What are the main neurotransmitters involved in sympathetic activity?
Key Terms
Name the four lobes of the cerebral cortex.
frontal parietal temporal occipital
What is the main function of the cerebral cortex?
It controls higher thought processes including language, memory, and consciousness. In terms of evolutionary time, the cerebral cortex arose more r...
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| Term | Definition |
|---|---|
What are the main neurotransmitters involved in sympathetic activity? | Epinephrine (commonly called adrenaline) and norephinephrine (commonly called noradrenaline) are the sympathetic neurotransmitters at the postganglionic synapse. While acetylcholine is released at the preganglionic synapse, it is not commonly tested in relation to the sympathetic system. |
When the sympathetic nervous system is activated, which hormone will be present at higher concentrations: insulin or glucagon? | glucagon The release of both glucagon and cortisol is correlated with sympathetic activity. Both hormones act to increase blood glucose levels, making energy more available for fight-or-flight activity. |
When the parasympathetic nervous system is activated, which hormone will be present at higher concentrations: insulin or glucagon? | insulin Insulin release from the beta islet cells of the pancreas can be directly promoted by parasympathetic stimulation. More importantly, simply remember that insulin is released after meals to promote the storage of glucose, while the parasympathetic system is also activated after eating to promote digestion. |
During the examination of a subject, it was found that the smooth muscle of her artery walls was temporarily dilated. Is this effect associated with sympathetic or parasympathetic activation? | Both To discern which division of the autonomic nervous system was active in this patient, we would need to know which artery walls are being described. Vasodilation of the arteries leading to the digestive system would imply parasympathetic activity, while dilation of the arteries that supply skeletal muscle is an effect of the sympathetic system. |
Name the four lobes of the cerebral cortex. | frontal parietal temporal occipital |
What is the main function of the cerebral cortex? | It controls higher thought processes including language, memory, and consciousness. In terms of evolutionary time, the cerebral cortex arose more recently than the cerebellum or brainstem. |
What is the main function of the cerebellum? | It controls balance, posture, and related movements. The cerebellum evolved before the cerebral cortex, but is more recent than the brainstem. |
What is the main function of the brainstem? | it maintains essential life processes such as breathing and heart rate. It also plays a homeostatic role through its promotion of thirst and hunger and maintenance of body temperature. The brainstem is simpler than, and evolved before, the cerebellum and the cerebral cortex. |
Name the three major parts of a neuron. | dendrites a cell body an axon Dendrites are branched structures that receive incoming signals. The cell body contains the nucleus and organelles. The axon is a projection along which the signal propagates away from the cell body. |
Which part of the neuron receives incoming signals from previous neurons in the form of neurotransmitter-containing vesicles? | dendrites A neuron releases neurotransmitters, held inside membrane-bound vesicles, into the synapse in a calcium-dependent process. These vesicles reach the dendrites of another cell and activate its receptors. |
Which part of the neuron contains the nucleus, as well as organelles like the endoplasmic reticulum and mitochondria? | the cell body | (or soma) The region of the cell body immediately next to the axon is called the axon hillock. Here, incoming signals are summed and create an action potential if they surpass a certain threshold. |
Which part of the neuron ends in a single terminal and can release neurotransmitters? | the axon These NTs can range from glutamate to acetylcholine, but all must be held in membrane-bound vesicles. Calcium influx promotes the fusion of these vesicles to the cell membrane, allowing their contents to be sent into the synapse. |
What is the axon hillock, and what function does it serve? | It is the region of the cell body situated immediately before the axon. Incoming signals from the dendrites meet here, are summed, and create an action potential if they are greater in magnitude than a certain threshold. |
How is myelin composed, and what is its function? | It is a white, lipid-based material that contains cholesterol and various proteins. It insulates the axon, allowing the action potential to propagate faster. Myelin is produced by glial cells in both the CNS and PNS. |
In the brain, what is the difference between white matter and gray matter? | White matter is mainly composed of myelinated axons, which give it its color. Regions associated with communication, like the thalamus, are made of white matter. Gray matter is mainly composed of the cell bodies of neurons and does not contain myelinated projections. Regions made of gray matter generally function in cognitive processes like language. About 60% of the brain's volume is white matter; the rest is gray matter. |
Define: glial cells | They are structural or support cells abundant in both the CNS and PNS. Unlike neurons, they do not transmit impulses, but perform a variety of other functions. Different types of glia can produce myelin, provide nutrients to other cells, and facilitate the maintenance of the blood-brain barrier. More glial cells are present in the brain than actual neurons. |
Name three types of glial cells that are present in the central nervous system. | Astrocytes Microglia Oligodendrocytes Astrocytes have a variety of roles, including detoxification, provision of nutrients, and recovery from injury. Microglia perform an immune function and act similar to macrophages. Oligodendrocytes produce myelin around the axons in the white matter. |
Oligodendrocytes produce myelin in the central nervous system. Which cells perform the same function in the peripheral nervous system? | Schwann cells make the myelin that wraps around the axons of the PNS. |
Which debilitating disease is the result of the deterioration of the myelin surrounding nerve cells in the central nervous system? | Multiple sclerosis | (MS) |
What structures does the unlabeled arrow point to in the figure below? | Two of the nodes of Ranvier. The myelin sheath insulates the axon, allowing nerve impulses to travel quickly. However, this insulation prevents Na+ and K+ ions from entering and exiting the cell. Nodes of Ranvier are gaps in the myelin where this ion exchange is free to occur. |