Nerve cells and Electro-chemical Signaling

Question 1

what is nerves system?

Answer 1

a regulatory
communication network that allows an
organism to respond to environmental
stimuli and to regulate the organism’s
metabolism and activity in response to
changes in its circumstance

Question 2

what is neurons made out of?

Answer 2

neurones

Question 3

what is the fuction of efferent neuron?

Answer 3

transmit from the CNS to the effector organs. cell bodies and dendrites wiithin the CNS

Question 4

what is the fuction of afferent neurons?

Answer 4

transmits form the periphery to CNS. cell bodies located outside the CNS in a ganglion

Question 5

what is ganglion?

Answer 5

clusters of cell bodies outside the CNS

Question 6

what is interneurons?

Answer 6

account for 99% of all neurons in the body, located within the CNS, involved in processing efferent and afferent signals

Question 7

what is action potential?

Answer 7

a self-regenerating wave of electrochemical activity that allows nerve cells to carry signals throughout the nervous system

Question 8

what is Ohm’s Law?

Answer 8

I(current) = V(voltage) /R(resistance)

Question 9

what is responsible for the existance of Resting Membrane Potential (RMP)?

Answer 9

the K+ that leaks from the inside of the cell to the outside via leak K+ channels and generates a negative charge in the inside of the membrane. At rest, the membrane is impermeable to Na+, as all of the Na+ channels are closed.

Question 10

what is RMP depends on?

Answer 10

the concentration of ions across the permeable membrane and teh presence of ion channels in the permeable membrane

Question 11

what is leak channels?

Answer 11

non-gated channels in plasma membrane throughout neurone. always open

Question 12

what is the equillibrium potential of any ion depend on?

Answer 12

charge and size of concentration gradient

Question 13

what is sodium-potassium pump?

Answer 13

it’s electrogenic and helps in establishing and maintaning the chemical gradient

Question 14

What causes changes in membrane potential during an action potential?

Answer 14

Changes in membrane potential during an action potential are due to changing membrane permeabilities to Na+ and K+ ions.

Question 14

What mediates the changes in membrane permeabilities during an action potential at the biochemical level?

Answer 14

Voltage-gated Sodium channels and voltage-gated Potassium Channels, which undergo conformational changes.

Question 15

What happens when voltage-gated Na+ channels open during an action potential?

Answer 15

Na+ enters the cell, leading to depolarization, making the inside of the cell positively charged.

Question 16

What is the concept of threshold stimulus in action potentials?

Answer 16

A stimulus must reach a critical level before generating an action potential. Sub-threshold stimuli are insufficient, while supra-threshold stimuli result in action potentials of the same magnitude and duration.

Question 17

How does frequency coding relate to action potentials?

Answer 17

Action potentials convey the intensity of stimuli. A supra-threshold stimulus can generate a burst of action potentials, increasing frequency but not amplitude

Question 18

What is the concept of lateral inhibition in the context of action potentials?

Answer 18

Lateral inhibition refers to the mechanism where certain neurons inhibit the activity of neighboring neurons, influencing the propagation of action potentials.

Question 19

Describe the structure of voltage-gated Sodium channels (Nav).

Answer 19

Nav channels have four domains, each composed of six transmembrane spanning alpha-helices. They include a voltage sensor in alpha-helix S4 and a pore loop acting as a selectivity filter.

Question 20

What is the significance of mutations in Na+ channels?

Answer 20

influencing the operation of voltage-gated sodium channels and contributing to various physiological and pathological conditions.

Question 21

what is synapse?

Answer 21

Site of information transfer between
neuron and target

Question 22

examples of neurotransmitters involved in action potential.

Answer 22

The amino acids: glutamate, glycine, GABA
The biogenic-amines: acetylcholine, dopamine,
serotonin