AP 2 2.6: Nervous System Injury and Disease Flashcards
concussion
Brain Injury and Disease
If the head is moving and is suddenly stopped as it hits an object, brain damage can occur at the site of the impact. As the brain recoils, it also hits the opposite side of the skull, causing more widespread damage. A slight injury of this type is called a concussion since the symptoms are mild and transient, including dizziness or brief loss of consciousness. No permanent neurological damage is sustained.
brain contusion
Brain Injury and Disease
A more serious impact injury, a brain contusion, results in significant tissue damage, which usually causes unconsciousness (coma), ranging in duration from hours to a lifetime.
hemorrhage
Following head blows
Following head blows, hemorrhage, or rupture in a blood vessel, causes blood to accumulate inside the skull.
Intracranial pressure
Two symptoms of several brain disorders include apraxia and ataxia
Intracranial pressure is the amount of pressure available inside the skull. Intracranial pressure rises after a hemorrhage because the extra blood volume takes up additional space, compressing the brain tissue. If this pressure continues, it forces the brain stem down through the foramen magnum (opening in the skull for the spinal cord). This damages the brain stem, as control of blood pressure, heart rate, and respiration is lost with possible fatal consequences. A hemorrhage in the brain is very serious because of the limited space inside the skull for the brain to swell.
Parkinson’s disease
Two symptoms of several brain disorders include apraxia and ataxia
Parkinson’s disease is a disorder of the basal ganglia. Apraxia, or impaired motor planning, is a symptom of Parkinson’s disease. Apraxia results in rigid movements and difficulty executing a motor plan. Ataxia is impaired motor coordination, resulting from an injury to the cerebellum.
CVA (cerebrovascular accident)
CVA (cerebrovascular accident) is also known as a stroke. A CVA occurs when blood circulation to a brain area is blocked. The tissue in that area of the brain dies due to lack of oxygen and nutrients being supplied to brain cells. The severity of a CVA depends on the vessel that is blocked. If a large artery is blocked, then there is much more widespread damage than if a smaller artery is blocked. A CT scan (or CAT scan) is an imaging technology called a computer tomography scan. A CT scan uses x-ray technology to take visual cross-sections of the brain.
There are two different types of strokes: ischemic and hemorrhagic
ischemic stroke
There are two different types of strokes: ischemic and hemorrhagic
An ischemic stroke is due to a blockage, such as caused by a clot or fat deposit blocking a cerebral artery.
TIA is a transient ischemic attack
There are two different types of strokes: ischemic and hemorrhagic
ischemic attack
A TIA occurs when a very small clot causes a temporary block in blood flow, but then dissolves. Once the clot dissolves, the person no longer experiences stroke symptoms.
hemorrhagic stroke
There are two different types of strokes: ischemic and hemorrhagic
A hemorrhagic stroke occurs due to a “brain bleed” when a blood vessel in the brain ruptures. A severe stroke often causes death. People who survive usually have paralysis, cognitive deficits, speech problems, emotional difficulties, and pain. Some patients recover at least a portion of their lost function through physical rehabilitation, such as occupational and physical therapy. The undamaged neurons in the surrounding area sprout new branches that spread into the area of injury and take over some lost functions. This phenomenon is known as neural plasticity.
dementia
Alzheimer’s disease is a form of dementia, which is a general term for all brain disorders with memory deficits.
Alzheimer’s disease
Alzheimer’s disease is a progressive degenerative disease of the brain, usually seen in the elderly, that ultimately results in mental decline until the brain can no longer control bodily functions. Alzheimer’s disease is associated with structural changes in the brain, particularly in the cerebral cortex. From a physiological perspective, plaques form and entangle the dendrites within the brain, preventing neurons from firing. Lack of neural firing eventually leads to cell death. As neurons die, they cause more plaques and tangles to form on other neurons, spreading the disease throughout all the brain tissue. Decreased brain tissue is seen in the brain by a shrinkage of the cerebral cortex gray matter and enlarged ventricles.
In the early stages, people with Alzheimer’s disease exhibit difficulty remembering newly learned information. Over time, the symptoms interfere with more basic memory skills, including disorientation to their surroundings. The progressive loss of brain tissue, particularly in the frontal lobe, causes mood and behavior changes, such as suspicions about family, friends, and caregivers. These changes often make it stressful to care for loved ones with this disease. Eventually as the disease progresses to its final stages, the person will have difficulty speaking, swallowing and walking.
Amyotrophic lateral sclerosis (ALS)
Spinal Cord Injuries and Diseases
Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, is a rare neuromuscular condition that involves progressive destruction of ventral horn motor neurons (motor neuron cell bodies). As the disease progresses, it causes paralysis. The person progressively loses the ability to speak, swallow, and eventually breathe.
Paralysis (loss of motor function) or sensory loss is caused by any localized damage to the spinal cord or spinal nerve roots. Damage to the ventral root or anterior horn cells results in paralysis of the associated skeletal muscles because nerve impulses cannot reach these muscles. Over time, the muscles begin to atrophy from lack of stimulation from the neurons. A complete (or total) spinal cord injury occurs If the spinal cord is completely severed at any level. Total motor and sensory loss is experienced in body regions below the site of the damage, even if the spinal cord is intact below the level of injury. This occurs because the segment of the spinal cord that was completely damaged can no longer allow signals to be sent up to the brain or receive signals from the brain. Paraplegia, lower limb paralysis, may occur if the spinal cord is injured between T1 and L1. Quadriplegia, paralysis of all four limbs, may occur if the spinal cord is injured in the cervical region.
claw hand
Ulnar Nerve
The ulnar nerve supplies part of the flexor muscles of the forearm, wrist, and hand as well as the skin of half the ring finger and pinky finger. If the ulnar nerve is damaged, it results in a condition known as claw hand. This is marked by the inability to open the fourth and fifth fingers caused by flexion at the IP joints and hyperextension of the MCP joints in digits 4 and 5
carpal tunnel
Peripheral Nervous System Diseases: Median Nerve
Recall that the median nerve supplies flexor muscles of the forearm and the skin of the first three digits and half of the fourth digit. The median nerve and the flexor tendons of the hand travel through the carpal tunnel, a small space created by the flexor retinaculum as it passes through the wrist.
Compression of the median nerve in the carpal tunnel causes carpal tunnel syndrome or decreased sensation in the first three digits and half of the fourth digit. If a person has severe carpal tunnel syndrome or does not have treatment, muscle atrophy results in decreased hand strength.
