Topic 4 Circulation: Brain Structure and Blood Brain Barrier

Circulation of the Brain

• The brain receives 15-20% of the total blood supply despite being only 2% of the total body weight.
• The brain requires a steady flow of blood to deliver oxygen, glucose, vitamins, amino acids, minerals, and other nutrients.
• Cerebral blood circulation also removes waste products, such as CO2, toxins, and metabolic waste.

Importance of Blood Flow to the Brain

• Blood flow to the brain is critical, as it keeps the brain hydrated (more than 70% water) and maintains a constant temperature and pH.
• Brain cells suffer and can lead to brain damage or death when circulation is restricted.

Cerebral Circulation

• Cerebral circulation is the movement of blood through a network of cerebral arteries and veins supplying the brain.
• The rate of cerebral blood flow in an adult human is typically 750 ml per minute, which is about 15% of cardiac output.

Blood Supply to the Brain

• The brain receives blood from two sources: the internal carotid arteries and the vertebral arteries.
• The brain stem controls circulation.

Cerebrospinal Fluid (CSF)

• CSF plays a crucial role in cushioning and protecting the brain from major shocks.
• CSF also plays a role in the homeostasis and metabolism of the CNS.

Symptoms of Poor Blood Flow to the Brain

• Poor focus and concentration
• Dizziness
• Frequent headaches
• Mental fatigue
• Memory loss
• Cold nose, feet, or hands
• Needing to wear socks to bed
• Cramping in feet and hands
• Unhealthy nails (fungus or white nail beds)

Causes and Risk Factors for Impaired Blood Flow to the Brain

• Sedentary lifestyle
• Underlying health conditions

Improving Blood Flow to the Brain

• Engage in regular physical exercise
• Eat the right foods
• Practice mind-body techniques like meditation
• Partake in mentally stimulating activities
• Aerobic exercise is particularly effective in increasing blood flow to the hippocampus, a region crucial to memory.

Blood-Brain Barrier (BBB)

• The BBB is a unique feature of the microvasculature of the CNS that controls the passage of substances from the blood into the CNS.
• The BBB is formed by microvascular endothelial cells lining the cerebral capillaries.
• The BBB restricts movement of substances between endothelial cells and uses specific transport proteins to determine which substances can cross the barrier.