Cell and Neurophysiology Flashcards
what is the smallest unit of life?
cell
what is the fluid that is found within cells?
intracellular fluid (ICF)
what is the fluid found between cells?
extracellular fluid (ECF)
what is the fluid found portion of blood?
plasma
the ECF is considered the body’s ___ _____
internal environment
the fluid of the ____, ___, and ___ ____ Are part of the external environment
lungs, gut, urinary system
nutrients and waste move between the external environment by crossing a ___ ____
cell layer
CO2 is a byproduct of what?
metabolism
____ is the maintence of the internal environment
homeostasis
in feedback loops, the ___ ____ is what we want to regulate
controlled variable
the ____ ____ is the optimal range of variables for the level that is to be controlled
set point
the _____ detects changes in the controlled variable
sensor/receptor
the ___ ____ is generated by the receptor
input signal
the ____ decides what active needs to be taken based on the stimulus
control (integrating center)
what is the most common control/integrating center?
brain (others are spinal cord, some cells)
neuron and hormone are examples of what in the feedback loop?
output signals
targets/effectors include what?
specific tissues
the ___ occurs when the signal reaches the target
response
in a negative feedback loop, the action ____ the stimulus
opposes
what is the most common physiological type of feedback loop?
negative
in positive feedback loops, an __ ____ is needed to shut off the cycle
outside factor
when you are fasting and your liver releases stored glucose, this is what type of feedback?
negative
when you have low oxygen from hiking in altitudes and your respirations increase, this is what type of feedback?
negative
when cool temps outside induce shivering of skeletal muscles to generate heat in the body, this is what type of feedback?
negative
what platelets in the blood release clotting factors which cause more platelets to coagulate, this is what type of feedback?
positive
what is it called when your body is anticipating a change?
feedforward mechanisms
what has the function of being the body’s major integration center?
brain and spinal cord
what makes up the central nervous system?
brain and spinal cord
what has the function of sending information to the CNS and relaying information from the CNS to effectors?
peripheral nervous system
what are all of the nerves that branch from the brain and spinal cord?
peripheral nervous system
information flows into and out of the spinal cord via ___ ___
peripheral nerves
___ ___ can process sensory information and send output signals without involving the brain
local circuits
reflexes are known as ___ _____ because they do not involve the brain
local circuits
what does the CNS split into?
sensory division, motor division
what are the three divisions of the sensory CNS?
somatic senses, special senses, visceral senses
___ senses are the ones you are conscious of
somatic
____ senses include taste, vision, sight, hearing, and balance
special
___ senses are the ones you are not conscious of
visceral
what are the two divisions of the motor CNS?
somatic, autonomic
the ____ nervous system is that of the gut
enteric
___ means that information flows from the peripheral nervous system to the integrating center
afferent
___ arrives at the integration center
afferent
afferent is ____ information and comes in three types
sensory
blood pressure, body pH, and osmolarity and examples of what type of afferent signal?
visceral
vision, hearing, equilibrium, smell, and taste are examples of what type of afferent information?
special
touch, pain, and temperature and examples of what type of afferent signal?
somatic
____ is information that flows from the integration center to the effectors
efferent
by what means does information flow from the integrating center to effectors?
peripheral nerves
efferent information is considered what type of signal?
motor
involuntary muscle such as smooth and cardiac as well as glands are what type of efferent signal?
visceral
voluntary movement via skeletal muscle is what type of efferent signal?
somatic
a neuron is considered ____ when there is only one projection coming from the cell body
unipolar
most sensory neurons are ___polar
uni
a neuron is considered _____ where there are multiple projections coming from the cell body
multipolar
most interneurons are considered ____polar
multi
an _____ is a neuron that processes sensory information and can either send output signals to motor neurons or send the signal further in the CNS
interneuron
what is contained in the dorsal root?
axons of sensory neurons
the _____ of the spinal cord is where sensory information is processed
dorsal/posterior
what is contained in the ventral root?
axons of motor neurons
what is gray matter made of?
cell bodies and synapses of neurons
what is the main function of gray matter?
integrate and process information
_____ refers to a collection of cell bodies and synapses in the peripheral nervous system
ganglion
what is white matter made of?
myelinated axons of neurons
what is the main function of white matter?
transmission of signals
____ refer to a collection of myelinated axons in the peripheral nervous system
nerves
the ventral root is responsible for what action?
motor
the dorsal root is responsible for what action?
sensory
___ tracts contain sensory/afferent information
ascending
____ tracts contain motor/efferent information
descending
how many pairs of spinal nerves are there?
