Think of a stroke as a "brain attack"— it is an emergency! When symptoms appear call 911 immediately; every minute counts. A stroke occurs when the brain is deprived of blood supply. Without oxygen brain cells die. Depending on the area affected, a person may have problems speaking, walking, seeing, or thinking. It may result in permanent brain damage, disability or death. If the stroke is caused by a blood clot, a clot-busting drug may be given to restore blood supply.To understand stroke, it is helpful to understand the circulatory system of the brain (see Anatomy of the Brain). Blood is carried to the brain by two paired arteries, the internal carotid arteries and the vertebral arteries (Fig. 1). The internal carotid arteries supply the anterior (front) areas and the vertebral arteries supply the posterior (back) areas of the brain. After passing through the skull, the right and left vertebral arteries join together to form a single basilar artery.
The basilar artery and the internal carotid arteries “communicate” with each other in a ring at the base of the brain called the Circle of Willis by the anterior communicating (Acom) and posterior communicating (Pcom) arteries. The middle cerebral artery is the artery most often occluded in stroke.
Answer:
macrophages
Explanation:
Macrophages are a type of immune cells that function as phagocyte. They are produced by white cells called the monocytes. Upon ingestion of bacterial cells, cytotoxic compounds e.g cytokines are produced that digest the bacteria.
The macrophages are activated by the presence of microbes in the blood. They activate antigen T presenting cells to produce cytokines that further destroy the engulfed bacteria.
This is because blood is pumped out of the heart at greater pressure from these chambers compared to the atria. ... This is due to the higher forces needed to pump blood through the systemic circuit (around the body) compared to the pulmonary circuit.
