The Meninges• Function: The dura mater- is the outer layer. Like its name implies, it surrounds the brain and spinal cord, providing a layer of durable, tough, and inelastic protection. The arachnoid membrane- lies just below the dura mater. It resembles a matrix of spider webs, and hence the name. The pia mater- is the layer closest to the brain and spinal cord. It is actually intimately close to the brain and spinal cord
The CSF and Spinal Chord• Function of CSF: : Cerebrospinal fluid has three important, life-sustaining functions: 1) to keep the brain tissue buoyant, acting as a cushion or "shock absorber"; 2) to act as the vehicle for delivering nutrients to the brain and removing waste; and 3) to flow between the cranium and spine to compensate for changes in intracranial blood volume (the amount of blood within the brain).• Where is it found? located between the brain and skull.• Function of Spinal Chord: : Structurally, the cord is a double-layered tube, roughly cylindrical in cross section. The outer layer consists of white matter, i.e., myelin-sheathed nerve fibers. The inner layer, or gray matter, is primarily composed of nerve cell bodies.• Where is it- The spinal cord is contained within the spine, extending from the base of the skull to the second lumbar vertebra at the base of the spine.• Shape- the spinal cord has a shape that is compressed dorso-ventrally, giving• Nerve Roots:The nerve roots run through the bony canal, and at each level a pair of nerve roots exits from the spine.
Cerebral Cortex Thin layer of grey matter made up of neuron dendrites and cell bodies that compose the surface of the cerebrum.N.d. n.p. Web. 5 Nov 2012.<http://www.memorylossonline.com/glossary/images/cerebralcortex.jpg>.
Afferent and Efferent NervesN.d. n.p. Web. 5 Nov 2012. <http://www.getbodysmart.com/ap2/nervoussystem/organization/sensorymotor/tutorial.html>.
Autonomic Nervous System The organs (the "viscera") of our body, such as the heart, stomach and intestines, are regulated bya part of the nervous system called the autonomic nervous system (ANS). The ANS is part of the peripheralnervous system and it controls many organs and muscles within the body. In most situations, we are unawareof the workings of the ANS because it functions in an involuntary, reflexive manner. For example, we do notnotice when blood vessels change size or when our heart beats faster. However, some people can be trained tocontrol some functions of the ANS such as heart rate or blood pressure.The ANS is most important in two situations: In emergencies that cause stress and require us to "fight" or take "flight" (run away)In nonemergencies that allow us to "rest" and "digest."The ANS regulates:Muscles-- in the skin (around hair follicles; smooth muscle -- around blood vessels (smooth muscle) -- in the eye (the iris; smooth muscle) -- in the stomach, intestines and bladder (smooth muscle) -- of the heart (cardiac muscle)GlandsThe ANS is divided into two parts:The sympathetic nervous systemThe parasympathetic nervous system Source 5
Sympathetic Nervous System• the sympathetic nervous system originates in the spinal cord. Specifically, the cell bodies of the first neuron (the preganglionic neuron) are located in the thoracic and lumbar spinal cord. Axons from these neurons project to a chain of ganglia located near the spinal cord. In most cases, this neuron makes a synapse with another neuron (post-ganglionic neuron) in the ganglion. A few preganglionic neurons go to other ganglia outside of the sympathetic chain and synapse there. The post-ganglionic neuron then projects to the "target" - either a muscle or a gland. Source 5
Parasympathetic Nervous System• The cell bodies of the parasympathetic nervous system are located in the spinal cord (sacral region) and in the medulla. In the medulla, the cranial nerves III, VII, IX and X form the preganglionic parasympathetic fibers. The preganglionic fiber from the medulla or spinal cord projects to ganglia very close to the target organ and makes a synapse. This synapse uses the neurotransmitter called acetylcholine. From this ganglion, the post-ganglionic neuron projects to the target organ and uses acetylcholine again at its terminal.