1.) Explain the changes in a neuron during an action potential? 2.) List the ste
ID: 3510248 • Letter: 1
Question
1.) Explain the changes in a neuron during an action potential?
2.) List the steps in chemical synaptic transmission
3.) List the types of neuroglia and their function
4.) Explain what happens to spinal cord tissue during injury
5.) List the differences between the sympathetic and parasympathetic nervous systems
6.) Explain how the cerebral cortex and subcortical structures interact to produce motor output
7.) Explain how the location of a stroke or traumatic brain injury can determine the symptoms
Explanation / Answer
1) During action potential:
Depolarization/Hyperpolarization: It is generally triggered by another nurone. Neurotransmitter is relesed from presynaptic nurone. This neurotransmitter binds to the post synaptic nurone and opens up various types of ion channel and alters cell membrane permeability. This can cause two types of response, either excitatory(depolarization) or inhibitory(hyperpolarization) depending on the nurone type. This depolarization or hyperpolarization then travel accross the axon hillock to axon. In axon terminal there are vesicle filled with neurotransmitter. The depolarization cause these vesicle to propagate to the axon terminal and eventually relses the nurotranmitter. Then those neurotransmitter helps to initiate action potential to next nurone.
If it is a motor nurone, then the relesed neutotransmitter can cause contract a muscle, can cause a gland to secret etc.
2. These are the steps in chemical synaptic transmission:
a) Nerotransmitter synthesis and storage at presynaptic neurone.
b) Release of neurotransmitters from presynaptic nurone.
c) Diffusion of the neurotransmitter through the synaptic cleft and then binds to receptor at post synaptic neurone and deliver the message to postsynaptic nurone.
d) Inactication of those neurotransmitter.
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3. Types of neuroglia:
A Macroglia
a) Astrocyte:
Main structural cell.
Acts as glycogen fuel buffer for brain .
Forms blood brain barrier.
Regulate electrical transmission inside brain.
b) Cilliated/ non cilliated Ependymal cell : Create and secrets cerebrospinal fluid.
c) Oligodendrocytes:Forms myelin sheath in central nervous system.
d) Radial cell:acts as neuro progenitor cells
e) Schwann cells: helps in myelination of neuroen in peripheral nervous sytem.
B. Microglia: Specialized macrophages helps in phagocytosis.
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4. During injury in spinal cord:
Haemorrhaginc necrosis of grey matter: First ischemic necrosis the reperfusion damage.
In white matter there is gliosis then demyelination of axon and ultimately axonal loss.
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5.
6. Cerebral cortex is where all the sensory information is processed and then after anlysis of the sensory signal, cerebral cortex sends effector message via motor neurone to the desire oragan. For example when a heated plate is touched by skin it sends signal to brain and then cerebral cortex sends message via motor nurone to the muscle under that skin to contract and withdraw the skin from hot surface.
7. Location of stroke or brain injury can determind the symptom because there is specific area in cerebral cortex for each sensory and motor action. Like broca's area ( area 44, 45 of brain, at iferior frontal gyrus) is language processing area. Injury in broca's area will impair the talking ability. Likewise, total injury in internal capsule will cause paraplegia because all motor fibres travel through internal capsule.
Parasympathetic nervous system Sympathetic nervous system Active at resting condition of human system Active when there is a stimulus, injury etc. Preganglionic nerve fibres are long Preganglionic nerve fibres are short. Constricts pupil. Dilates pupil Inhibit lacrimal secretion Increase lacrimal secretion Activates salivary gland and digestive system Inhibit Salivary gland and digestive system. Increase gut persitalsis Inhibit gut persitalsis. Contracts urinary bladder Relaxes Urinary bladder. Vasodilator Vasoconstrictor.Related Questions
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