31
___ spinal nerves go to the neck, shoulders, arms, and hands
cervical
____ spinal nerves go to the chest and upper abdomen
thoracic
____ spinal nerves go to the lower abdomen, hips, and legs
lumbar
____ spinal nerves go to the genital and lower digestive tract
sacral
____ spinal nerves go to the skin lying above the tailbone
coccygeal
there are ___ pairs of cervical nerves
8
there are ____ pairs of thoracic nerves
12
there are ____ pairs of lumbar nerves
5
there are ___ pairs of sacral nerves
5
there are ___ pairs of coccygeal nerves
1
what part of the spinal cord has the most white matter?
cervical
what part of the spinal cord has the most gray matter?
lumbar
what part of the brain has the main function of regulating voluntary and conscious activity
cerebrum
what part of the brain controls things like perception, initiation, control of movement, and cognition?
cerebrum
what are the 3 parts of the diencephalon?
thalamus, hypothalamus, epithalamus
what part of the diencephalon plays a role in processing sensory information?
thalamus
what part of the diencephalon plays a role in regulating homeostasis?
hypothalamus
what part of the diencephalon plays a role in melatonin and the regulation of some emotions?
epithalamus
what part of the brain’s major function is the control of movement, posture, balance, and motor learning?
cerebellum
what are the 3 parts of the brainstem?
midbrain, pons, medulla oblongata
what part of the brain has the major function of regulating subconscious activity and reflexes such as heart rate and breathing?
brainstem
the cerebral cortex is made of ____ matter and has 6 layers
grey
___ ____ are groups of gray matter found within the CNS
basal nuclei
basal nuclei are groups of ___ matter
gray
what are the 2 functions of basal nuclei?
regulating motion and preventing unwanted movement
the plasma membrane is ____ permeable
selectively
what two qualities allow a substance to freely diffuse?
non-polar, uncharged
how do O2, CO2, and steroids diffuse?
freely
water and urea are examples of _____, _____, and ____ molecules
small, uncharged, polar
Do ions freely diffuse?
no
glucose is a ____, ____, and ____ molecule
large, uncharged, polar
a cell diffusing without any type of help is called ___ _____
simple diffusion
the blood brain barrier allows ____ to exit the brain and ____ to enter freely
CO2, O2
what makes Benadryl easily able to enter the brain and pass through the blood brain barrier?
very lipophilic
what makes it so that Allegra is unable to pass through the blood brain barrier and make you drowsy?
it has similar structure to Benedryl but is more polar
when a molecule moves down its concentration gradient through a channel or transporter/carrier, this is called ___ ____
facilitated diffusion
_____ open and close and allow for molecules to pass through a pore
channels
_____ bind to the molecule, cause a change in shape to itself, and allow the molecule to move into the cell
transporter
the lipid bilayer creates _____ between the intra and extra cellular fluid
gradients
net diffusion of molecules occurs ___ a concentration gradient
down
two of the most important ions to maintain the concentration gradients of are ___ and ____
sodium, potassium
what is used to maintain levels of sodium and potassium?
sodium/potassium ATPase/pump
in the first step of the Na/K pump, _____ from the intracellular fluid binds to the pump
Na
what is the second step of the Na/K pump
the pump is phosphorylated by ATP
in the third step of the Na/K pump, the pump shape changes and causes ____ to be released into the extracellular fluid
Na
in the fourth step of the Na/K pump, ____ is released from the pump into the intracellular fluid
K
what is the fifth step of the Na/K pump?
