Chapter 1

Question 1

differences between afferent , efferent and intrinsic

Answer 1

afferent: brings information into a structure
efferent: carries information away from structure
intrinsic: dendrites and axon contained within single structure

Question 2

astrocytes

Answer 2

synchronize activity of the axon by wraping around the presypnatic terminal and taking up chemicals released by axon

Question 3

microglia

Answer 3

remove was material

Question 4

oligodendrocytes and schwann cell

Answer 4

build myelin sheath that surrounds axons

Question 5

radial glia

Answer 5

guide migration of neurons and growth of axons

Question 6

what process does the blood brain barrier use to carry protein

Answer 6

active transport

Question 7

explain action potential

Answer 7

1. resting state
   - resting membrane potential at -70mV
   - voltage-gated Na and K channels are closed
2. threshold and depolarization
   - stimuli triggers membrane potential to reach threshold at -55mV
   - voltage-gated Na channels open, rush into cell
   positive ions causes the inside of membrane to become positive (+30mV)
   - all or nothing principle, stimuli must be strong enough to bring the membrane potential to the threshold level
3. repolarization
   - at peak of action potential, Na channels close and voltage gated K channels open
   - K exists the cell, restoring membrane potential to more negative state (+30 to -70mV)
   - absolute refractory period
4. hyperpolarization
   - K channels remain open longer, causing membrane potential to drop below resting level (more negative than -70mV)
   - neuron cannot dire another action potential immediately (relative refractory period)
5. return to resting state
   - K channels close, and sodium-potassium pump restores the original ion concentrations
   - membrane potential returns to -70 mV

Question 8

unmyelinated sections called

Answer 8

nodes of ranvier
- action potential is regenarated by chain of positively charged ions pushed along
-jumping (rapid conduction of impulses)