GENERALITIES - ARRYTHMIAS Flashcards
The change in transmembrane voltage triggers the Na ion channels to open, which in turn causes the transmembrane voltage to be even higher. The mechanism in this is:
A. Open loop
B. Positive feedback
C. Servo mechanism
D. Negative feedback
B. Positive Feedback
POSITIVE FEEDBACK CYCLE - opens the Sodium channels.
Event that will cause rise in -70mv may cause many voltage-sodium channels to begin open, then results to rapid inflow of sodium ions.
Part of the nervous system that determines the response to stimuli
A. ANS
B. CNS
C. Sensory input portion
D. Motor output portion
B. CNS
The Central Nervous System composed of brain & spinal cord.
Brain - stores information, generates thoughts, creates ambition, and determines reaction that the body performs in response to sensations. Appropriate signals is transmitted through motor output portion of the nervous system
NOT TRUE regarding the fluid transport in the circulatory system
A. Liver stores absorbed stuff
B. Blood flows through the lungs at all times
C. Carbon dioxide is removed from the blood
D. Substances absorbed in the GIT will be used in its absorbed form
D. Substances absorbed in the GIT will be used in its absorbed form
ORIGIN OF NUTRIENT IN THE ECF
Respiratory System - provides oxygen for the body & remove CO2
GIT System - digest food and facilitate absorption of nutrients
Liver - change chemical composition of absorb substances to more usable form
Musculoskeletal system - protects internal organs and support the body
Protein channels have the ff characteristics
A. Impermeable
B. Open to engulf ions through endocytosis
C. Passage of water through pores
D. Voltage-gated channel release of Ach
D. Voltage-gated channel release of Ach
Protein Channels 2 important characteristics:
1. often selectively permeable to certain substance
2. many channels can be opened or closed by gates that regulates electrical signals (voltage-gated) or chemicals that bind to channel proteins (ligand-gated)
Differentiate Pinocytosis and Phagocytosis
A. Size of the substance engulfed
B. Action
C. Exocytosis occur at the end
A. Size of the substance engulfed
Pinocytosis VS. Phagocytosis
Pinocytosis:
1. intake of fluid
2. vesicles-invagination
3. Pinosomes release contents inside
4. May or may not be digest w/ help of lysosome
5. No exocytosis at the end
6. Size of vesicle - small (0.1-0.2)
Phagocytosis:
1. intake of solid
2. vesicles - evagination
3. Phagosomes do not directly release contents inside
4. Lysosomes combined to digest
5. exocytosis occur at the end
6. Size of vesicles - large (1-2)
Shared characteristic of simple and facilitated diffusion
A. Inhibition of Na-K pump
B. Carrier-mediated
C. Stereospecificity
D. Doesn’t need metabolic energy
D. Doesn’t need metabolic energy
SUMMARY OF MEMBRANE TRANSPORT
Simple diffusion - Passive, downhill; Carrier-mediated(NO); ATP use(NO); Na+ gradient dep. (NO)
Facilitated diffusion - Passive, downhill; YES; NO; NO
Primary Active Transport - Active; uphill; YES; YES, direct; NO
Cotransport Symport - Secondary Active; YES; YES, indirect; YES (move same direction)
Counter-transport symport - Secondary active; YES; YES, indirect; YES (moves in opposite direction)
Osmosis is primarily governed by:
A. Pressure difference
B. Degree of permeability
C. Molecular weights of solute & solvent
D. Concentration difference of solvent
D. Concentration difference of solvent
Difference of the water concentration across the cell membrane will cause to cell either shrink or swell depends on the direction of water movement.
The process of net movement of water caused by concentration difference of water is called OSMOSIS.
Peripheral membrane proteins function is primarily as:
A. Carrier for substances to pass through
B. Receptors for water soluble substance
C. Controllers of transport substances through the membrane
D. Second messengers allow communication between the interior to the environment
C. Controllers of transport substances through the membrane
Peripheral protein molecules - often attached to integral proteins. Its function almost entirely as enzymes or as controllers of transport of substances through cell membrane pores
Integral membrane proteins - serve as receptors for water-soluble chemicals (i.e peptide hormones)
Functional characteristics of Smooth Endoplasmic reticulum
A. Provides the enzyme for detoxifying substances
B. Budding off of transport vesicles for protein processing
C. Grows extensively to accommodate production of protein and lipid
D. Provides energy for the breakdown of glycogen during metabolism
A. Provides the enzyme for detoxifying substances
SIGNIFICANT FUNCTIONS OF ER, especially sER:
1. Provides enzyme that control glycogen breakdown when glycogen is to be used for energy
2. provides enzymes that are capable of detoxifying substances. Detoxification such as coagulation, oxidation, hydrolysis, & conjugation w/ glycuronic acid
Correct sequence of phagocytosis
A. Formation of phagocytic vesicle
B. Pinching off of the phagocytic vesicle
C. Inward pushing of the phagocytic vesicle
D. Cellular membrane attachment to the surface ligand of the particle
E. Contractile fibrils surround the phagocytic vesicle
D > A > E > C > B
PHAGOCYTOSIS STEPS:
1. Cell membrane receptor attached to the surface ligand of the particle
2. Formation of vesicle by evagination
3. Actin & contractile fibers surround the phagocytic vesicle
4. They contract, resulting to inward pushing of the phagocytic vesicle
5. Contractile protein pinch the vesicle for completely separation to cell membrane
Diffusion of positively charged ion outside the cell is increased
A. Pressure outside the cell
B. Negativity inside the cell
C. Positivity charged ions outside the cell
D. Concentration of substance inside the cell
B. Negativity inside the cell
Electrogenic Nature of Na+-K+ Pump
- 3 Na+ ions to the exterior every 2 K+ ions moved to the interior means a “net of one positive charge” to the “exterior”, results to “deficit of positive ion inside” the cell causes the “negativity” on the inside
Which transport mechanism DOES NOT require ATP?
