Coordenation & regulation nervous systems Flashcards
organ systems must be coordinated within…
an animal
the environment
what are the two major systems involved with coordination and reulation
-nervous system
-endocrine system
what is the speed of reaction for the nervous system and endocrine system
nervous- very fast (milliseconds)
endocrine- slow (sec, hrs, days)
what animals is the nervous system found in
all except sponges
what are the three major roles of the nervous system
-collects information
-process & integrate information
-transmits information
how does the nervous system collect information
-form internal or external environment
-using modified neurons
how does the nervous system process & integrate information
evaluates based on past experiences or genetics
how does the nervous system transmit information
coordinates/regulates effector organ/cells
what is the process of a system when things have been senced
-sensory receptors
-sensory input (afferent) (peripheral nervous system)
-integration (central nervous system)
-motor out put (efferent)
-effector cells
(all activities depend on bioelectricity)
what does efferent mean
coming out of the central nervous system
what does afferent mean
going into central nervous system
what do neurons do
-generate bioelectrical signal
-used to transmit information to other cells
what do glial cells do
-they are the support cells
-assist in neuron signalling
-produce cerebrospinal fluid
-maintain environment around neurons
what are the three types of neurons
-motor neuron
-sensory neuron
-interneuron
what peices make up the neuron
signal reception:
-dendrites
-cell body
signal integration:
-spike initiation zone = axon hillock
signal conduction:
-axon
-cell body of sensory neurons
signal transmission:
-axon terminals
where do motor, sensory, and interneurons connect to
motor- muscle
sensory and intern- another neuron
what is a neuron
an individual cell
what is a nerve
a bundle of axons (a few to a millions)
what is an axon
a nerve fiber
what is synapse
connection between axon terminal & effector cell
what is effector cell
can be a neuron, muscle cell, any other cell that does something based on inputs form nervous system
what is potential
-difference in electrical charge between regions
-measured in volts or millivolts
what is current
-flow of electrical charges between regions
-opposites attract, like repels
-charge can move and that is the current
what is membrane potential
-unequal charge distribution across a cell membrane
-potentail form inside the cell
what is bioelectricity
-potential
-current
-membran potential
what does it mean that all cells are electrically polarized
-have membrane potential
-inside is negative relative to exterior side
-size ranges form -10 to -90mV
how are neurons and muscle cells specially adapted
-have large membrane potentials
-special mechanism to regulate membrane potentials and currents
what are the three types of membrane potentials
-resting membrane potential
-electrotonic potential
-action potentials
what do membrane potentials and currents depend on
inorganic ions
what is the resting membrane potential
-measured when neuron is inactive
-about -70mV in neutrons & muscle cells (less then out side)
-due to unequal distribution of ions across the membrane
-principal ions involved are Na+ and K+
extra cellular fluid always has…
high [Na+]
low [K+]
intracellular fluid always has…
high [K+]
low [Na+]
sodium… potassium…
sodium outside cells; potassium inside cells
what is the ion gradient maintained by
active transport
where is ion gradient found
in all cells
how does the ion gradient move things
moves 3 Na+ out, 2 K+ in
how much potential does the ion gradient generate
-10mV potential
what kind of pump is an ion gradient pump
electrogenic pump
the resting membrane potential is -70mV in neurons and muscle cells where is this generated form
-electro negative pump: -10mV
-anionic proteins: -5mV
-passive diffusion of K+ through and open K+ channel
what are ion channels specific for
each ion
leak channels are always…
open
how are channels often regulated in neurons
voltage gated
what does it mean when a cell is polarized
it is negative inside
what does it mean when a cell is depolarized
it becomes more + inside
what is hyperpolarization
the cells become more - inside
when do cells become polarized or depolarized
it happens during electronic potentials or the action potentials which both happen for a small amount of time
what is electronic potential
small changes in membrane potentials
what is action potentials
large and rapid changes in membrane potentials
where does the current run on the membrane
current (ions) travel along the surface of membrane
what is repolarization
the coming back to the resting mem potential regardless of the direction of the initial movement
what are electronic potentials used to initiate
-an action potential in axon hillock
-also to conduct action potential along axon
what are action potentials
-they are initiated in axon hillock region
-found only in axons
-carries the signals from axon hillock to terminals
what are some special features of action potentials
-depolarize membrane (from -70 to +35mV)
-all or nothing but transient
