Receptor and Action Potential

Question 1

A mechanical, electric, or chemical stimulus causes _____ of the input area of the cell to open

Answer 1

Na+ gated ion channels

Question 2

When the Na+ gated ion channels of the input area of the cells opens, what happens?

Answer 2

• Changes the voltage of the membrane
• Na+ ions come in
• Depolarization, makes membrane more positive

Question 3

If the receptor potential reaches the spike initiation zone of the neuron and depolarizes it to threshold (-40mV)

Answer 3

An all or none AP will be conducted

Question 4

The spike initiation zone (trigger zone) is the area with the _____ density of voltage gate Na+ channels therefore it has the _____ threshold for generating an AP

Answer 4

• Highest
• Lowest

Question 5

At threshold, both Na+ and K+ voltage gated channels get activated, BUT ___ channels respond with a 1 msec delay (falling phase/undershoot) which allows ___ to depolarize the membrane (rising phase/overshoot)

Answer 5

• K+
• Na+

Question 6

A period of time during an AP when it is impossible to initiate another AP

Answer 6

Absolute refractory period (falling phase)