key questions/poll ev unit 3

Question 1

Which type of the following connective tissue are tendons composed of?

Answer 1

dense regular connective tissue

Question 2

The intracellular concentration of _____ is higher than the extracellular concentration

Answer 2

K+ potassium

Question 3

A mutation in TnC decreases its capacity to bind Ca2+. Consequentially, which state of the thin filament does this mutant TnC promote? (troponin)

Answer 3

blocked

Question 4

Which ingredients would you choose, if asked to prepare a solution to make the muscle contract?

Answer 4

Ca2+ calcium

Question 5

In addition to EGTA )a Ca2+ chelator) which of the following would be a critical component of a muscle relaxing solution?

Answer 5

ATP

Question 6

Which functional state of the thin filament is favored by the mutant?

Answer 6

blocked

Question 7

What are the different layers of connective tissue that surround the skeletal muscles and what do they surround?

Answer 7

-whole muscle: epimysium
-single bundle: mycelium
-single muscle cell/fiber: endomysium

Question 8

What are the unique features of the skeletal muscle compared to a typical cell?

Answer 8

-presence of t-tubules
-sarcoplasmic reticulum
-sheer length
-multiple nuclei present in skeletal muscle
-presence of sarcomeres

Question 9

What is the structural and functional unit of the muscle?

Answer 9

sarcomere

Question 10

What proteins in muscle regulate muscle contraction and relaxation?

Answer 10

-actin
-myosin
-troponin

Question 10

What are some structural and functional differences of skeletal and cardiac muscles?

Answer 10

cardiac muscles: under control of autonomic nervous system
-much smaller cell size
-single nucleus
-structure of sarcoplasmic curriculum and t-tubules

Question 10

What causes muscles to contract

Answer 10

Calcium entering and binding to the thin filament

Question 10

What causes muscles to relax?

Answer 10

calcium being removed

Question 11

What are some structural and functional differences of skeletal and smooth muscles?

Answer 11

smooth muscles: under control of autonomic nervous system
-how they contract

Question 11

What are the various fuels used by muscles depending on the intensity and duration of physical activities?

Answer 11

-quick bursts: phosphate/ small amounts of glucose
-longer: more glucose/ some fats

Question 11

What are the major differences between fast, slow and intermediate muscle fibers?

Answer 11

-diameter
-vasculature
-type of metabolites
-contraction speed
-fatigue resistance

Question 11

How would fast, slow, and intermediate muscle fibers affect the respiratory coefficient? (RQ value)

Answer 11

-slow will use more fats
-fast will use more glucose

Question 12

How does aging affect the muscular system?

Answer 12

-protein synthesis will decrease
-decrease in muscle fiber
-diameter
-elasticity
-ability to recover
-tolerance for exercise

Question 13

How are contractions classified based on the muscle length and the load?

Answer 13

-isotonic: weight doesn’t change
-isometric: muscle length doesn’t change
-concentric: muscle length shortens
-eccentric: muscle length lengthens

Question 14

What is difference between fatigue and DOMS?

Answer 14

-fatigue is during exercise
-DOMS is after the exercise

Question 15

How do autorhythmic cells generate an action potential?

Answer 15

HCN channels
Hyperpolarization-activated cyclic nucleotide–gated

Question 16

What are the steps involved in the action potential of the pacemaker cells? (autorythmic cells)

Answer 16

-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

Question 17

What are the steps involved in the action potential of contractile cells?

Answer 17

-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

Question 18

What are the notable parts on the EKG and how does it relate to the cardiac cycle? (contraction and relaxation of the heart)

Answer 18

-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

Question 19

Pathologies related to electrical activity of the heart

Answer 19

-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

Question 20

Pathologies related to cardiac blood vessels

Answer 20

-Atherosclerosis: plaque build up in vessels, lumen size decreases causing less blood to be passed to tissues

Question 21

Pathologies related to force generation by cardiac myocytes/ the myocardium

Answer 21

-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

Question 22

How does the autonomic nervous system increase or decrease the heart rate?

Answer 22

-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

Question 23

What are the various changes that occur to the blood pressure as it moves from the aorta to the vena cava?

Answer 23

major drop in blood pressure, gradually keeps decreasing

Question 24

Where is the smooth muscle in the blood vessels and what is its role?

Answer 24

-tunica media -arteries function: constrict or dilate

Question 25

Describe how the blood vessels progressively branch between the aorta and the capillary beds.

Answer 25

-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

Question 26

How do the diameters of individual vessels change with branching? What affect will this have on the pressure in the vessels?

Answer 26

-as blood vessels branch, diameter gets smaller and smaller the diameters the cross-sectional layers will decrease. -smaller diameter pressure will drop, slows flow

Question 27

How does the total cross-sectional area of all the vessels change with branching?

Answer 27

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.

Question 28

What is the relationship between pressure, flow, and resistance? (pressure= flow x resistance)

Answer 28

-higher blood viscosity; higher resistance -longer the vessels; increase resistance -larger diameter of vessels: resistance will drop

Question 29

The connective tissue surrounding a muscle bundle is referred to as ____

Answer 29

perimysium

Question 30

cross-bridges permit the thin filament to transition from the ______ to _____ state

Answer 30

closed to open

Question 31

arrival of the stimuli at the presynaptic cleft of the motor neuron will release acetyl choline to activate ____

Answer 31

ligand gated Na channels

Question 32

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 ____

Answer 32

ligand-gated Na+ channels

Question 33

______ binds actin in the absence of Ca2+ to prevent actin-myosin interaction

Answer 33

Troponin TnI

Question 34

Muscles with predominantly ____ fibers are most resistant to lactic acid build up

Answer 34

slow

Question 35

A mutation that inactivates the myosin light chain phosphatase enzyme will likely cause what in smooth muscles.

Answer 35

myosin will remain bound to actin

Question 36

Which of the following is common to smooth and cardiac muscles but not skeletal muscles?

Answer 36

gap junctions

Question 37

A person with an RQ value of 0.8 is most likely:

Answer 37

resting, using combo of both glucose and fats

Question 38

Isotonic eccentric contraction occurs when you ____

Answer 38

lowering dumbbell by extending arm

Question 39

A stimuli from the CNS is not required for ____

Answer 39

myofilament Ca2+ sensitivity

Question 40

does the speed of the balls change as the box size changes?

Answer 40

no dumbass

Question 41

which alveoli will require the greatest concentration of surfactant to maintain compliance

Answer 41

smaller one will need more