the pump returns to the original conformation
in the final step of the Na/K pump, extracellular ___ binds to the pump and causes _____
K, dephosphorization
since movement of a solute from an area of low concentration to high concentration is not energetically favorable, ___ is needed
ATP (an energy source)
When ATP is needed for transport, this is called ___ _____ _____
primary active transport
an ___ _____ refers to when there is a difference in charge between two compartments and ions move down the level of charge
electrical gradient
when there is an electrical gradient, ions move from areas of ___ charge to ____ charge
higher, lower
what two factors are considered when determining net movement of an ion?
electrical gradient, chemical gradient
using the movement of ions down their electrochemical gradients to move other molecules against their gradient is using a ___-_____
co-transporter
___-______ move ions at the same time in different directions
anti-transporters
what are the two main examples of secondary active transport?
co-transporters, anti-transporters
what is the main form of energy for primary active transport?
ATP
what is the main form of energy for secondary active transport?
the energy of an ion moving down its electrochemical gradient
in simple diffusion, how do molecules move in relation to their concentration gradient?
down
in facilitated diffusion, how do molecules move in relation to their concentration gradient?
down
in primary active transport, how do molecules move in relation to their concentration gradient?
against
in secondary active transport, how do molecules move in relation to their concentration gradient?
against
is simple diffusion active or passive transport?
passive
is facilitated diffusion active or passive transport?
passive
is primary active transport active or passive transport?
active
is secondary active transport active or passive transport?
active
does simple diffusion use a channel/transporter?
no
does facilitated diffusion use a channel/transporter?
yes- transporter or channel
does primary active transport use a channel/transporter?
yes- pumps
does secondary active transport use a channel/transporter?
yes- antiporters or cotransporters
what is the concentration of ECF sodium and ICF sodium?
145/150 mM ECF, 15 mM ICF
what is the concentration of ECF potassium and ICF potassium?
5 mM ECF, 150 mM ICF
what is the concentration of ECF calcium and ICF calcium?
.0002 mM ECF, 2 mM ICF
the ___ ____ creates gradients between the intracellular and extracellular fluid
lipid bilayer
the ____ fluid of a resting cell is slightly more negative
intracellular
the resting membrane potential is polarized and is therefore more ____ inside compared to outside
negative
what three components are needed to have a resting membrane potential?
concentration gradient between ICF and ECF, difference in ion permeability, action of Na/K ATPase
the Na/K ATPase brings sodium _____ the cell and potassium _____ the cell
out of, into
what type of channels have a big impact on the resting membrane potential?
leak potassium and sodium channels
what is the resting membrane potential of a cell?
-70 mV
what does it mean when a resting membrane potential is negative?
there is more negative charge on the outside than inside
what is occurring at a cell’s equilibrium potential?
chemical concentration and electrical gradients are equal and opposite directions
what equation is used to calculate the equilibrium potential?
Nernst equation
Eion= 60/z log [(ion)ECF/(ion)ICF] is what equation?
Nernst (equilibrium potential)
what is the equilibrium potential for sodium?
+60 mV
what is the equilibrium potential for potassium?
-90 mV
if the membrane potential is less than equilibrium potential, what is the flow of ion movement?
in the direction of the concentration gradient
if the membrane potential is greater than the equilibrium potential, what is the flow of ion movement?
in the direction of the electrical gradient
what equation is used to calculate membrane potential?
GHK
what does the GHK equation take into account that is not in the Nernst equation?
ion permeability
the greater the number of channels and ion has into or out of a cell, the greater it’s _____
permeability
where is the sensory receptor located?
peripheral nervous system
where is the interneuron located?
central nervous system
where is the motor neuron located?
peripheral nervous system
changes in the ___ ____ of a neuron leads to the general of a neuronal signal
membrane potential
____ _____ are what change the membrane potential
transduction channels
what is described as the process in which a stimulus is converted into an electrical (graded) potential?
transduction
where does transduction occur?
at sensory receptors
what ion leads to depolarization?
sodium
the graded potential of sodium makes the cell membrane more ______
positive
what ion leads to hyperpolarization?
potassium
the graded potential of potassium makes the cell membrane more _____
negative
why are graded potential deemed graded?
the size of the potential is directly related to the size of the stimulus
what transduction channel transduces a temperature stimulus into graded potential?
theromoreceptors
what transduction channel transduces a chemical stimulus into graded potential?
