will progressively contract more weakly if they do not have an adequate oxygen supply.

obtain most of the oxygen they need directly from the blood in the heart’s chambers.

synthesise and store most of the ATP they need during times when the person is resting.

normally rely mostly on anaerobic glycolysis for producing the ATP they need.

Increased levels of metabolic waste products and decreased oxygen concentration in tissues promote increased blood flow through the tissues.

Applying cold to a tissue causes arterioles in that tissue to dilate so as to increase the blood flow and warm the tissue back up.

If blood flow to a tissue is blocked for a period of time and then the block is removed, the result is a reactive hyperemia in which blood flow through the affected tissue remains low.

If the arterial blood pressure to an organ suddenly decreases, arterioles in the organ will constrict in response to ensure that blood flow to the organ is not affected.

the onset of isovolumetric ventricular relaxation.

ventricular contraction.

the phase of passive ventricular filling.

contraction of the atria.

Systolic pressure tends to decrease with age as the arterial walls become stiffer.

The pulse pressure is the average of the diastolic and systolic pressures.

Arterial pressure rises during systole as blood ejected by the heart stretches the elastic walls of the large arteries.

Pressure is higher in the small arteries than the large arteries because of their smaller diameter.

The spread of action potentials from cell to cell via gap junctions in the intercalated disks.

The degree of filling of the heart with blood during diastole.

Changes in cardiac muscle cell length.

The amount of calcium stored within the sarcoplasmic reticulum.

only becomes important when the body is exposed to extreme external conditions.

refers to dynamic constancy of the internal environment.

refers only to the regulation of body temperature.

is maintained primarily by positive feedback.

the spread of excitation from the right atrium to the left atrium

all of the above.

ventricular contraction to occur.

contraction of the atria and the ventricles to be properly coordinated.

lungs

right ventricle

left atrium

right atrium

Keeps arterial pressure relatively constant when vascular tone changes

Keeps blood flow relatively constant when arterial pressure changes

Keeps arterial pressure relatively constant when blood flow changes

Keeps vascular tone relatively constant when blood flow changes