BIO 3324 1nd Edition Lecture 7 Outline of Last LectureI. Organization of The CNS Outline of Current Lecture II. Organization of The CNSIII. MeningesIV. Cerebrospinal fluidV. Blood brain barrierVI. Brain stemCurrent LectureCentral nervous system- is divided into two different types of material. gray matter white matter. This is about organization. Brain matter is cell bodies of the neuron found in central nervous system. Gray matter: consists of unmyelinated cell bodies, dendrites and axon terminals.Cell bodies are organized to form layers in brain or clusters. (Called nuclei) with similar function. Red spots are gray matterWhite matter: consists of myelinated axons with very few cell bodies.Bundles of axons are organized into tracts which connect different regions of the CNS.They demonstrate direction or signaling that occurs between cells in central nervous system. Or whether they or entering or exiting.Cell-is plasma membrane that wraps it over and over again. Lipids-white (meat before it is cooked, you see white.)These notes represent a detailed interpretation of the professor’s lecture. Grade Buddy is best Used as a supplement to your own notes, not as a substitute.Four major features help protect the CNS from injury:Create a helmet in structures that protect the brain and spinal cord from the outside world.Have a hard building structure (helmet). Cranium and vertebrae protect spinal cordUnder that are three layers which are meninges (membrane), meninx (protective layer between bone and soft tissues) and then have fluid cushion. Then we have blood brain barrier which helps keeps nasty things from floating around in our body.Blood brain barrier is physical barrier between blood supply and actual tissue itself.Meninges-Protective layer.D-Dura Mater- outer most layers. It is Very tough and inelastic. Example would be a gallon size freezer zip lock bag. It doesn’t stretch and tough. It is two layers. They separate and create sinusand blood accumulates and start connecting. Blood leaves bread and goes into sinus then find vein and find way to heart. Spinal fluid also mixes with blood. It is pushed out into sinuses and fluid mixes with plasma of blood and gets recycled like other fluidsA- Is Arachnoid Mater-middle later. (Spiders) this is where spiders in brain hide. Looks like spider webs. This is a highly vascularized region. A lot of blood vesicles moving back and forth creating this web look. The space in it is arachnoid space. It penetrates through space and makes it look more cobs webby. Subarachnoid is filled with CSF. Arachnoid villi penetrate through Dura and break through blood layer and lies into Dura space. P-Pia Mater-lowest and final layer. Highly vasculized. Delivers blood to the tissue closely here to the surface.Cerebrospinal fluid (CSF) - made within the context or the pia called the choroid plexus.2 lateralventricles then third ventricle and fourth ventricle in which it flows through. Create enough pressure to drive blood away from ventricle down from central canal to surround brain where you have arachnoid villa. Purpose of this it serves as a physical barrier to cushion the brain and spinal cord. Very buoyant. Have same density AS BRAIN. It’s very fatty almost like warm butter. Ifdidn’t have CSF brain would leak out skull. Brain has a lot of mass and serves as a shock absorber. So brain isn’t rattling around in the skull. So when brain has that inertia after being hit.Brain doesn’t move forward. It serves as a chemical barrier as well. It’s harder to in vision because dealing with transport of materials with CSF and blood and interstitial space. It is an Exchange of material back in forth with blood and interstitial fluid.Blood brain barrier-Serves as boundary between blood and brain to ensure only material brain wants and needs getin there. Why can alcohol affect brain and activity? Alcohol has a small molecule that is capable of passing through, just like certain drugs. They have to be lipid soluble. We are trying to prevent those materials to stay away from the brain. Drinking a lot of water can dilute the concentration of salt and can make you drown in your own fluids and die. Can bacteria in blood get to your brain? Meningitis? Blood brain barrier serves to prevent bacteria or proteins that shouldn’t be there. There is no such thing as a perfectly safe place. We have an anatomically structure that disallows material. We have the capillary system and most capillaries are leaky. It’s basically how water can drip through fingers because fingers aren’t tight. Anything that wants to get into brain has to pass through the actual cells that make up the capillaries. We are dealing with things that are moving across that barrier anything that is water soluble has to be transporter into the cell and out through the other side. Water can go back and forth across plasma membrane. Blood brain barrier doesn’t exist with hypothalamus. It must sample blood to control its output of hormones which also must enter the blood through the hypothalamic –hypophyseal portal system. Ingestion is a way to get something bad in our body. Vomiting centermonitors the blood for toxins and when it finds something that shouldn’t be there it heaves it on up. There are special nutritional requirements that the tissue needs-It does not use anaerobic metabolism. It needs glucose. But brain doesn’t store it. It needs glucose deliver to it. It needs constant oxygen to keep activity going.1st- brain requires constant blood supply for glucose plus oxygen for ATP production2nd- failure to maintain homeostasis can be detrimental to brain functionBrain uses 15 percent of blood pumped by the heart to get oxygen it needs.The brain uses 50 percent of the body’s glucose consumption. When think of glucose it wants your sugars. Think of the brain. You can get hypoglycemic (snickers commercial) it can alter behavior and not function the way it needs to. Lactose serves as a quick fix if run low on glucose.What meninx is the most superficial layer? The Dura.Spinal cord-It works its way up to the cerebrum. It exits from the base of the skull and is enclosed by the vertebral column. It is the major pathway. The Information comes in and out.There are four basic regions: cervical (neck), thoracic (chest), lumbar (lower back), sacral (butt bone)Each of these regions will see nerves that exit from spinal cord which are called spinal nerves that exit between the vertebrae. And