Challenge Deck (Exam 3)

Question 1

Myofibril

Answer 1

The long thin contracting protein subunits of a muscle cell that are composed of actin and myosin filaments.

Question 2

Function and location of troponin

Answer 2

function: sarcomeric Ca2+ regulator
location: attached to tropomyosin and lies within the groove between actin filaments

Question 3

Steps in the process of excitation-contraction coupling

Answer 3

Step 1
AP —>T-tubules
Step 2
Calcium —–> SR
Step 3
Calcium binds to actin, tropomyosin can’t block anymore
Step 4
Myosin heads contract
Step 5
Ca2+ removed and tropomyosin blocks actin’s binding sites
Step 6
M. relaxes

Question 4

Steps in cross bridge cycling, and the involvement of ATP, cross bridges, and the myosin head ATPase

Answer 4

Step 1: Myosin attaches to actin.

Step 2: The myosin head releases energy, bends, and pulls actin towards the center.

Step 3: Myosin lets go with the help of ATP. (via hydrolysis)

Step 4: The myosin head gets ready again by getting energy from ATP. (via the myosin ATPase)

Question 5

the attachment of the pulmonary and systemic circulation to the heart

Answer 5

SVC and IVC —–> R. atrium—–> Triscupid v. —–> R.ventricle——> Pulmonary artery——> lungs—-> Blood oxygenated by capillaries—-> O2 rich blood—> pulmonary veins—–> heart——> l. atrium—–> Bicuspid v. —–> l.ventricle—–> Aorta and Aortic arteries—–> Body Tissue via smaller arteries and arterioles —–> O2 poor blood—-> heart via the veins

Question 6

The steps in the cardiac cycle

Answer 6

Atrial diastole: AV valves open and SL closed.

Atrial systole: Ventricles fill w/ blood

Isovolumic contraction: Ventricles contract, no volume change. Both Valves closed

Ventricular ejection: Ventricles contract, and empty; SL valves open, AV valves close

Isovolumic relaxation: Pressure decreases; ventricles relax. AV and SL valves close

Ventricular filling stage: Blood flows from atria into ventricles. AV valves open, SL valves close

Question 7

the typical heart sounds, what produces them, and when they occur with respect to systole, diastole, and the cardiac cycle

Answer 7

s1 - “lub”: Valves closing during ventricular systole.(AV valves close)
s2 - “Dub”: Valves closing during ventricular diastole. (SL valves close)
s3 - Galloping sound: Blood hitting ventricle during early diastole
s4 - Galloping sound: Heard during late diastole

Question 8

Cardiac output

Answer 8

The volume of blood being pumped by a single ventricle of the heart, per minute

Question 9

End Systolic Volume

Answer 9

The amount of blood in a ventricle at the end of systole and the start of diastole.

Question 10

Typical values for ESV

Answer 10

50 and 100 mL

Question 11

factors influencing blood pressure

Answer 11

Cardiac output.
Peripheral vascular resistance.
Volume of circulating blood.
Viscosity of blood.
Elasticity of vessels walls.

Question 12

motor end plate in excitation-contraction coupling

Answer 12

Receives signals, creates EPPs, causes muscle contractions.