electric brain

Question 1

what are neurons (chem)

Answer 1

• tiny bubbles of phospholipid membranes filled with organic potassium (K+) ions and are bathed in an extracellular fluid rich in sodium cholride (Na+ Cl-)
• contain very few free calcium ions (Ca++), but there are more Ca++ ions in the extracellular space

Question 2

how do neurons control flow of ions?

Answer 2

through their membrane with channels made of protein that can be selective, allowing only certain types of ions through, and perhaps only at certain times.

Question 3

Why is the inside of a resting neuron negatively charged compared to the outside?

Answer 3

neurons have L+ ‘leakage’ channels open when at rest. little K+ leaks out and A- stay making the inside electrically polarized to around -70mV as when K+ leaves, more negative charge is left behind inside than out
so, more neg in than out

Question 4

Describe depolarization in neurons

Answer 4

when channels open, Na+ (sodium) is let in
this makes membrane of neuron less neg charged so it becomes pos

when neurons depolarize, it can encode parameters in outside world through membrane potential (eg: stretching skin)

Question 5

Discuss voltage gated sodium channels

Answer 5

neurons are long and slender
they need to send signals from one end to the other
the electricity inside gets weaker as it travels along the neuron
to solve this, neurons use voltage-gated sodium channels
they refresh elec currents (like a spark of elec)
but if too many are open at once, runs
–> runaway feed forward process
so neurons gotta be careful and open up at the right time and right amount