Shared Flashcard Set

Details

Physiology Unit 2 Exam
N/A
282
Physiology
Undergraduate 2
02/01/2012

Additional Physiology Flashcards

 


 

Cards

Term
In what direction does spontaneous movement tend to occur?
Definition
From high [] to low []
Term
What are the three types of driving forces?
Definition
chemical, electrical, and electrochemical
Term
What is a gradient?
Definition
the difference between two locations; the inside and outside of a cell
Term
Electrical driving force concerns ____ particles
Definition
charged
Term
Chemical driving force concerns ____
Definition
concentrations (sodium)
Term
Define membrane potential
Definition
difference in electrical potential across the plasma membrane
Term
There is usually excess ____ in the ICF while there is excess ____ in the ECF
Definition
anions; cations
Term
T/F:
the plasma membrane is permeable to ions
Definition
False
Term
What determines the sign of the membrane potential?
Definition
the net charge inside the cell
Term
What is membrane potential measured in?
Definition
millivolts
Term
Identify:
membrane potential at which the electrical driving force is equal and opposite to the chemical driving force
Definition
Equilibrium potential
Term
Define equilibrium
Definition
no net movement of molecules
Term
What must be known for the equilibrium to be calculated?
Definition
ions's charge; ICF and ECF []
Term
What is another name for the rate of transport?
Definition
Net flux
Term
What are the two general types of transport?
Definition
passive and active transport
Term
What are the three types of passive transport?
Definition
simple diffusion; facilitated diffusion; and diffusion through channels
Term
What are the two types of active transport?
Definition
primary and secondary
Term
Identify:
Spontaneous transport of molecules across the plasma membrane
Definition
simple diffusion
Term
What are the factors the affect rates of simple diffusion?
Definition
magnitude of the driving force; membrane SA; membrane permeability
Term
The magnitude of the driving force ____ with time
Definition
decreases
Term
When does the magnitude of driving forces stop?
Definition
when diffusional equilibrium occurs
Term
How do you increase SA anatomically?
Definition
Make the structure bigger: muscle and nerve cells
Term
What are some things that easily pass through the PM?
Definition
lipid soluble molecules; O2 and CO2
Term
What is the role of molecules in membrane permeability?
Definition
permeant
Term
What is the role of membranes in membrane permeability?
Definition
permeable
Term
What is the most important factor in membrane permeability?
Definition
lipid solubility
Term
What is the "helper" in facilitated diffusion?
Definition
carrier proteins
Term
What is the rate of facilitated diffusion?
Definition
transport rate of individual carriers
Term
How do you increase flux once saturation is reached?
Definition
increase the number of carriers
Term
what is another name for channels?
Definition
pores
Term
Channels can be regulated to be ____ or ____
Definition
open; closed
Term
What are the two common types of channels?
Definition
aquaporins and ion channels
Term
T/F:
Carrier proteins can open equally in either direction
Definition
FALSE; channels can
Term
What are pumps?
Definition
transmembrane proteins that use E to move molecules in a certain direction
Term
T/F:
Carriers have a greater affinity for a molecule on one side of a membrane versus the other
Definition
False; Pumps do
Term
What is the Steady State?
Definition
when the concentration gradient offsets affinity
Term
In primary active transport pumps act as a _____ and a ______
Definition
transporter; enzyme
Term
What is the difference between primary and secondary transport?
Definition
primary uses ATP directly while secondary is powered by a concentration gradient previously made by primary active transport
Term
Sodium/ Potassium pumps:
For every ___ sodiums there are ___ potassiums and ___ ATP
Definition
3;2;1
Term
There is a greater affinity for sodium when the pump is open to the ____
Definition
ICF
Term
What is another name for Na bonding?
Definition
phosphorylation
Term
Describe secondary active transport
Definition
as one thing moves passively down its gradient, it drives the movement of another substance up its gradient
Term
What is osmosis?
Definition
the flow of water across a membrane through aquaporins
Term
Osmosis has an influence on cell ____
Definition
volume (plasma volume and BP)
Term
Identify:
Total solute particle concentration of a solution
Definition
Osmolarity
Term
what is the symbol for osmotic pressure?
