QUESTION 2 How does the heart muscle extract O2 or nutrients from the blood? O A
ID: 260788 • Letter: Q
Question
QUESTION 2 How does the heart muscle extract O2 or nutrients from the blood? O A.via the pulmonary artery O B.via the vena cava ? ?.via the coronary circulation O D.abeorption through the atria QUESTION 3 What are the two determinants of cardiac output? O A.size of the ventricles and stroke volume B.blood pressure and heart size O C.size of the heart and blood pressure D.heart rate and stroke volume QUESTION 4 What happens to a muscle during an isometric contraction? o A.It lengthens. O B.It shortens. o C.It produces more calcium. o D.It is prevented from shortening. QUESTION 5 What molecules form the thick filaments ithin muscle? o A.myosin O B. actin o C.troponinExplanation / Answer
2) C. via Coronary circulation
The heart normally extracts 70 to 75 percent of the available oxygen from the blood in coronary circulation through coronary arteries.
3) D. Heart rate and stroke volume.
Cardiac output is the product of two variables, stroke volume and heart beat. CO = SV x HR.
4) D. It is prevented from shortening.
Isometric contractions generate force without changing the length of the muscle.
5) A. Myosin.
Myofibrils have two types of filaments: thick filaments of myosin and thin filaments of actin.