Block 1 - Excitable Cells

Question 1

Of Na+, K+, Ca2+, Mg2+, and Cl-…which are high outside the cell and which are high inside the cell with regard to concentration?

Answer 1

Na+, Ca2+, and Cl- are higher OUTSIDE the cell. K+ and Mg2+ are higher INSIDE the cell.

Question 2

T/F An electrical gradient can only enhance the movement of ions down a concentration gradient.

Answer 2

FALSE. It can enhance OR restrict

Question 3

At rest, the membrane is ____x more permeable to K+ than Na+

Answer 3

10

Question 4

Resting membrane potential is said to be approximately ____ mV

Answer 4

70

Question 5

ENa+ is ____ mV and EK+ is ____ mV

Answer 5

+60, -90

Question 6

The passive spread of charge across a membrane is called a ____ potential

Answer 6

Graded

Question 7

Graded potentials vary by what 3 factors?

Answer 7

Polarity, strength, location of stimulus

Question 8

Voltage gated ____ channels activate and open and deactivate and close very rapidly

Answer 8

Na+

Question 9

Nodes of ____ are the locations where there are clusterings of VG Na+ channels on a myelinated axon

Answer 9

Ranvier

Question 10

____ conduction are where large portions of the axon is jumped or skipped because of it’s myelination.

Answer 10

Saltatory

Question 11

What factors influence conduction speed?

Answer 11

Diameter (smaller the faster), myelination, type of fiber (somatic/visceral)

Question 12

____ cells produce myeline in the ____

Answer 12

Schwann, CNS

Question 13

Vesicle release of neurotransmitter is controlled by voltage gated ____ channels.

Answer 13

Ca2+