Gas Exchange

Question 1

How do alveoli get the energy they need?

Answer 1

By carrying out the process of cellular respiration

Question 2

What do you need to carry out cellular respiration?

Answer 2

Oxygen

Question 3

What is the role of our lungs?

Answer 3

To get the oxygen we need from the air all around us into our bloodstream. To be transported to the rest of the body. They are highly adapted organs in mammals for exchange of gases from the environment into their blood.

Question 4

Walkthrough the passage of air when you breathe in

Answer 4

When we breathe in:
1. air passes through our mouth or nose
2. goes down the trachea
3. once reaches the bottom of trachea - divides between 2 bronchi
4. further divides between many branches (bronchioles)
5. finally reaches bunches of air sacs (alveoli)

Question 5

Where does gas exchange occur?

Answer 5

Alveoli

Question 6

What is a single alveoli called?

Answer 6

Alveolus

Question 7

What are the adaptations of the alveoli for gas exchange?

Answer 7

1 layer of thin cells (single epithelial layer) creating a really short diffusion pathway. Increases the rate at which carbon dioxide and oxygen can diffuse across.

Large surface area because there are so many of them together. Which is good for gas exchange.

Very moist so it allows gases to dissolve - increasing the rate of diffusion.

Question 8

How does oxygenated blood leave the capillaries?

Answer 8

1. deoxygenated blood enters the capillaries and diffuses into the alveoli
2. the CO2 is then taken out and flows out of the alveoli
3. the blood then gains oxygen and becomes oxygenated
4. the oxygenated blood diffuses back into the capillaries and flows out

deoxygenated: blue
oxygenated: red

Question 9

What happens to the CO2 after the alveoli oxygenates the blood cells?

Answer 9

Carbon dioxide has a higher concentration of blood than the alveoli, easily diffusing across into the alveoli from the capillaries. Ready to just be breathed out.

Question 10

How is oxygen carried?

Answer 10

By red blood cells

Question 11

How is carbon dioxide carried?

Answer 11

Dissolved in blood plasma

Question 12

What are the ribs?

Answer 12

They are a cage of bones surrounding the lungs to protect them from damage.

Question 13

What is the thorax?

Answer 13

The area of the body from the chin all the way to the abdomen. It includes the ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli and pleural membranes

Question 14

How do calculate breathing rate?

Answer 14

Breathing rate changes depending on level of exercise.

Breaths per minute = number of breaths taken/number of minutes

bpm

Question 15

What are the intercostal muscles and diaphragm?

Answer 15

intercostal muscles: 2 sets of muscles joining each rib to the next

diaphragm : muscular sheet of tissue by the ribcage separating the contents of the thorax and abdomen. shallow dome shape forming walls.

Question 16

Where is the left bronchiole on a diagram?

Answer 16

On the right side of the thorax because it is inversed.

Question 17

What are the pleural membranes?

Answer 17

Two thin moist membranes separating the inside of the thorax. Forming an airtight seal.

Question 18

What is ventilation?

Answer 18

Simply breathing - moving air in and out of the lungs.

Question 19

What does ventilation recquire?

Answer 19

A difference in air pressure because the air moves from high pressure to low pressure to even it out. (even concentration gradient)

Also needs the thorax to be an airtight cavity.

Question 20

What happens when we breathe?

Answer 20

We change the volume of our thorax altering the pressure inside it. Causing air to move in an out of the lungs.

Question 21

What happens when you inhale?

Answer 21

Breathing in:
1. intercostal muscles contract
2. ribs move up and out
3. diaphragm contracts and flattens
4. volume of thorax increases - reducing pressure
5. air moves into lungs

Question 22

What happens when you exhale?

Answer 22

Breathing out:
1. intercostal muscles relax
2. ribs move down and in
3. diaphragm relax and return to dome shape
4. volume of thorax decreases - increasing pressure
5. air is forced out of lungs

Question 23

What are the biological consequences of smoking?

Answer 23

Smoking blocks air passages in the lungs and alveoli. In order for gas exchange air passages must be free from dirt particles and bacteria.

Smoking increases the risk of diseases: coronary heart diseases, lung cancer, emphysema, bronchitis, ulcers

Cilia helps keep free of dust and bacteria and smoke destroy them due to chemicals in cigarette smoke. Also irritating the lining of airways. Secreting more mucus.

Question 24

Why does our breathing rate differ based on the level of exercise?

Answer 24

Breathing rate increases with exercise. To provide our muscles with more oxygen so that we can respire aerobically to give us the energy we need. Also gets rid of CO2 produced (as it takes up space needed for blood stopping oxygen from getting around the body)