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17 Jan 2019

If you consciously forced more air out of your lungs each time you exhaled, how would that affect the PO2 and the loading and unloading of respiratory gases?

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Tod Thiel
Tod ThielLv2
17 Jan 2019

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Related questions

QUESTION 1

Cellular respiration uses________to produce energy and releases ________as a waste product.

O2; CO2

CO2; O2

ATP; G3P

G3P; ATP

5 points

QUESTION 2

Select all of the following that compose the conducting pathways in the respiratory system.

nasal cavity

Pharynx

Larynx

Trachea

Bronchi

Alveoli

5 points

QUESTION 3

Match each structure with its' function.

- A. B. C. D. E. F. G.

Nasal Cavity
- A. B. C. D. E. F. G.

Alveoli
- A. B. C. D. E. F. G.

Larynx
- A. B. C. D. E. F. G.

Trachea
- A. B. C. D. E. F. G.

Bronchi
- A. B. C. D. E. F. G.

Bronchioles
- A. B. C. D. E. F. G.

Pharynx
A.

Throat
B.

Very small branches of bronchi within the lungs.
C.

Larger branching passages for air within the lungs.
D.

Location of gas exchange with the blood.
E.

Carries air from larynx and branches into bronchi.
F.

Location of the voice box, earliest location where only air passes.
G.

Carry air into the pharynx, earliest location of cleaning, warming, and humidifying the air.

8 points

QUESTION 4

Mammals are able to inhale because increasing the volume of the thoracic cavity will decrease the pressure within the lungs. This is called_____

pump-controlled breathing

forced inflation breathing

negative-pressure breathing

stretch breathing

6 points

QUESTION 5

Indentify which muscles are primarily responsible for quiet (normal, relaxed) inspiration?

diaphragm

internal intercostals

sclaenes

abdominal muscles

I know the answers are A, A, C and D but I don't know how to arrive at those answers! Could you please walk me through th calculations.

If, Alice's cardiac output and tidal volume both increase by 50% but respiratory rate remains unaltered, what effect would that have on _______ (compared to just before the increase in cardiac output and tidal volume)

88) PO2 at the alveoli: a) increased by 10 mmHg, b) largely unchanged, c) decreased by 10 mmHg

89) [O2] at the left atrium: a) increased by 20 %, b) largely unchanged, c) decreased by 5-10%, d) decreased by 30-50%

90) PO2 at the right ventricle (mixed venous PO2):

a) increased by 10 mmHg, b) largely unchanged, c) decreased by 10 mmHg

91) Oxygen delivery to the systemic tissues

a) decreased by 2/3

b) decreased by 10-20%

c) largely unchanged

d) increased by 20-40%

e) increased by 100%

Background

Almost all animal and plant cells require oxygen and give off carbon dioxide. This is called gas exchange and it occurs by passive diffusion. Some animals do all or most of their gas exchange across their skin (for example amphibians) but they have very low metabolisms and use very little oxygen and get rid of very little carbon dioxide.

On the other hand humans (and other mammals) have very high metabolic requirements and we can’t rely on gas exchange over the limited 1.5 to 2.0 square meters of our skin to get enough oxygen in and carbon dioxide out fast enough. Our gas exchange takes place across a very thin membrane in the Alveoli of the lung and the gas exchange surface in humans is estimated to be between 50 and 100 square meters, or between 25 and 67 times our skin surface area.

Our lungs provide a huge surface for gas exchange but they are a dead-end system. Once the oxygen in the lungs is used up it needs to be replenished and carbon dioxide builds up in the air spaces in the lungs and needs to get out. This is where the diaphragm and a few of the skeletal muscles become important. In its relaxed state the diaphragm is at its longest and the space in the thoracic cavity (and the lungs) is small. When the diaphragm contracts it shortens, which increases the volume of the thoracic cavity (and the lungs). The increase in size means the pressure is lower in the lungs than outside so air comes into the lungs (inhalation). As the diaphragm relaxes, the lungs decrease in size enough that the pressure inside the lungs is higher than the external air pressure so air comes out (exhalation).

Introduction

In this lab you will be building a model of a lung and experimenting with different ways to breath.

Supplies:


In the Lab Kit

One round 9" balloon (one lung, we don’t need two for this)
medium-sized plastic bag large enough to fit over bottom end of bottle (diaphragm)
medium-size, thin rubber band

You supply

plastic 2-liter soda bottle with bottom cut off (thoracic cavity)

Tape (optional)

Directions:

1. Insert the balloon through the open bottom of a modified 2-liter soda bottle and up over the neck of the bottle. Pull the end of the balloon over the edges of the neck of the bottle. The balloon is held open by the neck of the bottle.

2. Place the plastic bag over the bottom (open) end of the 2-liter bottle and use the rubber band to hold it in place. This will serve as the diaphragm. To inflate the lung, blow into the balloon just before you fasten the rubber band. You can also wrap tape over the edges of the plastic bag to minimize air leaks

3. Grasp the bottom of the plastic bag and pull it down and push it up. Watch as the "lungs" (the balloon) expand and contract as you do this. The balloon has to change size because the air space between the balloon and bottle must remain constant. (Well, it would if the seal around the plastic bag and bottle were perfect).

You may block the "trachea" (the neck of the bottle) so that the air supply is cut off and watch as nothing happens when the "diaphragm" is pushed in and out.

This model isn’t perfect. None of the joints are air tight as they would be in a real thoracic cavity. Pull the “diaphragm down and watch the lungs expand . If you hold it in place, the lungs will collapse again over time. This is because of leaks and is not how real lungs work. Pushing the diaphragm in and pulling it out over and over does give you an idea of how lungs work. As the diaphragm tightens, contracts (pull down on the plastic bag) the lungs fill with air. As the diaphragm relaxes (push up on the plastic bag) air is expelled from the lungs .

There are several different ways we breath, i.e. expand our thoracic cavity so that our lungs can expand. You have just made a demonstration model of the diaphragm at work. You can also use your rib cage to expand and contract so that you can inhale and exhale. There are muscles between and around your ribcage which you can use to change the size of your thoracic cavity.

This is approximately what your model of a lung will look like.

Answer the questions on the Report Page

Report Page Name

1. Put a hand on your lower ribcage and try moving your ribs out and in. Does air also move in and out?

2. Someone with an upper back or neck injury may not have the options of using diaphragm or ribs to breath. They can learn to use the clavicle and the muscles attached to expand their thoracic cavity a small amount and breathe independently for short periods of time. Put your hand on you clavicle and try to raise and lower just that bone without using your diaphragm or your ribs. It isn’t easy but you should be able to get a little air into and out of your lungs this way. How effective do you think this way of breathing is?

3. When you take a really deep breath you use all these muscle groups to help. Take a really deep breath and notice that your ribs expand, your lower abdomen comes out (a sign that the diaphragm has contracted) and your shoulders lift a little (the upper chest and clavicle are working). Now take a relaxed breath. Only your abdomen should go in and out. The movement of your abdomen is a result of the contracting diaphragm pushing on the contents of your “gut” which forces your abdomen to push out.

Do you breath in or out when your diaphragm contracts?\

4. If a hole were poked in your thoracic wall (the wall of the pop bottle – the hole should be at least the diameter of a pencil)

a. what would happen when you tried to breath? (This is a pneumothorax).

b. Is the space between the balloon and plastic bottle still required to remain constant?

5. Would it be possible to live with a paralyzed diaphragm? Explain your answer.

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