Week Two A/P Flashcards
Osmotic Pressure
Osmotic pressure is greater where solute concentration is ______
Water will flow to the solution with ______ solute concentration, or in other words, the solution with ______ osmotic pressure
Water flows through the cell membrane through channels called _______
Higher
Higher, Greater
Aquaporins
Osmotic Pressure
Solution with high OP is ______
Solution with low OP is ______
_______ osmotic pressure is the pressure created by plasma proteins
[equals ___ mmHg]
Hypertonic
Hypotonic
Colloid
28 mmHg
Ion Channels
______ proteins that span the membrane when open, permitting the passage of certain ___
They are ______
Two different types of ion channels: _____-gated and _____-gated
Integral, Ions
Selective
Voltage-gated and Ligand-gated
Voltage Gated Channels
Opened or closed based on changes in ______ ______
Activation gate of the Na+ channel in nerve is opened by _______
When open, the nerve membrane is permeable to ____ (during upstroke of AP)
Inactivation gate of the Na+ channel in nerve is closed by _______
When closed, the nerve membrane is impermeable to ____ (during repolarization)
Membrane Potential
Depolarization
Na+
Repolarization
Na+
Ligand Gated Channels
Opened or closed by ______, _______ messengers, or _________
Ex: _______ receptor for Acetylcholine at motor end plate is an ion channel that opens when Ach binds to it
When open, it is permeable to ___ and ___, causing the motor end plate to depolarize
Hormones, Second Messengers, Neurotransmitters
Nicotonic
Na+ and K+
Ligand Gated Channels
______ channels are ligand-gated. These channels open when GABA binds to its receptor
When chloride channels are open, inward movement of _____ ions is allowed into the cells
Chloride
Cl-
GABA/Benzodiazepines
Binding of GABA is _____ by benzodiazepines, resulting in greater entry of ____ ions into the cell, leading to _______ (a more negative charge)
The hyperpolarization makes it more difficult to _______, and reduces neuronal excitability
Enhanced
Cl-, Hyperpolarization
Depolarize
Action Potential
Cells contain a high ___ concentration
Membrane electrical potential difference is generated from diffusion of ___ through leaky channels
Typical resting membrane potentials in neurons is ____ to ____ mV
K+
K+
-70 to -90 mV
Action Potentials
___ entry into cell causes a more _____ charge to occur within the cell
Only two cells, ______ and ______ cells can achieve the action potential spike
Conclusively, the AP process is initiated from _____ K+ channels
Na+, Positive
Neuron, Muscle
Leaky
Depolarization
Makes cell membrane potential less ______, due to movement of positively charged ____ ions into the cell
This leads to increased ________
Negative, Na+
Excitability
Repolarization
Returns the membrane back to its ______ potential
Repolarization results from the movement of positively charged ___ ions out of the cells
Resting
K+
Hyperpolarization
Makes membrane potential more _____ due to movement of negatively charged ____ ions into the cell
Decreased cell _______
Negative, Cl-
Excitability
Inward current is the flow of ______ charge into the cell. Inward current ______ the membrane potential
Outward current is the flow of _____ charge out of the cell. Outward current _______ the membrane potential
Positive, Depolarizes
Positive, Hyperpolarizes
Threshold
The membrane potential at which the action potential is ______
Resulting depolarization gives rise to upstroke of _____ _____
If net inward current is ____ than net outward current, no action potential will occur
Inevitable
Action Potential
Less
Upstroke (Depolarization)
Inward ___ movement
______ blocks these voltage sensitive Na+ channels, and abolishes action potential
No ___ entry = No depolarization
Na+
Lidocaine
Na+
Downstroke (Repolarization)
Outward __ movement
Outward flow of K+ ______ the membrane potential
K+
Hyperpolarizes
Absolute Refractory Period
Period during which another action potential cannot occur, no matter how large the ______. This is due to closure (inactivation) of ____ gates
Stimulus
Na+
Relative Refractory Period
Period during which an action potential can be elicited only if a ______ than usual stimulus is provided
The refractory period protects the cell from ____-_______, allowing a ______ period between action potentials
Larger
Over-Excitation
Recovery
Local Anesthetics
Local anesthetics are weak bases present in an ______ form (LA) and ______ form (LAH+)
______ form (LA) penetrates the cell membrane
pH is ____ inside the cells, causing more of the ______ form to produce
_____ form (LAH+) blocks the ____ channels from the inside, inhibiting conduction of pain impulses
Un-ionized, Ionized
Un-ionized
Acidic, Ionized
Ionized, Na+
Local Anesthetics
Slow the rate of _______ of the nerve action potential such that the ______ potential is not reached
Due to this, an _____ _____ cannot occur and a conduction blockade results
Depolarization, Threshold
Action Potential
Inhaled Anesthetics
(Isoflourane, Desflurane, Sevoflurane)