Definition
pi
Term
_____ = osmolarity= total solute concentration of a solution
Definition
osmotic pressure
Term
Water flows ___ its own concentration gradient but ___ an osmotic pressure gradient
Definition
DOWN; UP
Term
Define tonicity
Definition
concentration of impermeant solutes relative to ICF
Term
What type of solution causes a cell to shrink:?
Definition
hypertonic
Term
What type of solution causes a cell to swell?
Definition
hypotonic
Term
What is sweat made of?
Definition
Na, Cl, and water
Term
How does sweating affect the osmolarity of plasma?
Definition
it increases it; cells shrink
Term
How does water intoxication affect plasma osmolarity?
Definition
decreases; cells swell
Term
What happens to the glucose carriers in someone with diabetes?
Definition
the insulin-dependent glucose carriers are impaired or absent
Term
What is vesicular transport?
Definition
the transportation of substances in membrane-bound compartments
Term
What is the vessel for endocytosis?
Definition
endosome
Term
What is the vessel for exocytosis?
Definition
secretory vesicles
Term
Where is the only place you will find vesicles?
Definition
inside the cell
Term
What must be present in order for receptor-mediated endocytosis to occur
Definition
chemical messenger
Term
What are the three functions of exocytosis?
Definition
add components to the plasma membrane; recycle receptors removed during endocytosis; secretion of substances into the ECF
Term
What are the two methods of epithelial transport?
Definition
absorption and secretion
Term
Define epithelial transport
Definition
movement of substances across two plasma membranes
Term
Microvili are present in what type of cells?
Definition
secretory/ absorption
Term
Is epithelial transport of Na and K active or passive?
Definition
Active; secondary
Term
Describe water transport
Definition
active transport of solutes from the basolateral membrane to the interstitial fluid; creates an osmotic gradient that water passively follows
Term
How do pathogens travel?
Definition
via transcytosis
Term
Direct communication occurs through __ __ while indirect communication uses ___ ___
Definition
gap junctions; chemical messengers
Term
What are two examples of direct communication?
Definition
electrical coupling and metabolic coupling
Term
What is the name of the chemical messenger that binds proteins reversibly?
Definition
ligand
Term
What are the three functional classes of chemical messengers?
Definition
Paracrines, neurotransmitters, and hormones
Term
Define paracrines
Definition
chem. messengers that reach target cells via simple diffusion
Term
Describe autocrines
Definition
chem messengers that act on the cell that secreted them
Term
what is an example of neurotransmitters?
Definition
synaptic signaling
Term
What type of hormone is NOT released from a gland?
Definition
neurohormones
Term
What specific type of messenger is Histamine?
Definition
paracrine
Term
Histamine is part of what type of response?
Definition
inflammatory
Term
Why do antihistamines cause drowsiness?
Definition
because they block H1 receptors in neurons that are responsible for alertness
Term
T/F:
Antihistamines block histamines locally
Definition
False; universally
Term
What are the lipophilic classes of chem messengers?
Definition
steroids and elcosanoids
Term
What are the hydrophilic classes of chem messengers?
Definition
amino acids, amines, and peptides/proteins
Term
What are the are the four amino acids messengers?
Definition
Glutamate, aspartate, glycine, and GABA
Term
What is the only amino messenger NOT used in protein synthesis?
Definition
GABA
Term
T/F:
Hydrophilic chem messengers do not pass through the plasma membrane on their own
Definition
True
Term
What are the three types of Catecholamines?
Definition
dopamine (neurotransmitter), norepinephrine (neurotransmitter), and epinephrine (hormone)
Term
What are the four groups of amine messengers?
Definition
Catecholamines, Serotonin (neurotransmitter), Histamine (paracrine), thyroid (hormone)
Term
What is the only amine that is lipophilic?
Definition
thyroid hormones
Term
What is the other name for adrenaline?
Definition
epinephrine
Term
Where are most amines synthesized?
Definition
the cytosol
Term
What is done with Amines while they are waiting to be exocytosed?
Definition
they are packaged into vesicles
Term
T/F:
Peptide messengers have > 50 amino acids
Definition
False; they have < 50; proteins have >50
Term
What substaces create the final product in peptide/protein synthesis and release?
Definition
Proteolytic enzymes
Term
Steroid messengers always function as what?
Definition
hormones
Term
Where are most steroid messenger receptors located?
Definition
the cytosol
Term
T/F:
steroids can be stored
Definition
False
Term
Where are steroids synthesized?