chemoreceptors
what transduction channel transduces a light stimulus into graded potential?
photoreceptors
what transduction channel transduces a painful stimuli into a graded potential?
nociceptors
what channels are responsible for the resting membrane potential?
leak channels
what channels are responsible for graded potentials?
transduction
where are transduction channels located in the neuron?
dendrites and sensory receptors
where are leak channels located in the neuron?
all throughout
what four characteristics are needed for sensory receptors to talk to the nervous system?
intensity, location, modality, duration
does the amplitude of an action potential change?
no
the greater the size of the stimulus, the more ____ the action potential is
frequent (frequency is what will change)
graded potentials _____ in strength as they travel along the neuron
decrease
what is the local current flow?
the movement of depolarization that moves throughout the neuron
what are the three factors that determine the modality of a receptor?
type of transduction channel, structure that the channel is in, location of the receptor in the tissue
what ion voltage gated channel has an inactivation gate?
sodium
does the voltage gated potassium channel have an inactivation gate?
no
what type of channel is responsible for action potentials
voltage-gated ion channels
where are voltage-gated ion channels located in the neuron?
trigger zone, axons, axon terminals, between axon nodes
both the voltage-gated potassium channel and voltage-gated sodium channel will open at what resting membrane potential?
-55 mV
what voltage-gated channel opens and closes quickly?
sodium
what voltage-gated channel opens and closes slowly?
potassium
what are the four phases of the action potential?
resting, depolarizing, repolarizing, hyperpolarizing
what phase of the action potential is known as overshoot?
depolarization
what phase of the action potential is known as undershoot?
hyperpolarization
what three ion channels are responsible for the resting membrane potential?
leak potassium, leak sodium, Na/K pump
what channels are responsible for receptor potentials?
transduction
action potentials are generated at the ____ ____
trigger zone (first node)
graded potentials are generated at the ____ ____
sensory receptor
voltage-gated sodium channels are known as ___ feedback
positive
what is the outside factor that shuts off the voltage-gated sodium channel in the positive feedback loop?
inactivation gate
what channel opens at the repolarization phase?
voltage-gated potassium channel
what direction does potassium move during the repolarization phase?
out of the cell
what direction does sodium move during the depolarization phase?
into the cell
the voltage-gated potassium channel is an example of ____ feedback
negative
why does the undershoot phase occur in the action potential?
potassium channel takes a long time to close
do action potentials decay over time?
no
why do action potentials not decay over time?
voltage-gated sodium and potassium channels are located all throughout the axon and allow for replenishment
___ ____ only flow in one direction
action potentials
_____ conduction occurs in myelinated axons
saltatory
_____ ____ prevent local current leak
myelinated
____conduction is faster than ____ conduction
saltatory, continuous
why is the action potential slow in unmyelinated axons?
must wait for each section of the neuron to depolarize and generate an action potential
all molecules have ____ energy
kinetic
_____ is the random, continual movement of a substance due to a substance’s intrinsic, kinetic energy
diffusion
what three factors affect the rate of diffusion?
concentration gradients, temperature, molecular weight of the diffusing substances
what direction does net diffusion occur?
from areas of high concentration to low concentration
the greater the temperature, the ____ the rate of diffusion
greater
the greater the molecular weight of the diffusing molecules, the _____ the rate of diffusion
slower
what distance is diffusion the most effective at?
50-100 microns
does diffusion occur faster in a liquid or gas?
gas- more room for movement
glucose, urea, and salt are what type of solvents?
polar and hydrophilic
fats, steroids, and gases are what type of solvents?
non-polar hydrophobic
the higher the concentration of solute in a solution, the ____ the water concentration
lower
the net diffusion of water down its concentration gradient is called ______
osmosis
water undergoes ______ diffusion mediated by aquaporins
facilitated
what is known as the number of solute particles per liter of solution?
osmolarity (Osm)
how do you calculate osmolarity?
multiple molarity by the number of particles
how is molarity calculated?
moles of solute/liters of solution
how is total osmolarity calculated?
osmolarity1+osmolarity2…..
