Ch 11 Functional Organization of Nervous Tissue Flashcards by Abby Hinds

Nervous system divisions?

CNS & PNS. PNS includes:

Afferent (sensory) Nervous System
Efferent (motor) nervous system include:
a. somatic motor (voluntary)
b. autonomic (involuntary) which includes:
i. sympathetic (fight or flight)
ii. parasympathetic (rest & digest)
iii. enteric (controls digestive)

How well did you know this?

Not at all

Perfectly

cells of the nervous system

neurons and glial cells (neuroglia)

How well did you know this?

Not at all

Perfectly

characteristics of neurons?

respond to a stimulus, produce & transmit electrochemical impulses, release chemical messages

How well did you know this?

Not at all

Perfectly

which cells are more common in nervous system & by how much?

glial cells (make sure neurons keep working) ; 5X

How well did you know this?

Not at all

Perfectly

functional unit of a neuron

Action Potential

How well did you know this?

Not at all

Perfectly

parts of a neuron

soma= cell body
dendrite= receive messages in neuron
axon= carries impulses

How well did you know this?

Not at all

Perfectly

part of an axon

axon hillock, trigger zone, collateral, presynaptic terminal, , axolemma (membrane of axon), axoplasm (cytoplasm of axon)

How well did you know this?

Not at all

Perfectly

Axons in CNS are called? PNS?

CNS= tract

PNS=nerve

How well did you know this?

Not at all

Perfectly

Dendrites in CNS are called? PNS?

CNS= nuclei
PNS= ganglion

How well did you know this?

Not at all

Perfectly

two types of neuronal transport

axoplasmic flow: one direction; moves SOLUBLE compounds via rhythmic contractions; supply for growth, repair, renewal
axonal transport: multidirectional; moves INSOLUBLE along microtubules
a. anterograde= away from soma
b. retrograde= towards soma

How well did you know this?

Not at all

Perfectly

Functional classification of neurons

sensory/afferent: brings info to brain
motor/efferent: bring info to target organ
association/interneuron: strictly within CNS; send into to brain; connects motor and sensory

How well did you know this?

Not at all

Perfectly

structural classification of neurons

(pseudo-) unipolar: sensory neurons
Bipolar: retinal and olfactory neurons
multipolar: motor neurons

How well did you know this?

Not at all

Perfectly

Glial cells of the CNS

astrocytes, ependymal cells, microglia, oligodendrocytes

How well did you know this?

Not at all

Perfectly

astrocytes

CNS; most common glial cell; blood brain barrier

How well did you know this?

Not at all

Perfectly

ependymal cells

CNS; line ventricles and central canal

Specialized are the cerebrospinal fluid

How well did you know this?

Not at all

Perfectly

microglia

CNS; specialized macrophages; respond to inflammation

How well did you know this?

Not at all

Perfectly

oligodendrocytes

CNS; extensions insulate portions of several CNS axons= WHITE MATTER
GRAY MATTER= dendrites & soma

How well did you know this?

Not at all

Perfectly

glial cells of the PNS

schwann cells (wrap entire cell around axon), satellite cells (provide support and nutrients)

How well did you know this?

Not at all

Perfectly

unmyelinated axons are located where?

in folds of Schwann cells or oligodendrocytes

How well did you know this?

Not at all

Perfectly

multiple sclerosis

autoimmune disease

How well did you know this?

Not at all

Perfectly

schwann cells and oligodendrocyte extensions wrap around many times

myelin sheath

How well did you know this?

Not at all

Perfectly

completion of myelin sheath development at what age?

1-2 years; why it is pointless to potty train before 2 years, bc myelination to urinary bladder is not complete

How well did you know this?

Not at all

Perfectly

oligodendrocytes cont to produce 3 growth inhibiting proteins and astrocytes form glial scar that blocks regrowth when what?

when CNS axon is severed

How well did you know this?

Not at all

Perfectly

When schwann cells stop producing growth inhibiting proteins, form regeneration tube

when PNS axon is severed

How well did you know this?

Not at all

Perfectly

difference in change across a membrane

membrane potential

membrane potential is caused by?

presence of anions (neg. charge), membrane permeability, cation concentration gradients

What anion do we not like in our cells!?