Definition
smooth ER or mitochondria
Term
What are all the steps for steroid synthesis derived from?
Definition
cholesterol
Term
What type of chemical messenger are eicosanoids?
Definition
paracrines
Term
What are eicosanoid messengers derived from?
Definition
arachidonic acid
Term
which COX inhibitor is associated with homeostatic prostiglandinds (PG)?
Definition
COX-1
Term
Which COX inhibitor is activated by tissue damage/infection?
Definition
COX-2
Term
What does NSAID stand for and what is an example of it?
Definition
Non-Steroidal Anti-Inflammatory Drug
Term
What are the side effects of NSAIDs?
Definition
Low doses= prevents blood clot formation
High doses= promotes blood clot formation
Prevent PGE2 production which protects the stomach lining
Term
Which of the COX inhibitors increases the risk of heart attack and stroke
Definition
COX-2 selective inhibitors
Term
What is the substance that can be specific or non-specific and enhances the half life of a messenger?
Definition
carrier proteins
Term
What is the only substance that can bind to receptors of messenger molecules?
Definition
free hormone
Term
What are the three receptor locations?
Definition
membrane, cytosolic, and nuclear
Term
What is the factor the determines which receptor is used?
Definition
whether the messenger is lipophobic or lipophilic
Term
What is down regulation?
Definition
the removal of proteins concerning messenger molecules
Term
ID:
ligands that cause cellular response when receptor binding occurs
Definition
agonists
Term
Define antagonists
Definition
ligands that prevent cellular response when receptor binding occurs
Term
What are two examples of adrenergic receptors?
Definition
alpha and beta receptors
Term
Epi and norepi bind to _____ receptors
Definition
adrenergic
Term
What is another name for norepi?
Definition
noradrenaline
Term
How do alpha receptors effect the blood vessels?
Definition
constriction; increase BP
Term
How do beta receptors effect the heart?
Definition
faster/harder contractions
Term
ID:
Phenylepherine
Definition
alpha agonist
Term
ID:
Phenoxybenzamin
Definition
alpha antagonist
Term
What prevents and overreaction in the heart in cardic patients?
Definition
Beta blockers and Beta Antagonists
Term
What are the three types of membrane-bound receptors?
Definition
channel-linked; enzyme-linked; G-Protein
Term
Describe channel-linked receptors
Definition
ligand-gated channels (fast vs slow)
Term
What is the purpose of a secondary messenger?
Definition
takes message from plasma membrane away from it and into the cell to do something (calcium)
Term
What are the most common type of enzyme-linked receptors?
Definition
tyrosine kinases
Term
T/F
the effects of secondary messengers are short-lived
Definition
true
Term
ID:
Peripheral proteins that are loosely associated with transmembrane proteins
Definition
G-Protein linked receptors
Term
What do G-proteins regulate?
Definition
slow ligand-gated channels
Term
What are the effectors of G-protein linked receptors?
Definition
membrane-bound ion channels or enzymes (Gs or Gi)
Term
Gs is a ____ while Gi is a _____
Definition
stimulant; inhibitor
Term
T/F: Losts of Ca is stored in cells
Definition
False
Term
What are the five major second messengers?
Definition
cAMP; cGMP; DAG; IP3; Calcium
Term
The use of what substance results in the production/activation of a second messenger?
Definition
G-protein Regulated Enzyme
Term
ID:
the system that usually affects ion channels
Definition
Nervous system
Term
ID: the system that typically impacts protein synthesis or acts on G protein-linked receptors
Definition
Endocrine system
Term
T/F:
the affects of the endocrine system have a longer lasting affect
Definition
true
Term
Paracrines act ____
Definition
locally
Term
What is the function of primary endocrine glands?
Definition
secrete hormones
Term
What is the hypophysis?
Definition
the pituitary gland
Term
What is the adenohypophysis?
Definition
the anterior pituitary gland
Term
What is the neurohypophysis?
Definition
the posterior pituitary gland
Term
What is another name for ADH?
Definition
Anti diarrhetic hormone; vasopresin
Term
What are the two hormones secreted by the neurohypophysis?
Definition
ADH and oxytocin
Term
What is the primary hormone secreted by the adenohypophysis?
Definition
tropic hormone
Term
What is a portal vein?
