Gas exchange (breathing) + smoking (including CHD)

What are the structures in the thorax?

The ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli and pleural membranes

What is the description (use) of the ribs, trachea and larynx?

Bone structure that protects internal organs such as the lungs

Windpipe that connects the nasal passages to the lungs

Voice box, when air passes we can make sounds.

What is the description/use of the bronchi, bronchioles, alveoli and pleural membrane?

Large tubes branching off the trachea with one bronchus for each lung.

Bronchi split To form smaller tubes called bronchiolus in the lungs connected to alveoli.

Tiny air sacs where gas exchange takes place .

The fluid surrounding the lungs which reduce friction (allows the lungs to move freely) and keeps the lungs moist.

Describe the structure of the lungs

Trachea branches into two bronchi

Bronchi branch into bronchioles

Bronchioles terminate in alveoli.

Describe the intercostal muscles and the diaphragm.

These are a group of muscles (two sets) in between the ribs that are involved in breathing by changing the volume of the thorax.

Connective tissue and muscle (separating the thorax from the lower part of the body) that helps change the volume and pressure of the thorax to allow inhalation and exhalation.

What happens during inhalation?

- Ribs move up and out.

- (because of external set of) Intercostal muscles contract.

- Diaphragm contracts and flattens.

- Volume of the chest (thorax) increases.

- Pressure inside the thorax (relative to outside the body) decreases.

- Air is drawn in.

What happens during exhalation?

- Ribs move down and in.

- (because of external set of) Intercostal muscles relax.

- Diaphragm relaxes and raises becoming dome shaped.

- Volume of the chest (thorax) decreases.

- Pressure inside the thorax (relative to outside the body) increases.

- Air is forced out.

How is exhaled air different from atmospheric air?

It is warmer (heated by body's internal temperature as it passes through lungs) and has more water vapour (passes over moist surfaces from lungs to nose or mouth)

What are the adaptations of the alveoli?

For faster rate of diffusion:

- Many alveoli for large SA:V ratio.

-(Moist surface to allow gases to dissolve)

- One cell thick alveolar wall and capillary wall providing short diffusion distance.

- Many capillaries for good blood supply which maintains a steep concentration gradient for CO2 and (high in capillaries) and O2 (low in capillaries)

- Ventilation maintains steep concentration gradient.

Exercising practical: when designing experiment remember BREATHS PER MINUTE.

What are the results and why does this happen?

Frequency of breathing increases when exercising because muscles are working (contractions) harder and aerobically respiring more so they need more oxygen to be delivered to them (and CO2 removed) to keep up with the nervy demand.

If they can't meet the energy demand, they will also respire anaerobically, producing lactic acid.

Why did the breathing rate stay elevated for a period of time just after the exercise?

Because there has been a lactic acid build up in muscles and it needs to be removed. To do this a large amount of oxygen (oxygen debt) needs to be combined/break down the lactic acid into CO2 and water.

More time for breathing rate to return to normal = more lactic acid build up and more oxygen debt.

Design an experiment for this. This also tells us some limitations of the investigation.

C = exercise/no exercise

O = students with same age, size, general fitness, gender

R = repeat 5 times

M = breaths per minute

M = before and just after exercising

S = type of exercise, temperature of the environment, food intake of students before the experiment.

Give 4 health issues caused by smoking

- Cancer (e.g lung cancer)

- Bronchitis

- Coronary heart disease

- Emphysema

How can smoking affect unborn babies?

A woman's blood oxygen level will be lower meaning that the fetus can be deprived of oxygen so they won't grow as well as they should.

What are 3 examples of harmful chemical components in cigarettes?

Nicotine, carbon monoxide, tar

How does nicotine affect the body?

Increased heart rate (as it narrows blood vessels), increased blood pressure leading to blood clots and potentially resulting in heart attack or stroke.

How does carbon monoxide affect the body?

Binds to haemoglobin reducing the capacity of blood to carry oxygen.

Breathing frequency needs to increase to supply the same amount of oxygen.

Circulatory system needs to pump blood faster, raising blood pressure which can lead to coronary heart disease or stroke

How does tar affect the body?

- Tar is a carcinogen and can lead to increased chances of cancerous cells developing in the lungs.

- Tar can also lead to bronchitis and emphysema.

What is chronic bronchitis? What causes it?

Bronchitis a lung disease caused when tar (in cigarettes) causes more mucus to be produced and immobilizes/damages cilia meaning that mucus accumulates so dirt and pathogens build up in airways (infections) and the irritatio of bronchial tree.

Bronchitis blocks normal air flow, so the sufferer has difficulty breathing normally.

What is smoker's cough?

Tar causes more mucus production so it accumulates. Smokers cough is the attempt to remove it.

What is emphysema? What causes it?

A lung disease where smoke damages the walls of the alveoli, which break down and fuse again forming enlarged, irregular air spaces. This reduces SA for gas exchange making breathing very hard (patients may need a constant supply of oxygen to stay alive). Blood carries less oxygen and in serious cases, patient can't even do milk exercise. There is no cure so patient usually dies.

Smoking is liked to lung cancer. If you smoke you are not bound to get it, but the risk is much greater. How does smoking do this?

Cigarette smoke contains many chemicals that are carcinogens and are contained in the tar.