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Nervous System
This category is for questions about the mechanical and chemical process of reactions to internal and external stimuli, ranging from the brain down to the spinal cord, and all nerves, cells and tissues in between.
3,047 Questions
Signs and symptoms of a major stroke?
Causes and symptoms Causes There are four main types of stroke. http://www.answers.com/topic/cerebral-thrombosis-in-medicine and http://www.answers.com/topic/cerebral-embolism are caused by blood http://www.answers.com/topic/clot that block an http://www.answers.com/topic/artery supplying the brain, either in the brain itself or in the neck. These account for 70-80% of all strokes. http://www.answers.com/topic/subarachnoid-hemorrhage and http://www.answers.com/topic/intracerebral-hemorrhage occur when a blood vessel bursts around or in the brain. Cerebral thrombosis occurs when a blood clot, or http://www.answers.com/topic/thrombus, forms within the brain itself, blocking the flow of blood through the affected vessel. Clots most often form due to "http://www.answers.com/topic/hardening" (atherosclerosis) of brain arteries. Cerebral thrombosis occurs most often at night or early in the morning. Cerebral thrombosis is often preceded by a http://www.answers.com/topic/transient-ischemic-attack (http://www.answers.com/topic/tia), sometimes called a "mini-stroke." In a TIA, blood flow is temporarily interrupted, causing short-lived stroke-like symptoms. Recognizing the occurrence of a TIA and seeking immediate treatment are important steps in stroke prevention. Cerebral embolism occurs when a blood clot from elsewhere in the http://www.answers.com/topic/circulatory-system breaks free. If it becomes lodged in an artery supplying the brain, either in the brain or in the neck, it can cause a stroke. The most common cause of cerebral http://www.answers.com/topic/embolism is http://www.answers.com/topic/atrial-fibrillation, a disorder of the http://www.answers.com/topic/heartbeat. In http://www.answers.com/topic/atrial fibrillation, the upper chambers (atria) of the heart beat http://www.answers.com/topic/weakly and rapidly, instead of slowly and steadily. Blood within the atria is not completely emptied. This stagnant blood may form clots within the atria, which can then break off and enter the circulation. Atrial fibrillation is a factor in about 15% of all strokes. The risk of a stroke from atrial http://www.answers.com/topic/fibrillation can be dramatically reduced with daily use of http://www.answers.com/topic/anticoagulant medication. Hemorrhage, or bleeding, occurs when a blood vessel breaks, either from trauma or excess internal pressure. The vessels most likely to break are those with preexisting defects such as an http://www.answers.com/topic/aneurysm. An aneurysm is a "pouching out" of a blood vessel caused by a weak http://www.answers.com/topic/arterial wall. Brain http://www.answers.com/topic/aneurysm are surprisingly common. According to http://www.answers.com/topic/autopsy studies, about 6% of all Americans have them. Aneurysms rarely cause symptoms until they burst. Aneurysms are most likely to burst when blood pressure is highest, and controlling blood pressure is an important preventive strategy. Intracerebral hemorrhage affects vessels within the brain itself, while subarachnoid http://www.answers.com/topic/hemorrhage affects arteries at the brain's surface, just below the protective arachnoid membrane. Intracerebral hemorrhages represent about 10% of all strokes, while subarachnoid hemorrhages account for about 7%. In addition to http://www.answers.com/topic/deprive affected tissues of blood supply, the accumulation of fluid within the http://www.answers.com/topic/inflexible skull creates excess pressure on brain tissue, which can quickly lead to death. Nonetheless, recovery may be more complete for a person who survives hemorrhage than for one who survives a clot, because the blood http://www.answers.com/topic/deprivation effects are usually not as severe. Death of brain cells triggers a chain reaction in which toxic chemicals created by cell death affect other nearby cells. This is one reason why prompt treatment can have such a dramatic effect on final recovery Causes and symptoms Causes There are four main types of stroke. http://www.answers.com/topic/cerebral-thrombosis-in-medicine and http://www.answers.com/topic/cerebral-embolism are caused by blood http://www.answers.com/topic/clot that block an http://www.answers.com/topic/artery supplying the brain, either in the brain itself or in the neck. These account for 70-80% of all strokes. http://www.answers.com/topic/subarachnoid-hemorrhage and http://www.answers.com/topic/intracerebral-hemorrhage occur when a blood vessel bursts around or in the brain. Cerebral thrombosis occurs when a blood clot, or http://www.answers.com/topic/thrombus, forms within the brain itself, blocking the flow of blood through the affected vessel. Clots most often form due to "http://www.answers.com/topic/hardening" (atherosclerosis) of brain arteries. Cerebral thrombosis occurs most often at night or early in the morning. Cerebral thrombosis is often preceded by a http://www.answers.com/topic/transient-ischemic-attack (http://www.answers.com/topic/tia), sometimes called a "mini-stroke." In a TIA, blood flow is temporarily interrupted, causing short-lived stroke-like symptoms. Recognizing the occurrence of a TIA and seeking immediate treatment are important steps in stroke prevention. Cerebral embolism occurs when a blood clot from elsewhere in the http://www.answers.com/topic/circulatory-system breaks free. If it becomes lodged in an artery supplying the brain, either in the brain or in the neck, it can cause a stroke. The most common cause of cerebral http://www.answers.com/topic/embolism is http://www.answers.com/topic/atrial-fibrillation, a disorder of the http://www.answers.com/topic/heartbeat. In http://www.answers.com/topic/atrial fibrillation, the upper chambers (atria) of the heart beat http://www.answers.com/topic/weakly and rapidly, instead of slowly and steadily. Blood within the atria is not completely emptied. This stagnant blood may form clots within the atria, which can then break off and enter the circulation. Atrial fibrillation is a