Neuronal Signaling and Nervous System (part two)

how many millivolts is sodium

+60mV

Potential difference across neuron's cell membrane at REST is (inside is negative; outside is postive)

-70mV

how many millivolts is potassium?

-90mV

action potential is very rapid which is duration of

1-4ms

Factors that determine synaptic strength: Postsynaptic factors (name 4)

1. Immediate past history of electrical state of postsynaptic membrane 2. effects of other NTs or neuromodulators acting on postsynaptic neuron 3. Up or down regulation and desensitization of receptors 4. Certain drugs and diseases

The membrane potential VM is related to the state of gated channel like (name3)

1. Ligand-gated 2. Voltage-gated 3. Mechanically-gated

The nervous system function is (name 5)

1. Maintaining homeostasis 2. Sensation 3. Movement 4. sends rapid electrical signals for communication 5. Chemical communication

The membrane potential VM at a particular time is a function of two things:

1. The equilibrium potential of all ions 2. The permeability of the membrane to each ion

Factors that determine synaptic strength: General factors (name 4)

1. area of synaptic contact 2. enzymatic destruction of NT 3. geometry of diffusion patj 4. NT reuptake

Factors that determine synaptic strength: Presynaptic factor (name 5)

1. availability of NT 2. axon terminal membrane potential 3. axon terminal Ca2+ 4. Activation of membrane receptors on presynaptic terminal 5. Certain drugs and diseases, which act via the above mechanisms A-D

Catecholamies includes (name three)

1. dopamine 2, norepinephrine 3. epinephrine (adrenaline)

A drug might also... (name 5)

1. increase transmitter release into cleft 2. block transmitter release 3. inhibit transmitter synthesis 4. block transmitter uptake 5. block cleft enzymes that metabolize transmitter

3 facts about action potential

1. large changes (100mV) 2. always the same size & type of polarization 3. do not degrade with time and distance (regenerated)

Th function of ion K+ and Na+ concentration gradients (name 5)

1. more Na+ outside cell 2. more K+ inside cell 3. More Cl- outside cell 4. function of leak channels 5. function of relative numbers of channels

3 facts about graded potentials...

1. small changes 2. variable in size and type of polarization 3. degrade with time and distance

In the PNS, what is in the efferent division (name two)

1. somatic motor 2. autonomic motor

In the PNS, what is in the afferent division (name three)

1. somatic sensory 2. visceral sensory 3. special sensory

Extracellular Cl- concentration

100 mmol/L

Extracellular Na+ concentration

145 mmol/L

Intracellular Na+ concentration

15 mmol/L

Intracellular K+ concentration

150mmol/L

How many terminals do real neurons receive?

200,00

establishment of resting potential: Na+/K+ pump establishes concentration gradient generating a small negative potential.. Pump uses up to __% of the ATP produced by that cell!

40%

Extracellular K+ concentration

5mmol/L

Intracellular Cl- concentration

7 mmol/L

propagation of APs, mechanism of communication in nervous system (especially long distance) what is it

Action potential

what has two neuron chain (connected by synapse) between CNS and effector organ?

Autonomic ns

Afferent (sensory) input to

CNS

what is the nernest equation ?

Eion=61/Z * log (Cout/Cin)

adrenergic receptors

GPCRs

what can be excitatory (depolarizing) or inhibitory (hyperpolarizing)

Graded potential

synaptic potential

Graded potentials produced in the post-synaptic cell in response to NT

Ohm's Law is

I=V/R

What are catecholamine symptoms?

Mood, states of consciousness, movement, blood pressure regulation

In membrane potential changes: the result from change in permeability of membrane to ions when

NT binds to receptor at dendrite or soma

The absolute refractory period is when

Na+ channels cant reopen yet

What enters and exits a cell

Na+ enters the cell, K+ exits cell

Equilibrium potential can be calculated by using the

Nernest Equation

In ACh, what depolarizes membrane when activated?

Nicotinic receptor (N-AChR)

In AcH, what are the two types of receptors?

Nicotinic receptor and Muscarinic receptor

muscles, skins, sensory organs, internal organs is all examples of what type of nervous system?