tonicity accounts for the _____ particles in a solution
non-penetrating
all cells have a baseline of ______ mOsms
300
_____ is the minimal value of a variable needed to elicit physiological effect
threshold
what is the description of a threshold for neurons?
membrane potential needed to generate an action potential
what is the charge of the voltage-gated sodium channel inactivation gate?
positive
can an action potential be generated during a refractory period?
no
during what phase is the absolute refractory period?
repolarization
during what phase is the relative refractory period?
hyperpolarization
can another action potential be generated during the absolute refractory period?
no
can another action potential be generated during the relative refractory period?
yes, with a large stimulus
_____ summation is when several different neurons release neurotransmitters at the same time
spatial
_____ summation occurs when one neuron fires action potentials frequency
temporal
can temporal and spatial summation occur at the same time?
yes
what is it called when an axon terminal synapses onto another axon terminal?
axo axonic synapse
what is it called when the binding of neurotransmitters from neuron B to their receptors cause a decrease in the amount of molecule that enters the axon terminal of neuron A and reduces the amount of neurotransmitter released from neuron A?
presynaptic inhibition
what is it called when the binding of neurotransmitters from neuron B to their receptors causes an increase in the amount of molecule that can enter the axon terminal of neuron A and increased the amount of neurotransmitter that neuron A can release?
presynaptic facilitation
the amount of neurotransmitter that can be released goes ____ as action potential frequency increases
up
______ of a sensory receptor is the opening of a transduction channel that results in a graded potential
activation
_____ is the conscious or subconscious awareness of changes in the internal or external environment
sensation
______ is our brain interpretation sensations, and is called the conscious awareness, understanding, and organization that occurs in the cerebral cortex
perception
in what part of the brain does perception occur?
cerebral cortex
what are the three parts of the sensory system?
sensory receptor, neural pathways, CNS that processes information
what are the three types of senses?
special, somatic, visceral
in what two ways are the intensity of the stimulus encoded?
size of graded potential, frequency of action potentials
what are taste receptors an example of ?
modality of stimulus
___ ____ _refer to the area in which sensory receptors present on primary sensory neurons will respond to a stimulus
receptive fields
what kind of information is conveyed by receptive fields?
location of visual and somatic stimuli
what three factors determine the acuity of receptor fields?
size/density of the receptor field, whether primary sensory neurons converge, lateral inhibition
the smaller the receptive field, the ____ densely packed the sensory receptor is
more
____ receptive fields have low acuity
large
there is a ____ sense of acuity in smaller receptive fields
greater
what is the determining factor if you have the ability to discriminate between 2 stimuli?
whether primary sensory neurons converge
___-_____ ______ refers to how readily 2 stimuli can be distinguished from one another
two-point discrimination
_____ inhibition helps define the edges of a stimulus
lateral
what is regulated by presynaptic inhibition?
amount of neurotransmitter released at the synapse
how is presynaptic inhibition accomplished?
regulation of the amount of molecule released
what is regulated by postsynaptic inhibition?
membrane potential of a postsynaptic neuron
how is postsynaptic inhibition accomplished?
presynaptic neuron releases a neurotransmitter that causes the membrane potential to become more negative and make reaching threshold harder
what occurs with a sensory neuron that is able to adapt to a persistent stimulus?
no longer perceive the stimulus
what type of stimulus adaptation is associated with senses that must be constantly monitored such as blood pressure?
adapt very slowly
rapidly adapting receptors are best suited for signaling when a stimulus ______
changes
where do somatosensory pathways lead to?
primary somatosensory cortex
what are the 4 senses that are conveyed by the dorsal column pathway?
pressure, proprioception, vibration, touch
where does the primary neuron synapse with the secondary neuron in the dorsal column pathway?
meduall
where does the secondary neuron cross sides of the body in the dorsal column pathway?
medulla
where in the brain does the secondary neuron synapse with the tertiary neuron in the dorsal column pathway?
thalamus
what four senses are conveyed in the anterolateral pathway?
pain, itch, temperature, tickle
where in the body does the secondary neuron cross the body in the anterolateral pathway?
spinal cord
where in the brain does the secondary neuron synapse with the tertiary neuron in the anterolateral pathway?
