Clicker Qs & Last Minute Material Flashcards
Which of the following characteristics would be true of cardiac muscle cells but not skeletal muscle fibers?
- Cells have the sarcomeric banded pattern
- Cells utilize T-tubules
- Cells are mononucleated
- Cells utilize ryanodine channels
Cells are mononucleated
The resting potential of -85mV is characteristic of which of the following phases of the cardiac fast AP?
- Stage 1
- Stage 2
- Stage 3
- Stage 4
Stage 4
An increase in the production of TSH releasing factor results in an increase in the release of TSH, which results in the release of more thyroxine, which results in a decrease in the production of TSH releasing factor. Is this a (-) or (+) feedback loop?
Negative; the increase in thyroxine results in a decrease in the production of TSH releasing factor. Overall decreasing effect.
Which of the following would have to be a transmembrane protein?
- A receptor protein
- A protein binding to a cytoskeleton
- A channel protein
- A phosphorylase
A channel protein
Provide two examples of negative feedback
- TSH releasing hormone
- Arterial blood pressure via baroreceptors
Intracellular components of the cell consists of all the following except:
- Ca2+
- K+
- Phosphate (PO4)
- Organic anions
Ca2+
Is the negative feedback loop stabilizing or destabilizing?
Stabilizing
Negative feedback loops ____ the original change while positive feedback loops ____ the original change
Decrease; Enhance
What is the role of GPI?
Loosely attaches peripheral proteins to the phospholipid bilayer membrane; Glycophosphatidylinositol anchored proteins
Can lipid soluble molecules pass the cellular membrane?
Yes; think of the fatty acid tails
Which organelle(s) is/are associated with intracellular trafficking?
Golgi, ER, lysosomes
Which organelle(s) is/are associated with most ATP production?
Mitochondria
The Na+-Ca2+ pump is an example of which of the following:
- Diffusion
- Primary active
- Secondary active
- Facilitated diffusion
Secondary active
Of the following ions, which is the most concentrated in the ECM?
- Sodium
- Potassium
- Chloride
- Calcium
Sodium
The Na+-K+ pump is an example of which of the following kinds of transport?
- Diffusion
- Primary active transport
- Secondary active transport
- Facilitated diffusion
Primary active transport
Gucose transporters (GLUT transporters) employ which of the following:
- Diffusion
- Primary active
- Secondary active
- Facilitated diffusion
Facilitated diffusion
Which of the following transport mechanisms requires energy other than KE?
- Osmosis
- Diffusion
- Active transport
- Facilitated diffusion
Active transport
The sodium glucose pump is an example of which of the following?
- Diffusion
- Primary active transport
- Secondary active
- Facilitated diffusion
Secondary active
Define “kinetic energy” and “thermal energy” and explain how these relate to molecular movement
- KE = energy via motion
- TE = movement via heat
- These are the way in which molecules move
Is osmosis selective?
Yes; semipermeable membrane
What causes osmotic pressure?
When water moves from one side of a membrane to another and accumulates there due to [] differences
Define Van’t Hoff’s law
Osmotic pressure depends on the [osmotically active particles]
What type of channels are aquaporins?
Integral membrane Non-gated channels
What are multiporters?
Secondary active transporters (ATP indirectly)
- Symporters (cotransporters)
- Antiporters (countertransporters/exchangers)
Does diffusion depend upon kinetic energy or external energy?
Kinetic energy (energy of motion)
What are the factors that affect the rate of diffusion? (3)
- Membrane electric potential (Nernst)
- Pressure difference
- Proportional to [difference] across the membrane
Can O2, CO2, Nitrogen and OHs readily cross a membrane?
Yes
What is the only form of transport that is not carrier mediated?
Simple diffusion and osmosis
What type of transport does facilitated diffusion utilize?
Uniporter (contains binding sites; glucose, amino acids)
List the 3 types of non-gated channels
- Aquaporins
- Sodium channels
- Potassium channels
What type of energy does active transport require?
metabolic energy (not kinetic) and carrier proteins
Where is the energy derived from for secondary active transporters?
Cocentration differences from a primary active transporter; utilizes multiporters
If Na+ moves down its electrochemical gradient, why is this referred to as secondary active transport?
ATP is necessary for the Na+ gradient to occur and move down its gradient
Na+/Ca2+ antiporters move three Na+ ions per Ca2+ ion. Why does it take three Na+ ions to move one Ca2+ ion?
