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