What is the underlying pathologic mechanism associated with autonomic Hyperreflexia?
Autonomic dysreflexia (AD) is a serious cardiovascular disorder in patients with spinal cord injury (SCI). The primary underlying cause of AD is loss of supraspinal control over sympathetic preganglionic neurons (SPNs) caudal to the injury, which renders the SPNs hyper-responsive to stimulation.
Which pathophysiologic process causes the development of sensory and motor symptoms in multiple sclerosis?
Myelin damage and the nervous system
In multiple sclerosis, the protective coating on nerve fibers (myelin) in the central nervous system is damaged. This creates a lesion that, depending on the location in the central nervous system, may cause symptoms such as numbness, pain or tingling in parts of the body.
What is the main source of bleeding when considering subdural hematomas?
In a subdural hematoma, the blood seeps between the dura and the arachnoid layers. It collects inside the brain’s tough outer lining. This bleeding often comes from a blood vessel that breaks within the space around the brain. This most often happens because of a head injury.
What is the most common source of community acquired life threatening meningitis?
Viral infections are the most common cause of meningitis, followed by bacterial infections and, rarely, fungal and parasitic infections. Because bacterial infections can be life-threatening, identifying the cause is essential.
How do autonomic reflexes help maintain homeostasis quizlet?
The autonomic nervous system helps maintain homeostasis through the involuntary activity of autonomic reflexes. these reflexes enable the ANS to control visceral function: smoother muscle contractions ( or relaxation), cardiac muscle contractions, or stimulation of inhibition of secretion by glands.
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What is the effect of the autonomic nervous system on the heart?
THE AUTONOMIC NERVOUS SYSTEM AND THE HEART
The sympathetic nervous system (SNS) has a wide variety of cardiovascular effects, including heart-rate acceleration, increased cardiac contractility, reduced venous capacitance, and peripheral vasoconstriction.
What happens to myelin in multiple sclerosis?
What happens to myelin in MS? In MS, immune cells enter the brain and spinal cord and attack both the myelin and the cells that make it. When myelin becomes damaged, messages find it harder to get through – or can’t get through at all. That’s what causes the symptoms of MS.
What happens to the myelin sheath and how it disrupts nerve function in patients with multiple sclerosis?
Multiple sclerosis
In this disorder, your immune system attacks the myelin sheath or the cells that produce and maintain it. This causes inflammation and injury to the sheath and ultimately to the nerve fibers that it surrounds. The process can result in multiple areas of scarring (sclerosis).
What causes multiple sclerosis Pubmed?
The precise cause of MS is unknown. Nonetheless, genetic predispositions combined with environmental influences play an important role in the pathogenesis of this disease. The therapeutic effects of several agents including immunomodulating and anti-inflammatory drugs in MS have been studied.
Why is a patient with a subdural hemorrhage likely to lose consciousness?
The bleeding is under the skull and outside the brain, not in the brain itself. As blood pools, however, it puts more pressure on the brain. The pressure on the brain causes symptoms. If pressure inside the skull rises to a very high level, a subdural hematoma can lead to unconsciousness and death.
What causes SDH?
SDH’s are most often caused by sudden impacts shaking the skull. Sudden shifting of the brain within the skull (rattling around like a tennis ball in a can) can tear the small blood vessels that bridge between the skull and brain.
Which type of subdural hematoma progress rapidly and carry a high mortality?
Acute subdural hematoma (SDH) occurs most often after head injury and, despite rapid diagnosis and aggressive neurosurgical intervention, can result in high morbidity and mortality.
What are the precautions for meningitis?
Meningococcal meningitis patients should be placed on droplet precautions (private room, mask for all entering the room) until they have completed 24 hours of appropriate antibiotic therapy. Negative pressure ventilation is not required. Patients with pneumococcal or viral meningitis do not require isolation.
What are the most common causes of bacterial meningitis and the corresponding age groups most commonly affected?
Some causes of bacterial meningitis are more likely to affect certain age groups:
- Newborns: Group B Streptococcus, S. pneumoniae, L. monocytogenes, E. coli.
- Babies and young children: S. pneumoniae, N. meningitidis, H. …
- Teens and young adults: N. meningitidis, S. pneumoniae.
- Older adults: S. pneumoniae, N. meningitidis, H.
What is autonomic dysreflexia ATI?
Autonomic dysreflexia is a syndrome in which there is a sudden onset of excessively high blood pressure. It is more common in people with spinal cord injuries that involve the thoracic nerves of the spine or above (T6 or above).
How do reflexes contribute to homeostasis?
Reflexes are automatic, subconscious response to changes within or outside the body. a. Reflexes maintain homeostasis (autonomic reflexes) – heart rate, breathing rate, blood pressure, and digestion.
Which part of the autonomic nervous system helps maintain homeostasis?
Sympathetic Responses. The sympathetic division of the autonomic nervous system maintains internal organ homeostasis and initiates the stress response.
Which is a response of the autonomic nervous system that helps maintain equilibrium in the body?
The parasympathetic division of the autonomic nervous system helps maintain normal body functions and conserves physical resources. This division also performs such tasks as controlling the bladder, slowing down heart rate, and constricting eye pupils.
How does sympathetic stimulation increase the heart rate?
Sympathetic stimulation causes the release of the neurotransmitter norepinephrine (NE) at the neuromuscular junction of the cardiac nerves. NE shortens the repolarization period, thus speeding the rate of depolarization and contraction, which results in an increase in HR.
What effects autonomic system?
The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions, such as the heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal.
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| Autonomic nervous system | |
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| FMA | 9905 |
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How does the autonomic nervous system influenced the rate rate at which the SA node generates impulses?
