Respiratory System Flashcards
1
Q
Nose
A
- Air enters through the nose
- The lining of the nose and nasal cavity is convoluted and lined by mucous membranes. As air passes over the membranes, it is warmed and humidified.
- There are also hairs and mucous lining the nose. These trap debris and foreign particles, preventing it from reaching the lungs.
2
Q
Pharynx
A
- Pharynx aka the throat extends from the nasal cavity to the top of the trachea and oesophagus.
- Air travels through it
3
Q
Trachea
A
- Aka the windpipe because it carries the air into and out of the lungs
- Made up of C-shaped cartilage rings that hold the structure open. This ensures air can always pass through
- The epithelial lining of the trachea produces mucus, which is able to trap dust and debris, preventing entry into the lungs.
4
Q
Bronchi
A
- At the end of the trachea, the structure splits into two primary bronchi, one for each lung. These then split further into secondary bronchi which take the air into each lobe of the lung. The secondary bronchi continue to divide, forming tertiary bronchi.
- The structure is very similar to the trachea. As the bronchi get smaller, the cartilage is spread out, with smooth muscle and elastin forming more of the structure.
- Cilia and mucus work together to trap and remove particles
5
Q
Bronchioles
A
- When the tertiary bronchi divide, they form smaller airways called bronchioles, which continue to split until they end in millions of terminal bronchioles.
- Unlike bronchi, bronchioles do not contain cartilage; instead, they are made of smooth muscle and elastin. This allows the bronchioles to control the flow of air into the lungs, expanding when the body needs more oxygen.
- Cilia and mucus are also present in the bronchioles, protecting the lungs from contaminants.
6
Q
Lungs
A
- The two lungs take up most of the chest cavity, except for the space between them occupied by the heart and blood vessels.
- Each lung is divided into lobes. The left lung has 2 lobes, the right has 3 lobes.
- A membrane called the pleura covers the surface of the lungs and lines the inside of the chest. Between these two layers of membrane is a thin layer of pleural fluid.
7
Q
Alveoli
A
- Alveoli are tiny air sacs, each with a wall only one cell thick and surrounded by a network of blood capillaries.
- This is where gases move between the blood in the capillaries and the air in the alveoli. It is the location of gas exchange, allowing oxygen to pass from the airways into the blood, and carbon dioxide to pass from the blood into the airways.
8
Q
Diaphragm
A
A muscle that separates the chest from the abdomen. It contracts and flattens downwards, thereby increasing the volume of the chest cavity, and lungs during breathing in.
9
Q
Ribs
A
- The framework that encompasses the chest.
- Protects the lungs
10
Q
Intercostal Muscle
A
- Muscles between the ribs
- They move the rib cage upwards and outwards to increase the volume of the chest cavity and thus the lungs when breathing in.
11
Q
Inspiration
A
- 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.
- Decreasing the pressure of airs in the lungs is achieved by increasing the volume of lungs
- 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, lungs expand.
12
Q
Expiration
A
- The process of removing air from the lungs
- The diaphragm and external intercostal muscles relax. The diaphragm bulges and the rib cage moves downwards.
- This reduces the volume of the chest cavity and lungs
- Air pressure in the lungs is now greater than pressure outside the body
13
Q
Gas Exchange
A
The lungs are well suited to gas exchange for the following reasons:
- huge internal surface area (millions of alveoli)
- impressive supply of blood vessels. Continuous flow of blood helps to maintain a difference in concentration gradients of oxygen and carbon dioxide
- membrane is very thin (1 micrometre thick)
- position of lungs is deep inside the body to prevent excessive evaporation
- lung volume can be changed
14
Q
The process of gas exchange
A
- The blood in the capillaries surrounding the alveoli is brought to the lungs by the pulmonary arteries
- This blood has been through the capillaries of the body, where much of the oxygen has been taken up the body cells and has a low 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 blood arriving at the capillaries of the alveoli has come from the body circulation where it has picked up carbon dioxide produced by respiration in the cells.
- The concentration of carbon dioxide in the alveolar capillaries is higher than the concentration in the air in the alveolus. Therefore, carbon dioxide diffused out of the blood and into the air in the alveolus.
15
Q
The process of gas exchange
A
- For diffusion of gases into and out of the blood, there must be a concentration gradient.
- The concentration gradient is maintained by:
1. The constant flow of blood through the capillaries
2. The movement of air into and out of the alveoli as we breathe in and out. - There is a net diffusion of oxygen into the blood and carbon dioxide out of the blood due to the concentration gradients between the air and blood.
