -70mV, +70mV, -95mV, or +30mV

3.) Signals are passed from axon to axon when neurotransmitter molecules are released from the presynaptic axon and diffuses across a small distance, called the synaptic cleft, to reach the post synaptic axon. If the neurotransmitter released by the presynaptic axon is dopamine and the diffusion distance across the synaptic cleft is 20 nm then how long will it take to pass the signal? The viscosity of the interstitial fluid in the synapse is 0.012 Pa*s. (You must look up dopamine properties to solve) Synapse Suiknce Facts aut Synaptic vesicle Voltage-gated Ca? /channel Presynaptic neuron Neurotransmitter molecules Synaptic cleft lon channel receptor Postsynaptic- neuron

7.

1. Make a model or draw 3 multipolar neurons. Imagine you had something crawling on your arm. The first is a sensory neuron, getting its information from the skin and sensing the movement.  The second is an interneuron. It relays information from the first (sensory neuron) to the CNS.  The third is a motor neuron. It begins in the CNS but leads all the way to the muscle, so that you can move the fingers and scratch the area. On your images/model the "dendrites" should be blue, "axon" should be green and "soma" should be yellow. As you connect them to each other, take notice in which areas are the receiving end, and which are the transmissive ends.

10) Looking at model 3, describe how an action potential is able to pass along a nerve 11) Describe what is happening electrically at points C,B, and A

None

6. If the action potentials shown in the diagram below occur sequentially and in close temporal proximity, what will be the final result in cell D? In this notation, < indicates an excitatory an inhibitory synapse. Focus on overall effects – excitation and inhibition – don't worry about quantifying responses here. (Hint: you may want to identify what is happening at each cell and then how that will be affected by the activation of the previous cell) synapse and indicates Above Above threshold stimulation Above threshold stimulation threshold stimulation D

4. From the list of terms that follow, please label the figure (at least once) below accordingly: ده 35 • Ca ● . ● ● Vesicle Presynaptic membrane postsynaptic membrane ● Synaptic cleft ● Na* ● Voltage-gated channel Ligand-gated channel Neurotransmitter - لها Now, explain in 2-5 sentences how the stimulus is transmitted to another cell.

1. Certain neurological diseases, like multiple sclerosis, are hallmarked by progressive demyelination of neurons. Following demyelination, the neurons are incapable of firing action potentials. Given what you understand about the role of myelin in action potential transduction, propose a mechanism for why there is a loss of action potentials in these demyelinated neurons.

5. Which one of the following responses is most likely to occur when the body temperature of a healthy human becomes too low? J An increase in the production of the hormone thyroxine, causing a decrease in the metabolic rate K A decrease in the production of the hormone thyroxine, causing a decrease in the metabolic rate L An increase in the blood flow to the skin surface, causing a decrease in the amount of heat loss. M A decrease in the blood flow to the skin surface, causing a decrease in the amount of heat loss.

2. Neurons use action potentials to send information down the axon to stimulate a release of a chemical message for synaptic signalling. (a) Define action potential: (b) What triggers an action potential to occur? (c) Describe the four key steps involved in the generation of an action potential. Complete the task using a graph with membrane potential (mV) on the y-axis and time (ms) on the x-axis. Start with what happens when the membrane potential reaches threshold. For each step, note which channels are opening and closing, the direction of flow of ions across the plasma membrane, and the membrane potential at which this occurs. 3. Both the nervous system and the endocrine system work in parallel to maintain homeostasis around the body. Complete the table below comparing the two systems: Feature Tissue type Signal Signal pathway Nervous system Endocrine System

Please note these are all one question group and should be answered as such!   Which of the following statements accurately defines epineurium?   A. Fluid-filled space at a synapse through which neurotransmitters diffuse   B. A vesicle containing neurotransmitters in the axon terminal of a neuron   C. The CT sheath that binds together the groups of fascicles, blood vessels, and lymphatic vessels in a peripheral nerve   D. The branch of the ANS that adapts the body for rest and digestion Which of the following statements accurately defines sacral plexus?   A. The ventral rami of C1–C4 (and a small contribution from C5) that serve the head and neck   B. The ventral rami of L1–L4 that serve the pelvis and lower limb   C. The ventral rami of C5–T1 that serve the upper limb   D. The ventral rami of L4–S4 that serve the pelvis and lower limb