thalamus
what is sensory homunculus?
visualizing strength of sensation via size of body parts
what are the 3 types of somatic sense?
tactile, pain, proprioception
what type of somatic sense includes sensation of touch, pressure, vibration, itch, tickle, and temperature?
tactile
what type of somatic sense includes receptors that respond to mechanical, chemical, and thermal stimuli associated with tissue damage?
pain
what type of somatic sense includes the ability to know where our limbs are and how they are moving?
proprioception
what are the main type of proprioceptors in skeletal muscle?
muscle spindles
what are the 3 types of nociceptors?
mechanical, thermal, polymodal
what do nociceptors detect?
pain
what type of nociceptor detects intense mechanical stimuli such as pinch or puncture?
mechanical
what type of nociceptor detects extreme changes in temperature?
thermal
what type of nociceptor detects multiple modalities, including mechanical, thermal, and chemical stimuli?
polymodal
what are the 2 pathways for pain?
spinal, ascending
what type of pain pathway is responsible for unconscious, protective responses?
spinal
what type of pain pathway is responsible for conscious awareness of pain sensations?
ascending
____ reflexes are responsible for unconscious protective responses
spinal
__ ____ is a peptide that acts like a neurotransmitter for pain
substance P
____ pain results in activation of nociceptors in the internal organs
visceral
why is visceral pain felt in other areas of the body?
somatic and visceral sensory neurons converge on the same second order neuron
____ ____ is when pain in one area is also felt in another
referred pain
what is the body’s system of pain suppression?
endogenous analgesia system
what happens when the opioid produced by our body (enkephalins, endorphins, dynorphins) bind to opioid receptors?
reduced released of substance P, generates postsynaptic potential
what type of inhibition is the endogenous analgesia system reducing the release of substance P a part of?
pre-synaptic
what is generated by exogenous opioids?
inhibitory postsynaptic potential
how does lidocaine work in reducing/eliminating the sensation of pain in specific area?
inhibiting voltage-gated sodium channels and preventing action potentials
where does crossing over occur in the dorsal column pathway?
medulla
what senses are conveyed by the dorsal column pathway?
pressure, proprioception, vibration, touch
what senses are conveyed by the anterolateral pathway (spinothalamic)?
pain, itch, temperature, tickle
where does the neuron crossover in the anterolateral pathway?
spinal cord
where in the spinal cord does the parasympathetic nervous system originate?
brainstem, sacral
what nervous system is associated with rest and digest?
parasympathetics
where in the spinal cord does the sympathetic nervous system originate?
thoracic, lumbar
what nervous system is associated with fight or flight?
sympathetic
what nervous system is found within the walls of the gut?
enteric
somatic neurons release _____
acetylcholine
what does acetylcholine bind to?
nicotinic acetylcholine receptors
what is the effector of the somatic motor system?
skeletal muscle
what happens when acetylcholine binds to its receptor?
skeletal muscle contraction
___ motor pathways involve two motor neurons
autonomic
both the pre and postganglionic neurons of the ____ nervous system release acetylcholine
parasympathetic
what nervous system would decrease heart rate and increase gastric motility?
parasympathetics
what is released by the preganglionic neurons of the sympathetics?
acl
what is released by the postganglionic neurons of the sympathetics?
norepinephrine
what is the name of the receptor for norepinephrine?
adrenergic
what nervous system would increase heart rate and decrease gastric motility?
sympathetic
where in the brain would you find the primary visual cortex?
occipital lobe
what photoreceptor is less sensitive to light, responsible for vision at higher levels of light, and has high visual acuity for color vision?
cones
what photoreceptor is very sensitive to light, responsible for vision at low levels of light, and has low visual acuity?
rods
where in the eye is the sharpest sense of site located?
fovea
what is the area of the eye where the blind spot is located?
optic disc
___ ___ _____ is where right and left visual fields overlap
binocular visual field
the ability to discriminate between 2 stimuli depends on what?
whether primary sensory neurons converge
what four cues can determine object depth?
shadows, if objects “seem larger”, objects blocking each other, clarity of objects
there are less leak ____ channels than ____ channels
sodium, potassium