Ca2+ has a greater electrochemical gradient and is a larger anion, therefore Na+ must overcome this charge and size
In a Na+/K+ pump, are both ions moving with and against their [gradient]?
Against
What type of transporters are the Na+-H+ and Na+-Ca2+ pumps?
Secondary active antiporters/countertransporter; uses the [Na+ gradient] that was established in the Na+-K+ pump
Explain how body compartment volumes can be altered
- Diet
- Dehydration
Carrier proteins are required for which type of active tranporters?
Primary and secondary
Which ions are typically associated with primary active transport?
Na+, K+, Ca2+, Cl-, H
An ATPase pump is a _____?
Carrier protein
What types of channels do dendrites contain and what do they contribute to?
Ligand gated channels (bind NTs); local potential
What type of channels do the axolemma contain and what does it cause
Voltage-gated ion channels; an Action potential
What is a plasmalemma
Cell membrane; can change its permeability, dictating the ECM and ICM environments
What does the Nernst Equation measure?
Determines the diffusion potential across a membrane that opposes the net diffusion of a particular ion through the membrane. Measures the potential for one type of ion at a time
What are the assumptions of the Nernst Equation? (3)
- Ion must be at equilibrium
- Equation can be used for only one ion at a time
- Memebrane must be completely permeable to that ion
What forms the selectivity filter of K+ channels?
Carbonyl oxygens; which dehydrate the K+ ions when passing through
How many gates does a K+ channel contain and at what potential does this gate open?
1; opens slowly from +35 to -90mV; otherwise it’s closed
Which membrane channels contain a selectivity filter?
Both K+ and Na+
What are the two ways in which an AP can be increased?
- Increasing the diameter of the axon (more internal flow and less resistance)
- Myelination (capacitor effect)
Why do action potentials typically travel in the orthodromic direction?
To store charge, its the absolute refractory period
Where is sphingomyelin found?
The lipid portion of the myelin sheaths made by Schwann cells
Why do small diameter fibers conduct AP slower than large diameter fibers?
Because of the less resistance, the flow cannot occur more evenly and rapidly
The resting potential for a typical neuron such as a motor neuron is best represented by which of the following potentials?
- 74
- -74
- 90
- -90
-90
Saltatory conduction is characterstics of which part of a typical neuron
- Dendrite
- Nerve cell body
- Axon
- Axon hillock
Axon
A selectivity filter with carbonyl oxygens is associated with which of the following kinds of ion channels?
- Gated sodium
- Non-gated sodium
- Potassium
- Chloride
Potassium
What 4 mechanisms help in establishing a membrane potential?
- Diffusion potential
- Equilibrium potential (equilibrium est. by concentration and electrical forces)
- Donnan equilibrium (2 permeant ions)
- Principle of electrical neutrality (sum of cations must equal the sum of anions in same compartment)
Which components of sarcomere change during contraction?
- H band (all myosin)
- I band (all actin)
HI!!
What does Ca2+ bind to during the sliding filament model?
Troponin
Where are the myosin binding sites located and what shifts to release these binding sites?
On actin; a shift occurs on tropomyosin
When does ATP become involved in muscle contraction?
When myosin is bound to actin; it releases it from actin; otherwise will get rigor mortis
- Also at SERCA
- and to reestablish resting potential with the Na+ and K+ ions thru the sarcolemma
Rephosphorylation occurs via 3 ways
- Phosphocreatine (enough energy 5-8 secs)
- Glycolysis
- Oxidative metabolsim (main source of ATP)
Define eccentric contraction
Muscle lengthens
Define concentric contraction
Muscle shorterns
Are red fibers fast or slow fiber types?
Slow; contract slowly but have more endurance i.e. Soleus muscle (standing, walking)
What type of muscle fibers are white fibers?
Fast; less endurance, contract rapidly, less mito., more ATPase i.e gastrocnemius muscle (fast movements = running, jumping)
- Which of the following terms refers to a chain of sarcomeres?
- muscle
- myofiber
- myofibril
- myofilament
myofibril
Which of the following sarcomeric bands does not undergo a change in length during the contraction of a skeletal muscle?
- A band
- H band
- I band
- J band
A band
Which of the following sarcomeric bands is composed entirely of actin filaments?
- A band
- H band
- I band
- J band
I band
- DHP channels are part of which of the following structures?