______ the effect of GABA
Increase entry of ___
________ of cell (makes cell less responsive and more difficult to depolarize)
Enhance
Cl-
Hyperpolarization
Hypokalemia
______ the diffusion gradient
Serum hypokalemia will cause a _____ KCL leak from the cell to the serum, creating a _______ and ______ weakness
Increases
Larger, Hyperpolarization, Muscle
Hyperkalemia
______ the diffusion gradient
AP does not occur because inactivation gates of Na+ channels are closed by _______
Without action potential, there is no _____ (muscle weakness)
No ______ is allowed to occur
Decreases
Depolarization
Contraction
Repolarization
Cardioplegic Solution
Causes rapid membrane _______
No ______ can occur due to high extracellular ___
Na+ channels are locked in an _____ state
Heart muscle is in a permanent ______ ______ period
________ is a drug that also causes rapid depolarization
Depolarization
Repolarization, K+
Inactive
Absolute Refractory
Succinylcholine
Ligand Gated Channels
Open or close by the following ligands: ______, second ______, or ________
These ligand gated channels change membrane _______
Ex: _______ receptor for acteylcholine at motor end plate is an ion channel that _____ when Ach binds to it
(When open, it is permeable to ___ and ___, causing the motor end plate to _______)
Hormones, Second Messenger, Neurotransmitters
Permeability
Nicotinic, Opens
Na+ and K+, Depolarize
Ligand Gated Channels
______ channels are also ligand gated. These channels open when _____ binds to the receptor
Other examples of ligand gated channels are _______ and _____
These are not the same as voltage gate channels, which require a difference in ______ ______ l to elicit a response
Chloride, GABA
Glutamate, 5-HT
Membrane Potential
cAMP Mechanism
______ binds to a receptor
Activation of __ _______ (more than 50% of drugs act via this protein)
Gs protein stimulates _______ ______ to convert ____ to ____
cAMP activates ______ ______, which phosphorylates specific proteins
______ action occurs
Hormone
G Protein
Adenylate Cyclase, ATP to cAMP
Protein Kinase-A
Cellular
cAMP Mechanism
cAMP is broken down to an inactive state through _______
Name some things that inhibit phosphodiesterase breakdown?
In cardiac muscle, beta agonists (dobutamine) act through cAMP. Increased cAMP results in activation of _____ ______, which enhance entry of ___ into the myocardial cell (increasing force of contraction)
Phosphodiesterase
Caffiene, Aminophylline, Milrinone
Protein Kinases, Ca++
IP3 (inositol triphosphate) Mechanism
______ binds to a receptor in the cell membrane through a __ ______, which activates _________ ___
Phospholipase C liberates _______ (DAG) and _____ from mebrane lipids
IP3 mobilizes ______ from the ______ _______
____ and ______ (DAG) activate _______ _______, which phosphorylates proteins and produces cellular _______
Ex: Ach on _______ receptor
Hormone, G Protein, Phospholipase C
Diacylglycerol (DAG) and IP3
Ca++, Endoplasmic Reticulum
Ca++ and Diacylglycerol (DAG); Protein Kinase C, Action
Muscarinic
Catalytic Receptor Mechanism
Associated with ______ activity on receptors (No G protein involvement)
_____ ______ _____ (ANP) and _____ _____ (NO) act through ______ ______, which converts _____ to _______ (second messenger)
Insulin acts through ______ _______
Enzymatic
Atrial Natriuretic Peptide, Nitric Oxide
Guanylyl Cyclase; converts GDP to cGMP
Tyrosine Kinase
Steroid Hormones Mechanism
Steroid or thyroid hormones _____ across cell membranes of target cells, binding to a ______ receptor, then a _____ receptor
Binding to the ______ receptor causes a _______ change in the receptor, which exposes a ____-_______ _______
Diffuse, Cytosolic, Nuclear
Nuclear, Conformational
DNA-Binding Domain
Steroid Hormones Mechanism
In the _____, the DNA binding domain on the receptor interacts with hormone regulatory elements of specific DNA
_______ is initiated and results in the production of new ______
_______ is then translated in the cytoplasm, and results in production of specific _______ that produce physiological effects
Nucleus
Transcription, mRNA
mRNA, Proteins
Beta 2 Stimulants (Agonists) in Lungs
Terbutaline, which acts on _____ receptors, which activate __ ______, which activate ______ ______, causing an increase in ______ and activation of ______ ______, leading to ________
_________ is a PDE inhibitor that leads to maintained increase of _____, leading to ______
Beta 2, G Proteins
Adenyl Cyclase
cAMP, Protein Kinases, Bronchodilation
Aminophylline, cAMP, Bronchodilation
Nitric Oxide (NO) in Lungs
(NO) activates ______, leading to ________
(NO) _____ the cell membrane and does not require a cell ______
cGMP, Bronchodilation
Crosses, Receptor
Cholingeric Muscarinic Receptors (M3 receptors)
Stimulation of cholinergic M3 receptors activates __ ______, leading to the formation of _____, which increases the release of ___ from intracellular storage, leading to ________
Anticholinergics such as ______ also known as ______, Inhibit the ___ receptor, leading to ________
Gq Protein
IP3