PNS

Communication between brain/spinal cord and periphery, anything outside the brain and spinal cord, receptors and effectors... is

Peripheral nervous system

What is involuntary command: EMERGENCY!

Sympathetic

receptor potential

a graded potential produced at peripheral endings of afferent neurons

what curve is an EPSP?

a higher curve

presynaptic neuron

a neuron that SENDS the message to another neuron

Communication is when

a single neuron postsynaptic to one cell can be presynaptic to another cell

pacemaker potential

a spontaneously occurring graded potential change that occurs in certain specialized cells

Excitability

ability to respond to a stimulus

all or none is

action potential

what can change as much as 100mV

action potential

whats an large potential change in the membrane

action potential

Saltatory Conduction

action potentials jump from node to node

In the PNS

all neurons and nerves that are not in the brain or spinal spinal cord

Autonomic nervous system consists of

autonomic (involuntary, unconscious), excitatory or inhibitory, and has parasympathetic and sympathetic nervous system

What can either be excitatory or inhibitory?

autonomic ns

what innervates smooth, cardiac muscles, glands, GI neurons, but not skeletal muscle cells?

autonomic ns

Action potential occurs in

axon

Hyperpolarization

becomes MORE negative

Depolarization means

becomes less negative

Adrenergic neurons release

catecholamines

Two parts of the nervous system

central nervous system and peripheral nervous system

Neurotransmitters

chemical messengers

Acetylcholine (ACh), what type of neurons and what does it release?

cholinergic neurons which release ACh

In the CNS, the brain

control center, processes input, generates output

In Ohm's Law (I=V/R), I stands for

current

graded potential usually occurs where

dendrites or cell body

the slower opening of voltage gated K+ channels explains the _________________ and _____________________ phases that complete the action potential.

depolarization and afterhyperpolarization

excitatory neurotransmitters

depolarizes neuron (makes it less neg, closer to AP threshold)

How potential is measured with a voltmeter:

difference between IC and EC charges

What binds to receptor on postsynatic membrane to block or mimic transmitter action??

drugs

What inhibit or stimulate second messenger activity within postsynaptic cell?

drugs

what can increase leakage of neurotransmitter from vesicle to cytoplasm, exposing it to enzyme breakdown?

drugs

Distribution of charged particles at cell membrane relates to the

electrical activity there (communication between cells)

net flux of charged molecules determines

electrical charge and potential

In Ohm's Law (I=V/R), V stands for

electrical potential

carrying information is an example of

electrical potential

The equilibrium potential is

electrical potential that balances the chemical gradient of a certain ion

cells communicate by generating ___________________ that move along the cell or to adjacent cells

electrical signals

neurons carry

electrical signals

Gated channels can open and close to allow cells to produce

electrical signals to transmit information

NT can elict

epsps and ipsps

Gated channels that can open and close to allow cells to produce electrical signals to transmit information is called

excitability

NT effect can be

excitatory or inhibitory

graded potentials can be

excitatory or inhibitory

In the nernst equation (Eion= 61/Z log) (Cout/Cin), what does C out stand for

extracellular concentration of ion

Covergence is when

four primary neurons communicate to one secondary neuron

oligodendrocytes, astrocytes, microglia, ependymal cells, schwann cells are all examples of

glial cells

what physically and metabolically support neurons?

glial cells

Glial cells are like

glue

An excitatory postsynaptic potential (EPSP) is a

graded depolarization that moves the membrane potential closer to the threshold for firing an action potential (excitement)

An inhibitory postsynaptic potential (IPSP) is an

graded hyperpolarization that moves the membrane potential further from the threshold for firing an action potential (inhibition)

Small change in membrane potential, confined to small region of membrane is an

graded potential

pebble in water is an example of

graded potential

the size of a ______________ is proportionate to the intensity of the stimulus.

graded potential

Resistance:

hindrance of electrical charge movement

sodium potassium pump is always going to use

hydrolysis of ATP, (to break down into ADP)

inhibitory neurotransmitters

hyperpolarizes neuron (makes it more neg, further away from AP threshold)