- Sarcoplasmic reticulum
- Plasmalemma
- T tubules
- Z discs
T tubules
RyR are part of which of the following channels?
- SR
- Plasmalemma
- T tubules
- Z discs
SR
Which of the following events occurs first during the transmission of a signal from an alpha motor neuron to a skeletal muscle fiber end-plate-potential?
- EPP
- Ca2+ ion influx into axon terminal
- Exocytosis of synaptic vesicles
- Sarcolemma AP
Ca2+ ion influx into axon terminal
Which of the following represents the factor by which the concentration of Ca2+ increaess in the cytosol after release from the SR?
- 10
- 50
- 100
- 1000
100
Which of the following maintains an optimum Ca2+ [gradient] to facilitate return of Ca2+ to SR?
- Calsequestrin
- SERCA
- DHP
- Ryanodine
Calsequestrin
Fast twitch fibers have which of the following characteristics?
- They are reddish in color compared to slow twitch fibers
- They have more mito than slow twitch fibers
- They have more myoglobin than slow twitch fibers
- They are more fatigable than slow twitch fibers
They are more fatigable than slow twitch fibers
Which of the following represents an example of an eccentric contraction?
- The triceps muscle during the throwing of a ball
- The triceps muscle while raising the body from the floor during a push-up
- The triceps muscle while lowering the body to the floor during a push-up
- The biceps muscle while raising the body during a pull-up
The triceps muscle while lowering the body to the floor during a push-up
First class lever system with example
- Fulcrum is in the middle
- Ex: raising chin (atlas/axis = fulcrum), seesaw
- in and out force move in opposite directions
2nd class lever system and example
- Resistance/out-force in middle
- In and out force are on same side of fulcrum
- Ex: raising body on ball of foot; fulcrum = ball of foot
3rd class lever system and example
- Effort/In-force in middle
- Both forces move in same directions
- In and out forces on same side of fulcrum
- Ex: lifting a weight in palm of hand
Which of the following are anchored to the presynaptic membrane and associated with synaptic vesicles to which they are tethered by short filamens?
- Synaptic vesicles
- Calcium channels
- Dense bars
- DHP channels
Dense bars
4 characteristics of a single axon terminal
- Synaptic gutter (trough) - where axon terminal makes contact w/ the sarcolemma
- Synaptic cleft - narrow gap b/w axonlemma of axon terminal and sarcolemma of innervated muscle fibers
- Has an EPP
- AcH gated ion channels - 2 bind
The vesicles for AcH are transported to the axon terminal from where?
RER
Smooth ER
Axon terminal
Golgi
Golgi
The EPP initiates what?
The AP on the sarcolemma (muscle fiber membrane)
What do clathrin coated pits contain and where to do arise from?
AcH; arise from the plasmalemma, turn into new synaptic vesicles
How is Ach removed from the synaptic cleft?
Acteylcholinesterase degrades it into choline and acetate and reuptake
What is meant by excitation-contraction (electro-mechanical coupling)?
Electrical activity from the AP along the neuron and sarcolemma; which cause the Ca2+ to be released and that causes the transformation of a mechanical event when it binds to troponin
Function of neostigmine
Inactivates acetylcholinesterase and causes muscle spasms
What occurs during myasthenia gravis?
- Abs attack acetylcholine receptors
- EPP are too weak to initiate opening of v.g. Na+ channels
- Autoimmune disease
- Neostigmine can be used to inactive acetrylcholinesterase so that the Ach can bind to whatever receptors are still there
What is neostigmine’s role in myasthenia gravis?
Degrades acetylcholinesterase so that there is an abundance of ACH to bind to the few Ach receptors there are due to the disease degrading them
What is the mean electrical axis of normal ventricles?
59 degrees
Which of the following characteristics would be true of cardiac muscle cells but not skeletal muscle fibers?
Cells have the sarcomeric banded pattern
Cells utilize T-tubules
Cells are mononucleated
Cells utilize RyR channels
Cells are mononucleated
Define syncytium
A grouping of cardiac muscle cells connected together
What is the AP of a ventricular fiber?
about 105mV
The resting potential of -85mV is characteristics of which of the following phases of the cardiac fast AP?
- Stage 1
- Stage 2
- Stage 3
- Stage 4
Stage 4
What is a purkinje fiber?
- A modified cardiac muscle cell that generates an AP in the heart mainly in the ventricular parts
- Fast type non-contractile myocyte
Where are T-tubules found in skeletal muscle? Cardiac muscle?
