© 2016

Focus Figure 11.11 - Action Potential - Neurophysiology Activities

Set Details Share
Helpfulness: +1
show more

Interpreting an Action Potential Tracing.

Using the tracing above, drag each of the terms or values on the left to correctly complete the sentences on the right.

  • 1. This neuron is most depolarized at (+30) mV.
  • 2. This neuron spends approximately (2.5) msec in a hyperpolarized state.
  • 3. The ion (K+) is crossing the cell's plasma membrane at 1.5 msec.
  • 4. This cell reaches threshold at approximately (0.6) msec.

What does 0 mV on the Y-axis of an action potential tracing represent?

The cell's membrane is at equilibrium.

card image

Comparing and contrasting the two types of voltage-gated ion channels


- The stimulus that triggers opening

- The polarity of the substances they transport across the membrane

- The placement of channel protein relative to the membrane


Comparing and contrasting the two types of voltage-gated ion channels


- The direction of ion movement through the channel

- The inactivation mechanism


Comparing and contrasting the two types of voltage-gated ion channels

- Both channels have inactivation gates

- They move Na+ and K+ in the same direction

card image

Understanding the sequence of action potential events

An important aspect of learning physiology is understanding the cause-and-effect relationships in pathways. This activity will test your understanding of the sequence of events in an action potential. Place the action potential events below in the correct sequence. If two events occur simultaneously, place one on top of the other.

1. Activation gates on NA+ channels open; Na+ enters cell.

2. Cell Depolarizes.

3. Inactivation gates on Na+ channels close
Activation gates on K+ channels open; K+ leaves cell

4. Cell Repolarizes.

5. Activation gates on K+ channels begin to close

6. Cell experiences hyperpolarization.

card image

Matching ion channel states with the phases of the action potential

Match each phase of an action potential with the states of the ion channels you have studied. Drag the labels onto the table to indicate whether the channel is open, closed, or inactivated at the given phase of an action potential. You may use a label once or more than once.

Resting State: Na+ channels closed, K+ channels closed

Depolarization: Na+ open, K+ closed

Repolarization: Na+ inactivated, K+ open

Hyperpolarization: Na+ closed, K+ open


Understanding why hyperpolarization happens

Following repolarization, the neuron may become slightly hyperpolarized before it re-establishes its resting membrane potential.

Hyperpolarization is due to a difference between how the voltage-gated Na+ and K+ channels work. What is this difference?

Voltage-gated Na+ channels stop the flow of Na+ relatively quickly, while voltage-gated K+ channels are slow to close, resulting in the overshoot.


Making predictions based on your understanding

Interpreting tracings of membrane potential is an important skill in a course like this. In future chapters, you will see other instances of cells experiencing changes in membrane potential. For example, the tracing below is from a cardiac muscle fiber that is undergoing an action potential.

Based on your knowledge of action potentials in neurons, what can you conclude about how they occur in cardiac muscle fibers?

Cardiac muscle fibers depolarize more quickly and spend more time depolarized than neurons do.

Related pages

surgical removal of the gallbladder medical termbacillus subtilis spore stainare fruit flies asexuallayers of mucosadescribe the process of ossification of the skullocean omnivorechapter 14 questions human genomemnemonic for posterior forearm musclesepidermis functionsdefinition of glycogenolysisthe anatomy of the human digestive system answer keywhich of the following does not stimulate erythrocyte productionheredity worksheet answerswhat does dna primase doworlds hardest spelling wordswhich plant hormone is most closely associated with cell divisionhuman reflex physiology exercise 16 answerswhat does the nuclear envelope do in a plant celltheodora and her attendantswhich of the following is true about carbohydrate digestionto what does the term polypeptide referpronouns flashcardsself enema administrationimpossible quiz question 79what is a coccusfunction of lunulamicrotubules in animal cellthe modulating control valve allows you to control thetestis layersa vaccine works by ______this pigment absorbs ultraviolet lightwhere is spongy bone foundwhich sentence best describes the role of rnaoctanol molar massanatomy and physiology chapter 6 quizsirs.sksenterococcus faecalis morphology and arrangementimmobile jointsegmentation digestionfoetal skull anatomythe ventral rami of spinal nervesgerman numbers 1-31prefix meaning musclevolkmann canalcorresponding angles conjectureconnect anatomy and physiology saladininternal respiration occurstkam testabnormal psychology mood disorders quizradiographic projectionmuscle that abducts the armdo plants grow towards lightintrons and exons in protein synthesisintersegmental reflexwhat are sporophytes and gametophytesap biology chapter 51 reading guide answersshin bone diagramthe axial skeleton includes thethe adrenal gland is divided intolacteal digestive systemcampbell biology custom editionacceleration is defined as the change in velocity divided bylayers of skin mnemonicmeiosis picresearch paper notecardsfunction of the pancreas in the endocrine systembipolar interneuronsat word quizsutherland discovered that epinephrineisotonic fluid volume loss