respiratory system Flashcards
(25 cards)
lungs
The two lungs make up the whole of the chest cavity except for the space between them that is occupied by heart and blood vessels.
covered by pleural membrane that lines inside the membrane, with pleural fluid between the two layers holds the lungs against the inside of the chest.
pleura
membrane that covers the surface of the lungs and lines the inside of the chest
pleural fluid
thin layer of fluid within the pleura that allows the lungs to move during breathing. It holds the lungs against the inside of the chest wall and allows the lungs to slide along the wall when breathing
nasal cavity
contains projections that increase the internal surface area
filters warms and moistens air before it enters the lungs.
contains smell receptors
acts as a resonating chamber for speech sounds
hairs and music trap dust.
what is the epiglottis
a flap of tissue, that during swallowing closes off the trachea so food and liquid cannot the lungs.
what are the bronchi
2 primary bronchi branch from the trachea, they then divide into secondary and tertiary bronchi
bronchioles
very fine tubes with smooth muscle
the finest of them end in groups of air sacs called alveoli
alveoli
tiny air sacs that make up most of the lung
they occur in clusters and have very thin walls that are well supplied with blood capillaries for the exchange of oxygen and carbon dioxide.
diaphragm
a muscle that separates the chest from the abdomen .
it contracts and flattens downwards, so increasing the volume of the chest cavity and lungs during breathing in.
intercostal muscles
muscles between the ribs,
they move the ribcage upwards and outwards to increase the volume of the chest cavity and so the lungs when breathing in.
ribs
form the framework of the chest.
trachea or windpipe
carries air to and from the lungs.
lined with mucous membrane and cells with cilia
the cilia beat to move mucous and trapped particles upwards.
larynx
the organ of voice.
air passes through the larynx going to and from the lungs
contains the vocal cords which can vibrate to make sound.
pharynx
throat - air from nasal cavity passes through here
why are the lungs well suited to their exchange of gases?
The lungs are well suited to their gas exchange function because:
-The alveoli give the lungs a big internal surface area so that the large amounts of gases can be exchanged in a relatively short time. There are hundreds of millions of them and they have a total surface area of 50-80m2 (⅓ the area of a tennis court)
Each alveolus is supplied with blood vessels, this is so that as much blood as possible is close to the air in the alveolus. The continuous flow of blood aids to maintain a difference in concentrations fo oxygen and Co2 in the blood and in the air in the lungs
The membrane of the alveolus is very thin, this is good so that molecules do not have too far to travel when moving into or out of the blood. The wall has only 1 layer of cell and is 1 micrometer (1/1000 of a millimetre thick)
The lungs are positioned deep inside the body to prevent excessive evaporation of the fluid that covers the respiratory surfaces. It is important that the membrane of the alveolus be covered by a thin layer of moisture because gases can diffuse into and out of the blood only when they are dissolved in fluid
The lung volume can be changed by movements of the respiratory muscles so that air is made to flow into and out of the lungs. Constant changing of the air the alveoli helps to ensure that there is always a difference in the concentration fo oxygen and co2 in the air and in the blood.
ventilation
the process by which air is moved into and out of the lungs
how does air flow through and out of the lungs
Air flows from places of higher pressure to places of lower pressure, therefore, air flows into and out of the lungs due to the differences in air pressure
there must be a concentration gradient - that is a difference gas concentration between the air in the alveoli and the blood in the capillaries.
describe process of inhalation
Inspiration or inhalation is the process of taking air into the lungs.
For air to flow into the lungs, the pressure of air in the lungs must be less than the atmospheric pressure outside the body.
To decrease the air pressure in the lungs, the volume of the lungs is increased. To increase the volume of the lungs, the diaphragm and external intercostal muscles contract. The diaphragm becomes flatter and the rib cage moves upwards and outwards, increasing the volume of chest.
As the pleura adheres to the internal wall fo the chest cavity, the lungs expand with the expanding chest cavity.
Increased lung volume means that the air pressure inside the lungs is slightly lower than the pressure outside
Air flows in the nose and the trachea until the pressure becomes equal.
During quiet breathing, the diaphragm is responsible for changes in chest volume.
In heavy breathing, movements of the rib cage is more important.
describe the process of exhalation
Expiration or exhalation is the process of breathing out, releasing air out of the body.
The diaphragm and external intercostal muscles relax, so the diaphragm bulges more into the chest cavity and the rib cage moves downwards.
This reduces the volume of the chest cavity and so the lungs
Air pressure in the lungs is now greater than the pressure outside the body
Air flows out through the trachea and nose until the pressures are equal
When breathing quietly, expiration is a passive process, involving he relaxation fo the muscles hat have contracted during inspiration.
Heavier breathing involves more forceful expiration and the intercostal contract to lower the rib cage. The same contraction occurs when forcibly exhaling, like blowing a balloon
what % of carbon dioxide and oxygen does inspired air have
- 95% oxygen
0. 04% carbon dioxide
what % of carbon dioxide and oxygen does expired air have
- 8% oxygen
4. 3% carbon dioxide
emphysema
caused by the long term exposure to irritating particles in the air taken into the lungs
Smokers constantly exposed to inhaling irritants in tobacco smoke and people working where there is lots of dust are at risk.
People living in cities with continual high air pollution are at risk.
The irritating particles cause damage to the alveoli
The alveoli lose elasticity are then replaced with fibrous tissues and may break down, reducing the internal surface area of the lungs.
Due to the loss of elasticity of the lung tissue, the lungs are constantly inflated and breathing out requires voluntary effort
The sufferer has 2 problems, inadequate surface area for gas exchange and difficulty ventilating the lungs.
Cannot be cured, progression of the disease cannot be stopped.
lung cancer
A growth of a tumour, a mass of cells, in the lungs in a uncontrollable way
Smoking has the greatest risk for lung cancer. If contracted with other risk factors, the chances are greater
Ppl who work with asbestos and smoke have a 20-90 times risk of contracting lung cancer than similar workers not smoking
Chemical substances like tobacco smoke initiates cancerous growth and promotes growth of tumour.
Most common form of lung cancer begins in the walls of the air passages like bronchi
Inhaled smoke particles irritate the mucous lining the air passages.
Resulting in excess mucous
Cells at the base of cell membrane divide more rapidly and the accumulated mucous cannot be removed
This results in smokers cough.
The trapped mucous causes rupture of the alveoli
Cancerous growth develops in the air passage and spread to other parts of the body
lung infections?
Pneumonia is an infection of the lungs caused by bacteria, viruses, fungi or other organisms
The inflammation resulting from the infection causes secretion of fluid and mucus into the alveoli and so reduces the amount of air that they contain.
The SA available for exchange of gases is also reduced and breathing difficulty is a symptom of many pneumonia.
Tuberculosis (TB) is an infection of the lung by the bacterium Mycobacteruim Tuberculosis.
Tubercolisi and pnumeonia is spread by droplets
Symptoms involve coughing, sneezing or spitting tiny droplets of moisture containing bacteria, viruses or fungi that inhaled by others, infecting others