End of thick filaments; along the Z line
How many T-tubules are there per cisterna in skeletal muscle? Cardiac muscle? And what do they form within the sarcoplasic reticulum?
2 per cisterna and 3 = triad; 1 per cisterna and 2 = diad
How are muscle fibers arranged in skeletal muscle? Cardiac muscle?
Motor units; syncytium
Where are fast action potentials found, contractile or non-contractile?
- Atria, ventricles, and conducting system
- Rapid but non-contractile in Purkinje fibers
- High amplitude
- Rapid and contractile in atrial and ventricular fibers
Where are slow APs found in cardiac muscle?
- SA and AV nodal tissues
- Conducts slowly
- Low amplitude
- Automatically depolarizes during resting phase
Which ion contributes to the slow AP in cardiac muscle (SA and AV nodes)
Calcium; higher resting phase (-60, rather than -90); spontaneously depolarize during phase 4
Characteristics of fast type contractile myocytes (3)
- Large diameter
- High amplitude
- Rapid onset of AP
Characteristics of fast type non-contractile myocytes
- Very large diameter
- Very rapid upstroke
Characteristics of slow type non-contractile myocytes
- Small diameter
- Low amplitude
- Slowr rate of depolarization
What types of channels cause an AP in ventricular fibers? (2)
- Fast Na+ channels
- Slow Ca2+/Na+ channels
Where are the two sources that Ca2+ comes from during cardiac muscle AP?
- T-tubules via diffusion via DHP
- Cisternae of the Sarcoplasmic tubules via RyR receptors (external environment)
Why is there no plateau in skeletal muscle AP?
Because Na+ channels close rapidly;
What causes the plateau during cardiac AP?
- Ca2+ channels staying open for a longer period of time
- K+ channels have a delay in the opening
- Therefore, there’s a large [] of Ca2+ and K+ ions
What two transporters allow for relaxation of cardiac tissue?
- SERCA - assisted by phospholambian
- Na+/Ca2+ exchanger in the sarcolemma (not in skeletal muscle)
What is diastasis?
Midportion of diastole when blood enters ventricle slowly or ceases to enter prior to atrial systole
What occurs during the first third of diastole?
Rapid filling; 80%
What occurs during the middle third of diastole (diastasis)?
Small amount of blood flows into ventricles
What occurs during the last third of diastole?
Atria contract and push remaining 20% of blood into ventricles
How much blood is ejected during the period of rapid ejection?
- 70%
- When left ventricular pressure is above 80mmHg
- First 3rd of ejection
How much blood is ejected during the period of slow ejection and when does this occur?
- Remaining 30%
- During the last 2/3 of ejection
What occurs at the myofilament level in the Frank-Starling Law?
The stretching of the cardiac muscle brings the actin and myosin filaments to a more nearly optimal degree of overalp for force generation
Ejection fraction formula
EJ = SV / EDV
What are the phases in the SA nodal AP?
- 4
- 0
- 3
What accounts for the slow conduction of the heart?
The diminished number of gap junctions resulting in an increase in resistance to conduction
What causes a slight rise in the SA nodal AP?
Leaky Na+ channels
What nerve is contributed to the parasympathetic innervation of the heart and what hormones are used?
- Vagus nerve
- Ach
- Muscarinic receptors
- Negative chronotropic effect
- Increases permeability to K+ ions
Where does sympathetic innervation take place in heart and what hormone?
- Mainly ventricles, but all over
- NEpi
- Increases depolarization rate
- Positive chronotropic effect
In a typical ECG, which of the following waves occurs at the beginning of the contraction of the atria?
- T
- R
- S
- P
- Q
P
What is the PR Interval?
The heart’s delay - 0.16sec
Which of the following is the direction of bipolar lead II?
- 0
- 60
- 90
- 120
120
Of the 3 bipolar leads, which one is connected to both left and right arms?
- Lead I
- Lead II
- Lead III
- All leads are connected to only one arm each
Lead I
Where is limb lead I placed and what does it record
- (-) on right arm
- (+) on left arm
- Heart from left to right
Where is limb lead II placed and how does it look at the heart?
- (-) to right arm
- (+) to left leg
- Heart from upper right to lower left
- EKG records (+)
Where is limb lead III placed and where at the heart does it look at?
- (-) on left arm
- (+) on left leg
- Heart from upper left to lower left
- Records on EKG as positive
