nervous system 2

Question 1

direction of information flow through neurons

Answer 1

dendrites -> cell body -> axon

Question 2

types of specialised glial cells

Answer 2

astrocytes, schwann cells

Question 3

whats the most numerous cell type on the brain?

Answer 3

astrocytes

Question 4

what is the role of astrocytes

Answer 4

‘housekeeping’ role. regulate chemical content of extracellular space. support structure in spaces between neurons

Question 5

which type of specialised glial cells myelinate axons

Answer 5

schwann cells

Question 6

another name for sensory axons in PNS?

Answer 6

afferent axons

Question 7

another name for motor axons in PNS?

Answer 7

efferent axons

Question 8

which roots in the spinal cord contain which roots

Answer 8

dorsal roots = afferent axons
ventral roots = efferent axons

Question 9

what type of axons to spinal nerves contain

Answer 9

afferent and efferent axons (both)

Question 10

what are the actions of afferent and efferent axons

Answer 10

afferent axons - from skin send info to spinal cord and brain
efferent axons - innervate muscles

Question 11

what actions do the spinal cord take part in

Answer 11

reflexive actions which are automatic not requiring the brain.

Question 12

what are excitable cells? function?

Answer 12

electrically charged cells, use electrical currents to sense stimuli, transmit information, and ‘do something’

Question 13

can ions diffuse through the phospholipid membrane?

Answer 13

no!

Question 14

how must ions pass through the cell membrane?

Answer 14

through ion pumps or channels

Question 15

concentrations of sodium, chloride, potassium in the cytoplasm and extracellular fluid?

Answer 15

extracellular - high sodium and chloride, low potassium.
cytoplasm - high potassium, low sodium and chloride

Question 16

what does the sodium-potassium ATPase do?

Answer 16

used ATP to transfer 3Na+ ions in and 2K+ ions out

Question 17

what are ion channels

Answer 17

proteins which make pores/gated which allow ions to move across the lipid membrane. can be selective for particular ions

Question 18

what are leak potassium channels

Answer 18

open at rest, help set the resting membrane potential, selectively permeable to potassium

Question 19

what are leak potassium channels regulated by

Answer 19

pH, oxygen tension, stretch

Question 20

what are the two forces determining which side of the membrane potassium goes at rest

Answer 20

concentration gradient - diffuses out of cell as higher concentration inside
electrical force - diffuses into cell as imbalance of potassium and corresponding negative ion

Question 21

which side of the membrane is positive and which is negative during rest

Answer 21

inside - negative
outside - positive
concentration gradient means more K+ (positive ions) out and more corresponding negative ions inside

Question 22

what is the resting membrane potential in volts

Answer 22

-65mV

Question 23

two pumps that bring about the resting membrane potential

Answer 23

potassium leak channels, sodium/potassium ATPase

Question 24

another name for cell body

Answer 24

soma

Question 25

how does frequency of action potentials encode information

Answer 25

higher frequency of action potentials can mean greater sensory stimulus