Ca++, Bronchoconstriction
Ipratropium (Atrovent), M3, Bronchodilation
Muscle Structure
Each muscle fiber is ______ and behaves as a _____ unit. Each muscle fiber contains bundles of ______, surrounded by SR and invaginated by __ _______
Each myofibril contains thick and thin _____, arranged longitudinally in sarcomere
_______ runs from ___ line to __ line
Multinucleated, Single
Myofibrils, T-Tubules
Filaments
Sarcomere, Z line to Z line
Muscle Structure
Thick filament contains _____
Thin filament contains _____, ________, and _______
Troponin T binds with ______
Troponin I binds with ______
Troponin C binds with ______
Contraction results from the sliding action of interdigitating _____ and _____ filaments
Myosin
Actin, Tropomyosin, Troponin
Tropomysin
Actin
Calcium
Actin & Myosin
Muscle Structure
T-Tubules are ______ with the cell membrane and they invaginate the cells at the __ lines
T-Tubules carry ____ into the cell ______
Continuous, Z-lines
Action Potential, Interior
Muscle Structure
Sarcoplasmic reticulum are small diameter tubules that lie in close proximity to ______ elements
Sarcoplasmic reticulum is the site of storage and release of _____, for ______-______ coupling
Contractile
Calcium, Excitation-Contraction
Excitation-Contraction Coupling
The AP spreads from the cell membrane into the __ ______
___ enters the cell from the ECF ( inward ___ current ), through ___ _____ Ca++ channels ( ________ receptors)
This Ca++ entry triggers the release of even more Ca++ from the sarcoplasmic reticulum (Ca++ induced Ca++ release), nicknamed the ___ _____ through Ca+ release channels ( ______ receptors)
As a result of this ___ release, inctracellular Ca+ ______
T-Tubules
Ca++, Inward Ca++, L-Type, Dihydropyridine
Ca++ Spark, Ryanodine
Ca++, Increases
Excitation-Contraction Coupling
Ca++ binds to ______ and ______ is moved out of the way, removing inhibition of actin and myosin binding
Actin and myosin bind; the thick and thin filaments slide past each other and the muscle _____. This mechanism is also known as the _____ _____
The magnitude of the tension that develops is proportional to the ________ ___
Troponin C, Tropomyosin
Contracts, Power Stroke
Intracellular Ca++
Excitation-Contraction Coupling
_______ occurs when Ca++ is re-accumulated by the SR by an active ______ pump
Ca++ is also removed from the cell via the ______ exchanger
Relaxation, Ca++ ATPase
Na+/Ca++ Exchanger
Excitation-Contraction Coupling
Calcium channel blockers block _____ Ca++ channels ( ______ receptors)
Dantrolene (Dantrium) blocks ___ ______ channels ( ______ receptors) on the _______ _______
L-Type, Dihydropyridine
Ca++ Release, Ryanodine, Sarcoplasmic Reticulum
Excitation-Contraction Coupling
________ acts on Beta-1 receptors on the heart and causes increased ____, which increases ___ influx through the ______ channels, therefore, _______ the force of contraction
( ________ does the opposite )
What will happen if the beating heart and skeletal muscle are placed in a calcium free solution?
Norepinephrine, cAMP, Ca++, L-Type
Increasing
Acetylcholine
Heart will stop, Muscles won’t contract
Excitation-Contraction Coupling
A single AP causes the release of a standard amount of Ca++ from the SR and produces a _____ _____
If the muscle is stimulated _______, then more ____ is released from the SR, and there is a cumulative ______ in intracellular ___, extending the time for the cross-bridge cycling. The muscle does not have the chance to _____. This is what occurs with ______
Single Twitch
Repeatedly, Ca++, Increase, Ca++
Relax, Tetanus
Coupling (Cardiac Muscle)
AP moves along __ ______
_______ receptors are activated (voltage sensors that release small amount of calcium into the fiber)
Ca++ binds to the _______ receptor, which then opens, releasing a large amount of ___
Ca++ is pumped back into the SR and back into T-Tubule
_______ is terminated
T-Tubules
Dihydropyridine
Ryanodine, Ca++
Contraction
Malignant Hyperthermia
Characterized by ______ combustion, ______ ______ rigidity, and ______ ______ (hypermetabolism)
Can be triggered by _______ (halothane), _______ tendency (can be tested via muscle bx)
MOA: Constant leak of SR ___ through defective ______ receptor
Spontaneous, Skeletal Muscle, Metabolic Acidosis
Anesthetics, Familial tendency
Ca++, Ryanodine
Muscle Contraction (summary)
Myosin head attaches to _____
Through ____, myosin head releases and undergoes _______
Myosin head is “______,” and is ___ and ___ bound
Through action of ___, myosin head attaches to new site and _____ _____ is initiated. After this action, ____ is released
Actin
ATP, Hydrolysis
Cocked, ADP and Pi
Pi, Power Stroke, ADP
Coupling (Skeletal Muscle)
AP moves along __ ______
Voltage change sensed by _______ receptor, which is the communicated to the ______ receptor, which then opens, allowing _______ to occur
_______ is pumped back into the SR
Calcium binds to ______ to facilitate storage
_______ is then terminated
T-Tubules
Dihydropyridine
Ryanodine, Contraction
Calcium
Calsequestrin
Contraction
