Chapter 17 and 18 Study Guide

What is the first step that occurs during an action potential?

• Repolarization: potassium channels flows out, helping the cell rest

• Depolarization: Sodium channels open up, and stimulus flows in

• Action potential: cell reaches 35+ millivolt, Sodium channels close, and Potassium channels open up.

• Hyperpolarization: As Potassium channels close. Extra Potassium flows out, causing the potential to be below resting potential.

• Resting potential: The resting membrane potential sits at -70 millivolts with no stimulus.

What is the second step that occurs during an action potential?

• Repolarization: potassium channels (K+) flow out, helping the cell rest.

• Depolarization: sodium channels (Na+) open up, and stimulus flows in

• The resting membrane potential sits at -70 millivolts with no stimulus.

• Action potential peak: cell reaches +35 millivolts, Na+ channels close, and Potassium channels open up.

• Hyperpolarization: As K+ channels close. Extra Potassium flows out, causing the potential to be below resting potential.

What is the third step that occurs during an action potential?

• Action potential peak: cell reaches +35 millivolts, Na+ channels close, and Potassium channels open up.

• Hyperpolarization: As K+ channels close. Extra Potassium flows out, causing the potential to be below resting potential.

• Repolarization: potassium channels (K+) flow out, helping the cell rest.

• Depolarization: sodium channels (Na+) open up, and stimulus flows in

• The resting membrane potential sits at -70 millivolts with no stimulus.

What is the 4th step that occurs during an action potential?

• Hyperpolarization: As K+ channels close. Extra Potassium flows out, causing the potential to be below resting potential.

• Action potential peak: cell reaches +35 millivolts, Na+ channels close, and Potassium channels open up.

• The resting membrane potential sits at -70 millivolts with no stimulus.

• Depolarization: sodium channels (Na+) open up, and stimulus flows in
  

• Repolarization: potassium channels (K+) flow out, helping the cell rest.

What is the final process that occurs during an action potential?

• Action potential peak: cell reaches +35 millivolts, Na+ channels close, and Potassium channels open up.

• Repolarization: potassium channels (K+) flow out, helping the cell rest.

• Depolarization: sodium channels (Na+) open up, and stimulus flows in

• Hyperpolarization: As K+ channels close. Extra Potassium flows out, causing the potential to be below resting potential.

• The resting membrane potential sits at -70 millivolts with no stimulus.

Where are photoreceptors housed in the eye?

• Cornea

• Pupil

• Retina- There are two types cones and rods

• Sclera

Which is true of interneurons?

• Take messages to the CNS

• They cannot process, store, and retrieve i information and "make decisions that determine how the body responds to stimuli.

• Carry messages from the CNS to an effector.

• They are contained entirely within the CNS and carry signals from one neuron to another.

What role does myelin sheath play with human adult axons?

• Decreases the speed of action potential conduction

• increases the speed of action potential conduction.

• To wrap myelin around the axons

• Protects and conducts of many neurons.

Nearsightedness is caused by what?

• A particular cone is lacking or deficient in number.

• The cornea or lens is uneven, producing a fuzzy image

• Eye is shortened, so image is brought to focus behind the lens.

• Eyeball is too long (light rays from distant objects converge in front of the retina)

How are frequency and pitch defined in terms of sound?

• Near the tip, it responds to low pitches

• The frequency of a sound wave is associated with our perception of that sound's pitch.

• Near the base, it responds to higher pitches.

• Volume is a function of the amplitude of sound waves.