To increase heart rate, the autonomic nervous system increases sympathetic outflow to the SA node, with concurrent inhibition of vagal tone. Inhibition of vagal tone is necessary for the sympathetic nerves to increase heart rate because vagal influences inhibit the action of sympathetic nerve activity at the SA node.
Which activities of the body are controlled by the autonomic nervous system?
The autonomic nervous system controls internal body processes such as the following:
- Blood pressure.
- Heart and breathing rates.
- Body temperature.
- Digestion.
- Metabolism (thus affecting body weight)
- The balance of water. …
- The production of body fluids (saliva, sweat, and tears)
- Urination.
What happens to action potential When myelin is damaged?
The main function of myelin is to protect and insulate these axons and enhance the transmission of electrical impulses. If myelin is damaged, the transmission of these impulses is slowed down, which is seen in severe neurological conditions such as multiple sclerosis (MS).
How does MS affect the action potential?
In MS, the loss of myelin produces failure of axonal action-potential conduction that is associated with clinical exacerbations, but axonal conduction can recover as a result of expression of new sodium channels along demyelinated axons, providing a substrate for remission of clinical deficits (5).
What happens to myelin during remission and exacerbations?
The inflammation damages the myelin, slowing or disrupting the transmission of nerve impulses and causing the symptoms of MS. In the most common disease course in MS — called relapsing-remitting MS — clearly defined acute exacerbations are followed by remissions as the inflammatory process gradually comes to an end.
How does myelin affect the transmission of nerve impulses?
Myelin can greatly increase the speed of electrical impulses in neurons because it insulates the axon and assembles voltage-gated sodium channel clusters at discrete nodes along its length. Myelin damage causes several neurological diseases, such as multiple sclerosis.
Which mechanism allows the rabies virus to gain access to the central nervous system CNS )?
The highly neurotropic rabies virus (RABV) enters peripheral neurons at axon termini and requires long distance axonal transport and trans-synaptic spread between neurons for the infection of the central nervous system (CNS).
What do scientists hypothesize to be the causes of MS?
The cause of multiple sclerosis is unknown. It’s considered an autoimmune disease in which the body’s immune system attacks its own tissues. In the case of MS , this immune system malfunction destroys the fatty substance that coats and protects nerve fibers in the brain and spinal cord (myelin).
What does multiple sclerosis affect?
Multiple sclerosis (MS) is a chronic disease affecting the central nervous system (the brain and spinal cord). MS occurs when the immune system attacks nerve fibers and myelin sheathing (a fatty substance which surrounds/insulates healthy nerve fibers) in the brain and spinal cord.
Which of the following symptoms frequently occurs early in MS?
1. Vision Loss. One of the most common early signs of multiple sclerosis is vision loss. While there are many conditions that may cause vision problems, this symptom of MS is marked by pain and vision loss in only one eye.
What happens when you have a brain bleed from a fall?
This occurs when blood vessels — usually veins — rupture between your brain and the outermost of three membrane layers that cover your brain (dura mater). The leaking blood forms a hematoma that presses on the brain tissue. An enlarging hematoma can cause gradual loss of consciousness and possibly death.
What is the difference between subdural hematoma and subdural hemorrhage?
A subdural hematoma occurs when a blood vessel near the surface of the brain bursts. Blood builds up between the brain and the brain’s tough outer lining. The condition is also called a subdural hemorrhage. In a subdural hematoma, blood collects immediately beneath the dura mater.
Can a subdural hematoma cause a stroke?
However, a subdural hemorrhage can become large enough to push against the brain, causing significant neurological symptoms. If a subdural hemorrhage involves significant amounts of blood, it can cause a stroke, due to the pressure.
Can high blood pressure cause a hematoma?
The occurrence of acute spontaneous subdural hematoma (SDH) as a neurological end-organ damage complicating hypertensive crisis is rare and should receive tight blood-pressure lowering to prevent further bleeding.
What can you do for a hematoma?
To manage a hematoma under the skin, nail, or other soft tissue, a person should rest the injured area and apply an ice pack wrapped in a towel to reduce any pain or swelling. It may help to wrap or splint the area around the hematoma to keep the blood vessel from reopening as it heals.
What causes bilateral subdural hematoma?
The most common cause for a subdural hematoma is head injury. This can be from a car crash, fall, or violent attack. This sudden impact can strain the blood vessels within the dura, causing them to rip and bleed. Sometimes small arteries also break within the subdural space.
How does subdural hematoma cause death?
A subdural hematoma is most often the result of a severe head injury. This type of subdural hematoma is among the deadliest of all head injuries. The bleeding fills the brain area very rapidly, compressing brain tissue. This often results in brain injury and may lead to death.
Can subdural hematoma cause midline shift?
Most epidural, subdural, or intracerebral hematomas associated with a midline shift of 5 mm or more are surgically evacuated. In a patient who has a small hematoma causing less than a 5-mm shift and who is alert and neurologically intact, a conservative approach is justified.
What does crossing suture lines mean?
Cross suture lines since bleeding is below the dura, which is tightly attached to the calvarium, thus giving the “crescent shape” appearance on head CT. Can result in mass effect leading to uncal and/or tonsillar herniation if left untreated.
What are the precautions taken with clients with viral meningitis?
Should a person with viral meningitis be isolated? Strict isolation is not necessary. Since most cases are due to enteroviruses that may be passed in the stool, people diagnosed with viral meningitis should be instructed to thoroughly wash their hands after using the toilet.
What are contact precautions?
Contact Precautions are intended to prevent transmission of infectious agents, including epidemiologically important microorganisms, which are spread by direct or indirect contact with the patient or the patient’s environment as described in I.B. 3.