The Brain and the Spinal Cord

There are three types of Dura, the epidural space, dura mater, and subdural space. The epidural space is the space external to the sac of the spinal dura mater within the vertebral canal. The dura mater is the outermost of the meningeal layers covering the brain and spinal cord. The dura has a hard leathery outside. The subdural space is a fluid-filled space or potential space between the dura mater and the arachnoid. The arachnoid has no blood supplies and is web-like. The sub-arachnoid space is the cerebra spinal fluid.The pia mater is the delicate membrane that lies on surface of the brain and spinal cord.
Vessels are confluence like, two or more vessels will met and flow together with the same amount of blood. The vessels full of blood flow from the lungs where they become oxygenated to the left atrium to the bicuspid-mistral value. After the bicuspid-mistral value then to left ventricle to the semi lunar value then ascends to the aora then to the aortic arch. From the aortic arch the blood descends to the aorta.The blood also flows through the aortic arch to the right brachiocephalic to the right subclavian, and finally right common caryatid.

Metric Conversation, Some Neuroglial Cells

Schwanns Cells can wrap only one axon. Oligodendrocyte Cells can wrap many axons. Schwanns Cells go through the process of mitosis and produce many cells. This process of making Schwanns Cells will occur until the number of cells reaches the target cell. Schwanns cells are in the PNS, peripheral nervous system. Aster is star like and is the blood brain barrier. Astrocytes filter ammo acids. Astrocytes have a lot of rough and smooth er. Capillaries have the smallest diameter. They have simple squamous epitheliums.
When doing metric conversations, the trick is to remember that there are many steps that need to be done. When going from ounces to grams, you need to go from ounces to pounds to grams. There is no straight conversation from ounces to grams. There are many conversations that need to be done with multiply steps, they are the ones that go from one unit of measurement to another.

Neurons

There are many parts to a neuron. The cell body is called the soma. Inside the cell body is where the nucleus is. On the edges of the soma, there are objects that look like tree branches from a truck those are called dendrites. The dendrites are known as neurotransmitters. They collect information and send it through the body of the neuron and down the axon, which is covered with a myelin sheath, to the terminal button. The information travels from the terminal buttons of one neuron across a space known as a synapse to the dendrites of another neuron.
The neurons can be in three stages one is known as resting potential which is when the neuron is inactive or resting. Another stage is the action potential which is when the neurons is actively firing the messages through the axon to pass the message on. The last one is the local potential which is the graded potential receptor.
Channels have gates that are closed at a resting state, sodium ions that are positively charged move inward. The sodium channels are the first int the depolarization phase. Then the potassium channels open , allowing the potassium to flow out, producing repolarizing phase. Together the depolarization and repolarization phase last about one millisecond in a normal neuron.