Week 2: CNS, PNS, NEURONS

Question 1

CNS

Answer 1

Brain, spine.

Question 2

What two nervous systems are in the Peripheral nervous system

Answer 2

Contains the somatic nervous system, and the autonomic nervous system

Question 3

Afferent vs efferent

Answer 3

Afferent nerves are sensory, and efferent are motor nerves. So afferent brings infomation to the brain about the world, and efferent takes information away from the brain.

Question 4

What two systems are in the Autonomic nervous system

Answer 4

Sympathetic and parasympathetic

Question 5

What three meninges encase the cns

Answer 5

Dura mater, then arachnoid membrane, then the pia mater. Cerebral spinal fluid fills chambers around the cns for extra protection.

Question 6

Parasympathetic

Answer 6

rest n digest

Question 7

Sympathetic

Answer 7

fight or flight.

Question 8

autonomic

Answer 8

the automatic processes, like breathing.

Question 9

basic definition of what neurons do:

Answer 9

specialized cells for the receptions, conduction and transmission of electrochemical signals. They come in all shapes and sizes

Question 10

What do Glial cells

Answer 10

Plays a supportive role to neurons, recent evidence that they communicate and moderate neuron communications

Question 11

neurons

Answer 11

Cell body, axon and dendrites.

Question 12

Four types of glial cells

Answer 12

Oligodendrocytes: create myelin sheathes in CNS
Schwann Cells: create myelin sheathes in PNS. Can grow back after damage, and only do one small part of sheathe.
Microglia: small, respond to injury or disease by multiplying and engulfing debris.
Astrocytes: star shaped glial, appear to be able to manipulate passage of chemicals into blood but do a whole lot of other stuff too.

Question 13

The process of an action potential:

Answer 13

A neuron first recieves an electrical signal called a post-synaptic potential. This actives an electrical signal at the dendrites, that can either be an exciatory signal (positive), or a inhibatory signal (negative). Many different signals, both positive and negative travel down the axon and decrease as they travel. If the signal is positive enough, then it triggers an action potential. During an action potential, the sodium ion channels open and allow the sodium to rush in and depolarise the cell (as opposed to hyperpolarise, whch is when it becomes more negative). and potassium ions rush out. the sodium potassium pump restores equilibrium and the neuron goes back to resting state, around -70mv

Question 14

What is the refractory period?

Answer 14

When it is impossible to initiate another action potential.

Question 15

So, What happens when the action potential reaches the end of the axon terminal?

Answer 15

The AP triggers calcium channels at the end of the neuron, causing the vesicles to fuse with the cell membrane to release the neurotransmitters they have in them (e.g. dopamine.) The neurotransmitter binds to a post synaptic receptor on the next neuron, and so on down the chain.

Question 16

Okay, makes sense! So how do drugs influence the action potential system?

Answer 16

So, because we aren’t able to do truly localised interventions, drugs for one issue (such as parkinsons) gets dosed to the whole brain, including areas that need no interference. This explains side effects, such as parkinsons medicatin causing psychotic episodes as they bind to dopamine receptors.

Question 17

Agonists vs antagonists

Answer 17

Agonists increase and facilitate activity of receptor, stimulating it in the absence of neurotransmitters (dopamine and antidepressants).
Antagonists bind to post synaptic receptors and stops the neurotransmitter from activating (i’d imagine MDMA after a comedown or something like that.)