key questions/poll ev unit 3 Flashcards
Which type of the following connective tissue are tendons composed of?
dense regular connective tissue
The intracellular concentration of _____ is higher than the extracellular concentration
K+ potassium
A mutation in TnC decreases its capacity to bind Ca2+. Consequentially, which state of the thin filament does this mutant TnC promote? (troponin)
blocked
Which ingredients would you choose, if asked to prepare a solution to make the muscle contract?
Ca2+ calcium
In addition to EGTA )a Ca2+ chelator) which of the following would be a critical component of a muscle relaxing solution?
ATP
Which functional state of the thin filament is favored by the mutant?
blocked
What are the different layers of connective tissue that surround the skeletal muscles and what do they surround?
-whole muscle: epimysium
-single bundle: mycelium
-single muscle cell/fiber: endomysium
What are the unique features of the skeletal muscle compared to a typical cell?
-presence of t-tubules
-sarcoplasmic reticulum
-sheer length
-multiple nuclei present in skeletal muscle
-presence of sarcomeres
What is the structural and functional unit of the muscle?
sarcomere
What proteins in muscle regulate muscle contraction and relaxation?
-actin
-myosin
-troponin
What are some structural and functional differences of skeletal and cardiac muscles?
cardiac muscles: under control of autonomic nervous system
-much smaller cell size
-single nucleus
-structure of sarcoplasmic curriculum and t-tubules
What causes muscles to contract
Calcium entering and binding to the thin filament
What causes muscles to relax?
calcium being removed
What are some structural and functional differences of skeletal and smooth muscles?
smooth muscles: under control of autonomic nervous system
-how they contract
What are the various fuels used by muscles depending on the intensity and duration of physical activities?
-quick bursts: phosphate/ small amounts of glucose
-longer: more glucose/ some fats
What are the major differences between fast, slow and intermediate muscle fibers?
-diameter
-vasculature
-type of metabolites
-contraction speed
-fatigue resistance
How would fast, slow, and intermediate muscle fibers affect the respiratory coefficient? (RQ value)
-slow will use more fats
-fast will use more glucose
How does aging affect the muscular system?
-protein synthesis will decrease
-decrease in muscle fiber
-diameter
-elasticity
-ability to recover
-tolerance for exercise
How are contractions classified based on the muscle length and the load?
-isotonic: weight doesn’t change
-isometric: muscle length doesn’t change
-concentric: muscle length shortens
-eccentric: muscle length lengthens
What is difference between fatigue and DOMS?
-fatigue is during exercise
-DOMS is after the exercise
How do autorhythmic cells generate an action potential?
HCN channels
Hyperpolarization-activated cyclic nucleotide–gated
What are the steps involved in the action potential of the pacemaker cells? (autorythmic cells)
-HCN channels activated by hyperpolarization: cyclic amp to open and allow sodium into the cell
-sodium comes in and causes the threshold to be reached
-causes opening of voltage-gated calcium channels, causing rapid depolarization
-opening of voltage-gated potassium channels
-potassium efflux causing rapid repolarization leading to hyperpolarization of membrane potential
-then again activates HCN channels to open and sodium flows in
What are the steps involved in the action potential of contractile cells?
-respond to action potential generated in autorythmic cells which will initiate threshold to be reached
-sodium channels open causing rapid depolarization
-plateau phase where two channels are opened (Ca2+ causing influx/ K+ causing efflux)
-Calcium channels close and repolarization of membrane potential occurs because potassium leaves the cell
What are the notable parts on the EKG and how does it relate to the cardiac cycle? (contraction and relaxation of the heart)
-p wave: indicating depolarization of the atria- contract and eject blood into ventricles
-QRS complex : indicating repolarization of the atria, meaning atrial will relax- depolarization of ventricles
-t wave: showing ventricular repolarization, will relax and then fill again for next beat
Pathologies related to electrical activity of the heart
-first-degree av block: delay in signal, distance between p wave and QRS complex is greater (slower rate)
-second degree av block: missing QRS complex in some cases
-third degree av block: no correlation between period and QRS complex
Pathologies related to cardiac blood vessels
-Atherosclerosis: plaque build up in vessels, lumen size decreases causing less blood to be passed to tissues
Pathologies related to force generation by cardiac myocytes/ the myocardium
-hypertrophic cardiomyopathy: muscle is generating more force than needed for given calcium
-dilated cardiomyopathy: mutations which decrease calcium sensitivity, and so heart walls are generating less pressure with less blood pushed out to ventricles
How does the autonomic nervous system increase or decrease the heart rate?
-acetylcholine will hyperpolarize and delay heart rate
-epinephrine release will cause sodium and calcium channels to open, the threshold will be reached quickly and depolarization will happen rapidly and increase heart rate
What are the various changes that occur to the blood pressure as it moves from the aorta to the vena cava?
major drop in blood pressure, gradually keeps decreasing
Where is the smooth muscle in the blood vessels and what is its role?
-tunica media
-arteries
function: constrict or dilate
Describe how the blood vessels progressively branch between the aorta and the capillary beds.
-elastic arteries give rise to muscular arteries
-muscular arteries will give rise to arterioles and then capillaries
-capillaries can come together to join and form venules
-venules join together to form veins
-veins come together to form vena cava
brings blood to the heart
How do the diameters of individual vessels change with branching?
What affect will this have on the pressure in the vessels?
-as blood vessels branch, diameter gets smaller and smaller the diameters the cross-sectional layers will decrease.
-smaller diameter pressure will drop, slows flow
How does the total cross-sectional area of all the vessels change with branching?
a lot more aterials, capillaries, and venules in comparison to larger blood vessels, therefore total cross-sectional area is much higher
-depends on number of vessels not just diameters.
What is the relationship between pressure, flow, and resistance?
(pressure= flow x resistance)
-higher blood viscosity; higher resistance
-longer the vessels; increase resistance
-larger diameter of vessels: resistance will drop
The connective tissue surrounding a muscle bundle is referred to as ____
perimysium
cross-bridges permit the thin filament to transition from the ______ to _____ state
closed to open
arrival of the stimuli at the presynaptic cleft of the motor neuron will release acetyl choline to activate ____
ligand gated Na channels
Fish-hunting snails inject toxins into their victims that block acetylcholine receptors at the neuromuscular junction and cause muscle paralysis. The toxin is most likely blocking ____
ligand-gated Na+ channels
______ binds actin in the absence of Ca2+ to prevent actin-myosin interaction
Troponin TnI
Muscles with predominantly ____ fibers are most resistant to lactic acid build up
slow
A mutation that inactivates the myosin light chain phosphatase enzyme will likely cause what in smooth muscles.
myosin will remain bound to actin
Which of the following is common to smooth and cardiac muscles but not skeletal muscles?
gap junctions
A person with an RQ value of 0.8 is most likely:
resting, using combo of both glucose and fats
Isotonic eccentric contraction occurs when you ____
lowering dumbbell by extending arm
A stimuli from the CNS is not required for ____
myofilament Ca2+ sensitivity
does the speed of the balls change as the box size changes?
no dumbass
which alveoli will require the greatest concentration of surfactant to maintain compliance
smaller one will need more
