LSC: Respiratory System

What is the respiratory system mainly responsible for?

Breathing, gaseous exchange, and cellular respiration.

What is breathing?

The process where oxygen is inhaled and carbon dioxide is exhaled.

Is breathing an active or passive process?

An active process.

What are the two main functions of breathing?

• Supplying the body with oxygen

• Removing carbon dioxide from the body

Why does the body need oxygen?

For cellular respiration to release energy.

Why must carbon dioxide be removed?

It is a waste product and can be harmful if it builds up.

Is breathing the same as cellular respiration?

No.

• Breathing = movement of air

• Cellular respiration = chemical process in cells

What is the sequence from breathing to energy production?

Breathing → Oxygen enters → Gaseous exchange → Cellular respiration → Energy

What is inhalation?

Breathing in oxygen.

What is exhalation?

Breathing out carbon dioxide.

Is inhalation active or passive?

Active.

Is exhalation active or passive?

Passive.

What happens to muscles during inhalation?

They contract.

What happens to muscles during exhalation?

They relax.

What gas is taken in during inhalation?

Oxygen (O₂).

What gas is released during exhalation?

Carbon dioxide (CO₂).

Path of oxygen in the body?

O₂ → lungs → tissues.

Path of carbon dioxide in the body?

CO₂ → tissues → lungs.

Why is oxygen inhaled?

For cellular respiration (energy production).

Why is carbon dioxide exhaled?

It is a waste product.

Compare inhalation and exhalation.

• Inhalation: Active, muscles contract, oxygen enters

• Exhalation: Passive, muscles relax, carbon dioxide leaves

What is gaseous exchange?

The exchange of oxygen and carbon dioxide between the lungs and the blood.

What happens to oxygen after inhalation?

• Oxygen enters the alveoli

• Diffuses into the blood

• Transported to body tissues

What happens to carbon dioxide in the body?

• Produced in cells during respiration

• Transported by blood to lungs

• Diffuses into alveoli

• Exhaled out of the body

Where does gaseous exchange take place?

In the alveoli (tiny air sacs in the lungs).

Why are alveoli effective for gas exchange?

• Thin walls

• Large surface area

• Good blood supply

What process moves oxygen into the blood?

Diffusion.

What is diffusion?

Movement from high concentration to low concentration.

Describe gaseous exchange step-by-step.

1. Oxygen is inhaled

2. Oxygen enters alveoli

3. Oxygen diffuses into blood

4. Oxygen is transported to body cells

5. Carbon dioxide is produced in cells

6. Carbon dioxide is transported to lungs

7. Carbon dioxide diffuses into alveoli

8. Carbon dioxide is exhaled

Does oxygen go to the lungs or from the lungs?

From the lungs → to the body.

Does carbon dioxide go to the body or from the body?

From the body → to the lungs.

What is cellular respiration?

The process by which cells release energy from nutrients using oxygen.

What type of respiration occurs in humans?

Aerobic respiration.

What does “aerobic” mean?

It requires oxygen.

Where does cellular respiration take place in the cell?

In the mitochondria.

What two things are needed for cellular respiration?

• Oxygen

• Nutrients (e.g. glucose)

What is produced during cellular respiration?

• Energy (ATP)

• Carbon dioxide

• Water

What happens to carbon dioxide produced in cells?

• Diffuses into the blood

• Transported to the lungs

• Exhaled from the body

Describe cellular respiration step-by-step.

1. Oxygen enters the body (breathing)

2. Oxygen is transported to cells (blood)

3. Nutrients + oxygen enter mitochondria

4. Energy is released

5. Carbon dioxide is produced

6. Carbon dioxide goes to lungs

7. Carbon dioxide is exhaled

Why is cellular respiration important?

It releases energy needed for all life processes.

Is energy created or released in cellular respiration?

Released (from nutrients).

What is asthma?

A condition where the airways become swollen and inflamed, causing them to narrow and make breathing difficult.

What changes occur in the airways during asthma?

• Airways become inflamed

• Airways narrow

• Less air flows in and out of the lungs

What are common symptoms of asthma?

• Wheezing

• Tight chest

• Coughing

• Difficulty breathing

What can trigger asthma?

• Allergies

• Smoke and pollution

• Stress

Why does asthma make breathing difficult?

Because narrowed airways reduce airflow in and out of the lungs.

Why is avoiding smoke important for asthma patients?

Smoke irritates airways and worsens inflammation.

What is lung cancer?

A disease where abnormal cells grow uncontrollably in the lungs, forming tumours.

How does lung cancer affect the lungs?

Tumours damage lung tissue and reduce the ability to exchange gases properly.

What are common symptoms of lung cancer?

• Coughing up blood and mucus

• Shortness of breath

• Chest pain

• Unexplained weight loss

What is the main cause of lung cancer?

Smoking.

Name other risk factors for lung cancer.

• Air pollution

• Exposure to harmful chemicals (e.g. asbestos)

• Second-hand smoke

Why does lung cancer cause shortness of breath?

Damaged lung tissue and tumours reduce oxygen exchange.

How can lung cancer risk be reduced?

• Avoid smoking

• Avoid polluted environments

• Maintain a healthy lifestyle