Unit 1 Study Guide

Question 1

Difference between afferent vs efferent path?

Answer 1

Afferent path is sensory receptor to brain while efferent path is from brain to effector.

Question 2

Sequence of afferent path?

Answer 2

Internal/External Environment, Sensory Components, Central Nervous System

Question 3

Sequence of efferent path?

Answer 3

Central Nervous System, Motor Components, Effectors

Question 4

What are examples of sensory components?

Answer 4

Sensory ganglia and nerves, sensory receptors

Question 5

List some parts of the central nervous system.

Answer 5

Cerebral hemispheres, diencephalon, cerebellum, spinal cord, brainstem

Question 6

What are some examples of motor components in the visceral motor system?

Answer 6

Autonomic ganglia and nerves

Question 7

What are some examples of motor components in the somatic motor system?

Answer 7

Motor nerves.

Question 8

What are some examples of visceral motor system effectors?

Answer 8

Smooth muscles, cardiac muscles and glands

Question 9

What are some example of somatic motor system effectors?

Answer 9

Skeletal muscles

Question 10

What is the benefit of the lipid bilayer?

Answer 10

Prevents water soluble molecules from entering without shutting out useful molecules and small polar compounds. Also ensures that the only way ions can enter the membrane is through ion channels.

Question 11

What are ion channels?

Answer 11

Proteins that span the membrane

Question 12

What are the three distinguishing properties of ion channels?

Answer 12

Selectivity (recognizing ions), reactivity (opens/closes in response to specific signals) and speed

Question 13

What determines the flow of ions?

Answer 13

Flow of the ions is determined by the concentration gradient and electrostatic force.

Question 14

Do ion channels determine the direction of the flow?

Answer 14

Ion channels cannot determine the direction of ion flow. Flow is passive, but the opening and closing of these channels requires energy.

Question 15

What is chemical stimuli ligand gating?

Answer 15

Gate opens in the presence of chemical stimuli.

Question 16

What is phosphorylation gating?

Answer 16

Gate opens with phosphate group.

Question 17

What is electrical stimuli voltage gating?

Answer 17

Gate opens at specific voltage.

Question 18

What are mechanical stimuli-mechanical sensors?

Answer 18

Gate opens when a specific mechanical stimulus applied.

Question 19

Describe the differences between resting and closed state.

Answer 19

Resting state is when the gate is closed, but can be activated if triggered. Closed is when the channel is not open and held in a refractory period where it cannot be activated.

Question 20

How does an endogenous agonist modulate a channel?

Answer 20

Endogenous agonist has binding site that latches to the channel at the left and induces conformational change that changes channel from resting to open/activated. Usually the preferred approach in therapy.

Question 21

How does a reversible antagonist modulate a channel?

Answer 21

Reversible antagonist blocks the activity of the ligand, thereby preventing the channel from undergoing conformational change. However, once the antagonist is removed, the channel will function as normal.

Question 22

How does an irreversible antagonist modulate a channel?

Answer 22

An irreversible antagonist binds to the site and then permanently closes the channel.

Question 23

How do exogenous regulators work?

Answer 23

When an endogenous ligand binds on the right side of a protein channel, the exogenous regulator binds to the opposite side and allows it to open and close.

Question 24

How are ion channels categorized?

Answer 24

Structure (membrane proteins, subunit #) and gene families (ligand-gated, voltage-gated, gap-junction channels).

Question 25

What is the difference between hetero-oligmers, homo-oligmers and repeating motifs?

Answer 25

Hetero-oligmers have distinct subunits of different gene types and are unconnected. Homo-oligmers have same subunits of the same gene types and are unconnected. Repeating motifs the same subunits of the same gene types are are connected.

Question 26

What are the common characteristics of every ion channel?

Answer 26

Membrane proteins and central aqueous pore spanning membrane.

Question 27

What would be an example of a ion channel with auxillary subunits?

Answer 27

GABA-A receptors. They have an alpha subunit and gamma or betas subunits that helps to modulate the gate portion of the channel.

Question 28

What is myelin?

Answer 28

Protective wrap around axons in a

Question 29

What happens in epilepsy from a neuronal perspective?

Answer 29

Overactive firing of neurons resulting in regenerative action potentials.

Question 30

How do we treat epilepsy using neurotransmitters?

Answer 30

Using benzodiapenes, which cause the chlorine channels to remain open for longer than usual, the influx of chlorine ions inhibits the production of further action potentials because the chloride flows through GABA channels. GABA is an inhibitory neurotransmitter that stops the production of further APs, therefore decreasing seizure levels.

Question 31

What is the membrane potential?

Answer 31

Electrical potential across the membrane measured in volts

Question 32

What is the resting membrane potential?

Answer 32

Around -60 to -75 mV.

Question 33

Why is the resting potential of the membrane close to the potential of potassium?

Answer 33

Potassium leaks through a lot of channels on the neurons.

Question 34

What is the relationship between current and voltage?

Answer 34

Directly proportional.

Question 35

How does direction of current flow get affected by the sign of the current/voltage?

Answer 35

If the graph has positive voltage/current, the current flows outwards. If the graph has negative voltage/current, the current flows inwards.

Question 36

What is the resting potential as an equation?

Answer 36

Inside voltage - outside voltage

Question 37

What is the difference between ion channel and transporter?

Answer 37

Ion channels are passively fast, move through the channels in accordance with the EC gradient, don’t cost ATP and are facilitated by the channels. Transporters are used when the ions move slowly up the electrochemical gradient and costs ATP.

Question 38

Why do scientists use 50 mM KCI to activate neurons?

Answer 38

By inducing a highly concentrated solution of potassium chloride, you create a buildup of highly concentrated potassium on the outside of the cell. As the extracellular potassium rises, the magnitude of the potassium gradient decreases and the potassium EQ potential becomes more positive. Therefore, the membrane potential as a whole becomes more positive, leading to depolarization.