nervous system overview

Question 1

functions of nervous system

Answer 1

send and receive signals within body (from brain to rest of body and from body to brain)

Question 2

CNS vs PNS

Answer 2

CNS acts as control center in receiving information and generates response to stimuli (made of brain and spinal cord)

PNS sends information to CNS and carries out action
(made of nerves and ganglia)

Question 3

motor (efferent) vs sensory (afferent)

Answer 3

motor travels away from brain (action)

sensory travels towards the brain (stimulus)

Question 4

describe nervous system as a control system

Answer 4

sensory receptors detect a stimulus –> afferent pathways bring signal to control center –> control center decides on a response –> efferent pathways bring response signal to target where action occurs

Question 5

somatic motor vs autonomic motor divisions

Answer 5

somatic = voluntary control of muscles

autonomic = signals to involuntary tissue (organs, glands, etc)

Question 6

somatic vs visceral sensory divisions

Answer 6

somatic = receives signals from skin, muscle, and joint receptors

visceral = receives signals from organs

Question 7

composition and arrangement of gray vs white matter

Answer 7

gray matter = cell bodies, dendrites and axon terminals

white matter = myelinated axons (think communication)

Question 8

structure of typical nerves

Answer 8

cell body (soma) which contains nucleus and nucleolus

dendrites branch off cell body

axon hillock and trigger zone connects to axon

Question 9

dendrites vs axon

Answer 9

dendrites –> receive information

axon –> sends impulses

Question 10

structure and location of nucleus vs ganglion

Answer 10

nucleus are found in CNS

ganglion are found in PNS

Question 11

structure and location of tract vs nerve

Answer 11

tracts are found in CNS

nerves are found in PNS

Question 12

different structural types of neurons

Answer 12

multipolar –> 1 axon and many dendrites

bipolar –> 1 axon and 1 dendrite

unipolar –> axon and dendrite on same process (cell body on the side)

Question 13

3 different functional types of neurons

Answer 13

sensory –> receive information from receptors

interneurons –> in CNS and connect sensory and motor neurons (allows for communication)

motor –> sends response to stimulus

Question 14

oligodendrocytes

Answer 14

branched structure that connects to multiple axons forms myelin sheath
–> found in CNS

Question 15

ependymal cell

Answer 15

produces CSF
–> found in ventricles and central canal

Question 16

microglia

Answer 16

acts as macrophages
–> in brain and spinal cord

Question 17

astrocyte

Answer 17

provides supportive framework
(most abundant and looks like star)
–> in CNS

Question 18

schwann cell

Answer 18

wraps PNS and forms myelin sheath
–> found in PNS

Question 19

satellite cell

Answer 19

surrounds PNS cell bodies
–> found in PNS

Question 20

myelination function

Answer 20

allows electrical impulses to transmit quickly

Question 21

myelination in CNS vs PNS

Answer 21

CNS: oligodendrocytes produce myelin sheath but do not wrap around axon, instead it pushes new under old (centripetal)

PNS: schwann cells produce myelin sheath and wrap around axon (centrifugal)

Question 22

role of sodium potassium pump in maintaining the resting membrane potential

Answer 22

for every 3 sodium ions out, two potassium ions are brought in maintaining negative potential

Question 23

depolarization

Answer 23

brings sodium in the cell to turn resting membrane potential positive

Question 24

repolarization

Answer 24

releases potassium out of the cell to bring membrane potential back to negative

Question 25

hyperpolarization

Answer 25

moves past the membrane potential

Question 26

threshold

Answer 26

minimum level of depolarization that triggers an action potential
–> once hit fires at max to depolarize
—> if not hit it returns back to resting membrane potential

Question 27

graded vs action potentials location and ions/ion channels

Answer 27

graded: temporary, decremental (gets weaker), and reversible
–> ligand gated channel

action: all or nothing (threshold), nondecremental (gets stronger), and irreversible
–> voltage gated and leakage channel

Question 28

importance of voltage-gated channels in the conduction (propagation) of an action potential

Answer 28

depolarization caused by opening of voltage gated channels acts as dominos sequentially opening sodium channels of different axons

Question 29

how do axon diameter and myelination affect conduction velocity

Answer 29

myelination allows for a domino effect
–> faster more efficient movement of signals

Question 30

role of myelin in saltatory conduction

Answer 30

propagation instead of moving channel to channel nodes of ranvier (voltage gated channel) allows signal to jump node to node

Question 31

action potential conduction in unmyelinated vs myelinated axon

Answer 31

unmyelinated: move down axon

myelinated: jump from node to node