RESPIRATORY SYSTEM Flashcards
(23 cards)
The respiratory system
System that intakes oxygen and removes carbon-dioxide.
Organs
- Oral cavity
- Nasal cavity
- Pharynx
- Larynx
- epiglottis
- Trachea
- Primary Bronchi
- Secondary Bronchi
- Tertiary Bronchi
- Bronchioles
- Terminal Bronchioles
- Respiratory Bronchioles
- Alveoli
Nose and Nasal cavity
Air enters the body via the nasal cavity.
The lining of the nose is convoluted and lined with mucous membranes.
As the air passes over the membranes, it is warmed and humidified.
Hairs and mucous close to the lining also play a role in trapping dust and debris, preventing it from reaching the lungs.
Pharynx
Also known as the throat is the region from the nasal cavity to the top of the trachea and oesophagus
Air travels through it before reaching the epiglottis.
Epiglottis
A flap of elastic cartilage.
During inhalation the epiglottis covers the oesophagus preventing air from flowing through.
During swallowing, the epiglottis covers the trachea preventing food from going inside preventing a chocking hazard.
Larynx
Cartilage joining the pharynx and trachea.
Contains vocal chords, which are mucous membranes that are able to vibrate as air passes over them.
(Voice Box)
Trachea
Known as a wide-pipe, because it carries air into and out of the lungs.
It is made up of c-shaped cartilage rings, that hold the structure open. This ensures that air can pass through it.
At the base, the trachea splits into two branches, one of each taking air into each lung.
The epithelial lining of the trachea produces mucus, which is able to trap dust and debris. This prevents it from entering the lungs.
The cilia also attached to the lining moves in a wave like motion, taking mucus and debris up to the pharynx to be swallowed and digested.
Bronchi
At the end of the trachea, the structures spilt up into bronchi, these then split up into secondary bronchi and then tertiary bronchi.
They all have c shaped cartilage rings to keep the structure open in order to allow air to flow.
As the bronchi gets smaller, the cartilage is more spread out, with smooth muscle and elastin forming more of the structure.
As in the trachea, cilia are still found.
Bronchioles
When tertiary bronchi divide they form smaller airways called bronchioles.
They split up into terminal bronchioles.
Bronchioles don’t contain cartilage like bronchi, they are made up of smooth muscle and elastin, this allows them to control the flow of air in the lungs, expanding when the body needs more oxygen.
Cilia and mucus are also present protecting the lungs from all contaminants.
Lungs
The 2 lungs make up the whole chest cavity, except for the space in between them called the mediastinum
Lung has 2 lobes on the left side and 3 lobed on the right side.
A membrane called pleura covers the surface of the lungs and also lines the inside of the chest.
The pleura fluid is located between the visceral and parietal pleura.
This holds the lungs inside of the chest caving allowing them to slide along while breathing
Inside the lungs
The smallest bronchioles open into a cluster of tiny air sacs called alveoli.
Each alveolus has a 1 cell thick wall and is surrounded by a network of blood capillaries.
This is where gases move between the blood in capillaries and the air in the alveoli.
The alveoli are the functioning unit of the lungs.
This makes the alveoli the surface of gas exchange.
Ventilation / Breathing and air pressure
The process by which air is moved into and out of the lungs.
Air always flows from an area of higher pressure to an area of lower pressure.
Air flows into and out of the lungs due to the differences in air pressure.
Inspiration
- process of taking air into the lungs.
- Air flows into the lungs from an area of higher pressure (outside) to an area of lower pressure (in the lungs).
- Decreasing the pressure of the air is achieved by increasing the volume of the lungs.
- Air flows until the pressure is equal
- To increase the volume of the lungs:
- the diaphragm contracts and flattens.
- External intercostal muscles contract.
- The rib cage goes upwards and outwards increasing the volume of the thoracic cavity.
Expiration
- Process of taking air out of the lungs.
- Air flows for an area of higher pressure (in the lungs) to an area of lower pressure (outside).
- Air flows through the trachea till the pressure is equal.
- The diaphragm and intercostal muscles relax from contraction
- The diaphragm bulges more into the chest cavity.
- The rib cage moves downwards and inwards decreasing the volume of the thoracic cavity.
- When a person is breathing quietly at rest it is a passive process.
- Exhalation becomes acting when a person is forcing air out heavily. for example blowing a balloon
Why are the lungs well suited for gas exchange?
- The alveoli gives a large surface area, so that large amounts of air can be exchanged in a relatively short amount of time.
- Each alveoli is well supplied with a network of blood capillaries, so that as much blood as possible is close to the air in the alveolus.
- The membrane that forms the walls of the alveoli is approximately 1 cell thick, so that gas molecules do not have far to travel when moving into or out of the blood, and they can easily diffuse through.
The process of gas exchange.
- Blood in the capillaries surrounding the alveoli is brought to the lungs through the pulmonary arteries.
- Blood has been through these capillaries, where much oxygen is taken up by body cells. Therefore the blood in the capillaries has lower concentration of oxygen.
- Oxygen dissolves in the moisture on the inside of the alveolus and diffuses through the membrane, the walls of the capillaries and into the blood.
- The alveoli has a low concentration of carbon-dioxide compared to the alveolar capillaries, therefore carbon dioxide diffused out of the blood and into the alveoli
Percentage levels of air
INSPIRED:
OXYGEN: 20.95%
CARBON DIOXIDE: 0.04%
EXPIRED:
OXYGEN: 15.80%
CARBON DIOXIDE: 4.30%
Concentration gradient
For diffusion of gases into and out of blood, there must be a concentration gradient.
The concentration gradient is the difference in gas concentration between the air in the alveoli and the blood in the capillary.
It is maintained by:
- The constant blood flow through the capillaries.
- The movement of air into and out of the alveoli as be breathe.
Emphysema
A disease usually caused by long-term exposure to irritating particles in the air taken into the lungs.
People, that smoke, living in harsh environments or work in places with a lot of dust cant be affected by it.
The irritating particles damage the alveoli as it makes them lose their elasticity, which are replaced by a fibrous tissue, that may break down, losing the internal surface area of the lungs.
Sufferer has 2 problems:
1. Inadequate surface area for gas exchange.
2. Difficulty in ventilating lungs.
Lung Cancer
- The mass of cells that divide uncontrollably, also known as a tumour.
- occurs from exposer to pollutants.
- Tobacco also proposes a high risk to lung cancer
Pneumonia
- Pneumonia - Cause by bacteria and viruses. Inflammations causes secretions of mucus into the alveoli, Surface area for gas exchange are reduced.
Tuberculosis
An infection, inn the lungs by bacterial, spread by droplets as people cough.
Asthma
- medical condition that causes difficulty in breathing due to a narrowing of the airways.
- Smooth muscles contracting.
- Inflammation causing airways to narrow and thicken.
- Mucus filling the airway, narrowing the tube
- Gas exchange is impaired as volume of the lungs reduces.
