Basic structure and action potential

Question 1

What does the CNS consist of

Answer 1

brain and spinal cord

Question 2

What are the two main types of cells

Answer 2

• NEURONS (recieve and transmit info in electrochemical form)
• GLIAL CELLS (supports neurons in function e.g nutrition/cleaning)

Question 3

What are the main components of a neuron

Answer 3

• CELL BODY
• DENDRITES (brings info into neuron)
• AXON (mylen sheath, interruptions in the sheath is called nodes of ranvier)
• AXON TERMINAL

Question 4

Describe the Multipolor neuron, Bipolor neuron and Monopolar neuron

Answer 4

Multipolor neuron - many dendrites and a single neuron

Bipolor neuron - single dendrite at one end and single axon at other end

Monopolor neuron - single branch going in two directions with a soma in the middle

Question 5

What does PNS consits of

Answer 5

• Sensory neurons (afferent, skin to CNS)
• Motor neurons (efferent, CNS to muscle)
• interneurons (connection point between sensory and motor neurons)

Question 6

Outline the glial cell: Astrocytes

Answer 6

• largest glial cell
• helps regulate blood flow in the brain

Question 7

Outline the glial cell: Microglia

Answer 7

• smallest glial cell
• removes dead cells (part of immune system)

Question 8

Outline the glial cells: Oligodendrocytes/schwann cells

Answer 8

produces myelin which dramatically increases speed which action potential travels down axon

Question 9

What is a nerve impulse

Answer 9

An electrical message transmitted down axon

Question 10

What is the membrane potential

Answer 10

The difference in electrical charge between the inside and outside of the cell (-70 mV) (polarization)

Question 11

What is the resting potential

Answer 11

state of neuron prior to sending off a nerve impulse

Question 12

What kind of gradient does a neuron membrane potential maintain

Answer 12

electrical

Question 13

The membrane is selectively permeable (some chemicals pass more freely than others), what chemicals cant pass freely

Answer 13

• sodium (Na+)/Chloride (CL-) = higher concentration outside of the cell
• Potassium (K+) = higher concentration inside the cell.

Salty banana

Question 14

What two gradients drive Na+ in and pushes K+ out

Answer 14

• electrical gradient
• concentration gradient

Question 15

Describe hyperpolarization and depolarization in the action potential

Answer 15

hyperpolarization - membrane potential becomes more negative than when at resting potential

depolarization - membrane potential becomes more positive than when at resting potential

Question 16

When does a nerve impulse (action potential) occur

Answer 16

when the threshold of excitation is met, threshold varies (-65mv)

Question 17

What is the name for the state before membrane returns to resting potential

Answer 17

temporary hyperpolarisation

Question 18

The sodium potassium pump restores the original distribution of ions, what is the quantity of Na+ and K+

Answer 18

3Na+ ions exported out for every 2k+ ions brough into the cell

Question 19

What are absolute and relative refractory periods

Answer 19

Absolute = first part of the period, membrane cant produce an AP

Relative = second part of the period, stronger than usual stimulus to trigger another AP

Question 20

What quantity is resting potential

Answer 20

• 70 mv

Question 21

what is all or none law

Answer 21

when amplitude and velocity of action potential is the same for a given neuron

Question 22

What is the rate law

Answer 22

strength of a stimulus is represented by the firing rate of an axon

Question 23

how do signals travel through axon

Answer 23

jumps from node to node (saltatory conduction)

Question 24

What is the sights at which the cell synthasizes new protein molecules called

Answer 24

ribosomes

Question 25

what is the resting potential of a neuron

Answer 25

the net negative charge on the inside of the neuron

Question 26

what function cant glia cells do

Answer 26

transmit information