lecture 10 nervous sys

Question 1

define radiata

Answer 1

a major grouping that includes more or less radially symmetrical animals, as coelenterates (jellyfish, sea anemones, corals), ctenophores (comb jellies), and echinoderms (starfish, sea urchins, sea cucumbers)

Question 2

what type of nervous sys does radiata have?

Answer 2

basic radially arranged network of nerves.

Question 3

integration

Answer 3

receives input and decides what should be done about i

Question 4

name 3 jobs of the central nervous system

Answer 4

consists of brain and spinal cord 
receives and integrates sensory input from the PNS 
sends commands (based on PNS input) back to the PNS

Question 5

peripheral nervous system divides

Answer 5

divides into the sensory and motor division

Question 6

motor sys divides into the

Answer 6

somatic and autonomic

Question 7

autonomic divides into the

Answer 7

sympathetic and parasympathetic

Question 8

effector

Answer 8

an organ or cell that acts in response to a stimulus

Question 9

name 3 effectors of the pns?

Answer 9

muscle cells
secretory cells
any organ that can respond to a neural signal

Question 10

propogate

Answer 10

to transmit or spread from one generation to the next

Question 11

dendrites

Answer 11

receive signal input from other neurons

Question 12

soma

Answer 12

integrates synaptic potentials

Question 13

axon (= nerve fiber)

Answer 13

conducts signal away from the soma

Question 14

axon terminals

Answer 14

propagate the signal to the next neuron

Question 15

afferent

Answer 15

sensory signals from receptors –> CNS

CNS integrative centers process the input.

Question 16

efferent

Answer 16

control signals from the CNS –> effectors

Effectors (targets such as muscle or secretory cells) effect a response

Question 17

interneurons

Answer 17

connect neuron to neuron within the CNS.

Question 18

synapse

Answer 18

The space between the axon terminal of one neuron

and the dendrite of another

Question 19

excitatory synapse

Answer 19

increases probability of propagation to a postsynaptic cell.

Question 20

inhibitory synapse

Answer 20

decreases probability of propagation to a postsynaptic cell.

Question 21

innervate

Answer 21

Neurons with synaptic terminals connected to a cell

Question 22

glial cells

Answer 22

provide neurons with support and protection.

Question 23

name the 4 roles of glial cells

Answer 23

surround neurons and hold them in place
supply neurons with nutrients and oxygen
insulate neurons from each other
destroy pathogens and remove dead neurons

Question 24

oligodendrocytes

Answer 24

form myelin sheath for cns

Question 25

astrocytes

Answer 25

form communication link between capillaries and neurons

Question 26

ependymal cells

Answer 26

ciliated; line ventricles of brain and spinal cord central canal

Question 27

microglia

Answer 27

macrophages that mediate CNS immune response

Question 28

name the 3 type of ganglias of somas that satellite cells wrap themselves around?

Answer 28

sensory sympathetic parasympathetic

Question 29

what does mylin really do?

Answer 29

forms an insulating sheath around nerve fibers sheath increases speed of action potential transmission composed of proteins and phospholipids it prevents electrical signals that travel down the axons from decaying due to electrical current leaking out through the axon membrane

Question 30

invertebrates have myelin precursors but is it the same as the myelin of vertebrates?

Answer 30

no because the precursor does not spread long and last for up to 1 milisec while vertebrates have 20 to 100 milisec

Question 31

nerve

Answer 31

bundle of axons and their myelin sheaths in the PNS

Question 32

endoneutrium conn tiss

Answer 32

surrounds each axon/myelin sheath

Question 33

fasicle

Answer 33

Sheathed axons are bundled

Question 34

perineutrium con tiss

Answer 34

encases each fascicle.

Question 35

epineurium conn tiss

Answer 35

encases all the fascicles together.

Question 36

tracts

Answer 36

In the CNS, the structures analogous to fascicles

Question 37

ascending tracts

Answer 37

carry impulses along the spinal cord toward the brain.

Question 38

descending tracts

Answer 38

carry impulses from the brain (or higher spinal cord) | to lower spinal cord regions.

Question 39

ganglion

Answer 39

- cluster of nerve cells OR nerve cell bodies occuring somewhere along a nerve. Ganglia - form communication connections between neurological structures. - may interconnect with each other to form a plexus

Question 40

dorsal root ganglia

Answer 40

(a.k.a. spinal ganglia) are made up of afferent neuron bodies.

Question 41

cranial root ganglia

Answer 41

are made up of cranial nerve neuron bodies.

Question 42

Autonomic ganglia

Answer 42

contain autonomic neuron bodies.

Question 43

Preganglionic nerve fiber

Answer 43

travels from the CNS to the ganglion axons are myelinated are less numerous than postganglionic fibers

Question 44

Postganglionic fibers

Answer 44

travel from the ganglion to the effector axons are NOT myelinated are more numerous than postganglionic fibers

Question 45

Ganglial autonomic neurons are

Answer 45

dendritic

Question 46

Ganglial sensory neurons are mostly

Answer 46

unipolar

Question 47

intracellular charge is decreased by

Answer 47

less k+ which leaves more proteins that have a neg charge cl ions

Question 48

resting potential and charge

Answer 48

it is the unstimluation of a nerve cell potassium pump but sodium pump is closed about 70 mv

Question 49

equilibrium potential

Answer 49

the flow of potassium ions are equal inside and outside creates a voltage

Question 50

as the electric gradient inceases

Answer 50

the chemical gradient will decre

Question 51

define action potential

Answer 51

is a momentary reversal of membrane potential | from its resting state.

Question 52

three typicals of action potential

Answer 52

- causes internal charge to change from -70mV to ~ +40mV - lasts about one millisecond - ends when membrane potential is restored to its resting state

Question 53

what part of the action potential is always the same and what part of it always changes

Answer 53

the magnitude is always the same. the frequency always changes and depends on how strong the stimuli is

Question 54

what is the threshold for the depolarization and what is the peak of the depolarization for an action potential that also resembles the absolute refractory period?

Answer 54

``` threshold is (-) 55 depolarization peak is (+) 40 ```

Question 55

value for hyperbolize

Answer 55

-75 mv

Question 56

the less sodium channels that are closing due to the relative refractory period,

Answer 56

the more strength is needed to get a depolarization for an action potential

Question 57

depolarization of voltage-gated channels along the length of the axon is what direction?

Answer 57

unidirectional

Question 58

relative refractory period (RRP)

Answer 58

After peak depolarization, K channels open, allowing K+ to repolarize the cell. This takes a few milliseconds to stabilize.

Question 59

define electronic conduction and what happens

Answer 59

Change in voltage decreases exponentially with distance from the point of stimulation. This is known as electrotonic conduction (= passive or decremental spread). As current flows away from the point of stimulation, some K+ leaks out of ion through channels, reducing voltage.

Question 60

length constant

Answer 60

distance at which the decaying voltage change is 37% of its value at the point of stimulus/origin.

Question 61

Three factors can increase conduction velocity:

Answer 61

increase in axon diameter lower resistance smaller length constant myelination prevents leakage at internode regions sodium channels open at nodes, restoring lost potential increase in temperature higher temperatures increase molecular motion but above 40o, there is the risk of ion channel denaturation Homeothermy allows shorter axons with higher velocity conduction.

Question 62

ventral root

Answer 62

root is the efferent motor root of a spinal nerve.