Definition
a vein that connects two capillaries
Term
What is the purpose of tropic hormones?
Definition
regulate the secretion of other hormones and act as stimulatory or inhibitory hormones
Term
What hormone is secreted by the pineal gland?
Definition
melatonin
Term
The pineal gland is important in establishing what?
Definition
circadian rhythm
Term
What does calcitonin regulate?
Definition
blood calcium levels
Term
What is the purpose of T3 and T4 hormones?
Definition
(thyroid); regulate metabolism, growth, and development
Term
What other hormone regulates blood calcium levels?
Definition
PTH= Parathyroid hormone
Term
What gland shrinks as you age?
Definition
thymus gland
Term
What is the purpose of thymosin?
Definition
regulates T lymphocytes (T-Cells)
Term
What is another name for the adrenal glands?
Definition
suprarenal glands
Term
What are the two portions of the adrenal glands?
Definition
cortex and the medulla
Term
What are the outer three layers of the adrenal glands?
Definition
cortex
Term
What portion of the adrenal glands takes up the most mass?
Definition
cortex
Term
What are the hormones secreted by the adrenal cortex and what class do they fall under?
Definition
adrenocorticoids; steroids
Term
What is the primary mineralocorticoid and its function?
Definition
aldosterone; regulate Na reabsorption and K secretion in kidneys
Term
What are the three types of adrenocorticoids?
Definition
Mineralocorticoids; glucocortocoids; sex hormones
Term
What is the primary glucocortocoid and its function?
Definition
cortisol; regulate stress responses, substrate metabolism, and blood glucose levels
Term
What is the primary sex hormone?
Definition
androgens
Term
What is the chemical breakdown of catecholamines?
Definition
80% epinephrine; 20% norepinephrine; <1% Dopamine
Term
What is secreted by the male gonads?
Definition
androgens, testosterone, and androstenedione
Term
What is produced by the female gonads?
Definition
estrogens and progesterones
Term
What are the two types of steroid drugs?
Definition
corticosteroids and anabolic steroids
Term
What steroid is used for anti inflammatory purposes?
Definition
Corticosteroids
Term
What steroid is used for muscle growth?
Definition
anabolic steroids
Term
Describe anabolic steroids
Definition
synthetic forms of androgens; enhance secondary sex characteristics
Term
What are the secondary endocrine glands?
Definition
Heart, kidneys, stomach, small intestine, liver, skin
Term
What is an example of a hormone that is secreted at a constant rate?
Definition
thyroid hormones
Term
What type of hormone is aldosterone?
Definition
mineralicorticoid
Term
How do carrier proteins help hormones?
Definition
by increasing their half-life to keep them in the blood longer
Term
How long does it usually take for hormones to be broken down?
Definition
minutes
Term
What hormones are metabolized more slowly and why?
Definition
steroids and thyroid hormones because they are transported in blood bound to proteins and can be stored in fatty tissues
Term
ID:
abnormality that originates in the endocrine gland that secretes the hormone
Definition
Primary secretion disorder
Term
ID:
problem originate in the endocrine cells of either the ant. or pit. or the hypothalamus
Definition
Secondary Secretion disorder
Term
Define antagonism
Definition
effects are opposite
Term
Define additive
Definition
net effects equal sum of the individual effects
Term
ID:
net effects are greater than the sum of the individual effects
Definition
Synergistic
Term
ID:
presence of one hormone is necessary for another to exert its effects
Definition
Permissiveness
Term
What are the two divisions of the PNS?
Definition
Afferent and Efferent
Term
What are the two divisions of the Efferent nervous system?
Definition
Somatic and autonomic
Term
What are the two divisions of the autonomic nervous system and their function?
Definition
sympathetic (fight/flight) and parasympathetic (rest/digest)
Term
What does the sympathetic nervous system control?
Definition
cardiac muscle, smooth muscle, and glands
Term
What is another name for glial cells?
Definition
glue
Term
What is another name for axon terminals?
Definition
terminal boutons
Term
What is the name for a secondary branch of the the main axon?
Definition
collateral axon
Term
What are the three structural classes of neurons?
Definition
bipolar; unipolar; multipolar (most common)
Term
What does the term "polar" refer to?
Definition
the extensions off the soma
Term
T/F:
The cell body of an afferent neuron is in the CNS
Definition
False; PNS
Term
T/F:
the cell body of an efferent neuron is in the CNS
Definition
true
Term
Where are the dendrites of afferent neurons located?