A. Movement of sodium outside the cell
B. Movement of glucose to muscle cell
C. Movement of calcium to sarcoplasmic reticulum
D. Movement of ion to distal nephron
B. Movement of glucose to muscle cell
- facilitated diffusion
Movement of sodium outside cell
- primary active transport (Na,Ca,H,Cl)
What major mechanism directly contributes to resting membrane potential
A. Na K ATPase pump
B. Sodium leak channel
C. Potassium leak channel
D. Innate Nernst Potential of Na and K
C. Potassium leak channel
Leakage of Potassium Through the Nerve Cell Membrane
- may also leak sodium ions slight but MORE PERMEABLE to potassium, 100 times as permeable
- differential in permeability is a key factor in determining the level of the NORMAL RESTING MEMBRANE POTENTIAL
In a motor neuron, what will enter the pre-synaptic neuron after AP reaches its terminal?
A. Potassium
B. Sodium
C. Calcium
D. Chloride
C. Calcium
When AP spreads over the terminal, voltage-gated calcium channels open and allow calcium ions to diffuse from the synaptic space to the interior of the nerve terminal
Which of the ff statements regarding depolarization is TRUE?
A. Depolarization is the membrane potential in which occurrence of action potential is inevitable
B. Depolarization is the period in which a new AP can be elicited
C. Depolarization is the period in which a new action potential cannot be elicited
D. Depolarization is making the membrane potential less negative
D. Depolarization is making the membrane potential less negative
Depolarization Stage:
- the membrane becomes permeable to sodium ions (positively charged)
- The normal “polarized” state of -90mv is immediately neutralized by positively charge sodium ions, w/ potential rising rapidly in the positive direction
The myelin sheath of nerves is produced by supportive cells like oligodendrocytes in the CNS and Schwann cells in PNS. The ff is NOT a consequence of myelination of nerve fibers
A. Decrease in nonselective diffusion of ions across the axonal membrane
B. Increase in energy required to maintain ion gradients across the membrane
C. Increase in the velocity of nerve impulses along the axon
D. Generation of action potentials only at nodes of Ranvier only at the nodes
B. Increase in energy required to maintain ion gradients across the membrane
Saltatory Conduction is value for 2 reasons:
1. causing depolarization process to jump long intervals along nerve fibers
2. conserve energy
Which of the following statements best describes the adequate stimulus?
A. It is the minimum stimulus intensity that activates a sensory receptor
B. It is the specific form of stimulus that can generate an action potential in the sensory nerve
C. It is the only form of stimulus which can activate a sensory receptor
d. It is the form of energy to which a particular receptor has the lowest threshold
d. It is the form of energy to which a particular receptor has the lowest threshold
Adequate Stimulus
- particular form of energy to which a receptor is most sensitive; lower threshold
The resting membrane potential of the neuronal soma is primarily caused by:
Establishment of Resting Membrane Potentials under 3 conditions:
1. Potassium diffusion alone
2. Diffusion of both sodium and Potassium ions
3. Diffusion of both sodium and potassium ion plus pumping of both ions by Na+-K+ pump
The muscle end plate ACh, causes depolarization by which mechanism?
A. Opening of the voltage gated Na channel
B. Opening of the voltage gated Ca channel
C. Ca++ channel depolarization toward the Ca++ equilibrium potential
D. K+ channels depolarization toward the K+ equilibrium potential
A. Opening of the voltage gated Na channel
- Opening of ACETHYLCHOLINE-GATED CHANNEL allows large quantities of sodium ions to diffuse to interior causing a LOCAL DEPOLARIZATION that leads to the OPENING OF VOLTAGE-GATED SODIUM CHANNELS w/c initiates AP in the membrane
Which of the ff statements correctly describes Myofibrils?
