8.2 Structures of Nervous System (CQ - exam)

Question 1

Explain the differences between the functions of a neuron and a glial cell.

Answer 1

Neurons
- structural/functional units of nervous system
- Responds to physical & chemical stimuli
- Conducts electrochemical signals
- Releases chemicals for regulation

Glial Cell
- Nourishes neurons
- Removes neuron waste
- Defends against infection
- Supporting framework for neurons
- Not a conductor

Question 2

parts of a reflex arc and its function.

Answer 2

• Stimulus: change to the external body
• Receptor: detects stimulus
• Sensory neuron: carries the action potential to the spinal cord
• Interneuron: receives the info, processes it in milliseconds and decides response
• Motor neuron: carries the nerve impulse to effector
• Effector (muscle): acts in response to the stimulus

Question 3

what the resting membrane potential is

Answer 3

The resting membrane potential is the charge separation that forms potential energy.
- state of 0 stimulus effecting it
- Negative on inside, positive on outside —difference is -70mV

Question 4

three factors that contribute to the resting membrane potential of a neuron.

Answer 4

1. Sodium potassium pumps
2. Ion-specific channels
3. Large negatively charged proteins in intracellular fluid

Question 5

Explain the importance of repolarization in the transmission of a nerve impulse.

Answer 5

Repolarization in transmission of a nerve impulse is important for allowing neurons to reset and prepare for the next signal—brings it back to resting membrane potential

Question 6

What are Schwann cells and what is their relationship to myelinated neurons?

Answer 6

Schwann cells are cells in the PNS that produce myelin sheath around neuronal axons.

Question 7

Summarize the events involved in impulse transmission from the presynaptic neuron to the postsynaptic neuron.

Answer 7

Nerve impulse stimulate the movement of synaptic vesicles to the axon membrane (presynaptic)

vesicles fuse w/ presynaptic membrane and via exocytosis, releases neurotransmitter into synaptic cleft

Neurotransmitters diffuse across synaptic cleft

Neurotransmitters bind to receptors on post synaptic neuron and cause ion channels to open

Question 8

excitatory response and an inhibitory response

Answer 8

Excitatory response: molecules cause action potentials by opening sodium channels

Inhibitory response: molecules cause potassium channels to open, causing hyperpolarization