Week 2 Continuing the Education of Nuerotransmitters :)

Week 2 consisted of learning more about nuerotransmitters and their functions, and also where it all began later on in the week.

The only excitable cells are: Muscle (skeletal, smooth, and cardiac). The change in activity is based on charge!

Bonds are being broken in the ASE of the ATP. ATP is Adenosine Tryphosphate which is a nucleotide acid. ATP uses the break off of carbon atoms to move ions from low to high concentration. The ratio for ATP is 3/2 Sodium ions to Pottassium Ions.

Ach is the only sodium ion channel that will open with a Nuerotransmitter. A receptor is the channel. VRC is postively charged and takes place at the axon hillock. CRC channels are located at the dendrites. Slow gates or channels are always open, and the fast gates or channels opens when Ach attachs. Nuerotransmitter #1 is the Pre Syn, and Nuerotransmitter #2 is the Post Syn.

Astrocytes are the accessorie cell that determines how much calcium is extra to push through sodium ions from N.T. #1 to N.T. #2. Astrocytes are star shaped and are the former of the blood brain barrier. They filter cells. If nuerons die they cannot undergo mitosis, and will become scar tissue.

Capillaries have the smallest diameter which means higher resistance and better for diffusion of cells. Capillaries are made up up tubes from simple squamous cells.

Oligodendrocytes form myelin sheaths in the CNS (brain and spinal). One oligodendrocyte can wrap multiple axons (hundreds). They can go undergo mitosis but is very difficult after wrapping many axons they cannot go in one direction, and is very unlikely to occur.

Schwann cells form myelin sheaths in the PNS. They can undergo mitosis and can retarget after being severed or highly damaged which is called Wallerian Regeneration. They can only wrap around one axon which enables them to fix itself after being severed or highly damaged.

Microglia is the smallest of the CNS. Phagocytic, defense cells in the CNS. Microglia is "the little pac man" They ingulf foreign material and release enzymes.

Ependymal Cells produce, help circulate cerebrospinal fluid in the CNS. CSF is an extract of blood. Porous Capillaries = Fenestrated Capillaries + ependymal cells = choroid plexous. Ependymal cells sit on the fenestrated capillaries that are "leaky" to make CSF.

WEEK 1 Class Overview /// Nuerotransmitters!!!

After week one it was definitely time for a little review from A&P 1. We did start right where we left off though at neurons, and neurotransmitters woohooo.

Some things I learned in our first week was for sure how the class was going to go over which included homework assignments, quizzes, projects, etc. We are only required to buy one book (Anatomy and Physiology: From Science to Life, 2007), but recommended is Physiology Coloring Book, Mosby's Medical, Nursing and Allied Heath Dictionary, and Netter, Atlas of Anatomy.

For a little review I got refreshed about Ions, both sodium and potassium. Cations are postively charged and responsible for putting cells to rest. Sodium Ions are responsible for exciting cells. Both sodium and potassium are +1 charge.

Afferent means toward. Efferent means away from. Afferent is the sensory in nervous system versus efferent being the motar in the nervous system. When talking about the Brain and the Spinal Cord that means talking about the CNS or Central Nervous System. Nerves are collections of axons. Nerves are like highways, different highways have different targets, just like nerves.

Nuerons produce nuerotransmitters. MMJ nuerotransmitter is Ach. Ach is released onto muscle at the MMJ. Every nueron makes a certain nuerotransmitter. Examples of nerotransmitters are saratonin, acycholine, and dopine.

Dendrites have receptors deeply embeded to receive nurotransmitters. Nuerotransmitters are proteins, and receptors. Each protein has its own unique shape / function. Receptors can be multitaskers and bind to more than one nuerotransmitter.

Nuerotransmitters have three different stages, resting state, Inactive, and Resting Potential. Resting State is -70 mv. Once it gets to -55mv it is determined as action potential threshold and there is no turning back, all or nothing.

In the resting state the channel has a gate. The receptor is the gate, and when the Nuerotransmitter binds to the receptor/gate the gate opens and floods with sodium ions !!! This is called DEPOLARIZATION!!! Decrease in charged nuerotransmitters is known as REPOLARIZATION. Whenever it goes under -70mv for a brief second it is known as HYPERPOLARIZATION.