1. 6.4 Gas Exchange Applications:
Understanding:
Ventilation maintains concentration gradients of oxygen and carbon dioxide between air in alveoli and blood flowing in adjacent capillaries
Type I pneumocytes are extremely thin alveolar cells that are adapted to carry out gas exchange
Type II pneumocytes secrete a solution containing surfactant that creates a moist surface inside the alveoli to prevent the sides of the alveolus adhering to each other by reducing surface tension
Air is carried to the lungs in the trachea and bronchi and then to the alveoli in bronchioles
Muscle contractions cause the pressure changes inside the thorax that force air in and out of the lungs to ventilate them
Different muscles are required for inspiration and expiration because muscles only do work when they contract
Applications:
External and internal intercostal muscles, and diaphragm and abdominal muscles as examples of antagonistic muscle action
Causes and consequences of lung cancer
Causes and consequences of emphysema
Nature of science:
Obtain evidence for theories: epidemiological studies have contributed to our understanding of the causes of lung cancer.
Skills:
Monitoring of ventilation in humans at rest and after mild and vigorous exercises

2. Gas exchange Absorb one gas and release a different one.
For photosynthesis: Absorb carbon dioxide and release oxygen
For respiration: Absorb oxygen and release carbon dioxide

3. Label the key words Trachea Lung Bronchioles Bronchi Alveoli
Intercostal muscles
Ribs
Nose
Diaphragm
Mouth
Understanding:
Air is carried to the lungs in the trachea and bronchi and then to the alveoli in bronchioles

5. In Humans Diffusion Between air in alveoli and blood in capillaries
Concentration gradient of oxygen
High concentration in lungs →
Low concentration in capillaries
Ventilation must occur to supply fresh air in the lungs
Understanding:
Ventilation maintains concentration gradients of oxygen and carbon dioxide between air in alveoli and blood flowing in adjacent capillaries

6. Site where gas exchange happens
Alveoli
Site where gas exchange happens
Increase surface area
Thin cell walls
Two types of cells:
Type I pneumocytes
Type II pneumocytes
Understanding:
Ventilation maintains concentration gradients of oxygen and carbon dioxide between air in alveoli and blood flowing in adjacent capillaries

7. Type I pneumocytes Extremely thin alveolar cells
Make up most of epithelial cells of alveoli
Flat cells
0.15um thick
Adjacent capillary also very thin
Very small diffusion space
Understanding:
Type I pneumocytes are extremely thin alveolar cells that are adapted to carry out gas exchange

8. Type II pneumocytes Rounded cells Occupy 5% of alveolar surface area
Secrete a fluid which coats the inner surface of the alveoli
Allows oxygen to dissolve before diffusing to the blood
Also prevents the alveolus walls from sticking together and collapsing
Understanding:
Type II pneumocytes secrete a solution containing surfactant that creates a moist surface inside the alveoli to prevent the sides of the alveolus adhering to each other by reducing surface tension

10. Antagonistic Muscles Muscles have two states: Contracting (shorter)
Relaxing (longer)
Muscles can only work in one direction
If opposite directions are needed, more than one muscle is needed.
When two muscles work together they are call antagonistic muscles
Applications:
External and internal intercostal muscles, and diaphragm and abdominal muscles as examples of antagonistic muscle action

11. Antagonistic Muscles When we breathe in and out…
External vs Internal intercostal muscles
Diaphragm vs abdominal muscles
Applications:
External and internal intercostal muscles, and diaphragm and abdominal muscles as examples of antagonistic muscle action

12. Breathing In External intercostal muscles contract, lifting rib cage
Diaphragm muscles contract, pulling it downwards
Volume of lungs increases
Pressure inside the lungs decreases
Air rushes into the lungs from the trachea to attain a pressure equilibrium
Understanding:
Muscle contractions cause the pressure changes inside the thorax that force air in and out of the lungs to ventilate them
Different muscles are required for inspiration and expiration because muscles only do work when they contract

