Organismal Physiology Lecture 10

Front 1

What are the struggles at living 4500 m above sea level? What do organisms do to beat this?

Back 1

The pressure is different (much lower) above sea level, and the partial pressure of atmospheric gas is much lower above sea level.

Organisms are able to survive through this, they just go through adaptations.

Front 2

Briefly explain how Gas Exchange in Animals works.

Back 2

Animals use what's called a "Gas-Exchange Membrane", which is what seperates the internal tissue from the outside environment. Diffusion and active transport sometimes pushes the gases through the membrane.

Note: When looking at diffusion through the membrane, the partial pressures of the different gases don't matter, you just need to look at the gradient across the membrane.

Front 3

Breathing structures: Name and briefly describe the three kinds?

Back 3

Lungs, which are INvaginated. (Used for air)

Gills (used for water), which can either be

- External Gills: Evaginated (out in environmental medium)

- Internal Gills: Evaginated, but are covered from the external environment through a flap of skin.

Front 4

Equations for

1) Rate of O2 uptake

2) O2 Extraction Efficiency

What do the two equations tell you?

Back 4

Rate of O2 Uptake = Vmedium (Ci - Ce)

(Inhaled - Exhaled air)

O2 Extraction Efficiency = 100(Ci - Ce)/Ci

Rate of O2 Uptake is just that. The rate at which O2 is taken into the body.

O2 Extraction Efficiency is the amount of O2 needed to power the body.

Front 5

Define Tidal Gas Exchange and describe how it works!

Back 5

Tidal Gas Exchange is a very common mechanism for O2 uptake in animals. The oxygen comes in and the Oxygen is diffused from the Oxygen rich lungs to the oxygen deficient veins. They have to be in close physical space for this to occur.

Front 6

Concurrect Gas Exchange is?

Back 6

When the lung and the vein run CONCURRENTLY. This setup allows for lots of diffusion from the lungs to the veins. Both systems tend to equilibriate out at 50/50. (Medium/low extraction efficiency.)

Front 7

COUNTERcurrent Gas Exchange is? (Bonus: where does it happen)

Back 7

Kinda the same idea as the CONcurrent gas exchange, except the direction of the vein is REVERSED so that the beginning of the blood is more oxygen rich that in the concurrent design. This allows for diffusion the entire way through. Typically this leads to a 75/25 extraction efficiency.

BONUS: Fish!

Front 8

Cross-Current Gas Exchange is? In what species does it happen?

Back 8

- Uses unidirectional flow, through many tunnels across the oxygen rich membrane. Ends up with 5 different partial pressure, and the result is the mean of all five.

BONUS: happens in birds

Front 9

What is the relationship between surface area and area of gas exchange membrane in most animals?

Back 9

Typically, area of gas-exchange membrane and body size scale LINEARLY.

One thing to note is that endotherms typically have a HIGHER amount of gas exchange membrane than ectotherms of the same size.

Front 10

Scaling of surface area and membrane thickness?

Back 10

Again, they do scale together, but for membrane thickness, the slope is SUPER TINY. Almost a straight line. This time endotherms tend to have thinner than usual membranes.

Front 11

Describe fish breathing as best you can!

Back 11

Fish use gills (always external, only difference is if their covered or not). The water comes in through the mouth (containing O2) and if filtered out through the gills. Fish use COUNTERcurrent exchange to get the most oxygen diffused out of the water and into the blood.

Front 12

Describe amphibian (specifically, frog) breathing as best you can!

Back 12

Amphibians use a big mix of gills, skin (cutaneous) breathing and lungs. In tadpole form, only gills and skin are used, but as they mature, they develop lungs that they use, and stop the use of the aquatic gills.

Front 13

Describe reptilian breathing as best you can!

Back 13

Most reptiles have unicameral lungs. (Just one big chamber.) Some crocodiles and lizards have multicameral lungs. There tends to be LOTS of surface area for increased gas exchange.

Front 14

Describe breathing by mammals as best you can!

Back 14

Mammals use very HIGHLY branched lungs. Utilize both convectional and diffusional flow

Front 15

Describe the different capacities of mammalian lungs.

Back 15

- Inspiratory reserve volume, resting tidal volume, expiratory reserve volume, and residual volume.

Front 16

Describe breathing by birds as best you can.

Back 16

Birds use CROSScurrent exchange. One single stream of air is passed through MANY streams of blood that cross through the medium.

Front 17

Describe breathing by terrestrial and aquatic invertabrates as best you can.

Back 17

Aquatic invertabrates tend to use gills,

Terrestrial invertabrates tend to use trachea, which are essentially kinda like veins, and they diffuse with the outside environment through spiracles (which are kinda like holes in the body that let air in)