Definition
sensory/visceral receptors
Term
Where are the terminal boutons of efferent neurons located?
Definition
effector organs
Term
ID:
group of axons traveling together in the CNS (white matter)
Definition
Tract
Term
What are the three types of tracts in the CNS?
Definition
Commisural (allow interhemishperic comm.); projection (axons traveling up or down the CNS); Associational (allow interhemispheric comm.)
Term
ID:
group of neuronal soma in the CNS (grey matter)
Definition
Nucleus
Term
ID:
axons traveling together in the PNS
Definition
Nerve
Term
ID:
Group of neuronal soma in the PNS
Definition
Ganglion
Term
Schwann cells are in the ___ nervous system
Definition
peripheral
Term
Oligodedrocytes are in the ____ nervous system
Definition
central
Term
What is the space between two myelinated axons called?
Definition
Node of ranvier
Term
What is the purpose of the myelin sheath?
Definition
insulates that axon and speeds up the rate of action potential propagation
Term
what is the myelin sheath made of?
Definition
lipid bilayers
Term
What is the location of ion channels in the myelinated axon?
Definition
Nodes of ranvier
Term
What type of cell is the schwann cell?
Definition
glial cell
Term
What can change the electrical properties of the cell (neuron)?
Definition
the opening or closing of the ion channels
Term
At rest the plasma membrane is _____
Definition
polarized
Term
What are the three types of neuron ion channels?
Definition
Leak channels, ligand-gated channels, and voltage-gated channels
Term
What is the predominant neuron ion channel?
Definition
Leak channels
Term
Which of the neuron ion channels is always open?
Definition
leak channels
Term
Describe ligand-gated channels (2)
Definition
open or close floowing ligand-receptor binding; densely located in dendrites and soma
Term
Describe voltage-gated channels (3)
Definition
open or close following changes in the membrane potential; Na and K channels are most dense in axon and axon hillock; Ca channels are most dense in the axon terminal
Term
Nerve and muscle cells function through electrical signals in the form of ________________
Definition
changes in membrane potential
Term
The ___ the separation of charge the _____ the potential
Definition
greater; greater
Term
Define current (l)
Definition
movement of electrical charges; flow
Term
ID:
measurement of the hindrance of charge movement
Definition
Resistance (R)
Term
What is the inverse of R?
Definition
conductance
Term
What is the formula for conductance?
Definition
g=1/R
Term
Conductance increases as what else increases?
Definition
the permeability of the plasma membrane to an ion
Term
What is the relationship between potential difference, current, and resistance defined by?
Definition
Ohm's Law; L=E/R
Term
What does the E in the equation for Ohm's law stand for?
Definition
potential difference in voltage
Term
What are the equilibrium potentials for Na and K?
Definition
60; -94
Term
What is the resting membrane potential of neurons?
Definition
-70mv
Term
How are membrane potentials described?
Definition
the potential inside the cell vs outside the cell
Term
At rest a membrane is more permeable to ____
Definition
K
Term
What are the three important contributors to the Resting membrane potential?
Definition
Chemical driving forces, Differences in permeability and Na/K Pump
Term
Leak channels are ___ open
Definition
always
Term
Na tries to move ____ a cell while K wants to move ___ the cell
Definition
inside; outside
Term
The more permeable the membrane is to an ion, the closer ____ will be to that ion's ____
Definition
Vm(membrane potential); Ex (equilibrium potential)
Term
Leak channels help establish what?
Definition
resting Vm
Term
the plasma membrane is ___ at rest
Definition
polarized
Term
Depolarization makes the cell more ___ while hyperpolarization makes the cell more ____
Definition
positive; negative
Term
What does decremental mean?
Definition
that the stimuli signals can only travel so far
Term
Graded potentials can also be _____
Definition
polarized
Term
Define graded potentials
Definition
small, decremental changes in Vm that happen when ion channels open or close
Term
the change in Vm decreases as it moves ___ the stimulation
Definition
away from
Term
What structure is responsible for "catching' all graded potentials?
Definition
axon hillock
Term
Graded potentials can be ___ or ____
Definition
hyperpolarizing or polarizing
Term
What process is classified as an inhibitory graded potential and why?
