BIOL 2160 Chapter : Chapter 9 CNS 1
Document Summary
Cns: brain and spinal cord: necessary for the maintenance of homeostasis, contains 1011 neurons (100 billion, contains 1014 synapses (100 trillion, responsible for everything we perceive, do, feel, and think. Figure 9. 1: physical support of the cns fig 9. 2a. Meninges: dura mater, arachnoid mater, pia mater. Secreted by ependymal cells of the choroid plexus. Circulates to subarachnoid space and ventricles: reabsorbed by arachnoid villi. -very few proteins in csf compared to plasma. Increase intracranial pressure and or seizures: spinal tap (lumbar puncture) To check csf for invasion of bacteria or viral particles. Needle is inserted into subarachnoid space btw 3rd and 4th lumbar vertebrae. No damage to spinal cord since it doesn"t. Cns comprises 2% of body weight (3-4 pounds: receives 15% of blood supply. High metabolic rate: brain uses 20% of oxygen consumed by body at rest, brain uses 50% of glucose consumed by body at rest.
