Neurotransmission: The Action Potential and Synaptic Transmission

Question 1

What is the role of the nervous system? diagram?

Answer 1

• Receiving external sensory
• Monitoring internal physiology
• Interpreting the inputs
• Integrating the sensory input to produce a physiological response if appropriate (either voluntary or involuntary or unconscious)
• Coordinating all the activities of the body in response to the internal and external inputs

Question 2

What are the two types of the Nervous System?

Answer 2

-Central Nervous System
-Peripheral Nervous System

Question 3

What is the Central Nervous System?

Answer 3

-brain and spinal cords

Question 4

What is the Peripheral System?

Answer 4

• sensory nerves and nerves from the spine to muscles

Question 5

What is the neuron?

Answer 5

–Responsible for communication (Action potential / neurotransmission)

• Transmit from dendrite to axon terminal
• Many have a lipid sheath called myelin
• Neurones form networks
• Where they connect is termed a synapse
• There are other cell types in the peripheral and CNS
• Termed glia
• Variety of functions

Question 6

Diagram of the neuron?

Question 7

What is Bio-electricity?

Answer 7

-Membrane potential is fundamental to all cells, bio electricity

• Membrane potential is a result of ion gradients
• In some cells, membrane potential changes in response to stimuli, excitable cells
• Neurones are prime examples
• Nerve impulses are changes in membrane potential that travel down nerves

Question 8

Bio electricity diagram ?

Question 9

What is an ion gradient?

Answer 9

-Cell membrane is highly impermeable to ions

• Allows formation of ion gradients
• Membrane potential (membrane potential difference)
• Allows electrical signalling and excitability

Question 10

Membrane potential is the basis of …?

Answer 10

–Neurotransmission

-Muscle contraction

-Secretion

-Hormones, neurotransmitters, digestive enzymes, mucus, surfactant

-Immune responses

Question 11

An excitable membrane needs:

Answer 11

• A negative membrane potential
• Ion concentration gradients

Question 12

What are Voltage gated ion channels?

Question 13

What are Ligand Gated ion channels?

Question 14

Neurons have a positive or negative membrane potential ?

Answer 14

-Negative

Question 15

Ion gradients - neurons

Answer 15

• ie it is more negative on the inside than the outside of the cell
• Membrane potential is due to unequal ion distribution
• A gradient of ions across the membrane which provides a DIFFUSION gradient and a MEMBRANE POTENTIAL

Question 16

Gradients of key ions in the resting state. Highest concentrations shown: Diagram

Question 17

What is a neuron ?

Answer 17

-It is a nerve cell

-Neurones are highly specialised cells

• Transmit information as electrical signals (nerve impulses or action potentials)
• Action potentials only travel one way from dendrites to axons

Question 18

Action potentials only travel one way:

Answer 18

-from dendrites to axons

Question 19

What are dendrites?

Answer 19

-Receive information, start action potential

Question 20

What is the Soma?

Answer 20

-The cell body

Question 21

What is the axon?

Answer 21

-Propagates action potential

Question 22

What are the axon terminals?

Answer 22

-communicate with other neurons/muscles etc

Question 23

What is the Resting membrane potential of a neuron?

Answer 23

= -70mV

Question 24

Neurone at Rest..?

Answer 24

– Resting membrane potential of a neuron is -70mV

• Maintained by the permeability of the membrane to K+ and an energy dependent pump which moves the ions across the membrane

Question 25

Neurone: Action Potential

• An action potential changes the membrane potential to..?

Answer 25

=+30mV

Question 26

Neuron Action Potential Graphs Diagrams