factor in about 15% of all strokes. The risk of a stroke from atrial http://www.answers.com/topic/fibrillation can be dramatically reduced with daily use of http://www.answers.com/topic/anticoagulant medication. Hemorrhage, or bleeding, occurs when a blood vessel breaks, either from trauma or excess internal pressure. The vessels most likely to break are those with preexisting defects such as an http://www.answers.com/topic/aneurysm. An aneurysm is a "pouching out" of a blood vessel caused by a weak http://www.answers.com/topic/arterial wall. Brain http://www.answers.com/topic/aneurysm are surprisingly common. According to http://www.answers.com/topic/autopsy studies, about 6% of all Americans have them. Aneurysms rarely cause symptoms until they burst. Aneurysms are most likely to burst when blood pressure is highest, and controlling blood pressure is an important preventive strategy. Intracerebral hemorrhage affects vessels within the brain itself, while subarachnoid http://www.answers.com/topic/hemorrhage affects arteries at the brain's surface, just below the protective arachnoid membrane. Intracerebral hemorrhages represent about 10% of all strokes, while subarachnoid hemorrhages account for about 7%. In addition to http://www.answers.com/topic/deprive affected tissues of blood supply, the accumulation of fluid within the http://www.answers.com/topic/inflexible skull creates excess pressure on brain tissue, which can quickly lead to death. Nonetheless, recovery may be more complete for a person who survives hemorrhage than for one who survives a clot, because the blood http://www.answers.com/topic/deprivation effects are usually not as severe. Death of brain cells triggers a chain reaction in which toxic chemicals created by cell death affect other nearby cells. This is one reason why prompt treatment can have such a dramatic effect on final recovery
You could locate sites involved in transmitting a nerve impulse by finding the?
You could locate sites involved in transmitting a nerve impulse by finding the synapses. They are defined as a junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter.
What would happen if the neuron did not have a myelin sheath?
if neurons didn't have myelin sheath then the transmission of nerve impulses is slowed or stopped
What are the 2 main parts of pns?
The two main parts of the pns are the ,the sensory part and the motor part.
What is the number of neurons in nitrogen?
Nitrogen is an atomic element and does not have any 'neurons' because neurons are nerve cells.
I think you meant 'neutrons' :-
Nitrogen has an atomic mass of 14.00674 and an atomic number of 7. As the majority of mass in an atom is in the nucleus and as the atomic number represents the number of protons in the nucleus, the number of neutrons ROUGHLY = the atomic mass minus the atomic number. In other words Nitrogen would have 7 neutrons in its nucleus.
The fractional part of the atomic mass is because there are isotopes of nitrogen some with more or less neutrons than 7. In fact there are two stable isotopes of nitrogen: 14N and 15N the most common is 14N (99.634%).
What effects does the autonomic system have on the heart?
what effect does autonomic nervous system have on heart
How can sympathetic and parasympathetic fibers exert antagonistic effects?
Sympathetic fibers convey impulses that stimulate our "fight or flight" response. Parasympathetic are just the opposite, you might say they are for "rest and digest". They are both firing at the same time but depending on your environment and emotional state, one will dominate over the other.
Sympathetic and parasympathetic fibers release different neurotransmitters, which bind to different receptors. Three structures that receive sympathetic innervation are the adrenal glands, arrector pilli muscles, and sweat glands.
What type of word class is nervous?
"Nervous" is an adjective. It describes a state of anxiety or unease, often relating to feelings experienced in stressful situations. Adjectives like "nervous" modify nouns by providing more information about their qualities or characteristics.
What is composed of two parts central and peripheral?
The nervous system is composed of two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS includes the brain and spinal cord, which process and transmit information. The PNS consists of all the nerves that branch out from the CNS to the rest of the body, facilitating communication between the CNS and limbs or organs. Together, these two components coordinate bodily functions and responses to stimuli.
What is the site that is major determine peripheral resistance?
The major site that determines peripheral resistance is the arterioles. These small-diameter blood vessels can constrict or dilate to regulate blood flow and pressure throughout the circulatory system. Their ability to change diameter significantly influences total peripheral resistance, impacting overall cardiovascular function.
Also called visual purple rhodopsin is found in the retina of the eye within the phospholipid membrane of rod cells.
What keeps the neuron in working order and has specialized extensions that arise from it?
Myelin sheath
What is a table called with attached extensions sliding out from under each end?
The table can be called a drop leaf table, or a butterfly table. The table can be called a drop leaf table, or a butterfly table.
What are the stars you see before you blackout?
The light flashes or "stars" that you see right before blacking out, especially when you've hit (or been hit in) the back of the head are light impulses from the visual cortex (which is located in the occipital lobe).
What are the afferent and efferent fibers for Pretectal nucleus of the midbrain?
- It receives its afferent light impulses from the retina and occipital cortex.
- it gives efferents to the Edinger-Westphal nuclei of both sides.
What does the peripheral system do?
Peripheral System is a division of the Nervous System. They have 2 types of cells. The sensory nervous cells carry information to the central nervous system; and the motor nervous cells carry information from the central nervous system.
The Peripheral System is also divided into the somatic nervous system (controls the voluntary muscles) and the automatic nervous system (controls involuntary muscles).
