3.3.2 Gas Exchange In Humans

Question 1

Where does gas exchange happen in humans

Answer 1

The lungs

Question 2

How are the lungs connected to the mouth

Answer 2

Via the trachea, bronchi + bronchioles

Question 3

How is the trachea held open

Answer 3

By rigid cartilage

Question 4

What’s the diaphragm

Answer 4

Huge sheets of muscle to control chest volume

Question 5

Where in the lungs does gas exchange occur

Answer 5

The alveoli

Question 6

2 ways the body maintains a concentration gradient

Answer 6

Breathing (recycling)

It’s double circulatory system

Question 7

How many alveoli are there in each lung

What’s the surface area of all the alveoli

Answer 7

300 million in each lunch

SA = 70m

Question 8

What are alveoli walls made from

Why is this beneficial

Answer 8

Made from squamous epithelium that’s long + thin

Shorter diffusion path

Question 9

What is it that prevents alveoli from completely deflating when we inhale

Answer 9

Cells producing surfactant - reduces surface tension of fluid in alveoli (stops walls from touching)

Question 10

What does the gas exchange between the lungs and blood depend on

Answer 10

Concentration gradients and diffusion

Question 11

What much each RBC do to pass through a capillary

Why

Answer 11

Must flatten to pass through 1 by 1

As the capillary diameter is so thin

Question 12

Why are alveoli so close to capillaries

Answer 12

For a shorter diffusion pathway

Question 13

What allows alveoli to stretch + recoil

Wen do they need to do this

Answer 13

The fact they’re surrounded by elastic fibres
Stretch - when we inhale
Recoil - when we exhale

Question 14

What’s the fibrous protein used to give structure/strength/support

Answer 14

Collagen

Question 15

What allows air to flow in and out of the lungs

What is this achieved by(2)

Answer 15

Controlling the volume of the chest cavity

Achieved by:

• diaphragm
• intercostal muscles

Question 16

Where are internal intercostal muscles

Answer 16

Run down middle

Question 17

Where are external intercostal muscles

Answer 17

On sides

Question 18

What maintains the concentration gradient for diffusion + makes space for lungs to inflate + deflate

Answer 18

Ventilation

Question 19

2 words for breathing in

Answer 19

Inspiration

Inhalation

Question 20

How do we breath in(6)

Answer 20

Diaphragm contracts (flat)
Internal intercostal muscles relax
External intercostal muscles contract
Ribs are pulled up and out
Volume of chest cavity increases
Pressure decreases and air is drawn in

Question 21

2 words for breathing out

Answer 21

Expiration

Exhalation

Question 22

How do we breath out (6)

Answer 22

Diaphragm relaxes (dome)
Internal intercostal muscles contract
External intercostal muscles relax
Ribs fall down and in
Volume of chest cavity decreases
Pressure increases. Air is pushed out

Question 23

What pressure causes air to be pushed out of body

Answer 23

High pressure (exhalation)

Question 24

When is the diaphragm flat

Answer 24

When it contracts during inhalation

Question 25

When is the diaphragm a dome shape

Answer 25

When it relaxes during exhalation

Question 26

What type of breathing increases volume of chest cavity

Answer 26

Breathing in

Question 27

What does antagonistic mean

E.g

Answer 27

Things that work together but do the opposite

E.g skeletal muscles

Question 28

What’s PVR

Answer 28

Pulmonary Ventilation Rate

Question 29

How do you work out PVR

Answer 29

PVR = tidal volume x breathing rate

Question 30

What’s tidal volume

Answer 30

Volume of air breathed in per breath (at rest) - in lungs

Question 31

What’s the breathing rate

Answer 31

Number of breaths per minute (at rest)

Question 32

On a spirometer what’s the vital capacity

Answer 32

Maximum volume of air you can inhale after a forced breath out

Question 33

On a spirometer what’s the residual volume

Answer 33

Air that must remain in lungs (after exhalation)

Question 34

Why is it good that RBCs flow slower through alveoli capillaries

Answer 34

There’s more time for diffusion to donate their oxygen

Question 35

Why is each RBC flattened against the capillary membrane

Answer 35

To increase SA even more to pick up more oxygen

Question 36

Why do alveoli have a short diffusion path

Answer 36

Thin squamous epithelium

Question 37

What maintains the concentration gradient for gas exchange in the lungs

Answer 37

The heart pumping blood to the lungs + back to the heart

Question 38

Whats a collective name for respiratory diseases

Answer 38

COPD (Chronic Obstructive Pulmonary Disease)

Question 39

4 risk factors of COPDs

Answer 39

1. Smoking
2. Air pollution
3. Genetics
4. Occupation
5. Infections

Question 40

How can occupation effect COPDs

Answer 40

People can get them if they work with harmful chemicals,gases/dust that can be inhaled

Question 41

What does smoking do that causes less gas exchange

Answer 41

It breaks down Squamal cells so membranes merge so there’s less alveoli and so less surface area

Question 42

What happens in chronic bronchitis

Answer 42

Less oxygen can fit in the airway and less carbon dioxide can fit out

Question 43

What does cigarette smoke contain that increases cancer

E.g

Answer 43

1000s of chemicals, some being carcinogenic

E.g ammonia toilet cleaner, paint, carbon monoxide, arsenic poison

Question 44

What’s it called on a graph when a change in 1 variable causes a change in another

Answer 44

Causal relationship

Question 45

What’s it called on a graph when there’s an increase in 2 variables

Answer 45

Positive correlation

Question 46

What’s it called on a graph when there’s a decrease in 2 variables

Answer 46

Negative correlation