In the nernst equation (Eion= 61/Z log) (Cout/Cin), what does C in stand for

intracellular concentration of ion

NT receptors usually influence ____________ that directly affect excitation or inhibition of the postsynaptic cell

ion channels

Binding causes

ion channels to open (allows ions to pass---> changes charge)

sodium potassium pump is an active transport because

it uses atp

A cell is "polarized" because

its interior is more negative than its exterior

Define synapse

junction between two neurons

graded potentials are named according to

location or function of potential (receptor potential, synaptic potential, pacemaker potential)

what curve is an IPSP?

lower curve

Insulators:

materials with high electrical resistance

Conductors:

materials with low resistance (ex: H2O with dissolved ions)

NM receptors bring about

metabolic processes

graded potentials decay as they

move over distance

Current:

movement of electrical charge

Efferent (motor) output to

muscles/glands

In the CNS, the spinal cord

nerves; carries messages to and from the brain in nerves

neuron is an

nervous system cell

example like Na+, Cl- in ECF K+ ionized molecules in ICF are all examples of

net flux of charged molecules

What can amplify or dampen effectiveness of synapse

neuromodulators

postynaptic neuron

neuron that RECEIVES the message from another neuron

Acetylcholine is an

neurotransmitter

Electrical signal causes release of an _________________, to communicate with other cells

neurotransmitter

What bind to receptor in postsynaptic neuron

neurotransmitters

what has a cross synapse

neurotransmitters

The membrane potential VM is related to the

numbers of leak channels

Divergence is when

one primary neuron communicates to four secondary neurons

leak channels are always

open

what is involuntary command: rest and digest

parasympathetic

NT are chemical messengers released from presynaptic neuron to cause a response in

postsynaptic neuron

across a membrane (voltage) is an example of

potential difference

Strength or effectiveness is influenced by

presynaptic and postsynaptic events

somatic means

relating to the body

In Ohm's Law (I=V/R), R stands for

resistance

electrical potential is

separated electrical charges with opposite sign have the potential to do work if they come together

somatic nervous system is to

skeletal muscle

In action potential what happens to K+

slower opening, K+ channels open, K+ exits the cell, repolarizing neuron

Autonomic nervous system is to

smooth muscle, cardiac muscle, and glands

glial cells surround what? (name three)

soma, axon, and dendrites

what is a voluntary command: MOVE!

somatic

What innervates skeletal muscle cells

somatic ns

what can only lead to muscle cell excitation

somatic ns

what consists of a single neuron between CNS and skeletal muscle cells?

somatic ns

somatic NS consists of

somatic, voluntary, movement (muscle cell excitation)

opposite charges attract each other and will move toward each other if not separated by

some barrier

relative refractory period is when

some channels can open, but stimulus strength must be larger to cause an AP

Autonomic motor consists of

sympathetic, parasympathetic, and enteric

The propagation of the AP from the dendritic to the axon terminal end is typically one way because

the absolute refractory period follows along in the wake of the moving AP

The membrane potential of a real neuron typically undergoes many EPSPs and IPSPs, since it constantly receives excitatory and inhibitory input from ....

the axons terminals that reach it

In action potential what happens to Na+

the channels open, Na+ rushes in, depolarizing neuron, and AP occurs

overshoot refers

the development of a charge reversal

Potential difference is

the difference in charge between two points

In graded potential, the word "graded" is used because to state

the magnitude of change can vary

NT can cause ion channels in postsynaptic neuron to open or close, which changes

the membrane potential

threshold potential

the membrane potential at which an action potential is initiated (-55mV)

repolarization is

the movement back to the resting potential

Neuromodulators (NM) often modify

the postsynaptic cell's response to specific NTs (instead of causing EPSP or IPSP)

whats at the beginning of the action potential?

the rapid depolarization phase

-55mV needs to be met in order for ___________

the voltage gate to be received

In the nernst equation (Eion= 61/Z log) (Cout/Cin), what does Z stands for

valence of the ion (available ions)

Unit of electrical potential

volt (V)