Nervous System/Nerve cells

Question 1

What makes up the Central Nervous System (CNS) ?

Answer 1

Brain and spinal cord

Question 2

The Peripheral Nervous System is made up of all tissue outside of the CNS, What are the three main PNS?

Answer 2

Stomatic Nervous System

Autonomic Nervous System

Enteric Nervous System

Question 3

What are the sensory and motor functions of the Stomatic Nervous System?

Answer 3

Sensory: Special sense receptors transmit info to CNS

Motor: Transmits info from CNS to skeletal muscles

Question 4

What are the sensory and motor functions of the Autonomic Nervous System?

Answer 4

Sensory: Receptors in visceral organs transmit info to CNS

Motor: Transmits info from CNS to Cardiac and smooth muscle glands

Question 5

What are the sensory and motor functions of the Enteric Nervous System?

Answer 5

Sensory: Monitor chemical changes and stretch in GI tract

Motor: Innervates smooth muscle, glands, and endocrine cells in GI tract

Question 6

What are the two divisions in the Autonomic Nervous System that deal with flight or flight and rest and digest activities?

Answer 6

Sympathetic Division - Fight or Flight

Parasympathetic Division - Rest and Digest

Question 7

What are the 4 types of Neuroglia? (structures that hold the nerves together)

Answer 7

Astrocytes
Oligodendrocytes
Microglia
Ependyma Cells

Question 8

In the Peripheral Nervous System what is the difference between Schwann Cells and Satellite Cells?

Answer 8

Schwann Cell (PNS) - forms and maintains myelin sheath and involved in axon regeneration

Satellite Cells (PNS) - structural support and exchange of materials between interstitial fluid

Question 9

What two factors are necessary for the production of a nerve impulse

Answer 9

1. The existence of a resting membrane potential
2. The presence of a specific type of ion channel

Question 10

Explain the processes of an action potential and the corresponding ion movements/ion channel states

Answer 10

1. Resting Membrane Potential - Voltage-gated Na+ and K+ channels closed. Little movement of ions.
2. Depolarisation - Voltage-gated Na+ channel opens. Na+ moves into the cell
3. Repolarisation - Voltage-gated Na+ channel inactivated. Voltage-gated K+ channel opens. K+ moves out of cell
4. Hyperpolarisation - Voltage-gated Na+ channel closed. Voltage-gated K+ channel open. K+ continues to exit cell
5. Resting Membrane Potential - Voltage-gated Na+ and K+ channels closed. Na+/K+ pumps restore resting potential

Question 11

Explain Absolute Refractory Period and the Relative Refractory Period

Answer 11

A = Absolute Refractory Period - second action potential cannot be generated

B = Relative Refractory Period - second action potential can be generated

Question 12

What is the main difference between Continuous Propagation/Conduction and Saltatory Propagation?

Answer 12

Saltatory Propagation only occurs in nerve cells insulated with myelinated axons, allows the skipping of repolaristation and leaping of action potential between the Nodes of Ranvier

Question 13

In relation to signal transmission between synapses what ends are the Pre Synaptic cell and the Post Synaptic Cell?

Answer 13

Pre synaptic (neuron) cell - cell sending the signal

Post synaptic (neuron cell - cell receiving the signal

Question 14

What is the main feature of a Electrical synapse?

Answer 14

Both the Pre Synaptic and Post Synaptic cells have aligning channels forming a “Gap Junction”

Question 15

Explain the six steps involved in Chemical Synapse action potential transmission

Answer 15

1. Action potential moves down axon terminal
2. Voltage gated Ca2+ channels open
3. Ca2+ enters the cell
4. The influx of Ca2+ in the cell then signals the vesicles containing neurotransmitters
5. Vesicles then move to plasma membrane
6. Docked vesicles then release neurotransmitter by exocytosis into the synaptic cleft
7. Neurotransmitter diffuses across the synaptic cleft and binds to post synaptic receptors

Question 16

What is the space between the Presynaptic Cell and Postsynaptic in Chemical Synapse action potential transmission?

Answer 16

Synaptic Cleft

Question 17

In relation to Post Synaptic Potentials explain Excitatory postsynaptic potential and Inhibitory postsynaptic potential

Answer 17

1. (EPSP’s) Excitatory postsynaptic potential - depolarising postsynaptic potential brings postsynaptic membrane closer to threshold

OR

2. (IPSP's) Inhibitory postsynaptic potential - hyperpolarising postsynaptic potential takes the postsynaptic membrane closer from threshold