Gas Exchange

Gas Exchange

Respiratory System

Cellular Respiration

• Cells require a lot of energy to perform all the tasks they need to perform; can you think of any examples of those tasks?

• Nerve impulses, active transport of molecules, muscle contraction, warmth

• To do these tasks the cell requires chemical energy from glucose, and atmospheric oxygen

Single Celled Organisms

• For single-celled organisms, glucose and oxygen can simply diffuse over the cell membrane on its own.

• But what about a cell contained deep within a big organism like an elephant or a human?

• It needs a complex system to transport the molecules to cells

Multi-Cellular Organisms

Large organisms cannot get these molecules via diffusion, so have developed complicated systems to deliver them to all the cells and tissues throughout the body.

What two systems in a mammal deliver oxygen and glucose?

Circulatory & Respiratory Systems

• The heart pumps blood to the lungs where it picks up oxygen. This oxygen diffuses into the blood and is carried on a special protein called "haemoglobin"

• This oxygen-rich blood is sent back to the heart, where it is pumped to the body

• On the way, the blood picks up the carbon dioxide waste and is returned to the heart

Multiple Choice

What is the name of the protein in the blood which carries oxygen (and carbon dioxide)

• Oxygen carrier

• Amino acids

• Haemoglobin

• Haemophiliac

Multiple Choice

What percentage of the atmosphere's gas is oxygen?

• 4%

• 21%

• 50%

• 100%

Multiple Choice

How much of the atmospheric oxygen is actually absorbed into the blood during a breath?

• 100%

• 0%

• I dont understand the question

• 4%

Multiple Choice

What special structure in the lungs are the site of this gas exchange?

• Bronchi

• Trachea

• Larynx

• Alveoli

Multiple Select

What features do alveoli have to make them good for gas exchange? (tick more than one)

• Large surface area

• Thick walls

• Good blood supply

• Dry lining

Investigating Breathing

• There are a few experiments that can be done in the lab to investigate exercise and breathing.

• You can detect carbon dioxide in gases by using lime water.

• You can also measure the rate and amount of breathing.

Lung Disease

• There are certain diseases that impede the ability of gas to exchange properly. Can you think of any?

Lung Diseases

• Anything that blocks alveoli can mean it is harder to obtain oxygen gas. Common causes of this could be:

• Viral and bacterial infection (can we use antibiotics to fight viral infections?)

• Lung cancer

• Asthma

• Genetic disorder such as Cystic Fibrosis

• Pollution

Pollution

• Pollution kills around 9400 people in London every year

• Breathing in smoke and fumes can cause blockages in the alveoli

• Pollution can also cause an asthma attack

Asthma

• Asthma is a condition caused by inflammation of the airways and lungs

• Asthma causes wheezing, breathlessness, chest tightness, and coughing at night or early in the morning

• It is caused by inflammation (what does that mean?)

• Asthma can be treated with anti-inflammatory medicine

• Asthma attacks can be serious

Smoking

• Smoking is one of the leading causes of lung disease and kills around 7 million people per year (incl one million non-smokers)

• It contains chemicals which damage DNA, which can lead to cancer

• It also causes tar to block up alveoli

• It also causes inflammation

• People used to think smoking was healthy!

Acidosis

• When carbon dioxide is absorbed in the blood, it is made up of an acid (carbolic acid)

• The brain can detect the pH of the blood

• When the pH drops, it speeds up the rate of breathing to expel the carbon dioxide

• People with severe lung disease often have acidic blood due to this and have a fast pulse and breathing. This can be fatal

Multiple Choice

What type of liquid can be used to test for the presence of carbon dioxide gas?

• Ocean water

• Lemon water

• Orange water

• Lime water

Multiple Select

Smoking can cause lung disease because:

• The tar blocks up alveoli

• It causes inflammation

• It damages DNA which can lead to cancer

• It is good for you

Multiple Choice

How can severe lung disease cause blood pH to fall?

• Inability to take in enough oxygen

• Inability to expel carbon dioxide fast enough

• Because of smoking

• Because of asthma

Multiple Choice

What causes cancer at a cellular level?

• Enzymes

• Genetic damage (DNA damage)

• Cellular death

• Blood pH

Multiple Choice

What organ system causes inflammation?

• Respiratory

• Circulatory

• Digestive

• Immune System

Multiple Choice

How does air enter the lungs?

• The pressure in the lungs increases due to muscular contraction, and this sucks air in

• The pressure in the lungs decreases due to muscular contraction, and this sucks air in

• It diffuses in

• Wind blows it in