Neurological disorders

• The brain relies on the vascular system to deliver the essentials: oxygen and glucose.
• If the brain is deprived of oxygen and glucose damage will begin almost immediately
• Ischemia: a condition of low oxygen levels due to interruption to the blood supply to the brain
• the two types of stroke are blockage and hemorrhage
• the two types of stroke blockage is thrombosis and embolism
• Thrombosis is a build-up of material that blocks a blood vessel but doesn’t move from its point of origin
• Embolism is a build-up of material that moves to smaller and smaller vessels until it gets stuck
• The area of brain damage in a stroke is known as the infarct
• a hemorrhage is a rupture of a blood vessel
• a hemorrhage comes from hypertension, structural defects in arteries; and Aneurysms
• Aneurysms are bulges in arteries filled with blood that can burst
• Arteriovenous malformations (AVMs) are abnormally formed collections of blood vessels in the brain.
• Usually arteries and veins are separated by capillaries
• •Capillaries are porous, and allow nutrients to leave the blood and waste from the tissues to enter the blood
• In AVM the capillary tissue is either severely reduced or absent
• Cavernous malformations are similar to AVMs, but differ in that brain tissue generally does not develop within the abnormal area.
• Symptoms of cavernous malformations include headache, seizures, hemorrhage.
• cavernous malformations are probably genetic in origin
• the two types of head injuries are open head and closed head injuries
• Open head injuries involve penetration of the skull such as gunshot wounds or Fractures
• Closed head injuries do not involve penetration of the skull such as concussions
• an open head injury is one where the skill is penetrated
• consequences of open head injury depend on brain area affected
• generaly open head injury is fatal–Only ~20% of open head injury patients survive.
• closed head injuries are concussion or Traumatic Brain Injury (TBI)
• the severeness of closed head injury range from mild concussion (no loss of consciousness) to coma
• in a closed head injury the skull is not penetrated, so brain tissue is not directly damaged
• transportation accidents are the leading cause of closed head injury
• in general, the longer a person is unconscious the more severe the consequences will be
• Symptoms of concussion include: Lack of concentration, slow thinking, and problems with attention and memory
• The site of a blow is known as a coup.
• The area on the opposite side of the head is the countercoup
• bleeding from a closed head injury is hematoma
• white matter damage from a closed injury is usually due to twisting of the brain within the skull in response to the initial blow
• swelling in a closed head injury -remember, the cranium is a fixed space, so when brain tissue swells it puts pressure on surrounding tissue
• Repeated concussions may produce: slurred speech, memory and personality changes, and a Parkinson’s-like syndrome.
• Tumors are independent growths of cell that lack functionality
• brain tumors do not arise from mature neurons, which typically do not replicate.
• brain tumors typically arise from glia and the tissues of the meninges
• Infiltrating (malignant) tumors lack defined boundaries; they usually return after surgical removal and often shed cells or metastasize