Gas Exchange In Humans

Front 1

Why is it important that air passages have rings of cartilage?

Back 1

The rings of cartilage keep the shape of the air passages and stop them from collapsing, as if this were to happen you wouldn't be able to breathe.

Front 2

Why are the rings of cartilage in the air passages c-shaped?

Back 2

They are c-shaped, with the open side against the oesophagus so that food can easily pass along it through peristalsis. It stops it form 'catching' in the rings.

Front 3

Why are the pleural membranes important?

Back 3

They form an airtight seal between the lungs and thorax and and make up a continuous envelope around the lungs. There is a space between the membranes called the pleural cavity which contains pleural fluid. This acts as a lubrication so the surfaces pf the lungs don't stick to the inside of the chest wall as we breathe.

Front 4

What are ciliated cells and where do you find them?

Back 4

They are cells covered with tiny hair-like structures called cilia ('brush-borders'). The line the trachea and beat backwards and forwards, sweeping mucus and trapped particles out towards the mouth. This helps to prevent dirt and bacteria from entering the lungs where they could cause an infection.

Front 5

What is another name for your thorax?

Back 5

Your chest

Front 6

What happens when you inhale?

Back 6

Your chest expands. Your internal intercostal muscles relax, external intercostal muscles contract pulling ribs up and out. Your diaphragm contracts and flattens. There is an increase in thoracic volume, but a drop in thoracic pressure.

Front 7

How are alveoli adapted for efficient gas exchange?

Back 7

Short diffusion distance between very thin alvelous and capillary - only 2 cells thick - meaning quick gas exchange.

High CO2 concentration means gas can diffuse down steep concentration gradient very quickly.

Large surface area means an increased amount of gas exchange.

Enormous numbers of alveoli meaning lots of gas exchange.

Gas dissolves in the thin layer of fluid lining the alveolus meaning quick gas exchange.

Front 8

What harmful chemicals are found in cigarette smoke?

Back 8

Nicotine, tar, carcinogens, carbon monoxide, poisons.

Front 9

What is the effect of nicotine on the lungs?

Back 9

Can cause lung disease.

Front 10

What is the effect of tar on the lungs?

Back 10

Can cause lung cancer, blocks up the alveoli, clogs up the cilia so they cannot function properly causing "smokers cough" as mucus builds up, irritates the bronchi causing bronchitis, pneumonia.

Front 11

What is the effect of carcinogens on the lungs?

Back 11

Damages the DNA of alveoli cells which may cause them to reproduce at an increased rate and cause a cancerous tumour to grow.

Front 12

What is the effect of smoking on the alveoli?

Back 12

Tar causes the alveoli walls to break down and join together, forming larger air spaces than usual. This reduces the efficiency of gas exchange and can cause emphysema.

Front 13

What is the function of a goblet cell?

Back 13

It makes mucus to trap dirt and bacteria so as to prevent them from getting to the alveoli to help stop infection and disease.

Front 14

What is the function of a ciliated cell?

Back 14

It moves cilia side to side to remove the mucus containing pathogens and dirt so as to prevent them from entering the alveoli, where they can easily cause infection.

Front 15

Name 5 conditions smoking is associated with.

Back 15

Lung cancer

Bronchitis

Emphysema

Coronary heart disease

Stomach/duodenum ulcers

Front 16

How are ciliated cells affected by smoking and what adverse effects does this have on the lungs?

Back 16

Chemicals in cigarette smoke paralyse the cilia and eventually kills them, leading to a build up of mucus and a 'smokers cough' due to this not being able to be removed. The pathogens and dirt can't be removed which can increase infection and cause bronchitis. The trapped mucus blocks the airways so the smoker has difficulty breathing.

Front 17

What is emphysema? How does it effect the lifestyle of a sufferer?

Back 17

Emphysema is a lung disease caused when the walls of the alveoli break down and form large irregular air spaces and causes gas exchange to become very inefficient. A sufferer's blood carries less oxygen which can mean they're unable to carry out mild excercise such as walking. There is no cure and they often have to have a supply of oxygen nearby at all times or receive it through a nasal cannula.

Front 18

Is there proof that smoking causes lung cancer?

Back 18

No, but their is strong evidence to suggest it does. Many studies which question sufferers of lung cancer on their smoker status have been carried out and show a very strong positive correlation. Cigarette smoke also is known to contain chemicals that cause cancer.

Front 19

How can tumours form due to smoking?

Back 19

There are several chemicals known to cause cancer (carcinogens). These cause the DNA to mutate and the cells to divide uncontrollably. They can be removed and if caught early won't spread to other systems.

Front 20

How is haemoglobin affected by smoking?

Back 20

Carbon monoxide can combine with haemoglobin more tightly than oxygen can, forming a compound called carboxyhaemoglobin in the red blood cells which should carry oxygen. This means the blood carries less oxygen around the body.

Front 21

What consequences may there be if a pregnant woman smokes?

Back 21

She will be depriving her unborn child of oxygen. This has an effect on its growth and development and leads to the birth mass of the baby being lower, on average, than the mass of babies born to non-smokers.