What Is Cerebral Blood Flow?
Cerebral blood flow refers to the flow of blood through a cross-sectional area of the cerebral blood vessels per unit time, that is, the product of the linear velocity of the blood flow and the cross-sectional area of the blood vessels is the blood flow.
Cerebral blood flow
- Western Medicine Name
- Cerebral blood flow
- Affiliated Department
- Internal Medicine-Hematology
- Contagious
- Non-contagious
- Whether to enter health insurance
- no
- Cerebral blood flow refers to the flow of blood through a cross-sectional area of the cerebral blood vessels per unit time, that is, the product of the linear velocity of the blood flow and the cross-sectional area of the blood vessels is the blood flow.
- What is cerebral blood flow
The weight of the brain accounts for 2% -3% of the body weight, but the required blood flow accounts for 15% -20% of the cardiac output. Cerebral blood flow refers to the blood flow that per 100g of brain tissue passes in a unit time. This section focuses on whole brain blood flow in various physiological states.
Normal cerebral blood flow The normal value of cerebral blood flow varies depending on the measurement method of cerebral blood flow in a quiet state. In a quiet situation, the brain blood flow of a young man of average figure is 700-770ml per minute, which is about 50-55ml / 100g per minute. When the average hemisphere blood flow is reduced to 25-30ml / 100g per minute, mental disorders can occur and even loss of consciousness. The critical blood flow for neurological decline is approximately 18ml / 100g per minute.
Cerebral blood is supplied through both internal carotid arteries and vertebral arteries. The former accounts for about 4/5 of the total cerebral blood flow and the latter accounts for 1/5. The pressure difference between the carotid artery and the middle cerebral artery is almost equal to the pressure difference between the vertebral artery and the skull base artery ring. Therefore, although there is a difference in blood flow and circulation time between the left and right hemispheres, the carotid system, and the vertebral artery system in normal human brain blood circulation, no blood shunting or countercurrent phenomenon occurs.
The blood circulation in the brain is not only abundant in volume, but also fast in supply. The time required for blood to flow from the arteries into the cranial cavity and reach the sinuses is only 4-8s. Lower.