Decreases in obstructive and restrictive lung diseases.

Is the largest in the small-sized bronchioles.

Decreases in emphysema.

Is mainly determined by the inner diameter of the airways.

Joe has a lower resting mean arterial pressure and a higher total peripheral resistance than Jane does.

Joe has a higher resting mean arterial pressure and a lower total peripheral resistance than Jane does.

Joe has a lower resting mean arterial pressure and a lower total peripheral resistance than Jane does.

Joe has a higher resting mean arterial pressure and a higher total peripheral resistance than Jane does.

To keep the body's glucose high.

To maintain homeostasis.

To regulate excretion.

To control all body system tissues.

The same in the pulmonary arteries and the systemic arteries.

The same in the systemic arteries and the pulmonary veins.

The same in the pulmonary veins and the systemic veins.

Both (a) and (b) are correct.

They contribute to the pacemaker potential

They are open during the plateau of the action potential

They are found in the membrane of the T-tubule

They allow calcium entry, which in turn triggers calcium release from the sarcoplasmic reticulum

All of the Ca2+required for contraction enters a myocyte during the plateau phase of the action potential

The force of contraction is increased by circulating adrenaline

Heart muscle contracts in response to action potentials in the autonomic nerve fibres

The action potential has the same duration as that of skeletal muscle

the cardiac muscle cells are stretched to longer lengths and this allows them to contract with greater force.

more of the cardiac muscle cells within the wall of the heart are recruited to contract.

more oxygen is available to the cardiac muscle cells, allowing them to contract with greater force.

All 3 of the above mechanisms contribute to the increased strength of contraction.

They prevent cardiac muscle from going into prolonged tetanic contraction.

Both (A) and (B) are correct.

They allow action potentials to spread from one cardiac muscle cell to an adjoining cardiac muscle cell.

They allow the force of contraction to be transmitted from one cardiac muscle cell to an adjoining cardiac muscle cell.

increase.

remain unchanged.

decrease.

change direction so that there was net absorption of water from the interstitial fluid into the blood.

Doubling the viscosity of the blood.

Doubling the length of the blood vessel.

Doubling the pressure difference between the two ends of the blood vessel.

Halving the radius of the blood vessel.