1 - I bands contain only actin filaments
2 - A bands are isotropic to polarized light
3 - M line contain thick filaments linked by accessory proteins
4 - H zone are where thick and thin filaments overlap
A. 2&4 are correct
B. Only 1 is correct
C. All statements are incorrect
D. Only 1,2,3 are correct
E. 1&3 are correct
E. 1&3 are correct
1 - I bands contain only actin filaments
3 - M line contain thick filaments linked by accessory proteins
Light (I) bands - only actin filaments, they are “isotropic” to polarized light
Dark (A) bands - only myosin filaments & ends (overlapping) of actin filament; they are “anisotropic” to polarized light
Z line - where actin filaments anchored
M line - where myosin filaments anchored
H zone - contain only myosin filaments
Which of the ff achieves the side by side relationship bet actin and myosin filaments
A. Strong insertion of actin filaments into 2 discs by alpha actin
B. Large number of filamentous molecules of titin
C. Interaction of actin and myosin filaments through cross bridges
D. Absence of cross bridges in the very most center of myosin
B. Large number of filamentous molecules of titin
TITIN filaments molecules KEEP the MYOSIN and ACTIN filaments in place
- side by side relationship between myosin and actin filaments is maintained by a large number of filamentous molecule called titin
- It is “springy” due to its filamentous character
- spring titin act as framework that holds myosin and actin in place
Difference between 2 types of muscle fibers:
A. Fast fibers are rich in myoglobin to supply oxygen
B. Slow fibers have few mitochondria than fast fibers
C. Slow fibers have large amounts of glycolytic enzymes
D. Fast muscle fibers have less extensive blood supply
D. Fast muscle fibers have less extensive blood supply
Slow Fibers (Type 1, Red Muscle)
- smaller
- innervated by small nerve fibers
- more extensive blood vessel system & more capillaries ( > oxygen)
- increased in number of mitochondria; oxidative metabolism
- large amounts of myoglobin; red muscle
Fast Fibers (Type II, White Muscle)
- large
- extensive sarcoplasmic reticulum
- large amount glycolytic enzymes; glycolytic process
- less extensive blood supply
- fewer mitochondria, white muscle
Skeletal muscle contraction is termination by which action:
A. Removal of calcium from presynaptic terminal
B. Closure of Ach from the neuromuscular junction
C. Removal of Ach from the neuromuscular junction
D. Removal of intracellular calcium
A. Removal of calcium from presynaptic terminal
Removal of calcium ions from the myofibrils causes the muscle contraction to cease
Rigor mortis or post mortem rigidity results from which of the ff:
1 - Energy for muscle contraction is due to ATP from phosphocreatine and glycolytic metabolism
2 - calcium leaks from ECF and SR
3 - Binding of calcium to troponin uncovers actin binding sites
4 - Consumption of ATP disables myosin from detaching from actin
A. 1&3 are correct
B. 2&4 are correct
C. only 4 is correct
D. All are correct
C. only 4 is correct
Rigor Mortis
- muscle contract and become rigid , even w/out action potentials. Rigidity results from LOSS OF ALL THE ATP, which required to cause “separation of cross bridges from actin filaments”
- remain in rigor for 15-25hrs , until deteriorate from autolysis (enzyme released by lysosomes)
Low rate nerve impulse coming from the anterior motor neuron
Muscle tone
Skeletal Muscle Tone
- amount of tautness even the muscle at rest
- results from a low rate of nerve impulses coming from the spinal cord
Which of the ff enzymes dephosphorylates the myosin head to cause smooth muscle relaxation?
A. Calcium-calmodulin-dependent protein kinase
B. Myosin Light Chain Kinase
C. Calsequestrin
D. Myosin Phosphatase
D. Myosin Phosphatase
- remove phosphate from the myosin light chain, causing detachment of the myosin head from the actin filament and relaxation of the smooth muscle
Correct sequence of skeletal muscle excitation to contraction
- AP arrives at neuromuscular junction
- Ach released and binds to receptors
- Na ion channel open
- Depolarization in sarcolemma
- AP travels along T-tubules
- Thick and Thin interaction = muscle contraction; muscle shorten
- Calcium is reabsorbed; relaxation begins
- Thick & Thin filaments relax = muscle lengthens & relax
What is true of Sarcoplasmic Reticulum in skeletal?
A. Network forms around muscle fiber
B. Tubular network forms at Z line
C. Tubular network w/ ribosome
D. Junctional at T-tubules
A. Network forms around muscle fiber
Action Potentials w/ plateau observed in smooth muscles is due to which of the ff?
A. All of the choices
B. Slow opening of voltage-gated potassium channels
C. Rapid depolarization due to increased sodium conductance
D. Prolonged opening of voltage-gated calcium channels
E. Closure of sodium channels w/ influx of chloride
D. Prolonged opening of voltage-gated calcium channels
- the calcium channels open many times more slowly than sodium channels, and they also remain open much longer.
Not true about smooth muscles;
Similar to skeletal muscles fibers, smooth muscle fibers are capable of only all-or-nothing twitches
All-Or-Nothing Principle
- depolarization process travels over the entire membrane, but it does not travel at all conditions are not right. it applies to all normal excitable tissue, all or none law is not applicable for whole skeletal muscle
The T tubules of Skeletal muscles are located
A. I band
B. I-A band
C. M band
D. H band
B. I-A band
T Tubules
- communicated w/ the outside of the cell membrane
- lies adjacent to the ends of longitudinal sarcoplasmic reticulum
In Skeletal muscle - 2 T tubules per sarcomere; located at I-A band
