Transport System and Gas Exchange Test

Question 1

Be able to identify all of the parts of the heart in a diagram (including chambers, valves, and associated vessels)

Answer 1

Look at “The Heart Summary PDF” under the study guide in GCR

Question 2

Know the pathway of blood (both deoxygenated and oxygenated) to, through, and from the heart (systemic and pulmonary circulation - the “double pump”)

Answer 2

Pulmonary circulation:

1. Vena cavae deliver oxygenated blood from the body to the right atrium.
2. The right atrium pumps deoxygenated blood through the tricuspid valve (right AV valve) into the right ventricle.
3. The right ventricle pumps deoxygenated blood out of the heart through the right semilunar valve into the pulmonary arteries, which carries it to the lungs (to exchange CO2 for O2).

Systemic blood:

1. Oxygenated blood from the lungs returns to the heart through the pulmonary veins and is delivered to the left atrium.
2. Oxygenated blood is pumped through the bicuspid valve (left AV valve) into the left ventricle.
3. The left ventricle pumps oxygenated blood out of the heart through the left semilunar valve into the aorta, which carries it to the rest of the body.

Question 3

Be able to explain the roles of valves in the heart in maintaining a one-way flow of blood and in causing pressure changes (in order to aid in the timing of blood flow in the cardiac cycle)

Answer 3

Valves control the timing of blood flow in the cardiac cycle by opening and closing. This prevents the backflow of blood. Closed AV valves allow pressure to rise in atria. They open when atrial pressure is greater than ventricular pressure (giving atrial time to fill with blood). Closed semilunar valves allow ventricular pressure to rise and AV valves close when ventricular pressure is greater than arterial pressure as ventricles contract.

Question 4

Be able to explain the events in one cardiac cycle (including systole and diastole of the atria and ventricles)

Answer 4

Systole (Contraction):

1. Blood flows freely from atria to ventricles until they (ventricles) are almost full (~70%).
2. SA node fires = both atria contract = there is even higher atrial pressure to fill ventricles at maximum capacity (atrial systole).
3. Atria have thin walls, as pressure produced by atrial systole isn’t very high since most blood passively moves into the ventricle, so there is no need for high-pressure.
4. AV node activates, waits for 0.1 seconds, then send signals to cause ventricles to contract (ventricle systole) from bottom to top.
5. Increased ventricular pressure causes AV valves to close in order to prevent backflow (first heat sound (lub))

Diastole (Relaxation):

1. Large Increase of ventricular pressure causes semilunar valves to open and blood to flow away from the heart.
2. Pressure increases in pulmonary arteries and aorta and decreases in ventricles = semilunar valves close (second heart sound (dub))
3. Blood flows freely into the atria (atrial diastole)
4. Pressure in ventricles drops below pressure in atria (ventricular diastole) = AV valves re-open and systolic cycle starts again
   BOTH SIDES OF THE HEART UNDERGO THESE TWO CYCLES SIMULTANEOUSLY

Question 5

Be able to explain the control of the heartbeat (myogenic control/SA node)

Answer 5

1. SA (sinoatrial) node (pacemaker) - specialized collection of muscle cells/nerves located in the right atrium - starts to hurt beat by generating an impulse. This impulse travels through the walls of the atria, stimulating atria to contract from top to bottom.
2. Impulse reaches the junction between atria and ventricles and activates AV (atrioventricular) node.
4. AV node “waits” for approximately 0.1 seconds before sending signals through the walls of ventricles. This causes ventricles to contract from the bottom/apex of the heart up so blood is pushed up and out of ventricles to arteries.

The sequence maximize blood flow as it ensures that there is a delay between atrial and ventricular contraction.

Question 6

Be able to explain the control of the heartbeat (medulla oblongata)

Answer 6

1. The medulla oblongata (in the brain stem) monitors/chemically detects CO2 levels in the blood.
2. If CO2 levels rise, the medulla sends a signal through a cranial nerve called the cardiac nerve to the heart that causes the SA node to fire more frequently. This speeds up the heart rate.
3. If CO2 levels return to normal, the medulla sends a signal through a cranial nerve called the vagus nerve to the heart that causes the SA node to fire less frequently. This slows down the heart rate, returning the heart to resting myogenic rate.

Question 7

Be able to explain the control of the heartbeat (endocrine system)

Answer 7

The adrenal glands (located on top of the kidneys) can also speed up the heart rate by releasing the hormone adrenaline (epinephrine) into the bloodstream. This triggers “fight or flight reactions,” stress, excitement etc.

Question 8

Be able to use a cardiac cycle diagram (showing pressure and volume changes in the heart) to identify pressures changes in the left atrium, left ventricle, and aorta (and make sure you know which of these structures corresponds to which pressure line in the diagram)

Answer 8

Look at the last two slides in your heart notes presentation

Question 9

Be able to explain how blood vessel structure is related to its function for: arteries, veins, and capillaries

Question 10

Be able to explain how blood vessel structure is related to its function for: arteries, veins, and capillaries

Question 11

Be able to explain how blood vessel structure is related to its function for: arteries, veins, and capillaries

Question 12

Be able to identify arteries, veins, and capillaries in diagrams etc. based on structural differences (and be able to outline those structural differences as evidence for your identification)

Question 13

Know the components of blood and what is transported by the blood

Question 14

Be able to explain how materials are exchanged between the capillaries and tissues

Question 15

Be able to outline the role of valves in veins

Question 16

Know what atherosclerosis is (and that atherosclerosis of the coronary arteries is the cause of coronary heart disease), and be able to explain the process of how it can cause occlusions and/ or clot formation in the coronary arteries.

Question 17

Be able to explain the causes and consequences of occlusions of the coronary arteries

Question 18

Be able to explain how the structure of the ventilation system is adapted to its function (including the structure of alveoli and type I and type II pneumocytes).

Question 19

Be able to explain the antagonistic roles of the internal and external intercostal muscles, as well as the diaphragm and abdominal muscles in the processes of inspiration and expiration (and be able to explain the volume and pressure changes/ negative pressure mechanism caused by these muscles in the process of ventilation).

Question 20

Be able to explain the process of gas exchange in the alveoli of the lungs and the role of the ventilation system in maintaining concentration gradients of CO2 and O2 between the alveoli and the capillaries surrounding them.

Question 21

Be able to explain the causes and consequences of emphysema and lung cancer.

Question 22

Be able to define: ventilation, ventilation rate, tidal volume, cardiac cycle, cancer, inspiration, expiration, pneumocytes, gas exchange, respiration, cellular respiration, atrium, ventricle, artery, vein, pulmonary circulation, systemic circulation, myogenic, systole, diastole, atherosclerosis, occlusion, coronary heart disease

Question 23

Be able to explain the effects of increased exercise on ventilation rate (and tidal volume)

Question 24

Be able to explain how to use a spirometer to measure ventilation rate.

Answer 24

Be able to use spirometer data to calculate ventilation rate and tidal volume and make conclusions using that data.