Module 5 - Neuronal Communication Flashcards
What happens during action potential in terms of pump
Na+/K+ pump is operating
Voltage gated Na+ Channels are open
Voltage gated K+ Channels are closed
Explain one advantage of using a confocal microscope in this study.
It can be used with living cells
What describes the action of GABA?
GABA causes hyper polarisation of the post synaptic membrane.
The following information has been discovered about the effects of TTX on nerve cells:
- TTX binds to the external surface of the voltage gated sodium ion channels in the axon membrane.
- Binding of TTX changes the tertiary structure of the channel
- Channel cannot open
Explain how TTX affects the activity
TTX binding causes sodium gated channels to not be able to open.
So sodium ions cannot enter hence preventing depolarisation and action potential so membrane remains at resting potential.
Why is transmission of action potentials along the axon slower in the absence of saltatory conduction?
No nodes of Ranvier
Suggest how the immune system causes damage to the nervous system.
Antigens on neurones activate immune system. Antibodies against neurones are produced. Phagocytes breakdown the neurone.
MS reduced the speed at which nervous impulses are conducted. What does this mean.
MS damages the Schwann cells and no saltatory conduction can occur
Describe the components and events involved in a reflex arc.
action potential in sensory neurone
synapse - diffusion of neurotransmitters
relay neurone
Motor neurone passes impulse to effector
State the function of myelin sheath
Myelin sheath is a thermal insulator which increases the speed of impulse through saltatory conduction.
Outline the ways in which the structures of a sensory neurone and a motor neurone are similar
Sensory neurone and motor neurone both have an axon and dendrite.
They both have a cell body and myelin sheath.
What is the enzyme found in synaptic cleft
Acetylcholine esterase
where are acetylcholine receptors found
in the postsynaptic membrane
Suggest and explain the effect that nicotine has on the nervous system
Nicotine stops transmissions of action potentials. Nicotine binds to receptors and causes Na+ channels to open causing depolarisation. But nicotine remains in refractory stage for longer.
Outline the roles of synapses in the nervous system
Synapses allow neurones to communicate
they ensure transmission in one direction only
They allow convergence ( impulses from more than one neurone can be passed to a. single) and divergence (impulses from single can be passed to more than one neurone).
Name one chemical that transfers a nerve impulse from one neurone to another.
Acetylcholine
