Pre-Lecture Lesson 1.4: Respiratory & Circulatory Systems

What is the highest percent oxygenation of the blood that can be achieved if blood and water flow are in the same direction?

50% because of equilibrium

Diffusion

will always occur when there is a concentration gradient; the blood entering the gills

Explain how gills in a fish allow for a very efficient mechanism to absorb oxygen from their environment.

The gills of utilize countercurrent flow, meaning that the water can carry more oxygen into the blood as it is flowing from the opposite direction, and maintain a higher oxygenation of 70% versus 50% (in a concurrent flow)

What is the crucial difference between bird lungs and mammalian lungs that prevents us mammals from engaging in countercurrent flow

Mammals do not have undirectional airflow through their lungs (not possible with the tidal flow of mammals with their dead end aeoli). Birds air sacs act as bellows that allow the lungs to have undirectional airflow

How do respiratory pigments increase the rate of diffusion from alveoli into the blood fluid (plasma) in adjeacent capillaries?

By reducing the concentration of oxygen dissolved in the blood fluid.

Which variable of the Fick’s Law of Diffusion equation is optimized by moving respiratory gases largely via mass flow in the circulatory system?

L is minimized

• The oxygen molecule moves via _____ from the air outside your body into the air space of the alveoli. This is an _____ process, because it requires the contraction of your diaphragm and rib muscles.  

• The oxygen molecule then moves via _____ through the epithelial cell layer that lines your alveoli, and through the endothelial cell layer that lines your pulmonary capillaries. This is an _____ process because it requires no input of work.

• The oxygen molecule then continues its journey via the blood flow using _____. This again is an _____ process, requiring the contraction of the heart muscle in this case.

• Finally, once the oxygen molecule arrives in systemic capillaries, it moves into a cell of your body via _____, crossing the endothelial cell layer of the capillary, and the cell membrane of the final cell it reaches. Note how every body cell is no more than 1-3 cells away from the nearest capillary. This part of its journey is _____ again.  

• All in all, the oxygen molecule only had to cross a length equivalent to __ cell widths via _____.

• mass flow, endergonic

• diffusion, exergonic

• mass flow, endergonic

• diffusion, exergonic

• ~4, diffusion

• A: [vena cava] [deoxygenated] [toward the heart]

• B: [right atrium] [deoxygenated]

• C: [right ventricle] [deoxygenated]

• D: [pulmonary artery] [deoxygenated] [away from heart]

• E: [pulmonary capillaries] [site of gas exchange]

• F: [pulmonary vein] [oxygenated] [toward the heart]

• G: [left atrium] [oxygenated]

• H: [left ventricle] [oxygenated]

• I: [aorta] [oxygenated] [away from heart]

• J: [systemic capillaries] [site of gas exchange]

Pulmonary circuit

deoxygenated blood moved through the respiratory surfaces (blood and lungs) and moves through and becomes oxygenated; moving from the heart into the lungs

systemic circuit

freshly oxygenated blood that returned to the heart, branches to blood vessels, moves to the rest of the tissue to supply oxygen

arteries

blood vessels that come out of the heart; move deoxygenated blood

veins

return blood to the heart

pulmonary veins

two veins that move from the two lungs

vena cava

veins that come from the two main regions of the body; above the heart (superior) and below the heart (inferior)

vena cava

deoxygenated blood, flowing toward the heart

right atrium

deoxygenated blood

right ventricle

deoxygenated

pulmonary artery

deoxygenated blood, flowing away from heart

pulmonary capillaries

site of gas exchange

pulmonary vein

oxygenated blood, flowing toward the heart

left atrium

oxygenated blood

left ventricle

oxygenated blood

aorta

oxygenated blood, away from heart

systemic capillaries

site of gas exchange

What is a consequence of the separation and independent pumping of pulmonary and systemically-derived blood through the heart?

Respiratory gas exchange is maximized because blood with the lowest oxygen concentration (from vena cava) is directed towards the respiratory surfaces

Oxygenated and deoxygenated blood have no possibility of mixing

It allows for higher blood pressure in the systemic compared to the pulmonary circuit, leading to high efficiency of oxygenation of tissues