~Multiple Sclerosis (MS) Multiple sclerosis is a neurodegenerative disease in which the body's immune system attacks and breaks down the white matter in the nervous system. 1. What is another word (other than "white matter") for the structure or type of cells that are affected in patients with MS? 2. Given what these cells/ structures do, what effect on neural transmission do you think MS has? ~ Some common symptoms of MS are vision problems, dizziness and vertigo, and difficulty walking. 1. How are these symptoms a result of the effect on neural transmission you described above? 2. List which brain regions are likely impacted in each of the three symptoms described above.

Consider the image.  The neuron labeled number _____ in the figure is a motor neuron; its function is _____. A)2; stimulating muscles or glands B)3; stimulating muscles or glands C)1; connecting different types of neurons D)3; connecting different types of neurons

Describe two properties of neurons. Compare the NMJ with the normal synapse including two differences and two similarities (please try to be super specific).

Draw 3 diagrams of the 3 types of neurons (bipolar, multipolar, unipolar)For unipolar, use the terms central projection and peripheral projectionLabel the parts of the neuron for each neuron type (dendrite, axon, cell body, myelin, axon terminal)Do not use images from the internet.

6. Define white and gray matter and list what parts of a neuron are located in each. Discuss what activities occur in each.

2. 3. 4. Describe the major divisions and subdivisions of the nervous system. Identify the following parts on an image of a drawing or model of a neuron: Dendrite Schwann cell Myelin sheath Soma (cell body) Nucleus Node of Ranvier (myelin sheath gap) Axon terminals Axon hillock Axon Identify the following structures on a histological image of a multipolar neuron, longitudinal section of myelinated axons, and cross-section of an axon. Not all structures are present on every histological image. Dendrites Soma (cell body) Axon Axon hillock Schwann cell Myelin sheath Multipolar neuron Nucleolus Nucleus Node of Ranvier Myelinated axon Unmyelinated axon

Multiple sclerosis is a demyelinating disease affecting the central nervous system. What type of cell would be the most likely target of this disease? Why? Which type of neuron, based on its shape, is best suited for relaying information directly from one neuron to another? Explain why. Sensory fibers, or pathways, are referred to as “afferent.” Motor fibers, or pathways, are referred to as “efferent.” What can you infer about the meaning of these two terms (afferent and efferent) in a structural or anatomical context?

1. What would occur if there were holes in the myelin of a nerve cell that were not nodes?  If there was a disease of the cerebrospinal fluid which cells would be effected first? Which cells would respond? Acetylcholine is a well-known neurotransmitter at the neuromuscular junction (excitatory) and cardiac muscle (inhibitory). Explain how this works, and why this is interesting and useful?

8. Label the following diagram with the terms: sensory neuron, sensory receptor, interneuron, motor neuron, effector, axon, dendrite, cell body, Schwann cell, node of Ranvier. Note that some terms may be used more than once. The 3 main types of Neurons

1.show that the Mcculloch_Pitts formal model of a neuron may be approximated by a sigmoidal neuron(I. ا, neuron using a sigmoid activation function with large synaptic weights 2.Show that a linear neuron may be approximated by a sigmoidal neuron with small synaptic weights.

1. The graph above represent time in milliseconds.  At what time (in milliseconds) is the inside of the neuron the most positive and why? 2. Explain why the membrane potential changes at X 3. Explain what is happening at point C to the sodium and potassium ions and how this is affecting the membrane potential 4. Describe two things that contribute to the resting membrane potential

F B D Match the labelled synapse structure with the correct structure or function. Place the correct number in each blank. Use each letter only once. • Synaptic vesicle containing the neurotransmitters Postsynaptic membrane of the dendrite • Synaptic cleft Receptor site for the neurotransmitter on the dendrite Axon terminal Mitochondria, which supply ATP for synthesis of transmitters