Unit 1- Section 4 The Respiratory System

Question 0

What does ventilation consist of?

Answer 0

Inspiration (breathing in) and expiration (breathing out)

Question 1

What is the lung structure?

Answer 1

As you breathe in, air enters the trancha. This then splits into two bronchi- one bronchus leading to each lung. Each bronchus then branches into smaller tubes called bronchioles. The bronchioles end in small air sacs called alveoli. This is where the gases are exchanged the rib cage, intercostal muscles and diaphragm all work together to move air in and out

Question 2

What happens during inspiration?

Answer 2

The intercostal and diaphragm muscles contract. This causes the ribcage to move upwards and out wards and the diaphragm to flatten, increasing the volume of the thorax.
As the volume of the thorax increases as the lung pressure decreases. This causes air to flow into the lungs

Question 3

What process is inspiration ?

Answer 3

Active process

Question 4

What is expiration?

Answer 4

The intercostal and diaphragm muscles relax
The ribcage moves downwards and inwards and the diaphragm becomes curved again
The thorax volume decreases, causing the air pressure to increase
Air is forced out of the lungs

Question 5

What process is expiration?

Answer 5

Passive process

Question 6

What are alveoli surrounded by?

Answer 6

Network of capillaries

Question 7

Explain the alveoli structure

Answer 7

Each alveoli is made from a single layer of thin, flat cells called alveolar epithelium
The walls of the capillaries are made from capillary endothelium
The walls of the alveoli contain a protein called elastin. Elastin is elastic, it helps the alveoli to return to their normal shape after inhaling and exhaling air

Question 8

Describe gas exchange in alveoli

Answer 8

Oxygen diffuses out of the alveoli, across the alveolar epithelium and the capillary endothelium and into the compound called haemoglobin In the blood. Carbon dioxide diffuses into the alveoli from the blood and is breathed out

Question 9

What are the factors affecting the rate of diffusion?

Answer 9

• thin exchange surface (1 cell thick alveolar epithelium)
• large surface area
• steep concentration gradient of oxygen and carbon dioxide between the alveoli and the capillaries, which increases the rate of diffusion. This is maintained by the flow of blood and ventilation

Question 10

How does a constant flow of blood affect rate of diffusion?

Answer 10

The circulAtion of blood means that the blood high in oxygen is continually replaced with blood low in oxygen so creates a concentration gradient

Question 11

What is the equation for pulmonary ventilation?

Answer 11

Pulmonary ventilation = tidal volume x ventilation rate

Question 12

What is tidal volume and ventilation rate?

Answer 12

Tidal volume is the volume of air in each breath

Ventilation rate is the number of breaths per minute

Question 13

What is pulmonary ventilation?

Answer 13

It is a measure of lung function, it’s the volume of air taken into the lungs in one minute. Measured in dm3 min-1

Question 14

What is pulmonary tuberculosis?

Answer 14

It is a lung disease cause by bacteria. It is an infection, when someone becomes infected with tuberculosis bacteria. The immune system cells build a wall around the bacteria in the lungs. This forms small hard lumps known as tubercules. This infected tissue within the tubercles died and gaseous exchange surface is damaged so therefore tidal volume is decreased.

Tuberculosis also causes fibrosis. Which further reduces the tidal volume. If the bacteria enter the bloodstream, they can spread to other parts of the body

Question 15

What are the symptoms of pulmonary tuberculosis?

Answer 15

Persistent cough, coughing up blood and mucus, chest pains, shortness of breath and fatigue. Sufferers may also have a fever and lose weight
Many people with tuberculosis are asymptomatic (have the infection but do not show any symptoms because the infection is in a inactive form) but if their immune system because weakened the infection can become active and they will show symptoms and will be able to pass it on to other people

Question 16

How is pulmonary tuberculosis tansmitted?

Answer 16

droplet infection! when an infected person coughs or sneezes tiny droplets of saliva and mucus containing the bacteria are releases from their mouth and nose. If an uninflected person breathes in these droplets then the bacteria is passed on.
Tuberculosis tends to be much more wide spread in areas where hygiene levels are poor and where people live in crowded conditions. I can be prevented for the vaccine and antibiotics

Question 17

What is fibrosis?

Answer 17

Formation of scar tissue in the lungs. This can be a result of an infection or exposure to substances like aspestos or dust.

Question 18

Why is the efficiency of gas exchange decreased?

Answer 18

Scar tissue is thicker and less elastic than normal lung tissue.

They can’t expand as efficiently and also the diffusion path is increased so breathing is harder
Harder to force air out because of less elasticity

Question 19

Why do suffers feel tired and weak if they have fibrosis?

Answer 19

It reduces the gas exchange in the alveoli because diffusion is slower across the thicker scarred membrane. Less oxygen can diffuse into the blood stream so the body relieves less oxygen and the rate of aerobic respiration in cells is reduced

Question 20

What are the symptoms of fibrosis?

Answer 20

Tired and weak 
Shortness of breath 
Dry cough 
Chest pain 
Faster breathing rate

Question 21

What is asthma?

Answer 21

It is a respiratory condition where the airways become inflamed and irritated. This causes vary from case to case but is usually because of an allergic reaction to substances like pollen and dust

Question 22

What happens during an asthma attack?

Answer 22

The smooth muscle lining the bronchioles contracts and a large amount of mucus is produced. This causes constriction of the airways, making it difficult for the sufferer to breathe properly. Air flow in and out of the lungs is severely reduced, so less oxygen enters the alveoli and moves into the blood. This means the body cells receive less oxygen and the rate of aerobic respiration in the cells is reduced

Question 23

What are the symptoms of asthma?

Answer 23

Wheezing, tight chest, shortness of breath. During an attack the symptoms come on very suddenly. They can be relieved by drugs which cause the muscle in the bronchioles to relax, opening up the airways

Question 24

What is emphysema?

Answer 24

It’s a lung disease caused by smoking or long term exposure to air pollution. Foreign particles in the smoke or air become trapped in the alveoli. This causes inflammation, which attracts phagocytes to the area. The phagocytes produce an enzyme that breaks down the protein elastin, loss of elastin means the alveoli can’t recoil to expel air as well. It also leads to destruction of the alveoli walls which reduces the surface area of the alveoli. This reduces the rate of gas exchange in the alveoli, similar to fibrosis and asthma.

Question 25

What are the symptoms of emphysema?

Answer 25

Shortness of breath, wheezing, increased breathing rate