Na; K+ is inside the cell, Na- is outside

unequal distribution of charges across plasma membrane

potenial difference

we let what ion move easiest

K+; it is more permeable

at what are electrical and diffusion forces equal and opposite?

equilibrium potential

describes voltage across cell membrane if only one ion could diffuse

Nernst Equation

membrane voltage of cell not producing impulses (sending messages)

resting membrane potential

at rest all cells have a ______ internal charge & ______ distribution of ions

negative & unequal

value of RMP

-70 mV

three types of membrane ion channels

leak channels: open all the time voltage gated channels: respond to change in RMP ligand gated channels: little molecules bond to open

which channels are closed at resting membrane potential?

voltage and ligand gated channels

potential difference between K+ and Na+ becomes smalls;

depolarization: influx of Na+

potential difference between K+ and Na+ becomes greater

hyperpolarization: taking (+) away from inside or letting (-) inside the cell

excitable cells (neurons and muscle fibers) discharge RMP to generate/conduct impulses

action potential

MP becomes more positive

depolarization

MP returns to RMP

repolarization

MP becomes more negative

hyperpolarization

threshold value

-55 mV

``` during depolarization: influx? at threshold, which channels open? what type of feedback loop? peaks at what value? ```

Na+ influx voltage gated sodium channels positive feedback +30 mV

``` during repolarization: what happens to channels? what happens to ions? what type of feedback? value is back at? ```

VG Na+ channels inactivate, VG K+ channels open K+ is driven outward negative feedback -70 mV (RMP)

during hyperpolarization: what establishes RMP? MP becomes _____ __________ than RMP

``` Na+/K+ pump (3 Na+ out, 2 K+ in) more negative ( ```

unable to respond to stimulus?

refractory period

absolute refractory period?

ABSOLUTELY can't respond a new stimulus in this section (hill looking part of graph)

relative refractory period?

hyper polarized can respond but with BIG STIMULUS; doesn't happen often

APs are ___ __ _______

all or nothing

amplitude of APs remains constant

frequency-modulated

local potential not sufficient to initiate AP

subthreshold

not a good conductor

axon

ability of neuron to transmit charges through axoplasm (just enough Na+ to stimulate next channel)

cable properties

conduction in unmyelinated axons | also called?

depolarization in every single section along axon; one direction bc section before is in absolute refractory period CONTINUOUS CONDUCTION

conduction in myelinated axons | also called?

AP regenerated only at nodes of ranvier (where VG Na+ channels are concentrated); speeds up propagation SALTATORY CONDUCTION

functional connection between presynaptic neuron and post synaptic cell

synapse

axodendritic synapse? axosomatic synapse? axoaxonic synapse?

attach to dendrite attach to cell body (soma) attach--rarely

depolarization flows from presynaptic into postsynaptic cell through gap junctions; in syncytial tissues

electrical synapse; syncytial= muscles function as one unit

NT stored in synaptic vesicles and released into synaptic cleft

chemical synapse

results from changes in charge across membrane, graded, no threshold, no refractory period

local potentials

EPSP

excitatory postsynaptic potential: local depolarization occurs; stimulatory response; make membrane more (+)

IPSP

inhibitory postsynaptic potential: causes hyperpolarization; inhibitory response; add (-)

postsynaptic potenials summate what 2 ways?

spatial summation: impulses received from DIFFERENT SYNAPSES at the same time temporal summation: multiple sigmas arrive in RAPID SUCCESSION at the same synapse

spatial and temporal summation occur simultaneously

total summation

excitatory neuron synapses on presynaptic neuron and increases the amt of NT released by releasing more excitatory NT

presynaptic facilitation (ENHANCE)

inhibitory neuron synapses of presynaptic neuron and decreases amt of NT released by releasing more inhibitory NT

``` presynaptic inhibition (REDUCE) EX: loss of dopamine? lose inhibition --- Parkinson's with uncontrollable tremors ```

inhibitory neuron synapses onto postsynaptic cell

postsynaptic inhibition: won't completely stop the signal, just lessen it

types of synaptic pathways

convergent: synthesis of data in brain divergent: important info transmitted to many parts of brain oscillating circuits: memory and learning

different types of neurotransmitters

acetylcholine (ACh), acetylcholinesterase (AChE), monoamine NT, amino acid NT, polypeptide NT, lipid NT, gases NT

Receptors for ACh

cholinergic receptors--nicotinic--curare; ALWAYS EXCITATORY muscarinic receptors--atropine(nightshade) ; EXCITATORY OR INHIBITORY ex. or inhabit based on receptor it binds to

enzyme that breaks down ACh into acetic acid and choline

acetylcholinesterase

G protein couple receptors

serotonin: ex-tryptophan catecholamines: alpha and beta adrenergic receptors and dopanergic recepetors

loss of dopamine

parkinsons

neurotransmitters are inactivated by

presynaptic reuptake and 1. monoamine oxidase (MAO): breaks down all AA 2. catechol-O-methyltransferase (COMT): breaks down JUST catecholine

glutamic acid and aspartic acid

AA NT ; major CNS excitatory

glycine

inhibitory-block channels; w/strychine (rat poison) can't control voluntary mvmt

GABA

most common in brain

Huntingtons Disease

over time GABA receptors in brain degenerate (men mostly)

satiety following meals; released in gut when full

cholecystokinin (CCK)

natural painkiller NT

substance P, endorphins, enkephalins, dynorphin

similar to THC in marijuana

endocannabinoids

Ch 11 Functional Organization of Nervous Tissue Flashcards

(82 cards)