Definition
hyperpolarization because it makes it harder to reach membrane potential
Term
What process causes excitatory graded potential and opens Na channels?
Definition
depolarizing
Term
If a cell is depolarized to the ____ an ___ ____ will result which carries the signal down the axon
Definition
threshold; action potential
Term
T/F:
A single graded potential is typically enough to generate an action potential
Definition
False; will only work if that one fire very quickly
Term
Define Temporal Summation
Definition
1 neuron, 1 stimulus state, same location
Term
Define spatial summation
Definition
different neurons/locations
Term
T/F
Action Potentials are decremental
Definition
False
Term
Which phase is the hyperpolarization phase
Definition
phase 3
Term
why does Na decrease with repolarization?
Definition
because Na channels are closing
Term
Voltage-Gated Na Channels are an example of what and why?
Definition
positive feedback because the opening of one Na channel causes others to open
Term
T/F:
Action potentials only go in one direction
Definition
True
Term
how do APs "code" for strength of stimulus?
Definition
through frequency of APs
Term
In which direction do APs usually travel?
Definition
down the axon
Term
What is the explanation for the relative refractory period?
Definition
voltage-gated K channels are open during after-hyperpolarization
Term
a stronger ___ leads to and greater action potential
Definition
stimuli
Term
Why do action potentials only travel in one direction?
Definition
because of the refractory period
Term
myelinated axons allow for a ___ to be activated at a time instead of one ___ at a time
Definition
node; gate
Term
T/F:
Large axon diameter slows down the propagation of AP
Definition
False
Term
How does myelination affect speed of AP travel?
Definition
allow for the AP to jump from one NOR to the next
Term
What are the fastest and slowest nerve fiber classifications and their locations?
Definition
A fiber (skeletal muscle); C fibers (pain fibers)
Term
What are the two types of synapses in the nervous system?
Definition
electrical and chemical
Term
Describe electrical synapses
Definition
Gap junctions; electrical "coupling" of cells with similar function; less common
Term
Describe chemical synapses
Definition
Neurotransmitters to communicate with neurons, muscles, or glands; most common
Term
What are the three types of chemical synapses?
Definition
axodendritic; axosomatic; axoaxonic
Term
The more ___ allowed into the axon terminal, the more neurotransmitter released
Definition
Ca
Term
What does SSRI stand for?
Definition
Selective serotonin reuptake inhibitors
Term
What is the purpose of SSRI's?
Definition
prevent serotonin the is exocytosed from neurons from being "recycled" (put back into presynaptic axon terminal)
Term
What is the name of the receptor in fast response chemical synapses?
Definition
ionotropic receptor
Term
Fast response at chemical synapses results in a change in membrane potential called what?
Definition
post-synaptic potential (PSP)
Term
What process occurs in slow response chemical synapses?
Definition
direct coupling
Term
What is the name of the receptorin direct coupling?
Definition
metabotropic receptor
Term
What are the two types of slow responses in chemical synapses?
Definition
direct coupling and second messenger
Term
Define and describe EPSP
Definition
excitatory post-synaptic potential; brings membrane potential closer to threshold (depolarization)
Term
Define and describe IPSP
Definition
inhibitory post-synaptic synaptic potential; moves the membrane potential further from threshold; hyperpolarization or Vm stabilization; K or Cl movement
Term
What is the reason behind only one synapse not being able to determine whether or not an AP will result?
Definition
convergence
Term
If an AP is triggered and the Vm is depolarized to threshold at the axon hillock _____ is necessary
Definition
summation
Term
What is the purpose of Acetylcholine (ACh)
Definition
contracts skeletal muscle
Term
What is the most abumdant neorotransmitterin the PNS?
Definition
ACh
Term
T/F:
ACh is only released in the PNS
Definition
False; released in both PNS and CNS
Term
What does ACh bind to?
Definition
cholinergic receptors
Term
T;F:
AChE can be either presynaptic or post synaptic
Definition
True
Term
What substance breaks down ACh so that AP stops?
Definition
AChE
Term
What types of cholinergic receptors are found in skeletal muscle cells?
Definition
nicotinic
Term
What types of movement are nicotinic cholinergic receptors responsible for?
Definition
shakiness/jitteriness
Term
Where are muscarinic cholineric receptors located?
Definition
CNS
Supporting users have an ad free experience!