-once started conducted along the entire axon
-rely on ion currents through membrane via voltage gated ion channels
when do action potential voltage-gated channels open
only when cell is at certain state of depolerization
an action potential is…
transient
all or nothing
what is threshold
voltage at which AP is initiated
what does action potential depend on
ion currents and voltage gated channels
what is the difference between a channel boing closed and inactive
closed means it can open again
inactive means it cant open again
what kind of feedback is action potential
positive feed back
where is the action potential initiated
in the axon hillock
what initiates the acton potential
the concentration of NA+ voltage gated channels
what reduces backpropagation in soma
-the axon hillock [] of K+v channels reduces backpropegation into the soma
-when down stream Na+v channel reaches threshold (new AP) refractory period prevents backpropagation
in unmyelinated axons what determines the speed of conduction
axon diameter larger=faster
in unmyelinated axons how fast is the speed of conductivity
40+/- m/s
what kind of animals have unmyelinated axons
most invertebrates
what is the myelin
-made or proteins and lipids
-insulation prevents ions from crossing the membrane-reduces current loss
how do ions cross a myelinated axon
concentration of Na+v and K+v at nodes allows ions to cross membrane
what is the refractory period
after peak of action potential and on
how do axon hillocks vary in unmyelinated and myelinate neurons
they are very similar in there conduction process but current spreads quicker between nodes in myelinated
what is saltatory
jumping (in myelinated axon conduction from node to node to reach terminals
how fast is the conduction velocity in myelinated axons
higher conduction velocities (up to 100m/s)- vertebrates
what are the two types of synaptic transsmitions
electrical and chemical
what is electrical synaptic transmission
actual ions flow from cell to cell occurs via gap junctions
ex.
cardiac muscles and cells
neurons in a few invertebrate animals
what is chemical synaptic transmission
another molecule carries signal nerotransmitters from presynaptic cell
ex
majority of neurons
what do gap junctions do
-they directly connect cytoplasm of each cell
-ions flow between cells
-rapid flow of current
-cant be modulated only excitatory
what is pre and postsynaptic
-one side of the synapse is the axon terminal of a presynaptic cell (neuron that transmits the signal)
-On the other side is the dendrite a postsynaptic cell (the neuron or the surface of an effector that receives the signal)
how are pre and postsynaptic neurons separated in chemical synapses
by the synaptic cleft
how does chemical synapsis work
-there are neurotransmitters stored in vesicles and the action potental causes the Ca+ to influx
-vesicle binds to presynaptic membrane and neurotransmitter released into cleft
-neurotransmitter binds to poststnaptic receptors-channels open-depolarization or hyperpolerization
what is inhibitory and excitatory neurotransmitters
in-block or prevent the chemical message from being passed along any farther (hyperpolerization)
exc-“excite” the neuron and cause it to “fire off the message,” meaning, the message continues to be passed along to the next cell (depolarization)
what does chemical synapsis allow for
intergration of multiple presynaptic inputs
what are neurotransmitters
-there is many different kinds
-they have diverse effects
-can stimulate or inhibit and effector cell
-all bind to a receptor protein in post-synaptic membrane
-each NT has several different receptors
what is acetylcholine
-neurotransmitter
-in the CNS it stimulates the brain, important in memory, motor control, and more
-in the PNS it stimulates skeletal muscle at neuromuscular juction, inhibits cardiac muscles, promotes digenstion
what are biogenic amines and there function
-neurotransmitter
-catecholamine: dopamine, norepinephrine, epinephrine
-serotonin
-histamine
-CNS it regulates mood, attention, learning, and more
-PNS it catecholamines stimulates cardiac muscle, improves lung function, help animals respond to stressful situations
what are the amino acids and there functions
-neurotransmitters
-excitatory amino acids: glutamate, aspartate
-inhibitory amino acids: gamma-aminobutyric acid (GABA), glycine
-widespread mediators of activity in all areas of CNS; the majority on and off signals of the CNS
what are the neuropeptides and there functions
-neurotransmitters
-opiate peptides: endorphin, enkephalin, oxytosin
-in the CNS modulate postsynaptic cell response to neurotransmitters; play a role in mood, behavior, appetite, pain preception, and many others
what are the gas neurotransmitters and there functions
-nitric oxide, carbon monoxide
-CNS possible role in memory and odor sensation
-PNS relaxes smooth muscle, especially in blood vessels
when acetylcholine stimulates and inhibits different muscles how does it do it
-it has different receptors for different things it is activating or inhibiting
-i.g stimulates muscle contraction via a nicotine receptor
-inhibits cardiac muscle contractions via a muscarinic receptor
what are the two classes of receptor proteins