13. Breathing Out External intercostal muscles relax, rib cage falls
Diaphragm muscles relax and it moves upwards
Volume of lungs decreases
Pressure inside the lungs increases
Air rushes out of the lungs to attain a pressure equilibrium
Understanding:
Muscle contractions cause the pressure changes inside the thorax that force air in and out of the lungs to ventilate them
Different muscles are required for inspiration and expiration because muscles only do work when they contract

14. Body part
Inhaling
Exhaling
Diaphragm
Intercostal muscles
Chest cavity volume
Pressure in lungs
Air

15. Body part
Inhaling
Exhaling
Diaphragm
Contract
Relax
Intercostal muscles
Chest cavity volume
Increase
Decrease
Pressure in lungs
Air
Into lungs
Out of lungs

16. Put these into the correct order to make the cycle of gas exchange
Your diaphragm contracts and moves down
The space inside your Chest gets bigger and you breathe in
The air goes into your Lungs
Oxygen is taken from the air into the blood in your lungs
The blood deposits the waste carbon dioxide into the air in your lungs
You Diaphragm relaxes and moves up
The Space inside your chest gets smaller
The Air is squeezed out of your lungs and your breathe out
Put these into the correct order to make the cycle of gas exchange

17. The cycle of gas exchange
Your diaphragm contracts and moves down
The space inside your Chest gets bigger and you breath in
The air goes into your Lungs
Oxygen is taken from the air into the blood in your lungs
The blood deposits the waste carbon dioxide into the air in your lungs
You Diaphragm relaxes and moves up
The Space inside your chest gets smaller
The Air is squeezed out of your lungs and your breath out
The cycle of gas exchange

18. Define the terms below. Vital capacity… Tidal volume…
Volume of air moved in and out of the lungs with each breathe when you are at rest.
Vital capacity…
Largest volume of air that can be moved into and out of the lungs in any one breath.
Ventilation rate…
Skills:
Monitoring of ventilation in humans at rest and after mild and vigorous exercises

19. 6.4 Gas Exchange Applications:
Understanding:
Ventilation maintains concentration gradients of oxygen and carbon dioxide between air in alveoli and blood flowing in adjacent capillaries
Type I pneumocytes are extremely thin alveolar cells that are adapted to carry out gas exchange
Type II pneumocytes secrete a solution containing surfactant that creates a moist surface inside the alveoli to prevent the sides of the alveolus adhering to each other by reducing surface tension
Air is carried to the lungs in the trachea and bronchi and then to the alveoli in bronchioles
Muscle contractions cause the pressure changes inside the thorax that force air in and out of the lungs to ventilate them
Different muscles are required for inspiration and expiration because muscles only do work when they contract
Applications:
External and internal intercostal muscles, and diaphragm and abdominal muscles as examples of antagonistic muscle action
Causes and consequences of lung cancer
Causes and consequences of emphysema
Nature of science:
Obtain evidence for theories: epidemiological studies have contributed to our understanding of the causes of lung cancer.
Skills:
Monitoring of ventilation in humans at rest and after mild and vigorous exercises

20. How will exercise affect…
Tidal volume…
Volume of air moved in and out of the lungs with each breathe when you are at rest.
Vital capacity…
Largest volume of air that can be moved into and out of the lungs in any one breath.
Ventilation rate…
Amount of breaths taken per minute

22. Prescribed Practical Record your height Record your weight
Follow the sheet to complete the practical
You need two hypotheses before you begin. It can be anything to do with the data you will collect.
E.g. females will have a larger lung volume
Collect data
Analyse data
Draw graphs for both hypotheses
Write a conclusion (include data)
Record your height
Record your weight
Record your gender
Work out your BMI
Record your vital capacity
Record your tidal volume
Record your ventilation rate
Record your heart rate
Understanding:
Muscle contractions cause the pressure changes inside the thorax that force air in and out of the lungs to ventilate them
Different muscles are required for inspiration and expiration because muscles only do work when they contract

23. Lung Diseases Lung cancer and emphysema. For each disease:
What causes it? Give examples.
How common is it?
What are the consequences?
What are the symptoms?
Why is it an issue?
Is there a cure?
How can it be prevented?
Applications:
Causes and consequences of lung cancer
Causes and consequences of emphysema