ionotrophic receptors (eg nicotine recept) and metabotrophic receptors (eg muscarinic receptor)
how do ionotrophic receptors work
-they have ligand gated channels
-post synaptic response depends on ion current
-eg the nicotinic receptor is Na+ channel
-eg the GABA receptor is a Cl- channel
what stimulates and inhibits ionotrophic receptors
-acetylcholine stimulates by depolarization
-GABA inhibits by hyperpolarization
how do metabotropic receptors work
-they are influenced by post synaptic cell indirectly
-acts via an intracellular signal (2nd messanger)
-has diversity of effects on cells
why do ions move across post-synsptic membranes
due to nurotransmitter binding to receptor
what is post-synaptic electrophysiology
-ions move across post-synsptic membranes due to nurotransmitter binding to receptor
-causes an electronic potential (EP) in dendrites
-flows along membrane surfaces to axon hillock
-EP from dendrites called post-synaptic potentials (PSP)
what are electronic potentials (EP) from dendrites called
post synaptic potential (PSP)
at the hillock what will the PSP do
depolarize or hyperpolarize the membrane
how do you know what the PSP at the hillock will do
it depends in the type of receptor/ion channel in the dendrite
-Na+ channel will let Na+ flow in which causes the depolarization or excitatory PSP (EPSP)
-K+ channels will let K+ flow outward which causes a hyperpolarizing or inhibitory PSP (IPSP)
-Cl- channel will let Cl- flow inward which causes hyperpolarizaiton (IPSP)
what does nurotransmitter release trigger
action potential
what are EPSP and IPSP called
graded potentials
what does the size of PSPs depend on
amount of neurotransmitters released
how much output may a postsynaptic neuron have
up to 1000 inputs onto post synaptic neuron
where does the summation of subthreshold PSPs occur at
the axon hillock
what is summation
-summation of subthreshold PSPs occur at axon hillock
-can involve EPSPs and IPSPs
-occurs in time and space
-important for processing inputs, learning, memory
neurons have the same…
basic electrophysiology
how is the diversity of post synaptic regulation possible
-many, many synaptic inputs per effector
-a wide variety of neurotransmitters
-different receptors proteins
-several intracellular signalling pathway
what are cnidarian
sea anemone
what are echinoderm
sea star
what are planarian
flatworm
what are arthropod
grasshopper
what are mollusc
octopus
what are vertebrate
salamander
what do sponges have for a nervous system
no neurons but have basic cell physiology
what is ganglia
collection of neuronal cell bodies=site of intergration
what is cephalization
concentration of neurons/ganglia in a “head” region
what drive the relative representation of brain processing regions in different groups
selective pressure
what is the reason for all the fold in the brain
folding increases surface area (# of neurons/synapses)
what is somatic
voluntary control
what is autonomic
involuntary control
what is sympathetic
whole body
flight or fight
what is parasympathetic
organ specific
rest and digest
what tissues do the sympathetic and parasympathetic supply nerves to
both to most of them
how many efferent neurons and peripheral ganglia is there
two
where does integration occur in
ganglia
what is the size of the preganglionic neurons in (para) sympathetic system
syp- short
para- long
what is the size of the postganglionic neuron in the (para) sympathetic system
syp- long
para- short
what kind of effects does the sympathetic division have
more wide spread (whole body) effects
what kind of effects does the parasympathetic division have
more organ specific effects
what does the sympathetic division do to the body
-relaxes (inhibits) airway (more O2)
-increases heart beat and force of contraction (stimulates)(more blood flow)
-inhibits digestion and stomach activity
what does the parasympathetic division do to the body
-constricts (stimulates) airways
-slows heartbeat (inhibits)
-stimulates digestion and stomach activity
what does tissue specific responses depend on
neurotransmitters and type of receptor in effector cell
what the neurotransmitters and receptor for preganglionic fibers of both (para) sympathetic divisions
acetylcholine/nicotinic receptors
what the neurotransmitters and receptor for preganglionic fibers of sympathetic divisions
norepinephrine/adrenoceptors
what the neurotransmitters and receptor for preganglionic fibers of parasympathetic divisions
acetylcholine/muscarinic receptor
when is the sympathetic nervous system active and what are some example physiology
-when the body energy stores need to be used
-flight & fight system
-inhibits digestive tract (NOR via alpha-adrenoceptor)
-stimulates heart (nor epinerfin via beta-adrenoceptor)
when is the parasympathetic nervous system active and what are some example physiology
-more active when body energy stores are being conserved/restored
-rest and digest system
-stumulates digestive tract (acytolcholine via M3 receptors)
-inhibits heart (acytolcholine via M2 receptors)
what determines if the body is in sympathetic or parasympathetic responce
-both are always activated
-overall effect depends on which is more active
what is a digram flow form th
